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We describe the case of a newborn with congenital long QT syndrome, with 2:1 AV block and frequent episodes of Torsades de Pointes (TdP) requiring placement of a dual chamber ICD at 33 days and 3.63 kg, the youngest and smallest patient, thus far reported. Long QT syndrome was diagnosed due to bradycardia in the newborn nursery, with frequent episodes of TdP. The patient was initially treated with magnesium and esmolol then given lidocaine which resulted in dramatic transient normalization of the QTc with 1:1 AV nodal conduction. An attempt to transition to oral sodium channel and beta blockade was unsuccessful. An ICD was placed and dual chamber pacing was initiated which facilitated the transition to an oral medical regimen and ultimate discharge from the hospital. Soon after placement of the ICD, genetic testing revealed a novel F1473C mutation in the SCN5A gene. Episodes of TdP continued and left stellate gangliectomy was performed at 3 months of age. At 30 months follow-up, the patient has occasional, self-limited episodes of TdP and has received rare, successful, and appropriate ICD shocks. [ABSTRACT FROM AUTHOR]

Early spontaneous closure of a fenestration following Fontan palliation may complicate the postoperative management of such patients. The creation of a fenestration in the catheterization laboratory with an intravascular stent may improve these patients' hemodynamic status. The aim of this study is to present a new technique to reduce the diameter of stented Fontan fenestrations in those patients in whom the stent diameter is functionally made too large. [ABSTRACT FROM AUTHOR]

Medical practitioners are entrusted with the pivotal task of making optimal decisions in healthcare delivery. Despite rigorous training, our confidence in reasoning can fail when faced with pressures, uncertainties, urgencies, difficulties, and occasional errors. Day-to-day decisions rely on swift, intuitive cognitive processes known as heuristic or type 1 decision-making, which, while efficient in most scenarios, harbor inherent vulnerabilities leading to systematic errors. Cognitive biases receive limited explicit discussion during our training as junior doctors in the domain of paediatric cardiology. As pediatric cardiologists, we frequently confront emergencies necessitating rapid decision-making, while contending with the pressures of stress, fatigue, an earnest interest in "doing the right thing" and the impact of parental involvement. This article aims to describe cognitive biases in pediatric cardiology, highlighting their influence on therapeutic interventions for congenital heart disease. Whether future pediatric cardiologists or experienced professionals, understanding and actively combating cognitive biases are essential components of our ongoing medical education. Furthermore, it is our responsibility to thoroughly examine our own practices in our unwavering commitment to providing high-quality care., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2024 Padovani, Roy, Guerra, Cadeau, Ly, Vasile, Pass and Baruteau.)

Background: Right ventricular ejection fraction (RVEF) and end-diastolic volume (RVEDV) are not readily assessed through traditional modalities. Deep learning-enabled ECG analysis for estimation of right ventricular (RV) size or function is unexplored., Methods and Results: We trained a deep learning-ECG model to predict RV dilation (RVEDV >120 mL/m 2 ), RV dysfunction (RVEF ≤40%), and numerical RVEDV and RVEF from a 12-lead ECG paired with reference-standard cardiac magnetic resonance imaging volumetric measurements in UK Biobank (UKBB; n=42 938). We fine-tuned in a multicenter health system (MSH original [Mount Sinai Hospital]; n=3019) with prospective validation over 4 months (MSH validation ; n=115). We evaluated performance with area under the receiver operating characteristic curve for categorical and mean absolute error for continuous measures overall and in key subgroups. We assessed the association of RVEF prediction with transplant-free survival with Cox proportional hazards models. The prevalence of RV dysfunction for UKBB/MSH original /MSH validation cohorts was 1.0%/18.0%/15.7%, respectively. RV dysfunction model area under the receiver operating characteristic curve for UKBB/MSH original /MSH validation cohorts was 0.86/0.81/0.77, respectively. The prevalence of RV dilation for UKBB/MSH original /MSH validation cohorts was 1.6%/10.6%/4.3%. RV dilation model area under the receiver operating characteristic curve for UKBB/MSH original /MSH validation cohorts was 0.91/0.81/0.92, respectively. MSH original mean absolute error was RVEF=7.8% and RVEDV=17.6 mL/m 2 . The performance of the RVEF model was similar in key subgroups including with and without left ventricular dysfunction. Over a median follow-up of 2.3 years, predicted RVEF was associated with adjusted transplant-free survival (hazard ratio, 1.40 for each 10% decrease; P =0.031)., Conclusions: Deep learning-ECG analysis can identify significant cardiac magnetic resonance imaging RV dysfunction and dilation with good performance. Predicted RVEF is associated with clinical outcome.

Technological advancements have greatly impacted the healthcare industry, including the integration of e-health in pediatric cardiology. The use of telemedicine, mobile health applications, and electronic health records have demonstrated a significant potential to improve patient outcomes, reduce healthcare costs, and enhance the quality of care. Telemedicine provides a useful tool for remote clinics, follow-up visits, and monitoring for infants with congenital heart disease, while mobile health applications enhance patient and parents' education, medication compliance, and in some instances, remote monitoring of vital signs. Despite the benefits of e-health, there are potential limitations and challenges, such as issues related to availability, cost-effectiveness, data privacy and security, and the potential ethical, legal, and social implications of e-health interventions. In this review, we aim to highlight the current application and perspectives of e-health in the field of fetal and neonatal cardiology, including expert parents' opinions.

Background: Racial and ethnic disparities in outcomes for children with congenital heart disease (CHD) coexist with disparities in educational, environmental, and economic opportunity., Objectives: We sought to determine the associations between childhood opportunity, race/ethnicity, and pediatric CHD surgery outcomes., Methods: Pediatric Health Information System encounters aged <18 years from 2016 to 2022 with International Classification of Diseases-10th edition codes for CHD and cardiac surgery were linked to ZIP code-level Childhood Opportunity Index (COI), a score of neighborhood educational, environmental, and socioeconomic conditions. The associations of race/ethnicity and COI with in-hospital surgical death were modeled with generalized estimating equations and formal mediation analysis. Neonatal survival after discharge was modeled by Cox proportional hazards., Results: Of 54,666 encounters at 47 centers, non-Hispanic Black (Black) (OR: 1.20; P = 0.01), Asian (OR: 1.75; P < 0.001), and Other (OR: 1.50; P < 0.001) groups had increased adjusted mortality vs non-Hispanic Whites. The lowest COI quintile had increased in-hospital mortality in unadjusted and partially adjusted models (OR: 1.29; P = 0.004), but not fully adjusted models (OR: 1.14; P = 0.13). COI partially mediated the effect of race/ethnicity on in-hospital mortality between 2.6% (P = 0.64) and 16.8% (P = 0.029), depending on model specification. In neonatal multivariable survival analysis (n = 13,987; median follow-up: 0.70 years), the lowest COI quintile had poorer survival (HR: 1.21; P = 0.04)., Conclusions: Children in the lowest COI quintile are at risk for poor outcomes after CHD surgery. Disproportionally increased mortality in Black, Asian, and Other populations may be partially mediated by COI. Targeted investment in low COI neighborhoods may improve outcomes after hospital discharge. Identification of unmeasured factors to explain persistent risk attributed to race/ethnicity is an important area of future exploration., Competing Interests: Funding Support and Author Disclosures This work was supported by American Academy of Pediatrics CHANGE grant reference number 18-15592265. The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

The Fontan operation has resulted in significant improvement in survival of patients with single ventricle physiology. As a result, there is a growing population of individuals with Fontan physiology reaching adolescence and adulthood. Despite the improved survival, there are long-term morbidities associated with the Fontan operation. Pulmonary complications are common and may contribute to both circulatory and pulmonary insufficiency, leading ultimately to Fontan failure. These complications include restrictive lung disease, sleep abnormalities, plastic bronchitis, and cyanosis. Cyanosis post-Fontan procedure can be attributed to multiple causes including systemic to pulmonary venous collateral channels and pulmonary arteriovenous malformations. This review presents the unique cardiopulmonary interactions in the Fontan circulation. Understanding the cardiopulmonary interactions along with improved recognition and treatment of pulmonary abnormalities may improve the long-term outcomes in this growing patient population. Interventions focused on improving pulmonary function including inspiratory muscle training and endurance training have shown a promising effect post-Fontan procedure., Competing Interests: Funding Support and Author Disclosures The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Together, heart failure and arrhythmia represent the most important cardiovascular sources of morbidity and mortality among adults with congenital heart disease (ACHDs). Although traditionally conceptualized as operating within 2 distinct clinical silos, these scenarios frequently coexist within the same individual; consequently the mechanistic, therapeutic, and prognostic overlap between them demands increased recognition. In fact, given the near ubiquity of heart failure and arrhythmia among ACHDs, there is perhaps no other arena within cardiology where this critical intersection is more frequently observed. Optimal care for ACHDs therefore requires a heightened awareness of the relevant interactions as well as the pharmacologic and interventional resources that are increasingly available to the treating cardiologist. This review explores and highlights the overlap between these 2 fields to recommend a parallel, yet interactive, multidisciplinary approach to clinical management. Congenital heart disease categories are broken down into their archetypal subtypes to highlight subtleties of the pathophysiology, evaluation, and therapeutic approach., Competing Interests: Funding Support and Author Disclosures The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Published by Elsevier Inc.)

Background: Congenitally corrected transposition of the great arteries (ccTGA) is a rare disease of unknown cause. We aimed to better understand familial recurrence patterns., Methods: An international, multicentre, retrospective cohort study was conducted in 29 tertiary hospitals in 6 countries between 1990 and 2018, entailing investigation of 1043 unrelated ccTGA probands., Results: Laterality defects and atrioventricular block at diagnosis were observed in 29.9% and 9.3%, respectively. ccTGA was associated with primary ciliary dyskinesia in 11 patients. Parental consanguinity was noted in 3.4% cases. A congenital heart defect was diagnosed in 81 relatives from 69 families, 58% of them being first-degree relatives, including 28 siblings. The most prevalent defects in relatives were dextro-transposition of the great arteries (28.4%), laterality defects (13.6%), and ccTGA (11.1%); 36 new familial clusters were described, including 8 pedigrees with concordant familial aggregation of ccTGA, 19 pedigrees with familial co-segregation of ccTGA and dextro-transposition of the great arteries, and 9 familial co-segregation of ccTGA and laterality defects. In one family co-segregation of ccTGA, dextro-transposition of the great arteries and heterotaxy syndrome in 3 distinct relatives was found. In another family, twins both displayed ccTGA and primary ciliary dyskinesia., Conclusions: ccTGA is not always a sporadic congenital heart defect. Familial clusters as well as evidence of an association between ccTGA, dextro-transposition of the great arteries, laterality defects and in some cases primary ciliary dyskinesia, strongly suggest a common pathogenetic pathway involving laterality genes in the pathophysiology of ccTGA.

Purpose: Success rates for catheter ablation of supraventricular tachycardia (SVT) in the young exceed 90%. While studies have described reasons for initial ablation failure, less is known about outcomes of repeat ablation attempts. The purpose of this study was to report acute and mid-term success rates for second ablation attempts in young patients, as well as to analyze factors that may affect these outcomes., Methods: Retrospective single-center study of all patients undergoing a second ablation attempt for WPW (Wolff-Parkinson-White) or SVT from 2008 to 2017. Inclusion criteria are all patients < 21 years old at the time of their first ablation who underwent a second ablation attempt. An intention to treat analysis was performed., Results: Fifty-five patients met inclusion criteria, with a median age of 15 years (IQR 12-16). The most common arrhythmia mechanisms at repeat procedure were single accessory pathways (n = 32, 58%) and AVNRT (n = 14, 25%). Six patients (11%) were found to have a different SVT mechanism than at initial ablation. Acute success at repeat ablation was achieved in 48 patients (87%). At mid-term follow-up (10.5 months, IQR 0.6-25), four patients (8% of acute successes) experienced SVT recurrence. The overall success rate of repeat ablations, accounting for acute and mid-term failures, was 80%., Conclusions: In this report of 55 young patients who underwent repeat ablation for WPW and/or SVT, acute and mid-term success rates were 87% and 80%, respectively. These data may help inform decision-making when caring for patients with persistent or recurrent SVT after an initial ablation attempt.

Background: Abrupt loss of ventricular preexcitation on noninvasive evaluation, or nonpersistent preexcitation, in Wolff-Parkinson-White syndrome (WPW) is thought to indicate a low risk of life-threatening events., Objective: The purpose of this study was to compare accessory pathway (AP) characteristics and occurrences of sudden cardiac arrest (SCA) and rapidly conducted preexcited atrial fibrillation (RC-AF) in patients with nonpersistent and persistent preexcitation., Methods: Patients 21 years or younger with WPW and invasive electrophysiology study (EPS) data, SCA, or RC-AF were identified from multicenter databases. Nonpersistent preexcitation was defined as absence/sudden loss of preexcitation on electrocardiogram, Holter monitoring, or exercise stress test. RC-AF was defined as clinical preexcited atrial fibrillation with shortest preexcited R-R interval (SPERRI) ≤ 250 ms. AP effective refractory period (APERP), SPERRI at EPS , and shortest preexcited paced cycle length (SPPCL) were collected. High-risk APs were defined as APERP, SPERRI, or SPPCL ≤ 250 ms., Results: Of 1589 patients, 244 (15%) had nonpersistent preexcitation and 1345 (85%) had persistent preexcitation. There were no differences in sex (58% vs 60% male; P=.49) or age (13.3±3.6 years vs 13.1±3.9 years; P=.43) between groups. Although APERP (344±76 ms vs 312±61 ms; P<.001) and SPPCL (394±123 ms vs 317±82 ms; P<.001) were longer in nonpersistent vs persistent preexcitation, there was no difference in SPERRI at EPS (331±71 ms vs 316±73 ms; P=.15). Nonpersistent preexcitation was associated with fewer high-risk APs (13% vs 23%; P<.001) than persistent preexcitation. Of 61 patients with SCA or RC-AF, 6 (10%) had nonpersistent preexcitation (3 SCA, 3 RC-AF)., Conclusion: Nonpersistent preexcitation was associated with fewer high-risk APs, though it did not exclude the risk of SCA or RC-AF in children with WPW., (Copyright © 2020 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Objective: To assess clinical characteristics and outcomes of severe acute respiratory syndrome coronavirus 2-associated multisystem inflammatory syndrome in children (MIS-C)., Study Design: Children with MIS-C admitted to pediatric intensive care units in New York City between April 23 and May 23, 2020, were included. Demographic and clinical data were collected., Results: Of 33 children with MIS-C, the median age was 10 years; 61% were male; 45% were Hispanic/Latino; and 39% were black. Comorbidities were present in 45%. Fever (93%) and vomiting (69%) were the most common presenting symptoms. Depressed left ventricular ejection fraction was found in 63% of patients with median ejection fraction of 46.6% (IQR, 39.5-52.8). C-reactive protein, procalcitonin, d-dimer, and pro-B-type natriuretic peptide levels were elevated in all patients. For treatment, intravenous immunoglobulin was used in 18 (54%), corticosteroids in 17 (51%), tocilizumab in 12 (36%), remdesivir in 7 (21%), vasopressors in 17 (51%), mechanical ventilation in 5 (15%), extracorporeal membrane oxygenation in 1 (3%), and intra-aortic balloon pump in 1 (3%). The left ventricular ejection fraction normalized in 95% of those with a depressed ejection fraction. All patients were discharged home with median duration of pediatric intensive care unit stay of 4.7 days (IQR, 4-8 days) and a hospital stay of 7.8 days (IQR, 6.0-10.1 days). One patient (3%) died after withdrawal of care secondary to stroke while on extracorporeal membrane oxygenation., Conclusions: Critically ill children with coronavirus disease-2019-associated MIS-C have a spectrum of severity broader than described previously but still require careful supportive intensive care. Rapid, complete clinical and myocardial recovery was almost universal., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: The ability to differentiate right ventricular outflow tract (RVOT) from coronary cusp (CC) site of origin (SOO) by 12-lead ECG in pediatric patients may impact efficacy and procedural time. The objective of this study was to predict RVOT versus CC SOO by ECG in pediatric patients., Methods: Pediatric patients (<21 years) without structural heart disease with RVOT or CC premature ventricular contraction (PVC) ablations performed (2014-2018) were evaluated through multi-institution retrospective review. Demographics, ECG PVC parameters, ablation site, recurrence, and repeat procedures were collected., Results: Thirty-seven patients were evaluated (mean age 14.6 years, weight 60.6 kg): 11 CC and 26 RVOT PVC SOO. CC PVCs were less likely to exhibit left bundle branch block (64% vs 100%, P = .005), had larger R-wave amplitude in V1 (0.27 vs 0.11 mV, P = .03), larger R/S ratio in V1 (0.37 vs 0.09, P = .003), and had precordial transition in V3 or earlier (73% vs 15%, P = .002). A composite score was created with the following variables: isodiphasic or positive QRS in V1, R/S ratio in V1 > 0.05, S wave in V1 < 0.9 mV, and precordial transition at or before V3. Composite score ≥ 2 was associated with a CC SOO (OR 42.0, P = .001, and AUC 0.86)., Conclusions: 12-lead ECG of PVCs from the CC was associated with larger V1 R-wave amplitude, larger R/S ratio in V1, and precordial transition at or before V3. A composite score may help predict PVC/VT arising from the CC., (© 2020 Wiley Periodicals, Inc.)

Background: In previous pilot work we demonstrated that a novel automated signal analysis tool could accurately identify successful ablation sites during Wolff-Parkinson-White (WPW) ablation at a single center., Objective: We sought to validate and refine this signal analysis tool in a larger multi-center cohort of children with WPW., Methods: A retrospective review was performed of signal data from children with WPW who underwent ablation at two pediatric arrhythmia centers from 2008-2015. All patients with WPW ≤ 21 years who underwent invasive electrophysiology study and ablation with ablation signals available for review were included. Signals were excluded if temperature or power delivery was inadequate or lesion time was < 5 seconds. Ablation lesions were reviewed for each patient. Signals were classified as successful if there was loss of antegrade and retrograde accessory pathway (AP) conduction or unsuccessful if ablation did not eliminate AP conduction. Custom signal analysis software analyzed intracardiac electrograms for amplitudes, high and low frequency components, integrated area, and signal timing components to create a signal score. We validated the previously published signal score threshold 3.1 in this larger, more diverse cohort and explored additional scoring options. Logistic regression with lasso regularization using Youden's index criterion and a cost-benefit criterion to identify thresholds was considered as a refinement to this score., Results: 347 signals (141 successful, 206 unsuccessful) in 144 pts were analyzed [mean age 13.2 ± 3.9 years, 96 (67%) male, 66 (45%) left sided APs]. The software correctly identified the signals as successful or unsuccessful in 276/347 (80%) at a threshold of 3.1. The performance of other thresholds did not significantly improve the predictive ability. A signal score threshold of 3.1 provided the following diagnostic accuracy for distinguishing a successful from unsuccessful signal: sensitivity 83%, specificity 77%, PPV 71%, NPV 87%., Conclusions: An automated signal analysis software tool reliably distinguished successful versus unsuccessful ablation electrograms in children with WPW when validated in a large, diverse cohort. Refining the tools using an alternative threshold and statistical method did not improve the original signal score at a threshold of 3.1. This software was effective across two centers and multiple operators and may be an effective tool for ablation of WPW., Competing Interests: The authors have declared that no competing interests exist.

Purpose: Device implantation requires fluoroscopic guidance, which carries inherent risks of ionizing radiation. We evaluated the impact of a low-dose fluoroscopic protocol on radiation exposure during device implantation., Methods: All patients who underwent pacemaker or ICD implantation with new transvenous leads from July 2011 to January 2018 were included. A novel ALARA protocol consisting of ultra-low frame rates (2-3 frames/s), low dose/frame (6-18 mGy/frame), and use of the "air-gap" technique in patients < 20 kg was employed. Demographics, procedural data, and radiation exposure levels were collected and analyzed., Results: Thirty patients underwent device implantation without additional catheterization, electrophysiology study, or ablation procedure (median age 15 years; range 5-50) with a total of 43 leads placed. Forty-seven percent of patients had a primary rhythm disturbance, 33% had cardiomyopathy, and 20% had congenital heart disease. Fifty percent were pacemakers (53% dual-chamber, 27% ventricle, 20% atrial) and 50% of devices implanted were ICDs (87% single-chamber). All implants were acutely successful with acceptable atrial and ventricular sensing and capture thresholds. The median fluoroscopy time was 11.5 min (inter-quartile range (IQR) 8.0-18.2), median air kerma dose 4.0 mGy (IQR 2.5-19.5), and median dose-area product 27.8 μGy/m 2 (IQR 17.1-106.5). Median implant procedure time was 133 min. One patient required revision secondary to device migration without lead derangement 2 days post-procedure., Conclusions: Use of a novel fluoroscopic protocol may help decrease radiation exposure to patients and staff without affecting efficacy or risk. These data may represent benchmarks against which future device implantation procedures can be compared.

There are few data on the incidence of echocardiographic (echo) abnormalities following catheter ablation in children in the era of 3D mapping. Wide practice variation exists regarding routine post-ablation echo. We hypothesized a low incidence of clinically significant echo abnormalities following SVT ablation in otherwise healthy children. Single center data from 2009 to 2015 were reviewed; routine post-ablation echo was standard practice. Cases were categorized as utilizing fluoroscopy alone (FLUORO) or 3D mapping with a low fluoroscopic protocol (CARTO3). Congenital heart disease was excluded. Outcomes of interest included new valvular abnormalities, pericardial effusions, and wall motion abnormalities. Findings were compared to baseline studies when available and classified as normal/unchanged, clinically insignificant, or clinically significant. Outcomes were compared between FLUORO and CARTO3 groups. Of 347 ablations, 319 (92%) underwent post-procedural echo: 57% male; 55% FLUORO; mean age 13.4 ± 3.6 years. The most common ablation target was an accessory pathway (AP) in 66% (n = 144 WPW, 66 concealed), followed by AVNRT in 32% (n = 102). Radiofrequency (RF) energy was utilized in 82% (n = 262). Post-ablation echos were normal in 81% (n = 259). Clinically insignificant findings were seen in 18% (n = 58), most commonly trivial-small pericardial effusions in 11% (n = 34). Two significant findings required additional follow-up or treatment. There were no cases of wall motion abnormalities or clinically significant effusions. There were no differences in frequency of echo abnormalities between the FLUORO and CARTO3 groups. Clinically significant echocardiographic abnormalities are rare following SVT ablation in children with structurally normal hearts, independent of the use of 3D mapping.

Background: Axillary venous access with ultrasound guidance for pediatric transvenous lead implantation may reduce risks for pneumothorax and hemothorax. The objective was to retrospectively evaluate ultrasound-guided axillary vein access as an alternative to the subclavian approach., Methods: The technique consists of ultrasonographic identification of the axillary vein at the deltopectoral groove after initial contrast venography. A micropuncture kit is used for initial ultrasound-guided percutaneous access with fluoroscopic confirmation of wire position. Pocket creation is performed, and sheath insertion and lead implantation proceed as usual. Demographic, procedural, and radiation exposure data were collected and analyzed., Results: Sixteen patients (median age = 13 years, 8-50 years; median weight = 56 kg, 29-77 kg) underwent lead implantation; two additional patients required fluoroscopy due to poor acoustic windows (89% success). Fifteen of 21 leads (71%) were ventricular; 50% of implants were pacemakers, and 31% were dual chamber. Median time to venous access was 13 min (interquartile range (IQR) = 9.25-20.25) and median implant procedure time was 156 min (IQR = 112-172). Median fluoroscopy time was 18.0 min (IQR = 11.9-29.6), median air kerma was 9.0 mGy (IQR = 3.0-28.5), and median dose-area product was 30.2 Gy-cm 2 (IQR = 16.1-234.5). One patient required generator pocket revision 2 days postprocedure without lead dislodgement. There were no other complications encountered., Conclusions: Transvenous pacemaker and implantable cardioverter-defibrillator lead implantation in the pediatric and adult congenital population through ultrasound-guided axillary venous access is safe and efficacious. This technique may provide a low-risk alternative for vascular access for pediatric implantation procedures., (© 2018 Wiley Periodicals, Inc.)

Catheter stability, an important factor in ablation success, is affected by ventilation. Optimal ventilation strategies for pediatric catheter ablation are not known. We hypothesized that small tidal volume and positive end-expiratory pressure are associated with reduced ablation catheter movement at annular positions. Subjects aged 5-25 years undergoing ablation for supraventricular tachycardia (SVT) or WPW at two centers from March 2015 to September 2016 were prospectively enrolled and randomized to receive mechanical ventilation with either positive end-expiratory pressure of 5 cm H 2 O (PEEP) or 0 cm H 2 O (ZEEP). Movement of the ablation catheter tip at standard annular positions was measured using 3D electroanatomic mapping systems under two conditions: small tidal volume (STV) (3-5 mL/kg) or large TV (LTV) (6-8 mL/kg). 58 subjects (mean age 13.8 years) were enrolled for a total of 266 separate observations of catheter movement. STV ventilation was associated with significantly reduced catheter movement, compared to LTV at all positions (right posteroseptal: 2.5 ± 1.4 vs. 5.2 ± 3.1 mm, p < 0.0001; right lateral: 2.7 ± 1.6 vs. 6.3 ± 3.5 mm, p < 0.0001; left lateral: 1.8 ± 1.0 vs. 4.3 ± 1.9 mm, p < 0.0001). The presence or absence of PEEP had no effect on catheter movement. In multivariable analysis, STV was associated with a 3.1-mm reduction in movement (95% CI 2.6-3.5, p < 0.0001), adjusting for end-expiratory pressure, annular location, and patient size. We conclude that STV ventilation is associated with reduced ablation catheter movement compared to a LTV strategy, independent of PEEP and annular position.

Background: Interpretation of pediatric ECGs is limited by lack of accurate sex- and race-specific normal reference values obtained with modern technology for all ages. We sought to obtain contemporary digital ECG measurements in healthy children from North America, to evaluate the effects of sex and race, and to compare our results to commonly used published datasets., Methods: Digital ECGs (12-lead) were retrospectively collected for children ≤18 years old with normal echocardiograms at 19 centers in the Pediatric Heart Network. Patients were classified into 36 groups: 6 age, 2 sex, and 3 race (white, black, and other/mixed) categories. Standard intervals and amplitudes were measured; mean±SD and 2nd/98th percentiles were determined by age group, sex, and race. For each parameter, multivariable analysis, stratified by age, was conducted using sex and race as predictors. Parameters were compared with 2 large pediatric ECG data sets., Results: Among ECGs from 2400 children, significant differences were found by sex and race categories. The corrected QT interval in lead II was greater for girls compared with boys for age groups ≥3 years ( P ≤0.03) and for whites compared with blacks for age groups ≥12 years ( P <0.05). The R wave amplitude in V6 was greater for boys compared with girls for age groups ≥12 years ( P <0.001), for blacks compared with white or other race categories for age groups ≥3 years ( P ≤0.006), and greater compared with a commonly used public data set for age groups ≥12 years ( P <0.0001)., Conclusions: In this large, diverse cohort of healthy children, most ECG intervals and amplitudes varied by sex and race. These differences have important implications for interpreting pediatric ECGs in the modern era when used for diagnosis or screening, including thresholds for left ventricular hypertrophy., (© 2018 American Heart Association, Inc.)

Background: Concealed left-sided accessory pathways (CLAP) are a cause of supraventricular tachycardia (SVT) in the young. Most are mapped with right ventricular (RV) apical/outflow pacing. Rarely, alternative means of mapping are required. We review our experience from three pediatric electrophysiology (EP) centers with a rare form of "hidden" CLAP., Methods: All patients <21 years undergoing EP study from 2008 to 2014 with a "hidden" CLAP (defined as an accessory pathway [AP] for which RV pacing at cycle lengths [CL] stable for mapping did not demonstrate eccentric retrograde conduction) were included., Exclusion Criteria: preexcitation. Demographic, procedural, and follow-up data were collected., Results: A total of 23 patients met the criteria (median age, 14.3 years [range 7-21], weight, 51 kg [31-99]). 21 (96%) had SVT and one AFIB (4%). APs were adenosine sensitive in 7/20 patients (35%) and VA conduction was decremental in six (26%). CLAP conduction was demonstrable with orthodromic reentrant tachycardia in all patients, with RV extrastimulus testing in seven (30%) and with rapid RV pacing (

Background: Smaller femoral arterial sheaths may be associated with fewer vascular complications. The 3.3 Fr Mongoose ® Pediavascular pigtail catheter is a catheter that allows higher flow rates, potentially resulting in improved angiographic quality. We reviewed our experience with this small catheter during patent ductus arteriosus (PDA) closure., Materials and Methods: Review of patients ≤20 kg in whom the Mongoose ® catheter was used during PDA closure from 12/13 to 4/15. Angiographic efficacy and procedural details were compared to ten 4 Fr catheter cases. Comparisons were performed using Mann-Whitney U-test; P < 0.05 was statistically significant., Results: Twelve (9 female) patients were catheterized with a 3.3 Fr Mongoose ® . Median weight 10.5 kg (range 6.4-18.2), height 81 cm (range 37-111), and body surface area (BSA) 0.47 m 2 (range 0.33-0.75) were similar to ten patients (3 females) in the 4 Fr control group ( P = NS); median weight 9.9 kg (range 6-16.8), height 80 cm (range 64-102), and BSA 0.46 m2 (range 0.31-0.74). Angiographic quality was subjectively adequate with both with no difference in the median pixel density between the two techniques (3.3 Fr: 76.7 [range 33.5-90] and 4 Fr: [70; 38-102]; P = NS). Contrast used was similar between the groups (3.3 Fr: median 4.2 ml/kg and 4 Fr: 4.9 ml/kg; P = NS). Median radiation dose was similar in the two groups (3.3 Fr: 28.1 mGy [range 17.2-38] and 4 Fr: 38 mGy [range 20.4-58.5]; P = NS). All ducts were closed at latest follow-up ( P = NS). No complications were encountered., Conclusions: The 3.3 Fr Mongoose ® allowed similar angiography to the 4 Fr pigtail catheter, allowing safe and effective transcatheter PDA closure in small children., Competing Interests: There are no conflicts of interest.

Background: Secundum atrial septal defects (ASDs) are treated by surgical closure (SC) or transcatheter device closure (TCC). Due to a scarcity of data directly comparing these approaches, it remains unclear which is superior. This meta-analysis compares the clinical outcomes of the two treatment options., Methods: A literature search was performed in MEDLINE, Embase, PubMed, Google Search, and Cochrane databases for studies directly comparing SC and TCC of ASDs. Outcomes studied were major and minor acute complications, all-cause mortality, residual shunt, reinterventions, and length of stay (LOS). Relative risk (RR), difference in mean (DM) and 95% confidence intervals (CI) were calculated using the Mantel-Haenszel method with a fixed effect model. In cases of heterogeneity (defined as I 2 >25%), random effect models were used. Sensitivity and meta-regression analyses were performed for each outcome., Results: Of the 1742 manuscripts screened, 26 observational studies fulfilled the inclusion criteria (total n=14,559 patients). TCC was superior to SC for the following outcomes: all-cause mortality (RR, 0.66; 95% CI 0.64-0.99), total complications (RR, 0.48; 95% CI 0.35-0.65), major complications (RR, 0.57; 95% CI 0.40-0.81), minor complications (RR, 0.35; 95% CI 0.23-0.53), and LOS (DM, -2.92; 95% CI -3.25 to (-2.58)). Residual shunts were more common with TCC (RR, 3.35; 95% CI 1.72-6.51). No difference was observed regarding the need of reintervention (RR, 1.45; 95% CI 0.60-3.51). Meta-regression analysis showed that older age increases the risk of death and complications in patients undergoing TCC., Conclusions: Though both approaches are effective, TCC is associated with lower mortality, complications, and LOS while SC has a lower rate of residual shunting., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Background: Ablation within the aortic cusp is safe and effective in adults. There are little data on aortic cusp ablation in the pediatric literature. We investigated the safety and efficacy of aortic cusp ablation in young patients., Methods: A retrospective, descriptive study of aortic cusp ablation in five pediatric electrophysiology centers from 2008 to 2014 was performed. All patients <21 years of age who underwent ablation in the aortic cusps were included. Factors analyzed included patient demographics, procedural details, outcomes, and complications., Results: Thirteen patients met inclusion criteria (median age 16 years [range 10-20.5] and median body surface area 1.58 m 2 [range 1.12-2.33]). Substrates for ablation included: nine premature ventricular contractions or sustained ventricular tachycardia (69%), two concealed anteroseptal accessory pathways (APs) (15%), one Wolff-Parkinson-White with an anteroseptal AP (8%), and one ectopic atrial tachycardia (8%). Three-dimensional electroanatomic mapping in combination with fluoroscopy was used in 12/13 (92%) patients. Standard 4-mm-tip radiofrequency (RF) current was used in 11/13 (85%) and low-power irrigated-tip RF in 2/13 (15%). Angiography was used in 13/13 and intracardiac echocardiography was additionally utilized in 3/13 (23%). Ablation locations included: eight noncoronary (62%), three left (23%), and two right (15%) cusps. Ablation was acutely successful in all patients. At median follow-up of 20 months, there was one recurrence of PVCs (8%). There were no ablation-related complications and no valvular injuries observed., Conclusion: Arrhythmias originating from the coronary cusps in this series were successfully and safely ablated in young people without injury to the coronary arteries or the aortic valve., (© 2017 Wiley Periodicals, Inc.)

Unlabelled: Atrioventricular block is classified as congenital if diagnosed in utero, at birth, or within the first month of life. The pathophysiological process is believed to be due to immune-mediated injury of the conduction system, which occurs as a result of transplacental passage of maternal anti-SSA/Ro-SSB/La antibodies. Childhood atrioventricular block is therefore diagnosed between the first month and the 18th year of life. Genetic variants in multiple genes have been described to date in the pathogenesis of inherited progressive cardiac conduction disorders. Indications and techniques of cardiac pacing have also evolved to allow safe permanent cardiac pacing in almost all patients, including those with structural heart abnormalities., Conclusion: Early diagnosis and appropriate management are critical in many cases in order to prevent sudden death, and this review critically assesses our current understanding of the pathogenetic mechanisms, clinical course, and optimal management of congenital and childhood AV block., What Is Known: • Prevalence of congenital heart block of 1 per 15,000 to 20,000 live births. AV block is defined as congenital if diagnosed in utero, at birth, or within the first month of life, whereas childhood AV block is diagnosed between the first month and the 18th year of life. As a result of several different etiologies, congenital and childhood atrioventricular block may occur in an entirely structurally normal heart or in association with concomitant congenital heart disease. Cardiac pacing is indicated in symptomatic patients and has several prophylactic indications in asymptomatic patients to prevent sudden death. • Autoimmune, congenital AV block is associated with a high neonatal mortality rate and development of dilated cardiomyopathy in 5 to 30 % cases. What is New: • Several genes including SCN5A have been implicated in autosomal dominant forms of familial progressive cardiac conduction disorders. • Leadless pacemaker technology and gene therapy for biological pacing are promising research fields. In utero percutaneous pacing appears to be at high risk and needs further development before it can be adopted into routine clinical practice. Cardiac resynchronization therapy is of proven value in case of pacing-induced cardiomyopathy., Competing Interests: Compliance with ethical standards Financial disclosure None of the authors has any financial relationships relevant to this article to disclose. Conflict of interest The authors declare that they have no conflict of interest. Funding None. Ethical approval This article does not contain any studies with human participants or animals performed by any of the authors.

Background: Sudden cardiac death is a major contributor to mortality for adults with congenital heart disease. The subcutaneous implantable cardioverter-defibrillator (ICD) has emerged as a novel tool for prevention of sudden cardiac death, but clinical performance data for adults with congenital heart disease are limited., Methods and Results: A retrospective study involving 7 centers over a 5-year period beginning in 2011 was performed. Twenty-one patients (median 33.9 years) were identified. The most common diagnosis was single ventricle physiology (52%), 9 palliated by Fontan operation and 2 by aortopulmonary shunts: d-transposition of the great arteries after Mustard/Senning (n=2), tetralogy of Fallot (n=2), aortic valve disease (n=2), and other biventricular surgery (n=4). A prior cardiac device had been implanted in 7 (33%). The ICD indication was primary prevention in 67% and secondary in 33% patients. The most common reason for subcutaneous ICD placement was limited transvenous access for ventricular lead placement (n=10) followed by intracardiac right-to-left shunt (n=5). Ventricular arrhythmia was induced in 17 (81%) and was converted with ≤80 Joules in all. There was one implant complication related to infection, not requiring device removal. Over a median follow-up of 14 months, 4 patients (21%) received inappropriate and 1 (5%) patient received appropriate shocks. There was one arrhythmic death related to asystole in a single ventricle patient., Conclusions: Subcutaneous ICD implantation is feasible for adults with congenital heart disease patients. Most candidates have single ventricle heart disease and limited transvenous options for ICD placement. Despite variable anatomy, this study demonstrates successful conversion of induced ventricular arrhythmia and reasonable rhythm discrimination during follow-up., (© 2016 American Heart Association, Inc.)

Background: Cardiac catheterizations expose both the patient and staff to the risks of ionizing radiation. Studies using the "air gap" technique (AGT) in various radiological procedures indicate that its use leads to reduction in radiation exposure but there are no data on its use for pediatric cardiac catheterization. The aim of this study was to retrospectively review the radiation exposure data for children weighing <20 kg during cardiac catheterizations using AGT and an "as low as reasonably achievable (ALARA)" radiation reduction protocol., Patients and Methods: All patients weighing <20 kg who underwent cardiac catheterization at the Children's Hospital at Montefiore (CHAM), New York, the United States from 05/2011 to 10/2013 were included. Transplant patients who underwent routine endomyocardial biopsy and those who had surgical procedures at the time of the catheterizations were excluded. The ALARA protocol was used in concert with AGT with the flat panel detector positioned 110 cm from the patient. Demographics, procedural data, and patient radiation exposure levels were collected and analyzed., Results: One-hundred and twenty-seven patients underwent 151 procedures within the study period. The median age was 1.2 years (range: 1 day to 7.9 years) and median weight was 8.8 kg (range: 1.9-19.7). Eighty-nine (59%) of the procedures were interventional. The median total fluoro time was 13 min [interquartile range (IQR) 7.3-21.8]. The median total air Kerma (K) product was 55.6 mGy (IQR 17.6-94.2) and dose area product (DAP) was 189 Gym2 (IQR 62.6-425.5)., Conclusion: Use of a novel ALARA and AGT protocol for cardiac catheterizations in children markedly reduced radiation exposure to levels far below recently reported values., Abbreviations: AGT: Air gap technique, ALARA: As low as reasonably achievable.

Background: CARTO3 is frequently used during ablation but is not designed to allow visualization of non-CARTO3 ablation catheters. We describe how cryoablation catheters can be visualized and recorded using CARTO3 with minimal fluoroscopy (FLUORO) usage., Methods: Retrospective review of patients ≤21 years undergoing cryoablation with CARTO3 from 2010 to 2013 for ablation of supraventricular tachycardia. After mapping with a Navistar catheter, the Navistar was removed and a cryocatheter was utilized. The cryocatheter was connected to the pin box via a jumper cable and the pin box was connected to the CARTO3 patient interface unit. Locations of ablation attempts with the cryocatheter were recorded with the "Create Snapshot" tool. Clinical characteristics and radiation doses were compared between patients undergoing cryoablation (cryoenergy [CRYO]) to an age- and diagnosis-matched control group (CONTROL) undergoing RF ablation., Results: A total of 174 ablations were performed and 14 patients underwent cryoablation (CRYO, 13.3 ± 4.7 years, weight 42 ± 14 kg). Indications for cryoablation were: five atrioventricular nodal reentry tachycardia (36%), four ectopic atrial tachycardia (29%), three concealed accessory pathways (21%), and two Wolff-Parkinson-White syndromes (14%). Acute success was achieved in all patients (100%) with no complications and one recurrence (7%). The site of successful cryoablation was successfully recorded on the CARTO3 system in all cases. Radiation doses were low and not different from an age-, era-, and diagnosis-matched control group undergoing RF ablation (CRYO 3.2 ± 0.8 mGy vs CONTROL 1.6 ± 0.4 mGy, P = 0.07)., Conclusions: Though a "closed" system, CARTO3 can be "tricked" to allow for the use of cryoablation, allowing clear catheter visualization, mapping, and recording of ablation lesions with minimal FLUORO usage., (©2015 Wiley Periodicals, Inc.)

Purpose: To compare the efficacy, safety, and cost-effectiveness of a three-catheter approach with a conventional five-catheter approach for the mapping and ablation of supraventricular tachycardia in pediatric patients with Wolff-Parkinson-White Syndrome (WPW) and concealed accessory pathways (APs)., Methods: A retrospective review from 2008 to 2012 of patients less than 21 years with WPW who underwent a three-catheter radiofrequency (RF) ablation of a left-sided AP (ablation, right ventricular [RV] apical, and coronary sinus [CS] decapolar catheters) was performed. The three-catheter group was compared to a control group who underwent a standard five-catheter (ablation, RV apical, CS decapolar, His catheter, and right atrial catheter) ablation for the treatment of left-sided WPW or concealed AP. Demographics, ablation outcomes, and costs were compared between groups., Results: Twenty-eight patients met inclusion criteria with 28 control patients. The groups did not differ in gender, age, weight, or body surface area. Locations of the AP on the mitral annulus were similar between the groups. All patients were ablated via transseptal approach. Note that 28 of 28 in the three-catheter group (100%) and 27 of 28 (96%) controls were acutely successfully ablated (P = 0.31). No complications were encountered. There was no difference in procedural time, time to loss of AP conduction, or number of RF applications. Use of the three-catheter technique resulted in a total savings of $2,465/case, which includes the $680 savings from using fewer catheters as well as the savings from a shortened procedure time., Conclusions: Ablation in patients with WPW and a left-sided AP can be performed using three catheters with similar efficacy and safety while offering significant cost savings compared to a conventional five-catheter approach., (© 2015 Wiley Periodicals, Inc.)

Background: "ALARA--As Low As Reasonably Achievable" protocols reduce patient radiation dose. Addition of electroanatomical mapping may further reduce dose., Methods: From 6/11 to 4/12, a novel ALARA protocol was utilised for all patients undergoing supraventricular tachycardia ablation, including low frame rates (2-3 frames/second), low fluoro dose/frame (6-18 nGy/frame), and other techniques to reduce fluoroscopy (ALARA). From 6/12 to 3/13, use of CARTO® 3 (C3) with "fast anatomical mapping" (ALARA+C3) was added to the ALARA protocol. Intravascular echo was not utilised. Demographics, procedural, and radiation data were analysed and compared between the two protocols., Results: A total of 75 patients were included: 42 ALARA patients, and 33 ALARA+C3 patients. Patient demographics were similar between the two groups. The acute success rate in ALARA was 95%, and 100% in ALARA+C3; no catheterisation-related complications were observed. Procedural time was 125.7 minutes in the ALARA group versus 131.4 in ALARA+C3 (p=0.36). Radiation doses were significantly lower in the ALARA+C3 group with a mean air Kerma in ALARA+C3 of 13.1±28.3 mGy (SD) compared with 93.8±112 mGy in ALARA (p<0.001). Mean dose area product was 92.2±179 uGym2 in ALARA+C3 compared with 584±687 uGym2 in ALARA (p<0.001). Of the 33 subjects (42%) in the ALARA+C3 group, 14 received ⩽1 mGy exposure. The ALARA+C3 dosages are the lowest reported for a combined electroanatomical-fluoroscopy technique., Conclusions: Addition of CARTO® 3 to ALARA protocols markedly reduced radiation exposure to young people undergoing supraventricular tachycardia ablation while allowing for equivalent procedural efficacy and safety.

Introduction: Three-dimensional mapping (3-D) systems are frequently used for ablation of supraventricular tachycardia. Prior studies have demonstrated radiation dosage reduction with 3-D, but there are no data on whether 3-D improves the efficacy of ablation of Wolff-Parkinson-White syndrome (WPW). We sought to determine if 3-D improves the success rate for ablation of WPW in children., Methods: Multicenter retrospective study including patients ≤21 years of age with WPW undergoing ablation from 2008 to 2012. Success rates using the 2 techniques (3-D vs. fluoroscopy alone [FLUORO]) were compared., Results: Six hundred and fifty-one cases were included (58% male, mean age 13 ± 4 years, 366 [56%] 3-D). Baseline characteristics including gender, weight, accessory pathway (AP) location, number of APs, and repeat ablation attempts were similar between the 2 groups (3-D and FLUORO) The 3-D group was slightly younger (12.7 ± 4.0 vs. 13.3 ± 4.0 years; P = 0.04) and less likely to undergo ablation utilizing cryoenergy (38 [10%] vs. 56 [20%]; P < 0.01). The 3-D group had a higher acute success rate of ablation (355 [97%] vs. 260 [91%]; P < 0.01). No differences were seen in recurrence (16 [5%] vs. 26 [9%]; P = 0.09) or complication rates (1 [0.3%] vs. 1 [0.4%]; P = 0.86) between the groups. On multivariable analysis, 3-D was shown to significantly improve success at ablation with an odds ratio of 3.1 (95% CI 1.44-6.72; P < 0.01)., Conclusions: Use of 3-D significantly improved success rates for ablation of WPW in children. The increase in acute success associated with 3-D suggests it is an important adjunct for catheter ablation of WPW in children., (© 2015 Wiley Periodicals, Inc.)

Exercise testing is commonly performed in children for evaluation of cardiac disease. Few data exist, however, on the prevalence, types of arrhythmias, predictors for arrhythmias, and safety of exercise testing in children. A retrospective review of all patients ≤21 years undergoing exercise testing at our center from 2008 to 2012 was performed. Patients with clinically relevant arrhythmias were compared to those not experiencing a significant arrhythmia. 1,037 tests were performed in 916 patients. The mean age was 14 ± 4 years, 537 (55 %) were male, 281 (27 %) had congenital heart disease, 178 (17 %) had a history of a prior arrhythmia, and 17 (2 %) had a pacemaker or ICD. 291 (28 %) patients had a rhythm disturbance during the procedure. Clinically important arrhythmias were noted in 34 (3 %) patients and included: 19 (1.8 %) increasing ectopy with exercise, 5 (0.5 %) VT, 5 (0.5 %) second degree AV block, 3 (0.3 %) SVT, and 2 (0.2 %) AFIB. On multivariate logistic regression, variables associated with the development of clinically relevant arrhythmias included severe left ventricular (LV) dysfunction on echo (OR 1.99, CI 1.20-3.30) and prior history of a documented arrhythmia (OR 2.94, CI 1.25-6.88). There were no adverse events related to testing with no patient requiring cardioversion, defibrillation, or acute anti-arrhythmic therapy. A total of 28 % of children developed a rhythm disturbance during exercise testing and 3 % were clinically important. Severe LV dysfunction and a history of documented arrhythmia were associated with the development of a clinically important arrhythmia.

Background. The use of digital ECG software and services is becoming common. We hypothesized that the introduction of a completely digital ECG system would increase the volume of ECGs interpreted at our children's hospital. Methods. As part of a hospital wide quality improvement initiative, a digital ECG service (MUSE, GE) was implemented at the Children's Hospital at Montefiore in June 2012. The total volume of ECGs performed in the first 6 months of the digital ECG era was compared to 18 months of the predigital era. Predigital and postdigital data were compared via t-tests. Results. The mean ECGs interpreted per month were 53 ± 16 in the predigital era and 216 ± 37 in the postdigital era (p < 0.001), a fourfold increase in ECG volume after introduction of the digital system. There was no significant change in inpatient or outpatient service volume during that time. The mean billing time decreased from 21 ± 27 days in the postdigital era to 12 ± 5 days in the postdigital era (p < 0.001). Conclusion. Implementation of a digital ECG system increased the volume of ECGs officially interpreted and reported.

Introduction: There are little data on the effect of catheter position and mechanical ventilation on ablation catheter stability during electrophysiology study in children. We sought to determine the magnitude of catheter movement with mechanical ventilation, the effect of ventilation maneuvers on catheter movement, and to compare the degree of movement observed between the right lateral (RL) and right posteroseptal (RPS) regions., Methods: From June 2012 to June 2013, patients ≤ 21 years of age undergoing ablation for supraventricular tachycardia with CARTO® 3 (Biosense Webster, Diamond Bar, CA, USA) were included. During mapping the ablation catheter was placed in the RPS and RL regions and the magnitude of catheter movement (mm) was measured using CARTO® 3. Measurements were made during routine ventilation and with a maximal inspiration maneuver between end-expiration (ENDEX) and peak-inspiration (PEAKINS)., Results: Twenty-one patients were included: 12 males (57%), age 13 ± 3 years, weight 55 ± 14 kg. Indications for ablation were: 10 Wolff-Parkinson-White, seven atrioventricular node re-entry tachycardia, four concealed accessory pathway. Mechanical ventilation was used in all cases. The magnitude of catheter movement was 3.6 ± 1.7 mm with routine ventilation and 6.2 ± 4.1 mm between ENDEX and PEAKINS (P ≤ 0.01). Catheter movement was greater in the RL compared to the RPS region with routine ventilation (RL 4.3 ± 1.6 vs RPS 3.0 ± 1.5; P < 0.01) and between ENDEX and PEAKINS (RL 8.3 ± 4.7 vs RPS 4.0 ± 1.7; P < 0.01)., Conclusions: Ventilation and catheter position both have significant impact on the degree of catheter movement during ablation. Movement was greatest in the RL position. This may partially explain the lower success rates of ablation in the RL region., (©2014 Wiley Periodicals, Inc.)

After heart transplantation (HT) in infants and young children, environmental and intrinsic factors may lead to changes in the geometry and compliance of the donor heart. Serial demographic, clinical, hemodynamic, and echocardiographic data were obtained from HT recipients younger than 4 years of age. Echocardiographic chamber measurement z-scores were compared using recipient body surface area from the time of HT to 1 week, 3 months, and last follow-up visit. Left ventricular end-diastolic volume (LVEDV) z-scores were correlated with pulmonary capillary wedge pressure (PCWP) at each time point. Heart transplantation was performed for 13 children between March 2009 and December 2012, 9 of whom (69%) were boys. The median age at HT was 8 months (range, 4-43 months), and the mean follow-up period was 13 ± 7 months. Left ventricular end-diastolic dimension z-scores decreased significantly (p = 0.03) between HT and 1 week, then increased from 1 week to 3 and 12 months. (-1.32 ± 1.7, -0.71 ± 1.8, 0.41 ± 2.1, 0.79 ± 2.3, respectively). A positive relationship (R(2) = 0.48) between the LVEDV z-score and PCPW was present at the last follow-up visit. For infants and young children, the allograft demonstrates appropriate growth by 1 year after HT. Left ventricular compliance improves over time.

Right pulmonary artery (RPA) stenosis following Waterston shunt is common. We report a case of RPA stenosis many years following tetralogy of Fallot repair with take-down of a Waterston shunt and demonstrate an unusual and important anatomic variant of proximity of the left coronary artery to the mid-portion of the RPA., (Copyright © 2013 Wiley Periodicals, Inc.)

Background: Surveillance endomyocardial biopsy (EMB) with right heart catheterization (RHC) is the standard of care for the assessment of post cardiac transplantation rejection. This procedure has traditionally relied upon fluoroscopy, which exposes both patient and staff to the risks of ionizing radiation. These risks may be of particular concern in the transplant patient who must undergo many such procedures lifelong. We present data on a new "ALARA - As Low As Reasonably Achievable" protocol to reduce radiation exposure during the performance of RHC with EMB., Methods: All cardiac transplantation patients < 21 years of age who underwent RHC with EMB at The Children's Hospital at Montefiore from 6/11-12/11 were included. EMB was performed after all right heart pressures including wedge pressure and thermodilution cardiac output were measured. A novel ALARA protocol consisting of multiple features including ultra-low frame rates (2-3 fps), low fluoro dose/frame (10-18 nGy/frame), use of the "air-gap" technique for patients < 20 kg, and multiple other techniques aimed at minimizing use of fluoroscopy were employed in all cases. Demographics, procedural data and patient radiation exposure levels were collected and analyzed., Results: 18 patients underwent 45 surveillance RHC with EMB in the study period and were the subject of this analysis. The mean age was 5.9 ± 6.1 years, weight was 20.4 kg ± 16.6 kg, and BSA was 0.75 ± 45 m(2) . PA fluoroscopy was used exclusively in 45/45. Vascular access was RFV (21/45; 47%), RIJV (17/45; 38%), LFV (4/45; 9%) and LIJV (3/45; 7%). The median number of EMB specimens obtained was 5 (range, 4-7). The median fluoroscopy time was 3.7 min (range, 1.2-9). The median air Kerma product (K) was 1.4 mGy (range, 0.4-14), and dose area product (DAP) was 15.8 uGym(2) (range, 3.5-144.5). The K and DAP are substantially lower than any prior published data for RHC/EMB in this patient group. There were no procedural complications., Conclusions: The use of a novel ALARA protocol for RHC and EMB in pediatric cardiac transplantation patients markedly reduced radiation exposure to levels far below any previously reported values without negatively affecting the safety or efficacy of these procedures., (Copyright © 2013 Wiley Periodicals, Inc.)

Background: Ablation for supraventricular tachycardia (SVT) relies upon fluoroscopy (fluoro), which exposes the patient and staff to ionizing radiation. The objective of this work was to present a new "ALARA--As Low As Reasonably Achievable" protocol with alterations to fluoroscopic x-ray parameters to reduce dose without an electroanatomical (EAM) approach., Methods: All patients <21 years of age undergoing ablation of SVT at our institution from June 2011 to April 2012 were included. EAM was not utilized in any case. An ALARA protocol of low frame rates (2 or 3 fps), low fluoro dose/frame (10-18 nGy/frame), and other techniques aimed at reducing use of fluoroscopy were employed. Demographics, procedural, and radiation data were analyzed., Results: Forty-two patients underwent ablation and were studied. Median age was 14.1 years (range 4.8-21.1 years), weight was 51 kg (range 18.2-75 kg), and body surface area was 1.51 m(2) (range 0.72- 1.94 m(2)). Seventeen (41%) had Wolff-Parkinson-White syndrome, 14 (33%) atrioventricular nodal reentrant tachycardia, and 11 (26%) concealed pathways. Median procedural time was 114 minutes (57-246 minutes). Median dose area product (DAP) for posterioanterior and lateral fluoroscopy was 343.2 uGym(2) (range 38.2-3,172 uGym(2)); the median air Kerma product (K) was 45.4 mGy (range 6.7-567.5 mGy). DAP and K are lower than prior data from EAM and fluoroscopy techniques. The acute success rate was 95%; no procedural complications., Conclusions: An ALARA protocol for ablation of SVT reduced radiation to below levels previously reported for combined EAM/fluoro approaches. Success rates were excellent with no complications and without the costs of EAM., (©2013, The Authors. Journal compilation ©2013 Wiley Periodicals, Inc.)

Right ventricular to pulmonary artery conduit tear after balloon dilation is a recognized potential complication, which can, in theory, be treated with a covered stent. We describe use of the Melody™ valve as a so-called "covered" stent for containment of bleeding from RV-PA conduit tear., (Copyright © 2013 Wiley Periodicals, Inc.)

Objectives: The aim of this study was to determine the efficacy of implantable cardioverter-defibrillators (ICDs) in children and adolescents with hypertrophic cardiomyopathy (HCM)., Background: HCM is the most common cause of sudden death in the young. The availability of ICDs over the past decade for HCM has demonstrated the potential for sudden death prevention, predominantly in adult patients., Methods: A multicenter international registry of ICDs implanted (1987 to 2011) in 224 unrelated children and adolescents with HCM judged at high risk for sudden death was assembled. Patients received ICDs for primary (n = 188) or secondary (n = 36) prevention after undergoing evaluation at 22 referral and nonreferral institutions in the United States, Canada, Europe, and Australia., Results: Defibrillators were activated appropriately to terminate ventricular tachycardia or ventricular fibrillation in 43 of 224 patients (19%) over a mean of 4.3 ± 3.3 years. ICD intervention rates were 4.5% per year overall, 14.0% per year for secondary prevention after cardiac arrest, and 3.1% per year for primary prevention on the basis of risk factors (5-year cumulative probability 17%). The mean time from implantation to first appropriate discharge was 2.9 ± 2.7 years (range to 8.6 years). The primary prevention discharge rate terminating ventricular tachycardia or ventricular fibrillation was the same in patients who underwent implantation for 1, 2, or ≥3 risk factors (12 of 88 [14%], 10 of 71 [14%], and 4 of 29 [14%], respectively, p = 1.00). Extreme left ventricular hypertrophy was the most common risk factor present (alone or in combination with other markers) in patients experiencing primary prevention interventions (17 of 26 [65%]). ICD-related complications, particularly inappropriate shocks and lead malfunction, occurred in 91 patients (41%) at 17 ± 5 years of age., Conclusions: In a high-risk pediatric HCM cohort, ICD interventions terminating life-threatening ventricular tachyarrhythmias were frequent. Extreme left ventricular hypertrophy was most frequently associated with appropriate interventions. The rate of device complications adds a measure of complexity to ICD decisions in this age group., (Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objective: To determine if pediatric patients with a history of lone atrial fibrillation (AF) have other forms of supraventricular tachycardia (SVT) that may potentially trigger AF., Study Design: A multicenter review of patients with lone AF who underwent electrophysiology (EP) study from 2006-2011 was performed., Inclusion Criteria: age ≤21 years, normal ventricular function, structurally normal heart, history of AF, and EP study and/or ablation performed., Exclusion Criteria: congenital heart disease or cardiomyopathy. Patient demographics, findings at EP study and follow-up data were recorded., Results: Eighteen patients met inclusion criteria. The mean age was 17.9 ± 2.2 years, weight was 82 ± 21 kg, body mass index was 27 ± 6, and 15 (83%) were males. Eleven (61%) were overweight or obese. Seven (39%) had inducible SVT during EP study: 5 atrioventricular nodal re-entry tachycardia (71%) and 2 concealed accessory pathways with inducible atrioventricular re-entry tachycardia (29%). All 7 patients with inducible SVT underwent radiofrequency ablation. There were no complications during EP study and/or ablation for all 18 patients. The mean follow-up was 1.7 ± 1.5 years and there were no recurrences in the 7 patients who underwent ablation. There were 2 recurrences of AF in patients with no other form of SVT during EP study., Conclusions: Inducible SVT was found in 39% of pediatric patients undergoing EP study for lone AF. EP study should be considered for pediatric patients presenting with lone AF., (Copyright © 2013 Mosby, Inc. All rights reserved.)