60 results on '"Khoo NS"'
Search Results
2. Perinatal Cardiac Functional Adaptation in Hypoplastic Left Heart Syndrome: A Longitudinal Analysis.
- Author
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Patey O, Hornberger LK, McBrien A, Lin L, Khoo NS, and Eckersley L
- Subjects
- Humans, Female, Infant, Newborn, Prospective Studies, Pregnancy, Male, Longitudinal Studies, Heart Ventricles diagnostic imaging, Heart Ventricles physiopathology, Cardiac Output physiology, Echocardiography methods, Stroke Volume physiology, Fetal Heart physiopathology, Fetal Heart diagnostic imaging, Echocardiography, Doppler methods, Hypoplastic Left Heart Syndrome physiopathology, Hypoplastic Left Heart Syndrome diagnostic imaging, Adaptation, Physiological physiology, Ultrasonography, Prenatal methods
- Abstract
Background: The perinatal transition is characterized by acute changes in cardiac loading. Compared with normal newborn combined cardiac output (CCO), single right ventricular (RV) output of neonates with hypoplastic left heart syndrome (HLHS) is markedly greater. The aim of this study was to examine the mechanisms of cardiac adaptation that facilitate this perinatal transition from late fetal to early neonatal life in HLHS., Methods: Prospectively recruited pregnancies complicated by fetal HLHS (n = 35) and healthy control subjects (Ctrl; n = 17) underwent serial echocardiography in late gestation (38 ± 1 weeks) and 6, 24, and 48 hours after birth. Cardiac function was assessed using conventional, Doppler tissue, and speckle-tracking echocardiography., Results: Term fetuses with HLHS had RV output comparable with Ctrl CCO via higher stroke volume. Compared with both left ventricular and RV indices of Ctrl, they exhibited globular and dilated right ventricles with reduced relative wall thickness (0.40 ± 0.08 vs 0.49 ± 0.10, P < .01), increased Tei index' (HLHS vs Ctrl left ventricle/Ctrl right ventricle: sphericity index, 0.9 ± 0.25 vs 0.5 ± 0.10/0.6 ± 0.11; RV area index, 28 ± 6 vs 15 ± 3/17 ± 5 cm
2 /m2 ; Tei index', 0.65 ± 0.11 vs 0.43 ± 0.07/0.45 ± 0.09; P < .0001 for all). Neonates with HLHS generated elevated RV cardiac output compared with Ctrl CCO via higher heart rate and stroke volume, with further RV dilatation, increased longitudinal systolic strain at 48 hours (-17 ± 4% vs -14 ± 3%/ 14 ± 5%) with reduced circumferential and rotational myocardial deformation and altered diastolic function. Neonates with HLHS also demonstrated right atrial enlargement with increased longitudinal strain: 6 hours (33 ± 12% vs 26 ± 6%), 24 hours (37 ± 15% vs 26 ± 13%), and 48 hours (38 ± 11% vs 24 ± 13%) (P < .0001)., Conclusions: Term fetuses with HLHS exhibit altered RV geometry and RV systolic and diastolic functional parameters. After birth, further alterations in these cardiac parameters likely reflect adaptation to acutely altered RV loading from increasing cardiac output and pulmonary artery flow demands., Competing Interests: Conflicts of Interest None., (Copyright © 2024 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.)- Published
- 2024
- Full Text
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3. Size and Function of the Right Atrium in Healthy Children by Three-Dimensional Echocardiography.
- Author
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Haughian B, Jone PN, Le L, Khoo NS, Colen T, Vetten Z, and Eckersley L
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- Humans, Male, Female, Child, Reference Values, Retrospective Studies, Child, Preschool, Adolescent, Organ Size, Infant, Reproducibility of Results, Atrial Function, Right physiology, Heart Atria diagnostic imaging, Heart Atria physiopathology, Echocardiography, Three-Dimensional methods
- Abstract
Purpose: Right atrial volume (RAV) and function have proven prognostic value in the assessment of cardiac disease and may be more accurately assessed using three-dimensional echocardiography (3DE). Normal 3DE reference values for the right atrial (RA) volume and function in healthy children have not yet been published. Furthermore, current methods of indexing cardiac measurements to body surface area (BSA) alone may be insufficient. We aimed to develop reference values for 3DE-derived RAV and function in the pediatric population, to provide a comparison of regression methods using BSA, height, weight, and sex, and to compare 3DE values to two-dimensional echocardiography (2DE) derived volumes., Methods: We retrospectively analyzed 187 3DE datasets acquired for a multi-center study on healthy children at two international centers. 3DE volumes were measured with vendor-agnostic software (Tomtec), and 2DE endo-diastolic volume (EDV) using the area-length single-plane approach. Regression curve-fitting of height (Ht), weight (Wt), BSA, and sex were explored to optimize Pearson coefficient and homoscedasticity., Results: The relationship of 3DE RAVs to BSA alone was heteroscedastic, with a residual positive relationship on indexing (R
2 = 0.2506). Optimal regression of Ln (Volume) = b0 + x*Ln (Ht) + y*Ln (Wt) + z*Sex was homoscedastic. Total RA emptying fraction (EF) did not vary across age or sex, however active and passive emptying was best fit by a spline curve with a knot at approximately BSA = 1 m2 . Strong agreement with 2DE-derived EDV was present (r2 = 0.83)., Conclusion: We provide reference values for RA size and function in the pediatric population and provide a comparison of methods for indexing these values., (© 2024 The Author(s). Echocardiography published by Wiley Periodicals LLC.)- Published
- 2024
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4. Double-orifice tricuspid valve: case series and literature review.
- Author
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Haughian BT, Khoo NS, and Lin LQ
- Abstract
The double-orifice tricuspid valve (DOTV) is a rare lesion. We present a series of three patients encountered at the Stollery Children's Hospital with a diagnosis of DOTV on 2D and/or 3D echocardiography. The patient's medical records are reviewed for presentation history, investigative findings, and clinical course. We discuss the cases in the context of a complete review of all literature documenting cases of DOTV. In the majority of cases, the lesion is relatively benign, with little change in valve function over the short to medium term, and outcomes are determined largely by significant concomitant heart defects.
- Published
- 2024
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5. Time to Look Up from Two Dimensions to See the Third in Mitral Valve Research.
- Author
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Khoo NS
- Subjects
- Humans, Mitral Valve diagnostic imaging, Mitral Valve Insufficiency diagnostic imaging
- Abstract
Competing Interests: Conflicts of Interest None.
- Published
- 2024
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6. Three-Dimensional Echocardiography Right Ventricular Volumes and Ejection Fraction Reference Values in Children: A North American Multicentre Study.
- Author
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Jone PN, Le L, Pan Z, Goot BH, Parthiban A, Harrild D, Ferraro AM, Marx G, Colen T, and Khoo NS
- Subjects
- Adolescent, Child, Child, Preschool, Female, Heart Ventricles diagnostic imaging, Humans, Infant, Infant, Newborn, Male, Reference Values, Reproducibility of Results, Stroke Volume, Ventricular Function, Left, Echocardiography, Three-Dimensional methods
- Abstract
Background: Three-dimensional echocardiography (3DE) evaluation of right ventricular (RV) volumes and ejection fraction (EF) is increasingly used for clinical serial assessments and management in children. This study aims to generate sex-specific reference values and z-score equations for RV volumetric parameters, independent of age and body size indices, derived from multiple populations across North America., Methods: We prospectively recruited 455 healthy children (ages 0 to 18 years) from 5 centres. 3DE of the RV were acquired using various vendors with analyses performed offline using vendor-independent software. 3DE datasets with all walls of the RV endocardium visible were included. We reported data on RV EF, and generated z scores for end-systolic volumes (ESV), end-diastolic volumes (EDV) and stroke volume (SV). Differences between the sexes were explored., Results: Of 455 3DE datasets, 312 (68%) met imaging criteria for analysis. Median age was 10.1 years (interquartile ratio [IQR]: 5.6, 14.0) with 17% being younger than 3 years of age. The mean and standard deviation for RV EDV, ESV, and SV for male and female patients were reported. We provided a downloadable z-score calculator with height and weight as independent variables to facilitate clinical utility. Although statistically significant differences between male and female RVEF was present (female 52.9 ± 3.9% vs male 51.6 ± 3.5%, P = 0.006), after adjusting for age, height, and weight, the magnitude of difference was clinically insignificant., Conclusions: Sex-specific reference values for pediatric RV volumes and EF, and z-score equations were derived from children 3DE datasets across 5 centres in North America., (Published by Elsevier Inc.)
- Published
- 2022
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7. Insights from 3D Echocardiography in Hypoplastic Left Heart Syndrome Patients Undergoing TV Repair.
- Author
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Mah K, Khoo NS, Martin BJ, Maruyama M, Alvarez S, Rebeyka IM, Smallhorn J, and Colen T
- Subjects
- Humans, Retrospective Studies, Treatment Outcome, Tricuspid Valve diagnostic imaging, Echocardiography, Three-Dimensional methods, Hypoplastic Left Heart Syndrome complications, Hypoplastic Left Heart Syndrome diagnostic imaging, Hypoplastic Left Heart Syndrome surgery, Tricuspid Valve Insufficiency complications, Tricuspid Valve Insufficiency diagnostic imaging, Tricuspid Valve Insufficiency surgery
- Abstract
Background: Tricuspid regurgitation (TR) in hypoplastic left heart syndrome (HLHS) is associated with morbidity and mortality. TR mechanisms and the impact of tricuspid valve repair (TVR) are unclear. We examined HLHS TR mechanisms, TVR's impact on tricuspid valve (TV), and features of poor TVR durability., Methods: We retrospectively compared 35 HLHS TVR cases and 35 age/stage-matched HLHS controls who do not undergo TVR. Pre-operative 3-dimensional echocardiography (3DE) assessed overall TV morphology (prolapse, normal, tethered), leaflet morphology, vena contracta area, and TR location. Two-dimensional echocardiography measured TV annulus diameter, RV fractional area change (RVFAC), sphericity, and TR grade at three time points (pre-op, early post-op, and latest follow-up)., Results: Pre-op, TVR group, and controls had no difference in age, RV function or shape, or TV dimension. TVR group most commonly had anterior leaflet prolapse followed by septal leaflet prolapse or tethering. TR jet arises centrally (63%) and anterior septally (26%). Posterior annuloplasty (69%), commissuroplasty (37%), and leaflet repair (37%) were surgical techniques commonly performed. At early post-op, TR grade and TV annulus decreased. At latest follow-up, TV annulus remained reduced; however, 50% had significant TR. 25% required TV reoperation. Larger vena contracta at TVR was associated with significant TR., Conclusion: HLHS patients undergoing TVR had more anterior leaflet prolapse and central TR. While TVR initially reduces annular size and TR grade, 50% redevelop significant TR despite maintained annular reduction. The association of greater TR severity prior to repair with post-op recurrence raises the consideration for earlier repair of TR in HLHS patients., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)
- Published
- 2022
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8. The Perinatal Transition and Early Neonatal Period in Hypoplastic Left Heart Syndrome Is Associated With Reduced Systemic and Cerebral Perfusion.
- Author
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Eckersley LG, Mills L, Hirose A, Khoo NS, Wernovsky G, and Hornberger LK
- Subjects
- Echocardiography, Female, Follow-Up Studies, Gestational Age, Humans, Hypoplastic Left Heart Syndrome diagnosis, Infant, Newborn, Middle Cerebral Artery diagnostic imaging, Pregnancy, Prospective Studies, Ultrasonography, Prenatal, Blood Flow Velocity physiology, Cerebrovascular Circulation physiology, Hypoplastic Left Heart Syndrome physiopathology, Middle Cerebral Artery physiopathology, Pulmonary Circulation physiology
- Abstract
Background: The impact of the striking perinatal circulatory changes on blood flow distribution have not to date been well examined in hypoplastic left heart syndrome (HLHS). This study aimed to document perinatal redistribution of cardiac output in HLHS compared with healthy control subjects, to further understand the impact of the perinatal transition on cerebral and systemic blood flow., Methods: Prospectively recruited HLHS case subjects (n = 31) and healthy control subjects (n = 19) underwent serial echocardiography from late fetal stages to 96 hours after birth. Combined cardiac output (CCO), systemic, pulmonary, cerebrovascular, and splanchnic flow data were compared between neonates with HLHS and control subjects, and the impact of vasoactive support and positive pressure ventilation in HLHS patients was examined., Results: In late gestation, CCO was similar between HLHS and control subjects, whereas middle cerebral artery (MCA) pulsatility index (PI) in HLHS was consistent with low cerebral vascular resistance. In the 96 hours after birth, CCO and pulmonary blood flow progressively increased in HLHS compared with control subjects (P < 0.001), and CCO was further increased in neonates with HLHS receiving vasoactive support (P = 0.01). Neonates with HLHS had reduced systemic and 6-24-hour superior vena cava (SVC) flow compared with control subjects (P < 0.001). Low systemic flow was further suggested by increased MCA and celiac artery PI at 6-48 hours in neonates with HLHS (P < 0.001). Systemic and SVC flow did not differ between those with and without vasoactive support., Conclusions: We provide quantitative echocardiographic evidence associating impaired cerebral and systemic blood flow with perinatal hemodynamic changes in the preoperative neonate with HLHS., (Copyright © 2021 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)
- Published
- 2021
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9. Tricuspid Valve Tethering Is Associated with Residual Regurgitation after Valve Repair in Hypoplastic Left Heart Syndrome: A Three-Dimensional Echocardiographic Study.
- Author
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Shigemitsu S, Mah K, Thompson RB, Grenier J, Lin LQ, Silmi A, Beigh MVR, Khoo NS, and Colen T
- Subjects
- Child, Echocardiography, Humans, Tricuspid Valve diagnostic imaging, Tricuspid Valve surgery, Echocardiography, Three-Dimensional, Hypoplastic Left Heart Syndrome diagnostic imaging, Hypoplastic Left Heart Syndrome surgery, Tricuspid Valve Insufficiency surgery
- Abstract
Background: Tricuspid valve regurgitation (TR) is a risk factor for morbidity and mortality in children with hypoplastic left heart syndrome (HLHS). Surgical tricuspid valve (TV) repair is common, but durable repair remains challenging. The aim of this study was to examine mechanisms of TR requiring surgery, features associated with unsuccessful repair, and TV changes after surgical repair., Methods: Thirty-six patients with HLHS requiring TV repair (TVR) and 36 matched control subjects with HLHS were assessed using two-dimensional and three-dimensional echocardiography. Using three-dimensional echocardiography, TV coordinates from the annulus, leaflet, and ventricle were used to measure annular, leaflet, prolapse, and tethering values and anterior papillary muscle angle. TR grade and ventricular size, function, and shape were assessed using two-dimensional echocardiography., Results: Patients requiring TVR had greater total leaflet prolapse, larger TV annular and leaflet areas, and flatter annuli, with no difference in tethering, coaptation index, or anterior papillary muscle angle. In patients with HLHS, successful TVR at follow-up (58%) was associated with preoperative total leaflet prolapse (especially posterior). Unsuccessful repair was associated with preoperative tethering of the septal leaflet. TVR in patients with HLHS caused a reduction of total annular and leaflet size and reduced prolapse and tethering of the posterior leaflet but did not affect anterior leaflet prolapse or septal leaflet tethering., Conclusions: Features associated with TVR include a flattened and dilated TV annulus with leaflet prolapse. The additional presence of a tethered septal leaflet before TVR is associated with significant postoperative TR. Current surgical techniques, predominantly posterior annuloplasty and commissuroplasty, adequately address annular size and posterior leaflet pathology, but not septal leaflet tethering. Individualized and innovative surgical techniques are vital to improve surgical repair success., (Copyright © 2021 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.)
- Published
- 2021
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10. Dynamic Systolic Changes in Tricuspid Regurgitation Vena Contracta Size and Proximal Isovelocity Surface Area in Hypoplastic Left Heart Syndrome: A Three-Dimensional Color Doppler Echocardiographic Study.
- Author
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Li L, Colen TM, Jani V, Barnes BT, Craft M, Tham E, Khoo NS, Smallhorn J, Danford DA, and Kutty S
- Subjects
- Echocardiography, Doppler, Color, Humans, Reproducibility of Results, Severity of Illness Index, Systole, Echocardiography, Three-Dimensional, Hypoplastic Left Heart Syndrome diagnostic imaging, Mitral Valve Insufficiency, Tricuspid Valve Insufficiency diagnostic imaging
- Abstract
Background: The aims of this study were to investigate the dynamic changes in the vena contracta (VC) and proximal isovelocity surface area (PISA) through systole in patients with hypoplastic left heart syndrome and tricuspid regurgitation and to identify the stage of systole (early, mid, or late) in which VC and PISA radius are optimal., Methods: Twenty-eight patients with hypoplastic left heart syndrome were prospectively studied using continuous two-dimensional (2D) and three-dimensional (3D) echocardiography. Two-dimensional VC width, 3D VC area, and PISA radii (2D and 3D) were measured frame by frame throughout systole. The maximal 2D VC width, 3D VC area, and PISA radii in the first, middle, and last thirds of systole were compared, and correlations were explored with 3D tricuspid annular areas, right atrial volumes, and right ventricular volumes., Results: In all, 35 data sets that met inclusion criteria were analyzed. On frame-by-frame analysis, maximal 2D VC width and 3D VC area were found in the first third of systole in 17% and 20% of studies, in the second third in 34% and 31%, and in the final third in 49% and 49%. Similarly, the maximal 2D and 3D PISA radii were found in the first third of systole in 26% and 17% of studies, in the second third in 28% and 34%, and in the final third in 46% and 49%., Conclusions: In hypoplastic left heart syndrome, detailed temporal analysis of tricuspid regurgitation-associated VC and PISA by 2D and 3D echocardiography reveals no reliable pattern predicting when in systole these parameters peak. Frame-by-frame measurement is necessary for identification of maximal VC and PISA radius on 2D and 3D color Doppler echocardiography because the severity of tricuspid regurgitation could be underestimated because of temporal variability in VC and PISA., (Copyright © 2021 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.)
- Published
- 2021
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11. Tricuspid Regurgitation in Hypoplastic Left Heart Syndrome: Three-Dimensional Echocardiography Provides Additional Information in Describing Jet Location.
- Author
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Mah K, Khoo NS, Tham E, Yaskina M, Maruyama M, Martin BJ, Alvarez S, Alami N, Rebeyka IM, Smallhorn J, and Colen T
- Subjects
- Child, Humans, Reproducibility of Results, Retrospective Studies, Echocardiography, Three-Dimensional, Hypoplastic Left Heart Syndrome diagnostic imaging, Tricuspid Valve Insufficiency diagnostic imaging
- Abstract
Background: Twenty-five percent of patients with hypoplastic left heart syndrome (HLHS) require tricuspid valve (TV) repair. The location of tricuspid regurgitation (TR) is important in determining the type of repair performed. Studies using three-dimensional echocardiography (3DE) have reported a high incidence of error on two-dimensional echocardiography (2DE) for the identification of TV leaflets. The aim of this study was to compare assessment of TR on 3DE and 2DE in patients with HLHS (jet location, TR grade, and reproducibility)., Methods: A retrospective, single-center review was performed. Fifty-six patients with HLHS with available two-dimensional and three-dimensional echocardiograms, and mild or greater TR, were included. TR location, grade, vena contracta area, and TV annular diameter were measured on 2DE and 3DE. Reproducibility was assessed by blinded reviewers., Results: Three-dimensional echocardiography identified the primary jet location as central (57%) followed by anteroseptal (36%). There was poor agreement between findings on 3DE and 2DE for jet location (κ = 0.05; 95 CI, -0.08 to 0.19). Interobserver reproducibility for location on 3DE was excellent (κ = 0.8), whereas reproducibility for 2DE was poor (κ = 0.32). The most common jet location pre-Norwood and pre-Glenn was central (70%), whereas pre-Fontan and post-Fontan, jet location was central (45%) and anteroseptal (48%). Vena contracta area on 2DE correlated moderately with vena contracta area on 3DE (r = 0.60, P < .0001). TV annular diameters on 2DE and 3DE for lateral (r = 0.85, P < .0001) and anteroposterior (r = 0.74, P = .001) dimensions were strongly correlated., Conclusions: In children with HLHS, assessment of TR location on 2DE had poor agreement with assessment on 3DE and was poorly reproducible. In contrast, TR jet location on 3DE was highly reproducible. Pre-Glenn, a central TR jet was the most common, while post-Glenn, central and anteroseptal locations were equal, highlighting the importance of preoperative identification of TR jet location in patients with HLHS., (Copyright © 2020 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.)
- Published
- 2021
- Full Text
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12. A multicenter study of three-dimensional echocardiographic evaluation of normal pediatric left ventricular volumes and function.
- Author
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Jone PN, Le L, Pan Z, Colen T, Shigemitsu S, Khoo NS, Goot BH, Parthiban A, Harrild DM, Ferraro AM, and Marx G
- Subjects
- Adolescent, Child, Child, Preschool, Heart Ventricles diagnostic imaging, Humans, Infant, Infant, Newborn, Reproducibility of Results, Stroke Volume, Ventricular Function, Left, Echocardiography, Three-Dimensional, Pediatrics
- Abstract
Background: Three-dimensional echocardiography (3DE) evaluation of left ventricular (LV) volume and function in pediatrics compares favorably with cardiac magnetic resonance imaging. The aim of this study was to establish from a multicenter, normal pediatric z-score values of 3DE left ventricular volumes and function., Methods: Six hundred and ninety-eight healthy children (ages 0-18 years) were recruited from five centers. LV 3DE was acquired from the 4-chamber view. A vendor-independent software analyzed end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), and ejection fraction (EF) using semi-automated quantification. Body surface area (BSA)-based z-scores were generated. Intraobserver and interobserver variability were calculated using intraclass correlation (ICC) and repeatability coefficient (RC)., Results: Z-scores were generated for ESV, EDV, and SV. The ICC for intraobserver variability for EDV, ESV, and SV was 0.99, 0.99, and 0.99, respectively. The ICC for interobserver variability for EDV, ESV, and SV was 0.98, 0.94, and 0.98, respectively. The RC for intraobserver and interobserver variability for LV EF was 4.39% (95% CI: 3.01, 5.59) and interobserver was 7.08% (95%CI: 5.51, 8.42)., Conclusions: We report pediatric z-scores for normal LV volumes using the semi-automated method from five centers, enhancing its generalizability. 3DE evaluation of LV volumes and EF in pediatric patients is highly reproducible., (© 2021 Wiley Periodicals LLC.)
- Published
- 2021
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13. Right Ventricular Remodeling in Hypoplastic Left Heart Syndrome is Minimally Impacted by Cardiopulmonary Bypass: A Comparison of Norwood vs. Hybrid.
- Author
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Mah K, Serrano Lomelin J, Colen T, Tham EB, Lin L, Eckersley L, Smallhorn JF, Becher H, Mertens L, and Khoo NS
- Subjects
- Cardiopulmonary Bypass adverse effects, Echocardiography methods, Female, Fontan Procedure methods, Heart Ventricles surgery, Humans, Infant, Infant, Newborn, Male, Palliative Care methods, Retrospective Studies, Cardiopulmonary Bypass methods, Heart Ventricles pathology, Hypoplastic Left Heart Syndrome surgery, Norwood Procedures methods, Ventricular Remodeling
- Abstract
Right ventricular (RV) remodeling in hypoplastic left heart syndrome (HLHS) begins prenatally and continues through staged palliations. However, it is unclear if the most marked observed remodeling post-Norwood is secondary to cardiopulmonary bypass (CPB) exposure or if it is an adaptation intrinsic to the systemic RV. This study aims to determine the impact of CPB on RV remodeling in HLHS. Echocardiograms of HLHS survivors undergoing stage 1 Norwood (n = 26) or Hybrid (n = 20) were analyzed at pre- and post-stage 1, pre- and post-bidirectional cavo-pulmonary anastomosis (BCPA), and pre-Fontan. RV fractional area change (FAC), vector velocity imaging for longitudinal & derived circumferential deformation (global radial shortening (GRS) = peak radial displacement/end-diastolic diameter), and deformation ratio (longitudinal/ circumferential) were assessed. Both groups had similar age, clinical status and functional parameters pre-stage 1. No difference in RV size and sphericity at any stage between groups. RVFAC was normal (> 35%) throughout for both groups. Both Norwood and Hybrid patients had increased GRS (p = 0.0001) post-stage 1 and corresponding unchanged longitudinal strain, resulting in decreased deformation ratio (greater relative RV circumferential contraction), p = 0.0001. Deformation ratio remained decreased in both groups in subsequent stages. Irrespective of timing of the first CPB exposure, both Norwood and Hybrid patients underwent similar RV remodeling, with relative increase in circumferential to longitudinal contraction soon after stage 1 palliation. The observed RV remodeling in HLHS survivors were minimally impacted by CPB.
- Published
- 2021
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14. Stereoscopic Display Is Superior to Conventional Display for Three-Dimensional Echocardiography of Congenital Heart Anatomy.
- Author
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Harake D, Gnanappa GK, Alvarez SGV, Whittle A, Punithakumar K, Boechler P, Noga M, and Khoo NS
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- Humans, Prospective Studies, Random Allocation, Cardiologists, Cardiology, Echocardiography, Three-Dimensional, Heart Defects, Congenital diagnostic imaging
- Abstract
Background: Three-dimensional echocardiography (3DE) improves visualization of cardiac lesions. Current viewing of 3DE studies on a conventional display diminishes the encoded stereoscopic (stereo) information for depth perception. This study aims to evaluate clinician subjective and objective experience of stereo display compared with nonstereo display of 3DE in congenital heart disease., Methods: In this prospective study, 22 cardiologists, advanced cardiology trainees, and cardiothoracic surgeons used a commercially available stereo display system with proprietary software to view 10 3DE data sets, alternating between simple and complex lesions. In part A, participants viewed each data set, randomized to 1 minute of stereo display followed by 1 minute of nonstereo display, or vice versa. In part B, participants could freely toggle between stereo and nonstereo display for an additional 90 seconds per data set. Participants answered a series of questions and rated their subjective experience using stereo versus nonstereo display mode on a Likert scale. Objective data on time spent in each display mode during part B and duration of interaction and degree of movement of the 3DE data set in parts A and B were also collected., Results: All clinician groups found stereo display preferable to nonstereo display of 3DE (P < .0001). Viewing complex lesions was rated lower than simple lesions when using nonstereo display (P < .01). Simple and complex lesions were equally well rated when using stereo display (P = .14). When given a choice of display modes in part B, participants spent more time in stereo display (P < .0001) and interacted more with the 3DE data sets in stereo display (P < .0001)., Conclusions: Interactive stereoscopic display of 3DE was preferred over conventional nonstereo display by all clinician groups for viewing both simple and complex lesions. This preference is especially true for viewing complex lesions., (Copyright © 2020 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.)
- Published
- 2020
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15. Cardiac rehabilitation in the paediatric Fontan population: development of a home-based high-intensity interval training programme.
- Author
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Khoury M, Phillips DB, Wood PW, Mott WR, Stickland MK, Boulanger P, Rempel GR, Conway J, Mackie AS, and Khoo NS
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- Adolescent, Adult, Child, Exercise, Exercise Therapy, Exercise Tolerance, Humans, Cardiac Rehabilitation, High-Intensity Interval Training
- Abstract
Introduction: We evaluated the safety and feasibility of high-intensity interval training via a novel telemedicine ergometer (MedBIKE™) in children with Fontan physiology., Methods: The MedBIKE™ is a custom telemedicine ergometer, incorporating a video game platform and live feed of patient video/audio, electrocardiography, pulse oximetry, and power output, for remote medical supervision and modulation of work. There were three study phases: (I) exercise workload comparison between the MedBIKE™ and a standard cardiopulmonary exercise ergometer in 10 healthy adults. (II) In-hospital safety, feasibility, and user experience (via questionnaire) assessment of a MedBIKE™ high-intensity interval training protocol in children with Fontan physiology. (III) Eight-week home-based high-intensity interval trial programme in two participants with Fontan physiology., Results: There was good agreement in oxygen consumption during graded exercise at matched work rates between the cardiopulmonary exercise ergometer and MedBIKE™ (1.1 ± 0.5 L/minute versus 1.1 ± 0.5 L/minute, p = 0.44). Ten youth with Fontan physiology (11.5 ± 1.8 years old) completed a MedBIKE™ high-intensity interval training session with no adverse events. The participants found the MedBIKE™ to be enjoyable and easy to navigate. In two participants, the 8-week home-based protocol was tolerated well with completion of 23/24 (96%) and 24/24 (100%) of sessions, respectively, and no adverse events across the 47 sessions in total., Conclusion: The MedBIKE™ resulted in similar physiological responses as compared to a cardiopulmonary exercise test ergometer and the high-intensity interval training protocol was safe, feasible, and enjoyable in youth with Fontan physiology. A randomised-controlled trial of a home-based high-intensity interval training exercise intervention using the MedBIKE™ will next be undertaken.
- Published
- 2020
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16. Tilt-table Echocardiography Unmasks Early Diastolic Dysfunction in Patients With Hemoglobinopathies.
- Author
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Mah K, Bruce A, Zahari N, Venner MA, Chow K, Thompson RB, Khoo NS, and Tham EB
- Subjects
- Case-Control Studies, Child, Female, Follow-Up Studies, Humans, Male, Prognosis, Ventricular Dysfunction, Left diagnostic imaging, Ventricular Dysfunction, Left etiology, Diastole, Echocardiography methods, Hemoglobinopathies complications, Ventricular Dysfunction, Left diagnosis
- Abstract
Individuals with hemoglobinopathy (sickle cell anemia and thalassemia major) are at risk for cardiac complications such as heart failure and cardiomyopathy. Diastolic dysfunction is known to precede systolic dysfunction in many cardiac diseases. This study sought to determine whether changes in left atrial (LA) function during manipulation of cardiac preload by tilt-table echocardiography can unmask subclinical diastolic dysfunction in pediatric patients with hemoglobinopathies. Eleven sickle cell anemia, 9 transfusion-dependent thalassemia major, and 10 control subjects underwent tilt-table echocardiogram in the supine (loading) and 30-degree upright (unloading) positions and cardiac magnetic resonance imaging (MRI). Echocardiography assessed LA and left ventricular (LV) strain, strain rate, mitral inflow, and annular velocities. MRI assessed LV function, myocardial T1 and T2* for iron deposition. Both thalassemia major and sickle cell anemia patients had normal LV function and no evidence of cardiac iron deposition on MRI T2* measurements. During cardiac loading, controls appropriately increased LA conduit (P=0.002) and reservoir strain (P=0.002), mitral e' velocity (P<0.0001) and medial e' velocity (P=0.002), while the hemoglobinopathy patients showed no change in these parameters. In pediatric sickle cell anemia and thalassemia, tilt-table echocardiography unmasked a failure to augment LA function in response to loading, suggesting altered myocardial relaxation is present, before evidence of iron overload or systolic dysfunction.
- Published
- 2020
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17. A Novel Right Ventricular Volume and Pressure Loaded Piglet Heart Model for the Study of Tricuspid Valve Function.
- Author
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Lin LQ, Hatami S, Coe JY, Colen TM, Sergi C, Thompson R, Di Martino ES, Herzog W, Abu Sara Z, Freed DH, and Khoo NS
- Subjects
- Anesthesia, Animals, Echocardiography, Female, Heart Ventricles diagnostic imaging, Hemodynamics, Imaging, Three-Dimensional, Male, Models, Animal, Organ Size, Pressure, Pulmonary Artery physiopathology, Pulmonary Artery surgery, Pulmonary Valve physiopathology, Pulmonary Valve surgery, Swine, Tricuspid Valve diagnostic imaging, Tricuspid Valve surgery, Heart Ventricles physiopathology, Tricuspid Valve physiopathology
- Abstract
Heart conditions in which the tricuspid valve (TV) faces either increased volume or pressure stressors are associated with premature valve failure. Mechanistic studies to improve our understanding of the underlying pathophysiology responsible for the development of premature TV failure are lacking. Due to the inability to conduct these studies in humans, an animal model is required. In this manuscript, we describe the protocols for a novel chronic recovery infant piglet heart model for the study of changes in the TV when placed under combined volume and pressure stress. In this model, volume loading of the right ventricle and the TV is achieved through the disruption of the pulmonary valve. Then pressure loading is accomplished through the placement of a pulmonary artery band. The success of this model is assessed at four weeks post intervention surgery through echocardiography, intracardiac pressure measurement, and pathologic examination of the heart specimens.
- Published
- 2020
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18. Effects of Early Myocardial Postnatal Maturation on Tolerance to Atrial Tachycardia With Altered Loading Conditions: An in vivo Swine Model.
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Fortin-Pellerin E, Khoo NS, Coe JY, Mills L, Cheung PY, and Hornberger LK
- Abstract
Post-natal maturation of the myocardium starts shortly after birth and could affect how clinicians should provide hemodynamic support during this transition. Our aim was to assess the impact of post-natal maturation on tolerance to tachycardia with altered loading condition in a piglet model. Methods: We report three series of experimentations. Six groups of landrace cross neonatal piglets (NP) (1-3 days) and young piglets (YP) (14-17 days) were assigned to tachycardia (NP, YP), tachycardia and hypervolemia (NPV, YPV) or tachycardia and increased afterload (NPA, YPA) groups ( n = 7/group). Under anesthesia, a pressure catheter was placed in the left ventricle and pacing wire in the right atrium. NPV and YPV groups had 60 ml/kg of normal saline infused over 20 min. NPA and YPA had balloon sub-occlusion of the descending aorta. Heart rate was increased by 10 bpm increments to 300 bpm. Left ventricular output was measured by echocardiography. Results: NP maintained left ventricular output throughout the pacing protocol but it decreased in the YP ( p < 0.001). With volume loading both NPV and YPV maintained their output with tachycardia. Although increased afterload resulted in reduced output during tachycardia in NPA ( p = 0.005), there was no added impact on output in YPA. Interestingly, 4 of 7 NPV had significant desaturation at 300 bpm (baseline 99.7% vs. 300 bpm 87.9%, p = 0.04), associated with a right to left shunt through the patent foramen ovale which resolved immediately on cessation of pacing. Conclusions: Early post-natal maturation is associated with improved myocardial tolerance to increased afterload and poor tolerance of tachycardia, the latter of which may be alleviated by increasing intravascular volume. These data could translate into the development of better strategies to optimize cardiac output at these early development ages., (Copyright © 2020 Fortin-Pellerin, Khoo, Coe, Mills, Cheung and Hornberger.)
- Published
- 2020
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19. Quantitative Assessment of Left Ventricular Dysfunction in Fetal Ebstein's Anomaly and Tricuspid Valve Dysplasia.
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Eckersley LG, Howley LW, van der Velde ME, Khoo NS, Mah K, Brooks P, Colen T, and Hornberger LK
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- Case-Control Studies, Evaluation Studies as Topic, Female, Gestational Age, Humans, Pregnancy, Prenatal Diagnosis methods, Reference Values, Retrospective Studies, Ventricular Dysfunction, Left physiopathology, Ebstein Anomaly diagnostic imaging, Ebstein Anomaly physiopathology, Pregnancy Outcome, Ultrasonography, Prenatal methods, Ventricular Dysfunction, Left diagnostic imaging
- Abstract
Background: Fetal Ebstein's anomaly and tricuspid valve dysplasia (EA/TVD) are associated with high perinatal mortality relative to pulmonary atresia with intact ventricular septum (PAIVS), despite both requiring redistribution of the cardiac output (CO) to the left ventricle (LV). LV dysfunction is suspected to contribute to adverse outcomes in EA/TVD., Objective: We sought to examine global and segmental LV function in fetal EA/TVD with comparison to normal controls and PAIVS. We hypothesized that LV dysfunction in EA/TVD is associated with abnormal LV remodeling and interventricular mechanics., Methods: We retrospectively identified 63 cases of fetal EA/TVD (40 with retrograde ductal flow) and 22 cases of PAIVS encountered from 2004 to 2015 and compared findings to 77 controls of comparable gestational age. We measured the combined CO and global LV function using two-dimensional, Doppler-derived, deformational (six-segmental vector velocity imaging) and dyssynchrony indices (DIs; SD of time to peak), and a novel global DI., Results: EA/TVD fetuses demonstrated abnormal LV global systolic function with reduced ejection fraction, fractional area change, and CO, while in PAIVS we observed a normal ejection fraction, fractional area change, and CO. PAIVS, but not EA/TVD, demonstrated increased LV sphericity, suggestive of remodeling, and associated enhanced radial function in the third trimester. In contrast, while EA/TVD fetuses had normal LV segmental longitudinal strain, there was abnormal radial segmental deformation and LV dyssynchrony with increased SD of time to peak and DI., Conclusions: Fetal EA/TVD is associated with a lack of spherical remodeling and presence of mechanical dyssynchrony, which likely contribute to reduced CO and ejection fraction. Clinical monitoring of LV function is warranted in fetal EA/TVD. Further studies incorporating quantification of LV function into prediction models for adverse outcomes are required., (Copyright © 2019 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.)
- Published
- 2019
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20. The Incremental Benefit of Color Tissue Doppler in Fetal Arrhythmia Assessment.
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Alvarez SGV, Khoo NS, Colen T, McBrien A, Eckersley L, Brooks P, Savard W, and Hornberger LK
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- Arrhythmias, Cardiac embryology, Arrhythmias, Cardiac physiopathology, Female, Fetal Diseases physiopathology, Fetal Heart physiopathology, Follow-Up Studies, Gestational Age, Humans, Pregnancy, Prospective Studies, Reproducibility of Results, Arrhythmias, Cardiac diagnosis, Echocardiography, Doppler, Color methods, Fetal Diseases diagnosis, Fetal Heart diagnostic imaging, Heart Rate physiology, Ultrasonography, Prenatal methods
- Abstract
Background: Accurate fetal arrhythmia (FA) diagnosis is key for effective management. Currently, FA assessment relies on standard echocardiography-based techniques (M mode and spectral Doppler), which require adequate fetal position and cursor alignment to define temporal relationships of mechanical events. Few data exist on the application of color Doppler tissue imaging (c-DTI) in FA assessment. The aim of this study was to examine the feasibility and clinical applicability of c-DTI in FA assessment in comparison with standard techniques., Methods: Pregnancies with diagnosed FA were prospectively recruited to undergo c-DTI following fetal echocardiography. Multiple-cycle four-chamber clips in any orientation were recorded (mean frame rate, 180 ± 16 frames/sec). With offline analysis, sample volumes were placed on atrial (A) and ventricular (V) free walls for simultaneous recordings. Atrial and ventricular rates, intervals (for atrial-ventricular conduction and tachyarrhythmia mechanism), and relationships were assessed to decipher FA mechanism. FA diagnosis by c-DTI, conventional echocardiographic techniques, and postnatal electrocardiography and/or Holter monitoring were compared., Results: FA was assessed by c-DTI in 45 pregnancies at 15 to 39 weeks, including 16 with atrial and/or ventricular ectopic beats; 18 with supraventricular tachyarrhythmias, including ectopic atrial tachycardia in 11, atrioventricular reentrant tachycardia in four, atrial flutter in two, and intermittent atrial flutter and junctional ectopic rhythm in one; three with ventricular tachycardias; and eight with bradycardias or atrioventricular conduction pathology, including five with complete atrioventricular block (AVB), one with first-degree AVB evolving into complete AVB, one with second-degree AVB, and one with sinus bradycardia. After training, FA diagnosis by c-DTI could be made irrespective of fetal orientation within 10 to 15 min. FA diagnosis by c-DTI concurred with standard techniques in 41 cases (91%), with additional findings identified by c-DTI in 10. c-DTI led to new FA diagnoses in four cases (9%) not definable by standard techniques. FA diagnosis by c-DTI was confirmed in all 20 with persistent arrhythmias after birth, including three with new diagnoses defined by c-DTI. c-DTI was particularly helpful in deciphering SVT mechanism (long vs short ventricular-atrial interval) in all 18 cases, whereas standard techniques permitted definition in only half., Conclusions: c-DTI with offline analysis permits rapid and accurate definition of FA mechanism, providing new information in nearly one-third of affected pregnancies., (Copyright © 2018 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.)
- Published
- 2019
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21. Active right atrial emptying fraction predicts reduced survival and increased adverse events in childhood pulmonary arterial hypertension.
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Kumar S, Vadlamudi K, Kaddoura T, Bobhate P, Goot BH, Elgendi M, Jain S, Colen T, Khoo NS, and Adatia I
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- Adolescent, Cardiac Catheterization mortality, Cardiac Catheterization trends, Child, Child, Preschool, Female, Humans, Hypertension, Pulmonary therapy, Infant, Male, Predictive Value of Tests, Retrospective Studies, Survival Rate trends, Atrial Function, Right physiology, Hypertension, Pulmonary diagnostic imaging, Hypertension, Pulmonary mortality
- Abstract
Background: Right atrial (RA) function has been studied rarely in childhood pulmonary arterial hypertension (PAH). We sought to determine if RA and right ventricular (RV) area changes measured by echocardiography predicted outcomes., Methods: We reviewed data from children with PAH undergoing cardiac catheterization and echocardiography. RA and RV areas were obtained from the apical 4-chamber view. Clinical worsening indicated initiation of parenteral prostanoid therapy, heart and/or lung transplantation, Potts shunt surgery or death., Results: We studied 57 children (27 females), median age 3 years (range 0.30-17 years), body surface area 0.56 m2 (0.2-1.8), follow up 3 years (0.21-8.35), time to clinical worsening was 1.14 years (0.03-6.14) and mortality was 1.55 years (range 0.88-4.95). We determined from receiver operator curves that RA active emptying fraction (RA EaF) ≥60% predicted clinical worsening (sensitivity 78%, specificity 69%, AUC 0.7) and mortality (sensitivity 100%, specificity 65%, AUC 0.82). RV fractional area change (RVFAC) <25% predicted clinical worsening (sensitivity 72%, specificity 79%, AUC 0.85) and death (sensitivity 67%, specificity 69%, AUC 0.77). The combination of RA EaF ≥60% and RVFAC <33% were best predictors of clinical worsening (sensitivity 72%, specificity 82%, partial AUC 0.65) and mortality (sensitivity 100%, specificity 77%, partial AUC 0.75)., Conclusion: In childhood PAH, RA EaF ≥ 60% and RVFAC <25% were associated with poor outcomes. RA EaF ≥60% and RVFAC <33% were best predictors of clinical worsening and may be useful markers in children with PAH who require closer observation and more intensive therapy., (Copyright © 2018 Elsevier B.V. All rights reserved.)
- Published
- 2018
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22. Reduced Right Ventricular Fractional Area Change, Strain, and Strain Rate before Bidirectional Cavopulmonary Anastomosis is Associated with Medium-Term Mortality for Children with Hypoplastic Left Heart Syndrome.
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Lin LQ, Conway J, Alvarez S, Goot B, Serrano-Lomelin J, Colen T, Tham EB, Kutty S, Li L, and Khoo NS
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- Area Under Curve, Child, Preschool, Cohort Studies, Databases, Factual, Echocardiography methods, Female, Fontan Procedure mortality, Humans, Hypoplastic Left Heart Syndrome diagnostic imaging, Hypoplastic Left Heart Syndrome mortality, Infant, Male, Observer Variation, ROC Curve, Retrospective Studies, Risk Assessment, Statistics, Nonparametric, Survival Analysis, Time Factors, Ventricular Dysfunction, Right etiology, Ventricular Dysfunction, Right physiopathology, Ventricular Function, Right physiology, Cause of Death, Fontan Procedure methods, Hypoplastic Left Heart Syndrome surgery, Image Interpretation, Computer-Assisted, Ventricular Dysfunction, Right diagnostic imaging
- Abstract
Background: Ventricular dysfunction is associated with increased morbidity and mortality in children with hypoplastic left heart syndrome. The aim of this study was to assess the diagnostic performance of conventional and speckle-tracking echocardiographic measures of right ventricular (RV) function before bidirectional cavopulmonary anastomosis palliation in predicting death or need for heart transplantation (HTx)., Methods: RV fractional area change (RVFAC) and longitudinal and circumferential strain and strain rate (SR) were measured in 64 prospectively recruited patients with hypoplastic left heart syndrome from echocardiograms obtained before bidirectional cavopulmonary anastomosis surgery. The composite end point of death or HTx was examined. Receiver operating characteristic analysis was performed, and cutoff values optimizing sensitivity and specificity were derived., Results: At a median follow-up of 5.0 years (interquartile range, 2.8-6.4 years), 13 patients meeting the composite end point had lower longitudinal strain and SR, circumferential SR, and RVFAC compared with survivors (n = 51). The conventional cutoff of RVFAC < 35% was specific for death or HTx (86%) but had poor sensitivity (46%), with an area under the curve of 0.73. Speckle-tracking echocardiographic variables showed similar areas under the curve (range, 0.69-0.79), with negative predictive values >90%. Addition of speckle-tracking echocardiographic variables to RVFAC < 35% showed no added benefit. However, in a subpopulation of patients with RVFAC ≥ 35% (n = 44), those meeting the composite end point (n = 7) had lower longitudinal SR (median, -1.0 1/sec [interquartile range, -0.8 to -1.1 1/sec] vs -1.21/sec [interquartile range, -1.0 to -1.3 1/sec], P = .03). Interobserver reproducibility was superior for longitudinal strain and SR (intraclass correlation coefficient > 0.92) compared with RVFAC (intraclass correlation coefficient = 0.75)., Conclusions: Children with hypoplastic left heart syndrome with normal RVFAC and ventricular deformation before bidirectional cavopulmonary anastomosis have a low likelihood of death or HTx in the medium term. In the presence of reduced RVFAC, speckle-tracking echocardiography does not provide additional prognostic value. However, in patients with "normal" RVFAC, it may have a role in improving outcome prediction and warrants further investigation., (Copyright © 2018 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.)
- Published
- 2018
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23. Tricuspid Valve Adaptation during the First Interstage Period in Hypoplastic Left Heart Syndrome.
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Colen T, Kutty S, Thompson RB, Tham E, Mackie AS, Li L, Truong DT, Maruyama M, Smallhorn JF, and Khoo NS
- Subjects
- Female, Follow-Up Studies, Heart Ventricles physiopathology, Humans, Hypoplastic Left Heart Syndrome complications, Hypoplastic Left Heart Syndrome surgery, Infant, Newborn, Male, Norwood Procedures methods, Prospective Studies, Risk Factors, Tricuspid Valve Insufficiency diagnosis, Tricuspid Valve Insufficiency surgery, Echocardiography, Three-Dimensional methods, Heart Ventricles diagnostic imaging, Hypoplastic Left Heart Syndrome diagnosis, Tricuspid Valve diagnostic imaging, Tricuspid Valve Insufficiency etiology, Ventricular Function, Left physiology
- Abstract
Background: Tricuspid regurgitation (TR) is an important risk factor for morbidity and mortality in hypoplastic left heart syndrome (HLHS), yet the evolution of tricuspid valve (TV) dysfunction in HLHS is poorly understood. This study sought to examine changes in TV function in HLHS between the first two stages of surgical palliation and to determine the mechanism of TR at the time of stage two surgery-bidirectional cavopulmonary anastomosis (BCPA)., Methods: We prospectively investigated 44 infants at two time points-prior to Norwood-Sano (T1 - median age 5.4 days) and prior to BCPA (T2 - median age 4.7 months) using two-dimensional (2DE) and three-dimensional echocardiography (3DE). Right ventricular (RV) size, function and shape was assessed with 2DE. Extracted spatial coordinates from 3DE were used to calculate TV leaflet and annular area, tethering and prolapse volumes, bending angle, and coaptation index. TR was graded qualitatively, and 2D and 3D vena contracta (VC) were measured., Results: The cohort from T1 to T2 had increased indexed leaflet and annular area (P < .0001) and tethering volume (P < .0001), with no change in coaptation. Significant TR was present in 14 infants (32%) at T2 and was associated with greater leaflet (P = .02) and annular areas (P = .002) and greater prolapse volume (P = .008), but not tethering volume or reduced coaptation. At latest follow-up (median 23 months), 13 patients died or required transplantation. Only 3DE VC at T2 was associated with death or transplantation., Conclusions: The TV in HLHS adapts to interstage stressors (increased preload and afterload) by increasing leaflet size to maintain adequate leaflet coaptation. Significant TR at T2 was associated with greater leaflet size and prolapse. This may represent TV maladaptation from an excessive response in leaflet expansion to stressors., (Copyright © 2017 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.)
- Published
- 2018
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24. Tricuspid Valve Repair in Infancy Using Neochordae: Three-Dimensional Echocardiographic Imaging.
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Martin BJ, Khoo NS, Smallhorn J, and Aklabi MA
- Subjects
- Chordae Tendineae, Humans, Infant, Prosthesis Design, Tricuspid Valve abnormalities, Tricuspid Valve diagnostic imaging, Tricuspid Valve Insufficiency congenital, Tricuspid Valve Insufficiency diagnosis, Cardiac Surgical Procedures methods, Echocardiography, Three-Dimensional methods, Polytetrafluoroethylene, Prostheses and Implants, Tricuspid Valve surgery, Tricuspid Valve Insufficiency surgery
- Abstract
Tricuspid regurgitation (TR) in infancy poses a surgical challenge. Both two- and three-dimensional echocardiography (3DE) can provide detailed information about the mechanism(s) of valve failure and insights into valve adaptation during follow-up. We report two patients who underwent tricuspid valve repair using Gore-Tex neochordae, repairs which were facilitated by and assessed with 3DE. Both infants had less than mild residual TR and no valve tethering at hospital discharge. Furthermore, follow-up 3DEs have helped to confirm valve competence, lack of tethering, and growth of the valve and valve apparatus.
- Published
- 2017
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25. Strain Rate in Children and Young Piglets Mirrors Changes in Contractility and Demonstrates a Force-Frequency Relationship.
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Alvarez SV, Fortin-Pellerin E, Alhabdan M, Lomelin JS, Kantoch M, Atallah J, Hornberger LK, Coe JY, Cheung PY, Tham EB, Mah K, Lin L, Mills L, and Khoo NS
- Subjects
- Adolescent, Animals, Child, Female, Follow-Up Studies, Heart Rate, Humans, Male, Models, Animal, Prospective Studies, Swine, Echocardiography, Doppler methods, Heart Ventricles diagnostic imaging, Myocardial Contraction physiology, Stroke Volume physiology, Ventricular Function, Left physiology
- Abstract
Background: In adult humans and pig models, strain rate (SR) correlates strongly with invasive measures of contractility but does not demonstrate a force-frequency relationship, which is a fundamental behavior of myocardial contraction. Given the considerable maturational changes of the myocardium from fetal stages to adulthood, extrapolation of adult findings to the young heart may not be appropriate. We sought to evaluate the SR response of the immature heart to increased heart rate (HR) and inotropic stimulation., Methods: The study consisted of two parts. In part 1, children without obvious structural or functional cardiac abnormalities were evaluated following successful radiofrequency ablation. Echocardiography was performed at baseline HR and then with atrial pacing and isoprenaline infusion titrated to achieve 130% of baseline HR. Left ventricular (LV) speckle tracking-derived SR and tissue Doppler isovolumic acceleration (IVA, a load-independent marker of contractility) were measured. In part 2, young piglets were submitted to atrial pacing at 200, 230, and 260 bpm. Invasive LV dP/dt was assessed, and speckle tracking-derived SR was measured at all stages. Repeated measures analysis of variance was used for comparison with baseline values., Results: In part 1, the LV SR and IVA (septal and lateral) in 23 children (ages 7.8-17.5 years) increased significantly with pacing and isoprenaline infusion (P < .001). In part 2, SR and invasive dP/dt increased significantly with increasing HR in young piglets (1-17 days; P < .01 and P < .001, respectively). Both LV SR and dP/dt plateaued at highest HRs concurrent with the decrease in LV end-diastolic dimension from baseline (73.0% ± 9.9% of the baseline value at 260 bpm; P < .001)., Conclusions: SR in children is augmented with chronotropic and inotropic stimulation and in young infant piglets with chronotropic stimulation; in both children and piglets it has a force-frequency relationship, a behavior that is consistent with a measure of contractility., (Copyright © 2017 American Society of Echocardiography. All rights reserved.)
- Published
- 2017
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26. Right Atrial Dysfunction in the Fetus with Severely Regurgitant Tricuspid Valve Disease: A Potential Source of Cardiovascular Compromise.
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Howley LW, Khoo NS, Moon-Grady AJ, Patel SS, Alrais F, Tworetzky W, Colen T, Brooks P, Trines J, Ojala T, and Hornberger LK
- Subjects
- Boston epidemiology, California epidemiology, Causality, Comorbidity, Echocardiography, Doppler methods, Female, Heart Failure embryology, Humans, Incidence, Male, Reproducibility of Results, Risk Factors, Sensitivity and Specificity, Tricuspid Atresia embryology, Tricuspid Valve Insufficiency embryology, Ultrasonography, Prenatal methods, Ultrasonography, Prenatal statistics & numerical data, Echocardiography, Doppler statistics & numerical data, Heart Failure diagnostic imaging, Heart Failure epidemiology, Tricuspid Atresia diagnostic imaging, Tricuspid Atresia epidemiology, Tricuspid Valve Insufficiency diagnostic imaging, Tricuspid Valve Insufficiency epidemiology
- Abstract
Background: In severe right heart obstruction (RHO), redistribution of cardiac output to the left ventricle (LV) is well tolerated by the fetal circulation. Although the same should be true of severely regurgitant tricuspid valve disease (rTVD) with reduced or no output from the right ventricle, affected fetuses more frequently develop hydrops or suffer intrauterine demise. We hypothesized that right atrium (RA) function is altered in rTVD but not in RHO, which could contribute to differences in outcomes., Methods: Multi-institutional retrospective review of fetal echocardiograms performed over a 10-year period on fetuses with rTVD (Ebstein's anomaly, tricuspid valve dysplasia) or RHO (pulmonary atresia/intact ventricular septum, tricuspid atresia) and a healthy fetal control group. Offline velocity vector imaging and Doppler measurements of RA size and function and LV function were made., Results: Thirty-four fetuses with rTVD, 40 with RHO, and 79 controls were compared. The rTVD fetuses had the largest RA size and lowest RA expansion index, fractional area of change, and RA indexed filling and emptying rates compared with fetuses with RHO and controls. The rTVD fetuses had the shortest LV ejection time and increased Tei index with a normal LV ejection fraction. RA dilation (odds ratio, 1.27; 95% CI, 1.05-1.54) and reduced indexed emptying rate (odds ratio, 2.49; 95% CI, 1.07-5.81) were associated with fetal or neonatal demise., Conclusions: Fetal rTVD is characterized by more severe RA dilation and dysfunction compared with fetal RHO and control groups. RA dysfunction may be an important contributor to reduced ventricular filling and output, potentially playing a critical role in the worsened outcomes observed in fetal rTVD., (Copyright © 2017 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.)
- Published
- 2017
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27. Impaired Single Right Ventricular Function Compared to Single Left Ventricles during the Early Stages of Palliation: A Longitudinal Study.
- Author
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Suntratonpipat S, Khoo NS, Colen T, Alhabdan M, Troung D, Zahari N, Kutty S, Smallhorn JF, and Tham EB
- Subjects
- Disease Progression, Echocardiography methods, Female, Heart Ventricles diagnostic imaging, Humans, Image Interpretation, Computer-Assisted methods, Infant, Infant, Newborn, Longitudinal Studies, Male, Palliative Care methods, Reproducibility of Results, Sensitivity and Specificity, Stroke Volume, Treatment Outcome, Ventricular Dysfunction, Left surgery, Ventricular Dysfunction, Right surgery, Heart Ventricles abnormalities, Heart Ventricles physiopathology, Ventricular Dysfunction, Left diagnostic imaging, Ventricular Dysfunction, Left physiopathology, Ventricular Dysfunction, Right diagnostic imaging, Ventricular Dysfunction, Right physiopathology
- Abstract
Background: Single right ventricles (SRV) are postulated to be disadvantaged compared with single left ventricles (SLV). We compared the evolution of SRV versus SLV function during infancy using conventional measures and speckle-tracking echocardiography (STE). We hypothesized that the SRV is mechanically disadvantaged during early infancy., Methods: SRVs (n = 32) were compared with SLVs (n = 16) at the neonatal (presurgery) and pre-bidirectional cavopulmonary anastomosis (pre-BCPA) stages. Functional measures (fractional area change, indexed ventricular annular plane systolic excursion [iVAPSE], isovolumic acceleration [IVA], myocardial performance index, E and A velocities, tissue Doppler imaging annular velocities and STE-measured global longitudinal and circumferential strain, strain rate [SR], and early diastolic SR [EDSR]) were compared between SRV and SLV at each stage and between presurgery and pre-BCPA., Results: Compared with SLV, presurgery SRV had lower circumferential strain (-10.6% vs -16.5%; P = .0002) and EDSR (1.41%/sec vs 2.13%/sec; P = .001). Pre-BCPA SRV had decreased IVA (1.2 vs 2.1 m/sec
2 ; P = .006): longitudinal strain (-15.3% vs -19.1%; P = .001), SR (-0.97%/sec vs -1.53%/sec; P = .0001), EDSR (1.5%/sec vs 2.1%/sec; P = .001); circumferential strain (-10.6% vs -14.9%; P = .002), SR (-0.8%/sec vs -1.21%/sec; P = .0001), and EDSR (1.3%/sec vs 1.8%/sec; P = .009). SRV showed reduction of iVAPSE, IVA, s', e', a' velocities, longitudinal strain, SR, EDSR, and circumferential SR (P < .05) from presurgery to pre-BCPA, while circumferential strain was unchanged. SLV showed no significant change in these parameters during this interval., Conclusions: The progressive reduction in SRV longitudinal and circumferential function suggests that SRV may have a mechanical disadvantage from birth and progressive impairment with age., (Copyright © 2017 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.)- Published
- 2017
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28. Three-dimensional Echocardiography in Congenital Heart Disease: An Expert Consensus Document from the European Association of Cardiovascular Imaging and the American Society of Echocardiography.
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Simpson J, Lopez L, Acar P, Friedberg MK, Khoo NS, Ko HH, Marek J, Marx G, McGhie JS, Meijboom F, Roberson D, Van den Bosch A, Miller O, and Shirali G
- Subjects
- Child, Child, Preschool, Europe, Evidence-Based Medicine, Expert Testimony, Female, Humans, Infant, Infant, Newborn, Male, Pediatrics standards, United States, Cardiac Imaging Techniques standards, Echocardiography, Three-Dimensional standards, Heart Defects, Congenital diagnostic imaging, Image Enhancement standards, Practice Guidelines as Topic
- Abstract
Three-dimensional echocardiography (3DE) has become important in the management of patients with congenital heart disease (CHD), particularly with pre-surgical planning, guidance of catheter intervention, and functional assessment of the heart. 3DE is increasingly used in children because of good acoustic windows and the non-invasive nature of the technique. The aim of this paper is to provide a review of the optimal application of 3DE in CHD including technical considerations, image orientation, application to different lesions, procedural guidance, and functional assessment., (Copyright © 2016 European Society of Cardiology. Published by Elsevier Inc. All rights reserved.)
- Published
- 2017
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29. Autologous Doping with Cryopreserved Red Blood Cells - Effects on Physical Performance and Detection by Multivariate Statistics.
- Author
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Malm CB, Khoo NS, Granlund I, Lindstedt E, and Hult A
- Subjects
- Adult, Athletes, Blood Donors, Erythrocyte Count, Female, Humans, Male, Athletic Performance physiology, Blood Transfusion, Autologous, Cryopreservation, Doping in Sports methods, Erythrocytes, Substance Abuse Detection methods
- Abstract
The discovery of erythropoietin (EPO) simplified blood doping in sports, but improved detection methods, for EPO has forced cheating athletes to return to blood transfusion. Autologous blood transfusion with cryopreserved red blood cells (RBCs) is the method of choice, because no valid method exists to accurately detect such event. In endurance sports, it can be estimated that elite athletes improve performance by up to 3% with blood doping, regardless of method. Valid detection methods for autologous blood doping is important to maintain credibility of athletic performances. Recreational male (N = 27) and female (N = 11) athletes served as Transfusion (N = 28) and Control (N = 10) subjects in two different transfusion settings. Hematological variables and physical performance were measured before donation of 450 or 900 mL whole blood, and until four weeks after re-infusion of the cryopreserved RBC fraction. Blood was analyzed for transferrin, iron, Hb, EVF, MCV, MCHC, reticulocytes, leucocytes and EPO. Repeated measures multivariate analysis of variance (MANOVA) and pattern recognition using Principal Component Analysis (PCA) and Orthogonal Projections of Latent Structures (OPLS) discriminant analysis (DA) investigated differences between Control and Transfusion groups over time. Significant increase in performance (15 ± 8%) and VO2max (17 ± 10%) (mean ± SD) could be measured 48 h after RBC re-infusion, and remained increased for up to four weeks in some subjects. In total, 533 blood samples were included in the study (Clean = 220, Transfused = 313). In response to blood transfusion, the largest change in hematological variables occurred 48 h after blood donation, when Control and Transfused groups could be separated with OPLS-DA (R2 = 0.76/Q2 = 0.59). RBC re-infusion resulted in the best model (R2 = 0.40/Q2 = 0.10) at the first sampling point (48 h), predicting one false positive and one false negative. Over all, a 25% and 86% false positives ratio was achieved in two separate trials. In conclusions, autologous re-infusion of RBCs increased VO2max and performance as hypothesized, but hematological profiling by multivariate statistics could not reach the WADA stipulated false positive ratio of <0.001% at any time point investigated. A majority of samples remained within limits of normal individual variation at all times.
- Published
- 2016
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30. Impaired Left Ventricular Reserve in Childhood Cancer Survivors Treated With Anthracycline Therapy.
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Kaneko S, Tham EB, Haykowsky MJ, Spavor M, Khoo NS, Mackie AS, Smallhorn JF, Thompson RB, and Nelson MD
- Subjects
- Adolescent, Child, Echocardiography, Exercise Test, Female, Heart Ventricles diagnostic imaging, Heart Ventricles drug effects, Humans, Male, Neoplasms drug therapy, Oxygen Consumption drug effects, Survivors, Ventricular Dysfunction, Left diagnostic imaging, Ventricular Function, Left drug effects, Young Adult, Anthracyclines adverse effects, Antineoplastic Agents adverse effects, Cardiotoxicity etiology, Ventricular Dysfunction, Left chemically induced
- Abstract
Background: Childhood cancer survivors show evidence of diffuse myocardial fibrosis that is related to exercise capacity. The mechanism of reduced exercise tolerance in anthracycline cardiotoxicity remains unclear. We explored the determinants of exercise intolerance by evaluating left ventricular (LV) distensibility and functional reserve., Methods: Patients (n = 22) and healthy controls (n = 10) underwent two-dimensional echocardiography while supine, upright, and during cycle exercise. LV distensibility was measured as the change in end-diastolic cavity area (EDCA) from supine to the upright position. LV functional reserve was assessed during peak exercise, and measured as the exercise-induced change in systolic circumferential strain rate (SR) and early-diastolic SR (EDSR). The peak rate of oxygen consumption was measured by indirect calorimetry., Results: Median age of patients was 16 years (range 8-19) and controls 14 years (range 8-19). Median time since anthracycline therapy was 6 years (range 2-16). Peak oxygen consumption was significantly lower in patients compared to controls (35 ml/kg/min [28-60] vs. 45 ml/kg/min [44-53], P = 0.005). Transitioning from the supine position to the upright position caused a similar reduction in LV EDCA, suggesting similar LV distensibility between patients (-22% [-46 to -4]) and controls (-20% [-46 to -3], P = 0.3). However, during exercise, both systolic SR and EDSR reserve were significantly impaired in patients (∆SR: 93% [14-308], ∆EDSR: -4.5% [-88 to 121]) compared to controls (∆SR: 128% [54-230], P = 0.046; ∆EDSR: 74% [22-234], P = 0.02)., Conclusions: Our findings suggest that impaired LV contractility and functional reserve play a role in the reduced exercise capacity in anthracycline cardiotoxicity rather than LV distensibility., (© 2016 Wiley Periodicals, Inc.)
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- 2016
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31. Postnatal neonatal myocardial adaptation is associated with loss of tolerance to tachycardia: a simultaneous invasive and noninvasive assessment.
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Fortin-Pellerin E, Khoo NS, Mills L, Coe JY, Serrano-Lomelin J, Cheung PY, and Hornberger LK
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- Adaptation, Physiological, Age Factors, Animals, Animals, Newborn, Biomechanical Phenomena, Blood Pressure, Cardiac Catheterization, Cardiac Pacing, Artificial, Disease Models, Animal, Echocardiography, Doppler, Pulsed, Stress, Mechanical, Swine, Tachycardia, Supraventricular diagnosis, Tachycardia, Supraventricular etiology, Time Factors, Heart Rate, Myocardial Contraction, Tachycardia, Supraventricular physiopathology, Tachycardia, Supraventricular prevention & control, Ventricular Function, Left
- Abstract
Doppler studies at rest suggest left ventricular (LV) diastolic function rapidly improves from the neonate to infant. Whether this translates to its response to hemodynamic challenges is uncertain. We sought to explore the impact of early LV maturation on its ability to tolerate atrial tachycardia. As tachycardia reduces filling time, we hypothesized that the neonatal LV would be less tolerant of atrial tachycardia. Landrace cross piglets of two age groups (1-3 days; NPs; 14-17 days, YPs; n = 7/group) were instrumented for an atrial pacing protocol (from 200 to 300 beats/min) and assessed by invasive monitoring and echocardiography. NPs maintained their LV output and blood pressure, whereas YPs did not. Although negative dP/dt in NPs at baseline was lower than that of YPs (-1,599 ± 83 vs. -2,470 ± 226 mmHg/s, respectively, P = 0.007), with increasing tachycardia negative dP/dt converged between groups and was not different. Both groups had similar preload reduction during tachycardia; however, NPs maintained shortening fraction while YPs decreased (NPs: 35.4 ± 1.4 vs. 31.8 ± 2.2%, P = 0.35; YPs: 31.4 ± 0.8 vs. 22.9 ± 0.8%, P < 0.001). Contractility measures did not differ between groups. Peak LV twist and untwisting rate also did not differ; however, NPs tended to augment LV twist through increased apical rotation and YPs through increasing basal rotation (P = 0.009). The NPs appear more tolerant of atrial tachycardia than the YPs. They have at least similar diastolic performance, enhanced systolic performance, and different LV twist mechanics, which may contribute to improved tachycardia tolerance of NPs., (Copyright © 2016 the American Physiological Society.)
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- 2016
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32. Evolution of left ventricular function in the preterm infant.
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Hirose A, Khoo NS, Aziz K, Al-Rajaa N, van den Boom J, Savard W, Brooks P, and Hornberger LK
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- Female, Humans, Image Interpretation, Computer-Assisted methods, Infant, Newborn, Male, Pregnancy, Pregnancy Trimester, Third, Reproducibility of Results, Sensitivity and Specificity, Echocardiography methods, Heart Ventricles diagnostic imaging, Infant, Premature growth & development, Infant, Premature physiology, Ultrasonography, Prenatal methods, Ventricular Function, Left physiology
- Abstract
Background: The aim of this study was to evaluate left ventricular function in preterm infants from 28 days to near term using echocardiography., Methods: Thirty clinically stable preterm infants delivered at <30 weeks' gestational age were prospectively enrolled. At 28 days, conventional, tissue Doppler, and speckle-tracking echocardiography evaluations of left ventricular function were performed, with comparison made to findings in 30 healthy term infants of similar postnatal age. Sixteen preterm infants underwent repeat examinations near term., Results: Compared with controls, preterm infants at 28 days had decreased peak mitral valve (MV) E-wave velocities (P < .01), E/A ratios (P < .0001), annular e' velocities (P < .0001), and e'/a' ratios (P < .0001); increased MV E/e' ratios (P < .01); and lower basal circumferential early diastolic and higher late diastolic strain rates. No significant differences were found in fractional shortening, ejection fraction, and longitudinal or circumferential strain and strain rate between preterm infants and controls. Although preterm infants at 28 days had higher heart rates compared with controls (161 ± 15 vs 142 ± 16 beats/min), no significant correlations existed between heart rate and MV E, E/A ratio, e', e'/a' ratio, and E/e' ratio. Near term, the differences in diastolic function persisted, including decreased MV e'/a' ratio (P < .05), increased E/e' ratio (P < .01), and increased late diastolic strain rate., Conclusions: Clinically stable preterm infants have normal left ventricular systolic function but altered diastolic function, with greater dependence on atrial contraction, the latter of which persists despite nearing term. These findings may be relevant to the management of preterm infants and may relate to the longer term myocardial dysfunction observed in affected adults., (Copyright © 2015 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.)
- Published
- 2015
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33. Increased common atrioventricular valve tenting is a risk factor for progression to severe regurgitation in patients with a single ventricle with unbalanced atrioventricular septal defect.
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Vijarnsorn C, Khoo NS, Tham EB, Colen T, Rebeyka IM, and Smallhorn JF
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- Cardiac Surgical Procedures, Chi-Square Distribution, Child, Preschool, Female, Heart Septal Defects diagnosis, Heart Septal Defects physiopathology, Heart Septal Defects surgery, Heart Valve Diseases diagnosis, Heart Valve Diseases physiopathology, Heart Valve Diseases surgery, Heart Valves diagnostic imaging, Heart Valves surgery, Heart Ventricles physiopathology, Heart Ventricles surgery, Humans, Infant, Male, Multivariate Analysis, Odds Ratio, Palliative Care, Retrospective Studies, Risk Factors, Severity of Illness Index, Time Factors, Treatment Outcome, Ultrasonography, Abnormalities, Multiple, Heart Septal Defects complications, Heart Valve Diseases etiology, Heart Valves physiopathology, Heart Ventricles abnormalities
- Abstract
Objective: Significant atrioventricular valve regurgitation (AVVR) increases mortality in patients with unbalanced atrioventricular septal defects (uAVSDs) and a single ventricle. We tested the hypothesis that abnormal leaflet tethering is associated with progressive AVVR in patients with a single ventricle with uAVSD., Methods: We retrospectively reviewed the initial presentation and prebidirectional cavopulmonary anastamosis echocardiograms of 46 consecutive patients with uAVSD with single ventricle palliation. AVVR was graded as moderate to severe if the sum of vena contracta width to dominant valve annulus ratio was ≥ 0.33. We measured tenting height, annular to leaflet angle and annular diameter, indexed to patient size where appropriate. Multivariate analysis of variables to predict progressive AVVR was performed., Results: At follow-up of 3.3 ± 2.4 years, 24 patients had mild AVVR (Group A) and 22 had moderate to severe AVVR. Overall mortality was 6%, whereas 10 had valve repair/replacement surgery. Of 22 patients with severe AVVR at follow-up, 9 had severe AVVR at initial presentation (Group B), whereas 13 had mild AVVR at presentation but developed severe AVVR at their prebidirectional cavopulmonary anastamosis echocardiogram (Group C). Group A patients had a smaller tenting height at initial presentation compared with patients in Group B and Group C, and also had early progressive reduction of indexed tenting height (P < .01). An absolute tenting height >6 mm (odds ratio, 6.6; 95% confidence interval, 1.1-39.0; P = .03) at the initial echocardiogram was identified as an independent predictor of subsequent severe AVVR., Conclusions: Early leaflet tethering is predictive of subsequent AVVR in patients with a single ventricle with uAVSD. Patients with competent AVV had progressive reduction in the degree of leaflet tethering, whereas patients with AVVR did not. This may represent an important adaptive process to maintain valve competency in uAVSD., (Copyright © 2014 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)
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- 2014
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34. Tricuspid regurgitation in hypoplastic left heart syndrome: mechanistic insights from 3-dimensional echocardiography and relationship with outcomes.
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Kutty S, Colen T, Thompson RB, Tham E, Li L, Vijarnsorn C, Polak A, Truong DT, Danford DA, Smallhorn JF, and Khoo NS
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- Alberta epidemiology, Child, Preschool, Female, Follow-Up Studies, Humans, Hypoplastic Left Heart Syndrome diagnostic imaging, Hypoplastic Left Heart Syndrome mortality, Infant, Male, Nebraska epidemiology, Prognosis, Prospective Studies, Survival Rate trends, Tricuspid Valve Insufficiency diagnostic imaging, Tricuspid Valve Insufficiency surgery, Cardiac Surgical Procedures methods, Echocardiography, Three-Dimensional, Hypoplastic Left Heart Syndrome complications, Tricuspid Valve Insufficiency etiology
- Abstract
Background: Our purpose was to test the following hypotheses: (1) patients with hypoplastic left heart syndrome who develop significant tricuspid regurgitation (TR) or require tricuspid valve (TV) surgery in the medium term have detectable TV abnormalities by 3-dimensional echocardiography (3DE) prestage 1 palliation and (2) TR is associated with reduced survival and increased TV intervention., Methods and Results: Infants were prospectively studied with 3DE and 2DE prestage 1 and followed up for the end points of TR, TV surgery, transplantation, or death. From prestage 1 3DE, spatial coordinates of TV annulus and leaflets were extracted; annulus size, leaflet area, prolapse volume, tethering volume, bending angle, and papillary muscle angle were measured. TR was assessed prestage 1 and at latest follow-up. Of 70 patients, 62 (88.6%) had mild or less TR and 8 (11.4%) had moderate or greater TR prestage 1. Prestage 1 tethering volume correlated to leaflet area (r=0.736; P<0.001), annulus area (r=0.651; P<0.001), right ventricular end-diastolic area (r=0.347; P=0.003), fractional area change (r=-0.387; P<0.001), and TR grade (r=0.447; P<0.001). At follow-up, 46 (65.7%) had mild or less TR (group A) and 24 (34.3%) had moderate or greater TR (group B). Prestage 1 3DE showed greater TV tethering volume and flatter annulus in group B. Survival was better in group A., Conclusions: Increased TV tethering volume and flatter bending angle prestage 1 palliation is associated with TV failure at medium-term follow-up. Increased prestage 1 tethering is related to having larger TV annulus, larger leaflet area, larger right ventricular size, and reduced systolic function. TR progression results in increased TV intervention and decreased survival., (© 2014 American Heart Association, Inc.)
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- 2014
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35. Systolic and diastolic function of the fetal single left ventricle.
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Brooks PA, Khoo NS, and Hornberger LK
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- Diastole, Elastic Modulus, Female, Fetal Heart, Heart Ventricles diagnostic imaging, Humans, Male, Reproducibility of Results, Sensitivity and Specificity, Stroke Volume, Systole, Ventricular Dysfunction, Right diagnostic imaging, Echocardiography, Doppler methods, Elasticity Imaging Techniques methods, Heart Ventricles abnormalities, Heart Ventricles physiopathology, Ultrasonography, Prenatal methods, Ventricular Dysfunction, Right congenital, Ventricular Dysfunction, Right physiopathology
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Background: The functionally single fetal right ventricle demonstrates reduced longitudinal relative to circumferential contraction velocities and deformation, a pattern similar to the normal fetal left ventricle. Altered diastolic properties are also present, with greater reliance on atrial contraction for right ventricular filling. It is unknown whether the functionally single left ventricle (SLV) demonstrates similar altered deformation patterns and diastolic properties., Methods: Echocardiograms from 29 fetuses with SLVs were retrospectively compared with those from 48 controls with appropriately grown left ventricles. Ventricular function was assessed using Velocity Vector Imaging velocity, tissue deformation, two-dimensional, and Doppler flow parameters., Results: Fetuses with functionally SLVs showed no difference in peak global left ventricular longitudinal velocity or displacement or strain, while global radial displacement was increased (P < .001). The ratio of longitudinal to circumferential deformation was also no different from that in controls. The SLVs showed increased diameters (P < .001) with normal lengths. Mitral inflow peak E-wave (P < .05) and A-wave (P < .0001) velocities were increased, with a reduced E/A ratio (P < .001). A-wave inflow fraction was also increased (P < .05), with no change in A duration. Although ejection time was no different, inflow duration was increased (P < .01) and there was a trend toward reduction of the Tei index (P = .07)., Conclusions: The functionally single fetal left ventricle shows comparable changes to the single right ventricle, with a more spherical morphology and greater reliance on atrial contraction for ventricular filling than in controls. However, in contrast to the single right ventricle, the SLV had a normal longitudinal to circumferential deformation ratio with enhanced early diastolic filling., (Copyright © 2014 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.)
- Published
- 2014
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36. Insights into the evolution of myocardial dysfunction in the functionally single right ventricle between staged palliations using speckle-tracking echocardiography.
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Tham EB, Smallhorn JF, Kaneko S, Valiani S, Myers KA, Colen TM, Kutty S, and Khoo NS
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- Child, Preschool, Female, Humans, Infant, Infant, Newborn, Longitudinal Studies, Male, Prospective Studies, Plastic Surgery Procedures methods, Reproducibility of Results, Sensitivity and Specificity, Treatment Outcome, Echocardiography methods, Elasticity Imaging Techniques methods, Hypoplastic Left Heart Syndrome diagnostic imaging, Hypoplastic Left Heart Syndrome surgery, Palliative Care methods, Ventricular Dysfunction, Right diagnostic imaging, Ventricular Dysfunction, Right prevention & control
- Abstract
Background: The long-term prognosis of hypoplastic left heart syndrome is limited by progressive right ventricular dysfunction. The aim of this study was to determine the trends in single right ventricular systolic function between staged palliative surgeries using speckle-tracking and conventional echocardiography., Methods: There were 76 patients with functionally single right ventricles at the (1) pre-Norwood (n = 26), (2) pre-bidirectional cavopulmonary anastomosis (BCPA; n = 19), (3) pre-Fontan (n = 16), and (4) post-Fontan (n = 15) stages, compared with 30 controls of similar ages. Speckle-tracking-derived longitudinal and circumferential strain and strain rate, postsystolic strain index, and mechanical dyssynchrony index were compared with conventional measures of ventricular function. Differences between stages were analyzed using analysis of variance (P < .05)., Results: Strain rate was highest at the pre-Norwood stage and decreased at the other stages (longitudinal P < .0001, circumferential P = .0002), as opposed to controls, in whom strain rate was maintained. Longitudinal strain was significantly decreased at the pre-BCPA stage compared with the pre-Norwood stage (P = .004), but circumferential strain was maintained, resulting in a corresponding decrease in the ratio of longitudinal to circumferential strain, which failed to resemble that of controls. Longitudinal (P = .003) and circumferential (P = .002) postsystolic strain indices were greatest at the pre-BCPA stage., Conclusions: A decline in contractility occurred at the pre-BCPA stage. Although there was evidence of adaptation of the single right ventricle, this failed to resemble the normal left ventricle and may be insufficient to handle the chronic volume load or insult from previous surgery. These findings suggest an intrinsic inability of the single right ventricular myocardium to fully adapt to chronic systemic pressures., (Copyright © 2014 American Society of Echocardiography. All rights reserved.)
- Published
- 2014
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37. Modified single-patch compared with two-patch repair of complete atrioventricular septal defect.
- Author
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Ugaki S, Khoo NS, Ross DB, Rebeyka IM, and Adatia I
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- Cardiac Surgical Procedures methods, Female, Heart Septal Defects, Heart Ventricles anatomy & histology, Humans, Infant, Male, Mitral Valve physiology, Retrospective Studies, Treatment Outcome, Mitral Valve Insufficiency surgery
- Abstract
Background: We compared the outcomes of modified single-patch and two-patch surgical repair of complete atrioventricular septal defect (CAVSD) on left ventricular outflow tract (LVOT) diameter and on left atrioventricular valve (LAVV) coaptation., Methods: We reviewed retrospectively postoperative 2-dimensional echocardiograms of all CAVSD patients who underwent modified single-patch or two-patch repair between 2005 and 2011. We measured the leaflet coaptation length of the LAVV in the apical four-chamber view. The LVOT was measured in the long axis view., Results: Fifty-one patients underwent CAVSD repair at a median age of 4 months (range, 1 to 9 months) (single-patch, n=29; two-patch, n=22). The images from 46 echocardiograms were adequate for analysis. Modified single-patch repair required significantly shorter bypass time (102.0±33.6 vs 152.9±39.5 minutes, p<0.001) and ischemic time (69.0±21.7 vs 106.9±29.7 minutes, p<0.001) than did two-patch repair. The indexed coaptation length of the septal and lateral leaflets was not different between single-patch and two-patch (3.1±2.3 vs 4.1±3.1 mm/m2, p=0.25; 2.3±2.3 vs 3.3±3.0 mm/m2, p=0.21). Indexed LVOT diameter was not different in the two groups (26.1±5.2 vs 28.5±7.1 mm/m2, p=0.22). There was no hospital or late death during the median follow-up time of 35 months (range, 1 to 69 months). Five patients underwent reoperation after single-patch repair (3 with residual ventricular septal defect [VSD] and LAVV regurgitation, 1 with residual VSD, 1 with pacemaker implantation). After the two-patch repair, 1 patient required reoperation for a residual VSD and right atrioventricular valve regurgitation (p=0.22)., Conclusions: The modified single-patch repair was performed with significantly shorter bypass time and myocardial ischemic time. The postoperative LVOT diameter and LAVV leaflet coaptation length were not significantly different between techniques., (Copyright © 2014 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)
- Published
- 2014
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38. Severe left heart obstruction with retrograde arch flow influences fetal cerebral and placental blood flow.
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Yamamoto Y, Khoo NS, Brooks PA, Savard W, Hirose A, and Hornberger LK
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- Aorta, Thoracic pathology, Aortic Coarctation diagnostic imaging, Aortic Coarctation pathology, Cerebrovascular Circulation physiology, Echocardiography, Female, Fetal Diseases diagnostic imaging, Fetal Hypoxia physiopathology, Humans, Hypoplastic Left Heart Syndrome diagnostic imaging, Hypoplastic Left Heart Syndrome pathology, Infant, Newborn, Middle Cerebral Artery diagnostic imaging, Placental Circulation physiology, Pregnancy, Retrospective Studies, Transposition of Great Vessels diagnostic imaging, Transposition of Great Vessels pathology, Fetal Development physiology, Fetal Diseases pathology, Head physiopathology, Middle Cerebral Artery physiopathology, Pulsatile Flow physiology
- Abstract
Objective: Decreased middle cerebral artery (MCA) pulsatility index (PI) is a marker of fetal brain-sparing in placental insufficiency and it is also found in fetuses with severe congenital heart disease. This study sought to explore the impact of anatomical subtypes in fetal heart disease on MCA-PI and head growth., Methods: We retrospectively reviewed fetal echocardiograms of pregnancies complicated by fetal hypoplastic left heart syndrome (HLHS; n = 42) with and without anatomic coarctation (n = 28 and n = 10, respectively), isolated severe aortic coarctation (n = 21), D-transposition of the great arteries (TGA; n = 11) and pulmonary outflow tract obstruction without forward flow across the pulmonary valve (POTO; n = 15), comparing observations with gestational age-matched controls (n = 89). No fetus had major extracardiac pathology or aneuploidy. MCA and umbilical artery (UA) PI, the cerebral placental ratio (CPR = MCA-PI/ UA-PI) and neonatal head circumference were obtained and expressed as Z-scores., Results: Lower MCA-PI, higher UA-PI and lower CPR were observed in fetal HLHS and isolated coarctation with reversed arch flow (n = 6) (P < 0.001) but not TGA, POTO or isolated coarctation with antegrade arch flow (n = 15) compared with controls. No difference was found between HLHS with anatomical coarctation and those without; however, MCA-PI correlated positively with neonatal head circumference in HLHS with reversed distal arch flow (r = 0.33, P < 0.05)., Conclusions: Severe left heart obstruction with reversed aortic arch flow is associated with altered fetal cerebral blood flow, and in these conditions, MCA-PI positively correlates with head growth. Anatomical arch obstruction itself may not be a contributing factor to altered MCA flow in fetal HLHS., (Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd.)
- Published
- 2013
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39. Partial zone of apposition closure in atrioventricular septal defect: are papillary muscles the clue.
- Author
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Colen TM, Khoo NS, Ross DB, and Smallhorn JF
- Subjects
- Adolescent, Cardiac Surgical Procedures methods, Child, Child, Preschool, Echocardiography, Three-Dimensional, Humans, Infant, Reoperation, Young Adult, Heart Septal Defects surgery, Mitral Valve Insufficiency diagnostic imaging, Mitral Valve Insufficiency prevention & control, Papillary Muscles, Postoperative Complications diagnostic imaging, Postoperative Complications prevention & control
- Abstract
Background: Long-term survival after atrioventricular septal defect repair is excellent; however, postoperative left atrioventricular valve regurgitation affects morbidity and quality of life. Left atrioventricular valve regurgitation is the most common reason for reoperation after repair and it is critical that clinicians recognize pathologic mechanisms pre-repair., Methods: In this single-center experience, we identified a pattern of left atrioventricular valve abnormality in 5 cases presenting for routine surgical repair between 1 month and 24 years of age. We reviewed two-dimensional and real-time three-dimensional echocardiographic and surgical findings to assess for specific valvar or sub-valve abnormalities, including short chordae, commissural deformities, and an eccentric zone of apposition. Two-dimensional echocardiography was used to assess the degree of preoperative and postoperative left atrioventricular valve regurgitation., Results: Abnormal features identified included short, thickened chordae, poorly formed superior-mural commissure, and an eccentric zone of apposition. At surgical repair, 2 patients had limited closure of the zone of apposition, as part of a complete repair, and developed only mild left atrioventricular valve regurgitation in short-term follow-up. Two further patients had attempted complete closure of the zone of apposition with moderate postoperative regurgitation ultimately necessitating left atrioventricular valve replacement., Conclusions: This uncommon form of atrioventricular septal defect is identifiable with echocardiography and may be associated with significant postoperative regurgitation if the zone of apposition is completely sutured at time of repair. Limited closure of the zone of apposition may improve postoperative regurgitation., (Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)
- Published
- 2013
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40. The assessment of atrial function in single ventricle hearts from birth to Fontan: a speckle-tracking study by using strain and strain rate.
- Author
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Khoo NS, Smallhorn JF, Kaneko S, Kutty S, Altamirano L, and Tham EB
- Subjects
- Analysis of Variance, Case-Control Studies, Child, Child, Preschool, Cross-Sectional Studies, Electrocardiography, Female, Fontan Procedure, Heart Atria surgery, Heart Ventricles surgery, Humans, Infant, Infant, Newborn, Male, Cardiac Surgical Procedures, Echocardiography methods, Heart Atria abnormalities, Heart Atria diagnostic imaging, Heart Ventricles abnormalities, Heart Ventricles diagnostic imaging
- Abstract
Background: Single ventricle (SV) exercise performance is impaired and limited by reduced ventricular preload reserve. The atrium modulates ventricular filling, and enhancement of atrial compliance can increase cardiac performance. We aimed to study atrial mechanics in SV hearts across staged surgical palliation compared with healthy children by using novel speckle-tracking echocardiography techniques., Methods: A cross-sectional study of 81 patients with SV (1 day to 6.5 years) at 4 stages of surgical palliation (presurgery, 22; prebidirectional cavopulmonary anastomosis, 23; pre-Fontan, 22; post-Fontan, 14). The dominant atrium was assessed with speckle-tracking echocardiography for active (εact), conduit (εcon), and reservoir (εres) strain; strain rate (SR); and εact/εres ratio before each stage of surgical palliation. Findings were compared with the left atrium of 51 healthy children (1 day to 5.5 years)., Results: Single ventricle atrial size was increased (P < .01), and atrial εres was decreased (P < .01) compared with healthy controls. SV atrial εcon (P < .01) and SRcon (P < .0001) was decreased, increased εact persisted (P < .05), and εact/εres was increased (P < .001) between surgical stages. Although the expected maturational trend of increasing εcon, decreasing εact, and εact/εres occurred in SV, they lagged behind healthy maturational changes (P < .0001)., Conclusion: Single ventricle atrium is dilated, has deceased compliance, decreased early diastolic emptying, and increased reliance on active atrial contraction for ventricular filling. This deviates from normal early childhood maturational changes and appears to parallel those of an atrium facing early ventricular diastolic dysfunction., (Crown Copyright © 2013. Published by Mosby, Inc. All rights reserved.)
- Published
- 2013
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41. Newer imaging modalities in the assessment of heart function in single ventricle hearts.
- Author
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Khoo NS, Tham EB, and Kantor PF
- Subjects
- Adult, Child, Echocardiography methods, Humans, Magnetic Resonance Imaging methods, Cardiac Imaging Techniques methods, Heart Defects, Congenital physiopathology, Ventricular Function physiology
- Abstract
The limitations of geometry assumptions in 2-dimensional echocardiographic assessment of the single ventricle (SV) have been overcome by recent advances in 3-D echocardiography. Improved reproducibility for measuring ventricular volumes and ejection fraction using 3-D echocardiography makes it ideally suited for serial monitoring of SV systolic function and should be considered in routine echocardiography imaging protocols for SV. The moderate correlation of Doppler derived E/e' ratio with invasive ventricular end diastolic pressure in SV, suggests it might be useful in the assessment of SV diastolic function. Speckle tracking imaging is intensely studied and promises to be a simple and repeatable imaging tool for quantifying SV function. In contrast, the advances in cardiac magnetic resonance imaging techniques promise to offer insights into the pathogenesis of myocardial dysfunction in SV. Late gadolinium enhancement imaging is a robust tool in assessing macroscopic myocardial scarring and T1 mapping and stress perfusion imaging are newer modalities that might improve understanding of the mechanisms in progressive myocardial dysfunction in SV hearts., (Copyright © 2013 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)
- Published
- 2013
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42. Diffuse myocardial fibrosis by T1-mapping in children with subclinical anthracycline cardiotoxicity: relationship to exercise capacity, cumulative dose and remodeling.
- Author
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Tham EB, Haykowsky MJ, Chow K, Spavor M, Kaneko S, Khoo NS, Pagano JJ, Mackie AS, and Thompson RB
- Subjects
- Adolescent, Child, Contrast Media, Cross-Sectional Studies, Echocardiography, Exercise Test, Female, Gadolinium DTPA, Humans, Linear Models, Male, Neoplasms drug therapy, Oxygen blood, Risk Factors, Survivors, Ventricular Remodeling drug effects, Anthracyclines adverse effects, Endomyocardial Fibrosis chemically induced, Endomyocardial Fibrosis diagnosis, Endomyocardial Fibrosis physiopathology, Magnetic Resonance Imaging methods, Physical Endurance physiology
- Abstract
Background: The late cardiotoxic effects of anthracycline chemotherapy influence morbidity and mortality in the growing population of childhood cancer survivors. Even with lower anthracycline doses, evidence of adverse cardiac remodeling and reduced exercise capacity exist. We aim to examine the relationship between cardiac structure, function and cardiovascular magnetic resonance (CMR) tissue characteristics with chemotherapy dose and exercise capacity in childhood cancer survivors., Methods: Thirty patients (15 ± 3 years), at least 2 years following anthracycline treatment, underwent CMR, echocardiography, and cardiopulmonary exercise testing (peak VO(2)). CMR measured ventricular function, mass, T(1) and T(2) values, and myocardial extracellular volume fraction, ECV, a measure of diffuse fibrosis based on changes in myocardial T1 values pre- and post-gadolinium. Cardiac function was also assessed with conventional and speckle tracking echocardiography., Results: Patients had normal LVEF (59 ± 7%) but peak VO(2) was 17% lower than age-predicted normal values and were correlated with anthracycline dose (r = -0.49). Increased ECV correlated with decreased mass/volume ratio (r = -0.64), decreased LV wall thickness/height ratio (r = -0.72), lower peak VO(2)(r = -0.52), and higher cumulative dose (r = 0.40). Echocardiographic measures of systolic and diastolic function were reduced compared to normal values (p < 0.01), but had no relation to ECV, peak VO(2) or cumulative dose., Conclusions: Myocardial T1 and ECV were found to be early tissue markers of ventricular remodeling that may represent diffuse fibrosis in children with normal ejection fraction post anthracycline therapy, and are related to cumulative dose, exercise capacity and myocardial wall thinning.
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- 2013
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43. Unique case of total artificial cardiac support in failed Fontan circulation after cardiectomy: is continuous flow better than pulsatile flow?
- Author
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VanderPluym CJ, Khoo NS, Rebeyka IM, and Buchholz H
- Subjects
- Blood Flow Velocity, Echocardiography, Doppler, Embolization, Therapeutic, Extracorporeal Membrane Oxygenation, Fatal Outcome, Humans, Infant, Newborn, Male, Pulmonary Veins abnormalities, Pulmonary Veins diagnostic imaging, Pulmonary Veins surgery, Pulsatile Flow, Shock, Treatment Failure, Blood Vessel Prosthesis Implantation methods, Fontan Procedure, Heart-Assist Devices, Tricuspid Atresia surgery
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- 2013
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44. Spontaneous endogenous microbubbles in a child with Berlin heart ventricular assist device.
- Author
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Dhillon SS, Khoo NS, Quinonez L, and Buchholz H
- Subjects
- Child, Humans, Male, Cardiomyopathy, Dilated surgery, Embolism, Air etiology, Heart-Assist Devices adverse effects
- Abstract
We report the case of an 11-year-old boy with familial dilated cardiomyopathy on biventricular assist devices (Berlin Heart EXCOR) who was found to have spontaneous endogenous microbubbles in the left ventricular (LV) cavity on routine echocardiogram. Although no major sequelae resulted from the presence of these microbubbles, it did however lead to several noninvasive investigations. To our knowledge, this is a novel observation of spontaneous endogenous microbubbles in a patient with a Berlin Heart. The unknown clinical significance of this phenomenon highlights the need for further studies.
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- 2013
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45. Tricuspid valve repair improves early right ventricular and tricuspid valve remodeling in patients with hypoplastic left heart syndrome.
- Author
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Ugaki S, Khoo NS, Ross DB, Rebeyka IM, and Adatia I
- Subjects
- Child, Preschool, Echocardiography, Doppler, Female, Heart Ventricles diagnostic imaging, Hemodynamics, Humans, Hypoplastic Left Heart Syndrome complications, Hypoplastic Left Heart Syndrome diagnostic imaging, Hypoplastic Left Heart Syndrome physiopathology, Infant, Male, Retrospective Studies, Severity of Illness Index, Time Factors, Treatment Outcome, Tricuspid Valve diagnostic imaging, Tricuspid Valve physiopathology, Tricuspid Valve Insufficiency diagnostic imaging, Tricuspid Valve Insufficiency etiology, Tricuspid Valve Insufficiency physiopathology, Ventricular Dysfunction, Right etiology, Ventricular Dysfunction, Right physiopathology, Cardiac Surgical Procedures adverse effects, Heart Ventricles physiopathology, Hypoplastic Left Heart Syndrome surgery, Tricuspid Valve surgery, Tricuspid Valve Insufficiency surgery, Ventricular Function, Right, Ventricular Remodeling
- Abstract
Objective: Tricuspid regurgitation is a significant risk factor for reoperation and mortality in patients with hypoplastic left heart syndrome. The effects of tricuspid valve repair on quantitative measures of right ventricle and tricuspid valve remodeling have not been well documented., Methods: We reviewed retrospectively the 2-dimensional echocardiograms of 17 tricuspid valve repairs (male, n = 12; female, n = 5; median age, 30 months; age range, 1.5-53 months) performed 1 month before and after tricuspid valve repair between 2005 and 2011. From the apical 4-chamber view, we measured right ventricle end-diastolic area, right ventricle fractional area change, and tricuspid valve leaflet coaptation length. The severity of tricuspid regurgitation was graded qualitatively. A 2-sided paired t test was used to compare changes in tricuspid valve and right ventricle outcomes, and the Wilcoxon signed-rank test was used to compare changes in tricuspid regurgitation grades., Results: Right ventricle end-diastolic area decreased significantly after tricuspid valve repair from 14.1 ± 5.2 to 11.8 ± 3.9 cm(2) (P = .001), whereas right ventricle fractional area change declined from 44.4% ± 6.4% to 39.7% ± 8.5% (P = .016). The coaptation length of the lateral and septal leaflet improved significantly after tricuspid valve repair (0.4 ± 2.4 mm vs 3.1 ± 2.7 mm, P = .002; 2.0 ± 2.7 vs 3.4 ± 2.0 mm, P = .036; respectively). Furthermore, the tricuspid regurgitation grade improved after tricuspid valve repair (3.1 ± 0.6 to 1.7 ± 0.9, P < .001)., Conclusions: Tricuspid valve repair improved significantly the tricuspid valve coaptation length and reduced right ventricle volume in children with hypoplastic left heart syndrome. Further follow-up of decreased right ventricle function is required to determine whether this is a temporary phenomenon related to reduced right ventricle preload, permanent right ventricle dysfunction from late repair of the tricuspid valve, or unavoidable sequelae of a right ventricle exposed to systemic vascular resistance., (Crown Copyright © 2013. Published by Mosby, Inc. All rights reserved.)
- Published
- 2013
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46. Right ventricular and tricuspid valve remodeling after bidirectional cavopulmonary anastomosis.
- Author
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Ugaki S, Khoo NS, Ross DB, Rebeyka IM, and Adatia I
- Subjects
- Female, Humans, Hypoplastic Left Heart Syndrome physiopathology, Infant, Male, Time Factors, Heart Bypass, Right adverse effects, Heart Bypass, Right methods, Heart Ventricles physiopathology, Hypoplastic Left Heart Syndrome surgery, Tricuspid Valve physiopathology, Tricuspid Valve Insufficiency etiology, Tricuspid Valve Insufficiency physiopathology
- Abstract
Background: There are few investigations of the changes in tricuspid valve (TV) and right ventricular (RV) morphology following bidirectional cavopulmonary anastomosis (BCPA)., Methods and Results: The 2-D echocardiograms of 35 children (male, n=23; female, n=12; median age, 6 months; range, 3-10 months) with hypoplastic left heart syndrome, 1 month before and after BCPA performed between 2005 and 2011, were retrospectively reviewed. Patients who underwent TV repair at BCPA were excluded. From the 4-chamber view, the coaptation length, vena contracta width and RV end-diastolic area before and after BCPA were measured and indexed to surface area. The severity of tricuspid regurgitation was graded qualitatively. After BCPA, RV end-diastolic area decreased from 2,951 ± 584 to 2,580 ± 591 mm(2)/m(2) (P<0.001). The coaptation length of the anterior leaflet (8.8 ± 5.8 vs. 11.0 ± 6.2 mm/m(2), P=0.0014) and of the septal leaflet (13.5 ± 5.3 vs. 15.8 ± 5.4mm/m(2), P=0.0072) increased after BCPA. The vena contracta width decreased (5.8 ± 4.9 vs. 4.3 ± 4.2 mm/m(2), P=0.035), although there was no change in tricuspid regurgitation grade after BCPC (1.4 ± 0.7 vs. 1.4 ± 0.9, P=0.234)., Conclusions: In children with hypoplastic left heart syndrome after BCPA, the coaptation length of the anterior and septal leaflets of the TV improved concomitantly with vena contracta width and RV end-diastolic area despite unchanged tricuspid regurgitation grade. This suggests that favorable RV and TV remodeling accompanies the reduction in RV volume load following BCPA.
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- 2013
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47. Left ventricular distensibility does not explain impaired exercise capacity in pediatric heart transplant recipients.
- Author
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Altamirano-Diaz LA, Nelson MD, West LJ, Khoo NS, Rebeyka IM, and Haykowsky MJ
- Subjects
- Adolescent, Child, Child, Preschool, Female, Humans, Infant, Infant, Newborn, Male, Exercise Tolerance, Heart Transplantation, Heart Ventricles physiopathology
- Abstract
Background: Despite improved ventricular function after heart transplantation, the aerobic capacity, as measured by peak oxygen consumption (VO(2 peak)) of pediatric heart transplant recipients (HTRs), remains 30% to 50% lower than age-matched healthy individuals. Research in adult HTRs suggests that diastolic dysfunction is a major determinant of exercise intolerance; however, it is unknown whether the impaired VO(2 peak) in younger HTRs is due to reduced left ventricular (LV) distensibility., Methods: Eight HTRs (mean age, 15 years; mean time post-transplant, 7 years) and 8 matched healthy controls were studied. To evaluate LV distensibility, echocardiographic measurements of ventricular volumes were obtained in 3 positions: supine, head-up tilt, and head-down tilt. Subsequently, participants underwent exercise stress testing to evaluate VO(2 peak)., Results: As expected, VO(2 peak) was 26% lower in HTRs (p<0.05). Ventricular volumes in each position were small in HTRs (p = 0.01); however, the percentage change in LV end-diastolic volume indexed (EDVi) to body surface area after the transition from supine to head-up tilt and from head-up tilt to head-down tilt were similar between HTRs (p = 0.956) and controls (p = 0.801). The change in EDVi during the transition from head-up tilt to head-down tilt (LV distensibility) strongly predicted VO(2 peak) in patients (R(2) = 0.614, p = 0.021) and controls (R(2) = 0.510, p = 0.047). Importantly, the slope of this relationship did not differ between HTRs (1.01) and controls (0.977; p = 0.951)., Conclusions: LV distensibility does not appear to be a major determinant of exercise intolerance in young HTR., (Copyright © 2013 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.)
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- 2013
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48. Quantitative real-time three-dimensional echocardiography provides new insight into the mechanisms of mitral valve regurgitation post-repair of atrioventricular septal defect.
- Author
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Takahashi K, Mackie AS, Thompson R, Al-Naami G, Inage A, Rebeyka IM, Ross DB, Khoo NS, Colen T, and Smallhorn JF
- Subjects
- Adult, Computer Systems, Female, Heart Septal Defects complications, Humans, Male, Middle Aged, Treatment Outcome, Echocardiography, Three-Dimensional methods, Heart Septal Defects diagnostic imaging, Heart Septal Defects surgery, Mitral Valve Insufficiency diagnostic imaging, Mitral Valve Insufficiency etiology, Plastic Surgery Procedures adverse effects
- Abstract
Background: Mechanisms of mitral valve regurgitation after atrioventricular septal defect repair are unclear., Methods: To gain further insight into mitral valve regurgitation, real-time three-dimensional echocardiography was performed in 53 patients after atrioventricular septal defect repair (30 partial and 23 complete) and 40 controls. Mitral valve {x, y, z} coordinates from the annulus, leaflet surface, papillary muscle, and chordal attachments were recorded. Vena contracta area of the regurgitant jet(s) and volume of leaflet prolapse and tethering were measured., Results: Twenty-three patients had mild (group 1) and 30 moderate (group 2) mitral valve regurgitation. Patients in both groups 1 and 2 had more circular annuli than controls. Annular area was greater in group 2 than in group 1 and controls (P < .01). Group 2 had more frequent segmental prolapse in the superior-mural leaflet segment. The anterolateral papillary muscle was more laterally displaced in group 2 than in controls and group 1 at end-diastole (P = .01 and P = .05) and formed a more acute angle with the mitral valve annulus than in controls or group 1 (P = .01)., Conclusions: In patients with atrioventricular septal defects, significant mitral valve regurgitation is associated with leaflet prolapse, larger annular area, and lateral papillary muscle displacement., (Copyright © 2012 American Society of Echocardiography. All rights reserved.)
- Published
- 2012
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49. Single right ventricles have impaired systolic and diastolic function compared to those of left ventricular morphology.
- Author
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Kaneko S, Khoo NS, Smallhorn JF, and Tham EB
- Subjects
- Adult, Female, Heart Ventricles diagnostic imaging, Humans, Male, Stroke Volume, Ventricular Dysfunction, Left congenital, Ventricular Dysfunction, Left diagnostic imaging, Young Adult, Echocardiography methods, Heart Ventricles abnormalities, Heart Ventricles physiopathology, Ventricular Dysfunction, Left physiopathology
- Abstract
Background: Differences in single right ventricle (SRV) and single left ventricles (SLV) function are poorly described, although myocardial dysfunction is an important risk factor for morbidity and mortality. The aims of this study were to compare function between patients with SRVs and those with SLVs using newer echocardiographic techniques and to determine differences across staged palliation., Methods: In this cross-sectional study comparing 30 patients with SRVs and 30 with SLVs of similar ages (2.5 ± 1.7 vs 2.6 ± 1.6 years), patients were matched for surgical stage (20 pre-bidirectional cavopulmonary anastomosis, 20 pre-Fontan, and 20 post-Fontan patients). Circumferential and longitudinal strain, strain rate (SR), early diastolic SR, postsystolic strain index, and myocardial dyssynchrony index were measured. Comparisons between SRV and SLV parameters were made as a whole group and by subanalysis at each surgical stage., Results: Patients with SRVs had reduced systolic SRs (circumferential: -1.0%/sec vs -1.2%/sec, P = .01; longitudinal: -1.1%/sec vs -1.3%/sec, P = .002), reduced early diastolic SRs (circumferential: 1.4%/sec vs 1.9%/sec, P = .03; longitudinal: 1.6%/sec vs 2.2%/sec, P = .001), and increased circumferential postsystolic strain indexes (8% vs 0%, P < .0001). Subanalysis at each surgical stage showed that the greatest disparity in systolic parameters occurred before bidirectional cavopulmonary anastomosis (longitudinal SR, P = .009; postsystolic strain index, P = .005) and that parity was regained after the Fontan procedure, while traditional diastolic parameters (E velocity, P = .004; E/E' ratio, P = .0003) were reduced in patients with SRVs after the Fontan procedure., Conclusions: The SRV has reduced contractility and diastolic function compared with the SLV. Ventricular systolic performance in patients with SRVs was poorest before bidirectional cavopulmonary anastomosis, while differences in diastolic function were more prominent after Fontan completion., (Crown Copyright © 2012. Published by Mosby, Inc. All rights reserved.)
- Published
- 2012
- Full Text
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50. Right ventricular function in fetal hypoplastic left heart syndrome.
- Author
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Brooks PA, Khoo NS, Mackie AS, and Hornberger LK
- Subjects
- Female, Humans, Male, Reproducibility of Results, Sensitivity and Specificity, Echocardiography methods, Hypoplastic Left Heart Syndrome complications, Hypoplastic Left Heart Syndrome diagnostic imaging, Ultrasonography, Prenatal methods, Ventricular Dysfunction, Right diagnostic imaging, Ventricular Dysfunction, Right etiology
- Abstract
Background: The systemic right ventricle in palliated hypoplastic left heart syndrome (HLHS) has relatively reduced longitudinal compared with circumferential deformation, a pattern of contraction more akin to the normal left ventricle, which presumably improves right ventricular (RV) pumping efficiency. The aim of this study was to test the hypothesis that these changes in the RV contraction pattern in infants with HLHS are present prenatally., Methods: Echocardiograms from 48 fetuses with HLHS were retrospectively compared with those from appropriately grown RV and left ventricular controls. Ventricular function was assessed using Velocity Vector Imaging velocity, tissue deformation, two-dimensional echocardiography, and Doppler flow parameters., Results: Fetuses with HLHS demonstrated reduced peak global RV longitudinal velocity (P < .01), strain (P < .001), and displacement (P < .05), while radial displacement was increased (P < .001) compared with the normal fetal right ventricle. Mean RV diameter was increased in HLHS (P < .001), but length was unchanged. The ratio of longitudinal to circumferential deformation was reduced in HLHS compared with the normal right ventricle (P < .001) and equivalent to the normal left ventricle. Tricuspid inflow peak A-wave velocity (P < .01), A-wave duration, A-wave inflow fraction, RV Tei index (P < .05 for all), and inferior vena cava A-wave reversal (P < .0001) were increased in HLHS., Conclusions: The fetal right ventricle in HLHS becomes more spherical because of increased RV diameter. It has relatively reduced longitudinal compared with circumferential deformation and an increased reliance on atrial contraction for ventricular filling. These findings are similar to postnatal changes observed in the systemic right ventricle in palliated congenital heart disease, suggesting that ventricular remodeling is initiated in fetal life., (Copyright © 2012 American Society of Echocardiography. Published by Mosby, Inc. All rights reserved.)
- Published
- 2012
- Full Text
- View/download PDF
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