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Aims Longitudinal dyssynchrony correction and 'strain' improvement by comparable cardiac resynchronization therapy (CRT) techniques is unreported. Our purpose was to compare echocardiographic dyssynchrony correction and 'strain' improvement by conduction system pacing (CSP) vs. biventricular pacing (BiVP) as a marker of contractility improvement during 1-year follow-up. Methods and results A treatment-received analysis was performed in patients included in the LEVEL-AT trial (NCT04054895), randomized to CSP or BiVP, and evaluated at baseline (ON and OFF programming) and at 6 and 12 months (n = 69, 32% women). Analysis included intraventricular (septal flash), interventricular (difference between left and right ventricular outflow times), and atrioventricular (diastolic filling time) dyssynchrony and 'strain' parameters [septal rebound, global longitudinal 'strain' (GLS), LBBB pattern, and mechanical dispersion). Baseline left ventricular ejection fraction (LVEF) was 27.5 ± 7%, and LV end-systolic volume (LVESV) was 138 ± 77 mL, without differences between groups. Longitudinal analysis showed LVEF and LVESV improvement (P < 0.001), without between-group differences. At 12-month follow-up, adjusted mean LVEF was 46% with CSP (95% CI 42.2 and 49.3%) vs. 43% with BiVP (95% CI 39.6 and 45.8%), (P = 0.31), and LVESV was 80 mL (95% CI 55.3 and 104.5 mL) vs. 100 mL (95% CI 78.7 and 121.6 mL), respectively (P = 0.66). Longitudinal analysis showed a significant improvement of all dyssynchrony parameters and GLS over time (P < 0.001), without differences between groups. Baseline GLS significantly correlated with LVEF and LVESV at 12-month follow-up. Conclusion CSP and BiVP provided similar dyssynchrony and 'strain' correction over time. Baseline global longitudinal 'strain' predicted ventricular remodelling at 12-month follow-up. [ABSTRACT FROM AUTHOR]

Non-ischemic dilated cardiomyopathy (DCM) represents a significant cause of heart failure, defined as the presence of left ventricular (LV) dilatation and systolic dysfunction unexplained solely by abnormal loading conditions or coronary artery disease. Cardiac resynchronization therapy (CRT) has emerged as a cornerstone in the management of heart failure, particularly in patients with DCM. However, identifying patients who will benefit the most from CRT remains challenging. Speckle tracking echocardiography (STE) has garnered attention as a non-invasive imaging modality that allows for the quantitative assessment of myocardial mechanics, offering insights into LV function beyond traditional echocardiographic parameters. This comprehensive review explores the role of STE in guiding patient selection and optimizing outcomes in CRT for DCM. By assessing parameters such as LV strain, strain rate, and dyssynchrony, STE enables a more precise evaluation of myocardial function and mechanical dyssynchrony, aiding in the identification of patients who are most likely to benefit from CRT. Furthermore, STE provides valuable prognostic information and facilitates post-CRT optimization by guiding lead placement and assessing response to therapy. Through an integration of STE with CRT, clinicians can enhance patient selection, improve procedural success rates, and ultimately, optimize clinical outcomes in patients with DCM. This review underscores the pivotal role of STE in advancing personalized management strategies for DCM patients undergoing CRT. [ABSTRACT FROM AUTHOR]

Single ventricle patients, including those with hypoplastic left heart syndrome (HLHS), typically undergo three palliative heart surgeries culminating in the Fontan procedure. HLHS is associated with high rates of morbidity and mortality, and many patients develop arrhythmias, electrical dyssynchrony, and eventually ventricular failure. However, the correlation between ventricular enlargement and electrical dysfunction in HLHS physiology remains poorly understood. Here we characterize the relationship between growth and electrophysiology in HLHS using computational modeling. We integrate a personalized finite element model, a volumetric growth model, and a personalized electrophysiology model to perform controlled in silico experiments. We show that right ventricle enlargement negatively affects QRS duration and interventricular dyssynchrony. Conversely, left ventricle enlargement can partially compensate for this dyssynchrony. These findings have potential implications on our understanding of the origins of electrical dyssynchrony and, ultimately, the treatment of HLHS patients. [ABSTRACT FROM AUTHOR]

Cardiac conduction involves electrical activity from one myocyte to another, creating coordinated contractions in each. Disruptions in the conducting system, such as left bundle branch block (LBBB), can result in premature activation of specific regions of the heart, leading to heart failure and increased morbidity and mortality. Structural alterations in T-tubules and the sarcoplasmic reticulum can lead to dyssynchrony, a condition that can be treated by cardiac resynchronization therapy (CRT), which stands as a cornerstone in this pathology. The heterogeneity in patient responses underscored the necessity of improving the diagnostic approach. Vectocardiography, ultra-high-frequency ECG, 3D echocardiography, and electrocardiographic imaging seem to offer advanced precision in identifying optimal candidates for CRT in addition to the classic diagnostic methods. The advent of His bundle pacing and left bundle branch pacing further refined the approach in the treatment of dyssynchrony, offering more physiological pacing modalities that promise enhanced outcomes by maintaining or restoring the natural sequence of ventricular activation. HOT-CRT emerges as a pivotal innovation combining the benefits of CRT with the precision of His bundle or left bundle branch area pacing to optimize cardiac function in a subset of patients where traditional CRT might fall short. [ABSTRACT FROM AUTHOR]

This article discusses the potential harm caused by patient-ventilator interactions (PVIs) in patients receiving mechanical ventilation for acute hypoxemic respiratory failure. The authors conducted a study to assess the association between different types of breaths and surrogate markers of lung strain, stress, and mechanical power. They found that certain abnormal PVIs, such as double-triggered and flow-limited breaths, had the strongest potential to increase markers of lung stress and strain. However, there are limitations to the study, including the use of surrogate markers and the specific mode of ventilation used. Further research is needed to understand the impact of these interactions on clinical outcomes. [Extracted from the article]

The author, inspired by Anni Bergman's work with an autistic child, describes a single play session in her work with a neurodiverse child. In this session, the first session following a missed appointment, the analyst attempts to "make sense out of nonsense" by choosing the child's words she hopes to use as building blocks for a coherent narrative about separation and reunion, while passing over the words she finds unintelligible. A microanalysis of the analytic process reveals themes of dyssynchrony, surprise, and multiple perspectives. Using these themes to organize the meanings she takes from the verbal and nonverbal exchange in the session, she concludes that the experience of working with this – and other – neurodiverse patients offers the analyst a unique opportunity to challenge the usefulness of their clinical theories and to embrace a greater complexity. In doing so, the analyst is able to appreciate the essence of "co-creative meaning-making." [ABSTRACT FROM AUTHOR]

Aims Non-invasive left ventricular (LV) pressure–strain loops provide a novel method for quantifying myocardial work by incorporating LV pressure in measurements of myocardial deformation. Early studies suggest that myocardial work parameters such as global constructive work (GCW) could be useful and reliable in arrhythmia prediction, particularly in patients undergoing cardiac resynchronization therapy (CRT). The aim of this study was to evaluate whether the magnitude of GCW was associated with the occurrence of ventricular arrhythmias in patients after CRT. Methods and results Patients on guideline-recommended treatment with a CRT defibrillator (CRT-D) were evaluated by 2D speckle-tracking echocardiography including measurements of GCW at least 6 months after implantation. The primary outcome was a composite of appropriate defibrillator therapy and sustained ventricular arrhythmia under the monitor zone. A total of 162 patients [mean age 66 years (±10), 122 males (75%)] were included. Sixteen (10%) patients experienced the primary outcome during a median follow-up of 18 months (interquartile range: 12–25) after the performance of index echocardiography. Patients with a below-median GCW (<1473 mmHg%) had a hazard ratio (HR) for the outcome of 8.14 [95% confidence interval (CI): 1.83–36.08], P = 0.006 compared with patients above the median in a univariate model and remained an independent predictor after multivariate adjustment for the estimated glomerular filtration rate and QRS duration [HR 4.75 (95% CI: 1.01–22.28), P < 0.05]. Conclusion In patients treated with CRT-D, a GCW below median level was associated with a five-fold increase in the risk of ventricular arrhythmias. [ABSTRACT FROM AUTHOR]

While there have been many descriptions of characteristic motion findings in left bundle branch block (LBBB), there are few published descriptions of such findings in right bundle branch block (RBBB). The purpose of this study was to assess the frequency of particular regional motion findings in cardiac magnetic resonance imaging (CMR) studies of patients with RBBB, compared with normal subjects. We focused on three distinctive motion patterns that can be seen in RBBB during early systole: delayed apex-ward motion of the RV base, "reverse septal flash", and "basal bulge". The presence and relative magnitude of these findings were independently scored by four experienced observers, in 3-chamber and 4-chamber CMR cines, for both normal subjects and patients with RBBB. These motion patterns were found to be strongly associated with the presence of RBBB. While only moderately sensitive, they were quite specific for RBBB, when present. In particular, with ROC analysis, a combined feature set of the findings in the 4-chamber view had an area under the curve of 0.81.This previously undescribed set of RBBB-associated early-systolic regional motion features (delayed apex-ward motion of the RV base, "reverse septal flash", and "basal bulge") is strongly suggestive of RBBB when present, particularly in the 4-chamber view. Although here evaluated with CMR, it is also likely to be associated with RBBB when seen with other cardiac imaging modalities. [ABSTRACT FROM AUTHOR]

Background: Reports on the factors predicting long‐term survival of CRT‐D cases from Western countries are increasing, however, those from Asia including Japan are still sparse. We aimed to clarify the factors predicting long‐term survival of Japanese CRT‐D cases. Methods: We retrospectively analyzed consecutive 133 patients who underwent CRT‐D implantation between 2006 and 2021. We compared clinical factors between patients who died within 5 years after implantation (short‐survival group: n = 31) and who had survived for more than 5 years (long‐survival group: n = 36) after implantation. Results: Major underlying heart diseases were dilated cardiomyopathy (45%) and ischemic heart disease (12%). There was no difference between the short‐survival group and the long‐survival group in incidence of CLBBB (32% vs. 30%), whereas CRBBB was more common in the short‐survival group (26% vs. 0%, p =.004). Mechanical dyssynchrony at implantation was more frequent in the long‐survival group (48% vs. 78%, p =.02). The incidence of response to CRT at 1 year after implantation was higher in long‐survival group (19% vs. 50%, p =.02). Multiple logistic regression analysis identified NYHA class, mechanical dyssynchrony at implantation, and response at one year as predictors of long‐term survival. Conclusions: In Japanese CRT‐D cases, lower NHYA class, preexisting mechanical dyssynchrony, and 1‐year response to CRT predict long‐term survival. [ABSTRACT FROM AUTHOR]

Cardiac resynchronization therapy (CRT) is an effective therapy for patients who suffer from heart failure and ventricular dyssynchrony such as left bundle branch block (LBBB). When it works, it reverses adverse left ventricular (LV) remodeling and the progression of heart failure. However, CRT response rate is currently as low as 50-65%. In theory, CRT outcome could be improved by allowing clinicians to tailor the therapy through patient-specific lead locations, timing, and/or pacing protocol. However, this also presents a dilemma: there are far too many possible strategies to test during the implantation surgery. Computational models could address this dilemma by predicting remodeling outcomes for each patient before the surgery takes place. Therefore, the goal of this study was to develop a rapid computational model to predict reverse LV remodeling following CRT. We adapted our recently developed computational model of LV remodeling to simulate the mechanics of ventricular dyssynchrony and added a rapid electrical model to predict electrical activation timing. The model was calibrated to quantitatively match changes in hemodynamics and global and local LV wall mass from a canine study of LBBB and CRT. The calibrated model was used to investigate the influence of LV lead location and ischemia on CRT remodeling outcome. Our model results suggest that remodeling outcome varies with both lead location and ischemia location, and does not always correlate with short-term improvement in QRS duration. The results and time frame required to customize and run this model suggest promise for this approach in a clinical setting.

Non-ischemic dilated cardiomyopathy (DCM) represents a significant cause of heart failure, defined as the presence of left ventricular (LV) dilatation and systolic dysfunction unexplained solely by abnormal loading conditions or coronary artery disease. Cardiac resynchronization therapy (CRT) has emerged as a cornerstone in the management of heart failure, particularly in patients with DCM. However, identifying patients who will benefit the most from CRT remains challenging. Speckle tracking echocardiography (STE) has garnered attention as a non-invasive imaging modality that allows for the quantitative assessment of myocardial mechanics, offering insights into LV function beyond traditional echocardiographic parameters. This comprehensive review explores the role of STE in guiding patient selection and optimizing outcomes in CRT for DCM. By assessing parameters such as LV strain, strain rate, and dyssynchrony, STE enables a more precise evaluation of myocardial function and mechanical dyssynchrony, aiding in the identification of patients who are most likely to benefit from CRT. Furthermore, STE provides valuable prognostic information and facilitates post-CRT optimization by guiding lead placement and assessing response to therapy. Through an integration of STE with CRT, clinicians can enhance patient selection, improve procedural success rates, and ultimately, optimize clinical outcomes in patients with DCM. This review underscores the pivotal role of STE in advancing personalized management strategies for DCM patients undergoing CRT.

Background: Individuals with a Fontan circulation encompass a heterogeneous group with adverse outcomes linked to ventricular dilation, dysfunction, and dyssynchrony. The purpose of this study was to assess if unsupervised machine learning cluster analysis of cardiovascular magnetic resonance (CMR)-derived dyssynchrony metrics can separate ventricles in the Fontan circulation from normal control left ventricles and identify prognostically distinct subgroups within the Fontan cohort. Methods: This single-center, retrospective study used 503 CMR studies from Fontan patients (median age 15 y) and 42 from age-matched controls from January 2005 to May 2011. Feature tracking on short-axis cine stacks assessed radial and circumferential strain, strain rate, and displacement. Unsupervised K-means clustering was applied to 24 mechanical dyssynchrony metrics derived from these deformation measurements. Clusters were compared for demographic, anatomical, and composite outcomes of death, or heart transplantation. Results: Four distinct phenotypic clusters were identified. Over a median follow-up of 4.2 y (interquartile ranges 1.7–8.8 y), 58 (11.5%) patients met the composite outcome. The highest-risk cluster (largely comprised of right or mixed ventricular morphology and dilated, dyssynchronous ventricles) exhibited a higher hazard for the composite outcome compared to the lowest-risk cluster while controlling for ventricular morphology (hazard ratio [HR] 6.4; 95% confidence interval [CI] 2.1–19.3; P value 0.001) and higher indexed end-diastolic volume (HR 3.2; 95% CI 1.04–10.0; P value 0.043) per 10 mL/m2. Conclusion: Unsupervised machine learning using CMR-derived dyssynchrony metrics identified four distinct clusters of patients with Fontan circulation and healthy controls with varying clinical characteristics and risk profiles. This technique can be used to guide future studies and identify more homogeneous subsets of patients from an overall heterogeneous population.

Background: Ventricular dyssynchrony and its relationship to clinical outcomes is not well characterized in patients following Fontan palliation. Methods: Single-center retrospective analysis of cardiac magnetic resonance (CMR) imaging of patients with a Fontan circulation and an age-matched healthy comparison cohort as controls. Feature tracking was performed on all slices of a ventricular short-axis cine stack. Circumferential and radial strain, strain rate, and displacement were measured; and multiple dyssynchrony metrics were calculated based on timing of these measurements (including standard deviation of time-to-peak, maximum opposing wall delay, and maximum base-to-apex delay). Primary endpoint was a composite measure including time to death, heart transplant or heart transplant listing (D/HTx). Results: A total of 503 cases (15 y; IQR 10, 21) and 42 controls (16 y; IQR 11, 20) were analyzed. Compared to controls, Fontan patients had increased dyssynchrony metrics, longer QRS duration, larger ventricular volumes, and worse systolic function. Dyssynchrony metrics were higher in patients with right ventricular (RV) or mixed morphology compared to those with LV morphology. At median follow-up of 4.3 years, 11% had D/HTx. Multiple risk factors for D/HTx were identified, including RV morphology, ventricular dilation, dysfunction, QRS prolongation, and dyssynchrony. Ventricular dilation and RV morphology were independently associated with D/HTx. Conclusions: Compared to control LVs, single right and mixed morphology ventricles in the Fontan circulation exhibit a higher degree of mechanical dyssynchrony as evaluated by CMR-FT. Dyssynchrony indices correlate with ventricular size and function and are associated with death or need for heart transplantation. These data add to the growing understanding regarding factors that can be used to risk-stratify patients with the Fontan circulation. [ABSTRACT FROM AUTHOR]

Background: The response to cardiac resynchronization therapy (CRT) depends on septal viability and correction of abnormal septal motion. This study investigates if cardiac magnetic resonance (CMR) as a single modality can identify CRT responders with combined imaging of pathological septal motion (septal flash) and septal scar. Methods: In a prospective, multicenter, observational study of 136 CRT recipients, septal scar was assessed using late gadolinium enhancement (LGE) (n = 127) and septal flash visually from cine CMR sequences. The primary endpoint was CRT response, defined as ≥15% reduction in LV end-systolic volume with echocardiography after 6 months. The secondary endpoint was heart transplantation or death of any cause assessed after 39 ± 13 months. Results: Septal scar and septal flash were independent predictors of CRT response in multivariable analysis (both p < 0.001), while QRS duration and morphology were not. The combined approach of septal scar and septal flash predicted CRT response with an area under the curve of 0.86 (95% confidence interval (CI): 0.78–0.94) and was a strong predictor of long-term survival without heart transplantation (hazard ratio 0.27, 95% CI: 0.10–0.79). The accuracy of the approach was similar in the subgroup with intermediate (130–150 ms) QRS duration. The combined approach was superior to septal scar and septal flash alone (p < 0.01). Conclusions: The combined assessment of septal scar and septal flash using CMR as a single-image modality identifies CRT responders with high accuracy and predicts long-term survival. [ABSTRACT FROM AUTHOR]

Background and aim: The presence of mechanical dyssynchrony on echocardiography is associated with reverse remodelling and decreased mortality after cardiac resynchronization therapy (CRT). Contrarily, myocardial scar reduces the effect of CRT. This study investigated how well a combined assessment of different markers of mechanical dyssynchrony and scarring identifies CRT responders. Methods: In a prospective multicentre study of 170 CRT recipients, septal flash (SF), apical rocking (ApRock), systolic stretch index (SSI), and lateral-to-septal (LW-S) work differences were assessed using echocardiography. Myocardial scarring was quantified using cardiac magnetic resonance imaging (CMR) or excluded based on a coronary angiogram and clinical history. The primary endpoint was a CRT response, defined as a ≥15% reduction in LV end-systolic volume 12 months after implantation. The secondary endpoint was time-to-death. Results: The combined assessment of mechanical dyssynchrony and septal scarring showed AUCs ranging between 0.81 (95%CI: 0.74–0.88) and 0.86 (95%CI: 0.79–0.91) for predicting a CRT response, without significant differences between the markers, but significantly higher than mechanical dyssynchrony alone. QRS morphology, QRS duration, and LV ejection fraction were not superior in their prediction. Predictive power was similar in the subgroups of patients with ischemic cardiomyopathy. The combined assessments significantly predicted all-cause mortality at 44 ± 13 months after CRT with a hazard ratio ranging from 0.28 (95%CI: 0.12–0.67) to 0.20 (95%CI: 0.08–0.49). Conclusions: The combined assessment of mechanical dyssynchrony and septal scarring identified CRT responders with high predictive power. Both visual and quantitative markers were highly feasible and demonstrated similar results. This work demonstrates the value of imaging LV mechanics and scarring in CRT candidates, which can already be achieved in a clinical routine. [ABSTRACT FROM AUTHOR]

Background: In this review, we introduce the displacement encoding with stimulated echoes (DENSE) method for measuring myocardial dyssynchrony using cardiovascular magnetic resonance (CMR) imaging. We provide an overview of research findings related to DENSE from the past two decades and discuss other techniques used for dyssynchrony evaluation. Additionally, the review discusses the potential uses of DENSE in clinical practice. Methods: A search was conducted to identify relevant articles published from January 2000 through January 2023 using the Scopus, Web of Science, PubMed and Cochrane databases. The following search term was used: (DENSE OR 'displacement encoding with stimulated echoes' OR CURE) AND (dyssynchrony* OR asynchron* OR synchron*) AND (MRI OR 'magnetic resonance' OR CMR). Results: After removing duplicates, researchers screened a total of 174 papers. Papers that were not related to the topic, reviews, general overview articles and case reports were excluded, leaving 35 articles for further analysis. Of these, 14 studies focused on cardiac dyssynchrony estimation with DENSE, while the remaining 21 studies served as background material. The studies used various methods for presenting synchronicity, such as circumferential uniformity ratio estimate (CURE), CURE-singular value decomposition (SVD), radial uniformity ratio estimate (RURE), longitudinal uniformity ratio estimate (LURE), time to onset of shortening (TOS) and dyssynchrony index (DI). Most of the dyssynchrony studies concentrated on human heart failure, but congenital heart diseases and obesity were also evaluated. The researchers found that DENSE demonstrated high reproducibility and was found useful for detecting cardiac resynchronisation therapy (CRT) responders, optimising CRT device settings and assessing right ventricle synchronicity. In addition, studies showed a correlation between cardiac fibrosis and mechanical dyssynchrony in humans, as well as a decrease in the synchrony of contraction in the left ventricle in obese mice. Conclusions: DENSE shows promise as a tool for quantifying myocardial function and dyssynchrony, with advantages over other cardiac dyssynchrony evaluation methods. However, there remain challenges related to DENSE due to the relatively time-consuming imaging and analysis process. Improvements in imaging and analysing technology, as well as possible artificial intelligence solutions, may help overcome these challenges and lead to more widespread clinical use of DENSE. [ABSTRACT FROM AUTHOR]

Abstract Aims The pathophysiological effects of chronic right ventricular pacing and the role of right ventricular lead position are not well understood. Therefore, we investigated the association between left ventricular contractile dyssynchrony and pacing-induced cardiomyopathy (PICM) in patients with chronic right ventricular pacing. Furthermore, we assessed the association between right ventricular lead location and left ventricular contractile dyssynchrony. Methods This was a retrospective study using data from 153 pacemaker patients with normal (≥ 50%) pre-implant left ventricular ejection fraction (LVEF). Baseline and follow-up echocardiograms were analyzed, and PICM was defined as LVEF

Cardiac conduction involves electrical activity from one myocyte to another, creating coordinated contractions in each. Disruptions in the conducting system, such as left bundle branch block (LBBB), can result in premature activation of specific regions of the heart, leading to heart failure and increased morbidity and mortality. Structural alterations in T-tubules and the sarcoplasmic reticulum can lead to dyssynchrony, a condition that can be treated by cardiac resynchronization therapy (CRT), which stands as a cornerstone in this pathology. The heterogeneity in patient responses underscored the necessity of improving the diagnostic approach. Vectocardiography, ultra-high-frequency ECG, 3D echocardiography, and electrocardiographic imaging seem to offer advanced precision in identifying optimal candidates for CRT in addition to the classic diagnostic methods. The advent of His bundle pacing and left bundle branch pacing further refined the approach in the treatment of dyssynchrony, offering more physiological pacing modalities that promise enhanced outcomes by maintaining or restoring the natural sequence of ventricular activation. HOT-CRT emerges as a pivotal innovation combining the benefits of CRT with the precision of His bundle or left bundle branch area pacing to optimize cardiac function in a subset of patients where traditional CRT might fall short.

Wolf-Parkinson-White (WPW) accessory pathway (AP) may be associated with reentry supraventricular tachycardia (SVT) in addition to ventricular dyssynchrony and cardiac dysfunction. Electrophysiological studies (EPS) are the gold standard for the localization of the AP; however, 2D speckle-tracking echocardiography (2D-STE) may help in the localization of the AP noninvasively. Our study aims to evaluate the capability of 2D-STE for AP localization and the identification of AP-related contractile abnormalities and dyssynchrony in pediatric patients with WPW syndrome. This prospective multicenter cohort study involved 18 pediatric patients with ventricular preexcitation from January 2021 to January 2023. Tissue Doppler imaging (TDI), conventional echocardiography, and 2D-STE were done. Myocardial velocities, myocardial performance index (MPI), the global and segmental longitudinal strain of the left ventricle (LV), and time-to-peak longitudinal strain (TPLS) were measured before and after ablation. The longitudinal strain of the LV segments supplied by the AP, or the nearby segments close to the AP, was significantly impaired and improved after ablation (P = 0.0001). The abnormal strain pattern in the affected segments could predict the location of the AP. The TPLS of the affected segments significantly increased after ablation (P = 0.0001), denoting improved dyssynchrony. The ejection time and the LV MPI measured at the basal septum improved significantly after ablation. Conclusions: 2D STE may be used for noninvasive localization of the AP and to evaluate cardiac function and dyssynchrony in patients with WPW. Further research on more patients is necessary to validate this method for AP localization. What is Known: • Accessory pathways (AP) associated with the Wolf-Parkinson-White (WPW) syndrome have been linked to supraventricular tachycardia (SVT). Even without SVT, WPW can cause left ventricular dyssynchrony, contractile dysfunction, and cardiomyopathy. • Electrophysiology study is the gold standard for the localization of the AP in WPW syndrome. What is New: • The combination of 2D-speckle-tracking echocardiography (2D-STE) and the modified Arruda algorithm can precisely localize the AP associated with WPW syndrome. • 2D-STE can potentially assess cardiac function and dyssynchrony related to WPW syndrome. Additionally, 2D-STE can be utilized to evaluate the effectiveness of ablation in restoring cardiac function and dyssynchrony. [ABSTRACT FROM AUTHOR]

Electrocardiogram (ECG)-gated single photon emission computed tomography myocardial perfusion imaging (GSPECT-MPI) is widely used for assessing coronary artery disease. Phase analysis on GSPECT-MPI can assess left ventricular mechanical dyssynchrony quantitatively on standard GSPECT-MPI alongside myocardial perfusion and function assessment. It has been shown that phase variables by GSPECT-MPI correlate well with tissue Doppler imaging by echocardiography. Main phase variables quantified by GSPECT-MPI are entropy, bandwidth, and phase standard deviation. Although those variables are automatically obtained from several software packages including Quantitative Gated SPECT and Emory Cardiac Toolbox, the methods for their measurement vary in each package. Several studies have shown that phase analysis has predictive value for response to cardiac resynchronization therapy and prognostic value for future adverse cardiac events beyond standard GSPECT-MPI variables. In this review, we summarize the basics of phase analysis on GSPECT-MPI and usefulness of phase analysis in clinical practice. [Display omitted] • Phase variables can be obtained fully automatically from ECG gated SPECT-MPI. • Phase analysis has predictive and prognostic value in various clinical situations. • Phase variables should be routinely reported for SPECT-MPI studies. [ABSTRACT FROM AUTHOR]

Background: Mechanical systolic LV dyssynchrony is associated with poor outcomes in patients with cardiac failure. However, its role in predicting prognosis after acute MI has been remotely explored. Materials and methods: 62 patients with acute MI who were admitted to the Department of Cardiology, Govt General Hospital, Ongole were included in this study. All patients were subjected to echocardiography and their baseline parameters were noted. The patients were followed up for 6 months. Results: Dyssynchrony is present in 35% of the study population. The prevalence of dyssynchrony is significantly higher in AWMI compared to non-AWMI. Baseline LV dyssynchrony of 57 ms or more, as assessed by TDI, had a sensitivity of 94% and a specificity of 84% to predict LV remodeling at 6 months after acute infarction. Conclusion: Early identification of LV dyssynchrony aids in understanding the prognosis after acute MI and helps in intervening before the start of LV remodeling. [ABSTRACT FROM AUTHOR]

Among heart failure (HF) patients undergoing cardiac resynchronization therapy (CRT), those with unfavorable electrical characteristics (UEC) are less frequently CRT responders. In this study, the authors sought to evaluate the relationship between preprocedural echocardiographic parameters of electromechanical dyssynchrony (EMD) and outcome following CRT. Among 551 patients receiving CRT, 121 with UEC, defined as atypical left bundle branch, presence of right bundle branch block, or unspecified intraventricular conduction disturbance, were enrolled. Indices of EMD were presence of septal flash, apical rocking, septal deformation patterns, and global wasted work (GWW), determined with the use of speckle-tracking strain echocardiography. Endpoints were response to CRT, defined as a relative decrease in left ventricular end-systolic volume ≥15% at 9-month postoperative follow-up, and all-cause death or HF hospitalization during follow-up. Among the 121 patients, 68 (56%) were CRT responders. In multivariate analysis, GWW ≥200 mm Hg% (adjusted odds ratio [aOR]: 4.17 [95% CI: 1.33-14.56]; P = 0.0182) and longitudinal strain septal contraction patterns 1 and 2 (aOR: 10.05 [95% CI: 2.82-43.97]; P < 0.001) were associated with CRT response. During a 46-month follow-up (IQR: 42-55 months), survival free from death or HF hospitalization increased with the number of positive criteria (87% for 2, 59% for 1, and 27% for 0). After adjustment for established predictors of outcome in patients receiving CRT, absence of either of the 2 criteria remained associated with a considerable increased risk of death and/or HF hospitalization (adjusted HR: 4.83 [95% CI: 1.84-12.68]; P = 0.001). In patients with UEC, echocardiographic assessment of EMD may help to select patients who will derive benefit from CRT. (Echocardiography in Cardiac Resynchronization Therapy [Echo-CRT]; NCT02986633) [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] [ABSTRACT FROM AUTHOR]

Objectives: This prospective pilot study assessed the feasibility of cardiovascular magnetic resonance (CMR) imaging during biventricular (BIV) pacing in patients with a CMR conditional cardiac resynchronization therapy defibrillator (CRT-D) and compared the results with invasive volume measurements. Methods: Ten CRT-D patients underwent CMR imaging prior to device implantation (baseline) and six weeks after device implantation, including CRT-on and CRT-off modes. Left ventricular (LV) function, volumes, and strain measurements of LV dyssynchrony and dyscoordination were assessed. Invasive pressure–volume measurements were performed, matching the CRT settings used during CMR. Results: Post-implantation imaging enabled reliable cine assessment, but showed artefacts on late gadolinium enhancement images. After six weeks of CRT, significant reverse remodeling was observed, with a 22.7 ± 11% reduction in LV end-systolic volume during intrinsic rhythm (CRT-off). During CRT-on, the LV ejection fraction significantly improved from 27.4 ± 5.9% to 32.2 ± 8.7% (p < 0.01), and the strain assessment showed the abolition of the left bundle branch block contraction pattern. Invasively measured and CMR-assessed LV hemodynamics during BIV pacing were significantly associated. Conclusions: Post-CRT implantation CMR assessing acute LV pump function is feasible and provides important insights into the effects of BIV pacing on cardiac function and contraction patterns. LV assessment during CMR may constitute a future CRT optimization strategy. [ABSTRACT FROM AUTHOR]

Circadian clock proteins are endogenous timing mechanisms that control the transcription of hundreds of genes. Their integral role in coordinating metabolism has led to their scrutiny in a number of diseases, including nonalcoholic fatty liver disease (NAFLD). Discoordination between central and peripheral circadian rhythms is a core feature of nearly every genetic, dietary, or environmental model of metabolic syndrome and NAFLD. Restricting feeding to a defined daily interval (time-restricted feeding) can synchronize the central and peripheral circadian rhythms, which in turn can prevent or even treat the metabolic syndrome and hepatic steatosis. Importantly, a number of proteins currently under study as drug targets in NAFLD (sterol regulatory element-binding protein [SREBP], acetyl-CoA carboxylase [ACC], peroxisome proliferator-activator receptors [PPARs], and incretins) are modulated by circadian proteins. Thus, the clock can be used to maximize the benefits and minimize the adverse effects of pharmaceutical agents for NAFLD. The circadian clock itself has the potential for use as a target for the treatment of NAFLD.

Ventricular arrhythmia is one of the main causes of sudden cardiac death. Hence, identifying patients at risk of ventricular arrhythmias and sudden cardiac death is important but can be challenging. The indication for an implantable cardioverter defibrillator as a primary preventive strategy relies on the left ventricular ejection fraction as a measure of systolic function. However, ejection fraction is flawed by technical constraints and is an indirect measure of systolic function. There has, therefore, been an incentive to identify other markers to optimize the risk prediction of malignant arrhythmias to select proper candidates who could benefit from an implantable cardioverter defibrillator. Speckle-tracking echocardiography allows for a detailed assessment of cardiac mechanics, and strain imaging has repeatedly been shown to be a sensitive technique to identify systolic dysfunction unrecognized by ejection fraction. Several strain measures, including global longitudinal strain, regional strain, and mechanical dispersion, have consequently been proposed as potential markers of ventricular arrhythmias. In this review, we will provide an overview of the potential use of different strain measures in the context of ventricular arrhythmias. [ABSTRACT FROM AUTHOR]

Aims: The pathophysiological effects of chronic right ventricular pacing and the role of right ventricular lead position are not well understood. Therefore, we investigated the association between left ventricular contractile dyssynchrony and pacing-induced cardiomyopathy (PICM) in patients with chronic right ventricular pacing. Furthermore, we assessed the association between right ventricular lead location and left ventricular contractile dyssynchrony. Methods: This was a retrospective study using data from 153 pacemaker patients with normal (≥ 50%) pre-implant left ventricular ejection fraction (LVEF). Baseline and follow-up echocardiograms were analyzed, and PICM was defined as LVEF < 50% with ≥ 10% decrease in LVEF after pacemaker implantation. Relative index of contractile asymmetry (rICA), a novel strain rate-based method, was calculated to quantify left ventricular contractile dyssynchrony between opposing walls in the three apical views. Right ventricular lead position was categorized into anterior septum, posterior septum, free wall, and apex based on contrast-enhanced cardiac computed tomography. Results: Forty-seven (31%) developed PICM. Overall contractile dyssynchrony, measured by mean rICA, was higher in the PICM group compared with the non-PICM group (1.19 ± 0.21 vs. 1.03 ± 0.19, p < 0.001). Left ventricular anterior-inferior dyssynchrony, assessed in the apical two-chamber view, was independently associated with PICM (p < 0.001). Thirty-seven (24%) leads were implanted anterior septal, 11 (7.2%) posterior septal, 74 (48.4%) apical, and 31 (20.3%) free wall. Left ventricular anterior-inferior dyssynchrony was significantly different between the four pacing lead locations (p < 0.01) with the highest rICA observed in the posterior septal group (1.30 ± 0.37). Conclusions: PICM is significantly associated increased contractile dyssynchrony assessed by rICA. This study suggests that especially left ventricular dyssynchrony in the anterior-inferior direction is associated with PICM, and pacing the right ventricular posterior septum resulted in the highest degree of anterior-inferior dyssynchrony. Quantification of left ventricular dyssynchrony by rICA provides important insights to the potential pathophysiology of PICM and the impact of right ventricular lead position. [ABSTRACT FROM AUTHOR]

Background: Although cardiac resynchronization therapy (CRT) is beneficial in most heart failure patients, up to 40% do not respond to CRT. It has been suggested that multipoint left ventricle pacing (MPP) would increase the response rate. Aim: To assess the CRT response rate at 6 months in patients implanted with a CRT device with the MPP feature activated early after the implant. Methods: This was a multicentre, prospective, open‐label and non‐randomized study. The primary endpoint was response to biventricular pacing defined as >15% relative reduction in left ventricular end‐systolic volume (LVESV) comparing echocardiography measurements performed at baseline and 6 months by a core laboratory. Among secondary endpoints the combined endpoint of mortality or all‐cause hospitalizations was evaluated. Primary study endpoint and clinical outcomes were compared to a Quarto II control cohort. Results: Totally, 105 patients were included. The response rate was 64.6% (97.5% lower confidence bound 53%). Mean relative reduction in LVESV was 25.3%, and mean absolute increase in LVEF was 9.4%. The subjects with device programmed using anatomical approach showed a trend towards higher responder rate than those using the electrical approach (72% vs. 61.1%, p = 0.32). Finally, the combined incidence of mortality and or all‐cause hospitalizations at 6 month was 12.4%. Conclusions: Early activation of MPP was not associated to an advantage increasing echocardiography responders to CRT at 6 months of follow‐up. Nevertheless, patients programmed using widest pacing cathodes had a numerically higher responder rate. Finally, early activation of MPP was associated to a low incidence of clinical endpoints at 6 months of follow‐up. [ABSTRACT FROM AUTHOR]

Guided by a phenomenological perspective, this paper aims to account for the existence of a corporeal consciousness—something that clinicians should take into account, not merely in the case of physical pathologies but especially in the case of mental disorders. Firstly, I will highlight three cases: schizophrenia, depression, and autism spectrum disorder. Then, I will show how these cases correspond to three different kinds of bodily existence: disembodiment (in the case of schizophrenia), chrematization (in melancholic depression), and dyssynchrony (in the autism spectrum disorder). Finally, I will argue for the importance of an "expressive common environment" between the patient and the clinician, who are two distinct, embodied conscious subjects resonating with one another. In this view, the primary goal of the therapeutic process seems to develop a shared understanding of the patient's life-world, which finds its main expression through the disrupted body. [ABSTRACT FROM AUTHOR]

Aims Patients who undergo permanent pacemaker (PPM) implantation after transcatheter aortic valve replacement (TAVR) have a worse outcome. The aim of this study was to identify risk factors of worse outcomes in patients with post-TAVR PPM implantation. Methods and results This is a single-centre, retrospective study of consecutive patients who underwent post-TAVR PPM implantation from 11 March 2011 to 9 November 2019. Clinical outcomes were evaluated by landmark analysis with cut-off at 1 year after the PPM implantation. Of the 1389 patients underwent TAVR during the study duration and a total of 110 patients were included in the final analysis. Right ventricular pacing burden (RVPB) ≥ 30% at 1 year was associated with a higher likelihood of heart failure (HF) readmission [adjusted hazard ratio (aHR): 6.333; 95% confidence interval [CI]: 1.417–28.311; P = 0.016] and composite endpoint of overall death and/or HF (aHR: 2.453; 95% CI: 1.040–5.786; P = 0.040). The RVPB ≥30% at 1 year was associated with higher atrial fibrillation burden (24.1 ± 40.6% vs. 1.2 ± 5.3%; P = 0.013) and a decrease in left ventricular ejection fraction (−5.0 ± 9.8% vs. + 1.1 ± 7.9%; P = 0.005). The predicting factors of the RVPB ≥30% at 1 year were the presence of RVPB ≥40% at 1 month and the valve implantation depth measured from non-coronary cusp ≥4.0 mm (aHR: 57.808; 95% CI: 12.489–267.584; P < 0.001 and aHR: 6.817; 95% CI: 1.829–25.402; P = 0.004). Conclusions The RVPB ≥30% at 1 year was associated with worse outcomes. Clinical benefit of minimal RV pacing algorithms and biventricular pacing needs to be investigated. [ABSTRACT FROM AUTHOR]

Reverse triggering dyssynchrony is a frequent phenomenon recently recognized in sedated critically ill patients under controlled ventilation. It occurs in at least 30 to 55% of these patients and often occurs in the transition from fully passive to assisted mechanical ventilation. During reverse triggering, patient´s inspiratory efforts start after the passive insufflation by mechanical breaths. The most often referred mechanism is the entrainment of the patient´s intrinsic respiratory rhythm from the brainstem respiratory centers to periodic mechanical insufflations from the ventilator. However, reverse triggering might also occur because of local reflexes without involving the respiratory rhythm generator in the brainstem. Reverse triggering is observed during the acute phase of the disease, when patients may be susceptible to potential deleterious consequences of injurious or asynchronous efforts. Diagnosing reverse triggering might be challenging and can easily be missed. Inspection of ventilator waveforms or more sophisticated methods such as electrical activity of the diaphragm or esophageal pressure can be used for diagnosis. The occurrence of reverse triggering might have clinical consequences. Based on physiological data, reverse triggering might be beneficial or injurious for the diaphragm and the lung depending on the magnitude of the inspiratory effort. Reverse triggering can cause breath-stacking and loss of protective lung ventilation when triggering a second cycle. Little is known about how to manage patients with reverse triggering; however, available evidence can guide management based on physiological principles. [ABSTRACT FROM AUTHOR]

Aims Successful cardiac resynchronization therapy (CRT) shortens the pre-ejection period (PEP) which is prolonged in the left bundle branch block (LBBB). In a combined animal and patient study, we investigated if changes in the pulse arrival time (PAT) could be used to measure acute changes in PEP during CRT implantation and hence be used to evaluate acute CRT response non-invasively and in real time. Methods and results In six canines, a pulse transducer was attached to a lower limb and PAT was measured together with left ventricular (LV) pressure by micromanometer at baseline, after induction of LBBB and during biventricular pacing. Time-to-peak LV dP/dt (Td) was used as a surrogate for PEP. In twelve LBBB patients during implantation of CRT, LV and femoral pressures were measured at baseline and during five different pacing configurations. PAT increased from baseline (277 ± 9 ms) to LBBB (313 ± 16 ms, P < 0.05) and shortened with biventricular pacing (290 ± 16 ms, P < 0.05) in animals. There was a strong relationship between changes in PAT and Td in patients (r 2 = 0.91). Two patients were classified as non-responders at 6 months follow-up. CRT decreased PAT from 320 ± 41 to 298 ± 39 ms (P < 0.05) in the responders, while PAT increased by 5 and 8 ms in the two non-responders. Conclusion This proof-of-concept study indicates that PAT can be used as a simple, non-invasive method to assess the acute effects of CRT in real time with the potential to identify long-term response in patients. [ABSTRACT FROM AUTHOR]

Over the past two decades of CRT use, the failure rate has remained around 30–35%, despite several updates in the guidelines based on the understanding from multiple trials. This review article summarizes the role of mechanical dyssynchrony in the selection of heart failure patients for cardiac resynchronization therapy. Understanding the application of mechanical dyssynchrony has also evolved during these past two decades. There is no role of lone mechanical dyssynchrony in the patient selection for CRT. However, mechanical dyssynchrony can complement the electrocardiogram and clinical criteria and improve patient selection by reducing the failure rate. An oversimplified approach to mechanical dyssynchrony assessment, such as just estimating time-to-peak delays between segments, should not be used. Instead, methods that can identify the underlying pathophysiology of HF and are representative of a substrate to CRT should be applied.

BackgroundLeft bundle branch pacing (LBBP) produces delayed, unphysiological activation of the right ventricle. Using ultra-high-frequency electrocardiography (UHF-ECG), we explored how bipolar anodal septal pacing with direct LBB capture (aLBBP) affects the resultant ventricular depolarization pattern.MethodsIn patients with bradycardia, His bundle pacing (HBP), unipolar nonselective LBBP (nsLBBP), aLBBP, and right ventricular septal pacing (RVSP) were performed. Timing of local ventricular activation, in leads V1–V8, was displayed using UHF-ECG, and electrical dyssynchrony (e-DYS) was calculated as the difference between the first and last activation. Durations of local depolarizations were determined as the width of the UHF-QRS complex at 50% of its amplitude.ResultsaLBBP was feasible in 63 of 75 consecutive patients with successful nsLBBP. aLBBP significantly improved ventricular dyssynchrony (mean −9 ms; 95% CI (−12;−6) vs. −24 ms (−27;−21), ), p < 0.001) and shortened local depolarization durations in V1–V4 (mean differences −7 ms to −5 ms (−11;−1), p < 0.05) compared to nsLBBP. aLBBP resulted in e-DYS −9 ms (−12; −6) vs. e-DYS 10 ms (7;14), p < 0.001 during HBP. Local depolarization durations in V1–V2 during aLBBP were longer than HBP (differences 5-9 ms (1;14), p < 0.05, with local depolarization duration in V1 during aLBBP being the same as during RVSP (difference 2 ms (−2;6), p = 0.52).ConclusionAlthough aLBBP improved ventricular synchrony and depolarization duration of the septum and RV compared to unipolar nsLBBP, the resultant ventricular depolarization was still less physiological than during HBP.

Response to cardiac resynchronization therapy (CRT) is reduced in patients with high left ventricular (LV) scar burden, in particular when scar is located in the LV lateral wall or septum. Late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) can identity scar, but is not feasible in all patients. This study investigates if myocardial metabolism by 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) and contractile function by echocardiographic strain are alternatives to LGE-CMR. In a prospective multicenter study, 132 CRT candidates (91% with left bundle branch block) were studied by speckle tracking strain echocardiography, and 53 of these by FDG-PET. Regional myocardial FDG metabolism and peak systolic strain were compared to LGE-CMR as reference method. Reduced FDG metabolism (<70% relative) precisely identified transmural scars (≥50% of myocardial volume) in the LV lateral wall, with area under the curve (AUC) 0.96 (95% confidence interval (CI) 0.90–1.00). Reduced contractile function by strain identified transmural scars in the LV lateral wall with only moderate accuracy (AUC = 0.77, CI 0.71–0.84). However, absolute peak systolic strain >10% could rule out transmural scar with high sensitivity (80%) and high negative predictive value (96%). Neither FDG-PET nor strain identified septal scars (for both, AUC < 0.80). In CRT candidates, FDG-PET is an excellent alternative to LGE-CMR to identify scar in the LV lateral wall. Furthermore, preserved strain in the LV lateral wall has good accuracy to rule out transmural scar. None of the modalities can identify septal scar. The present study is part of the clinical study "Contractile Reserve in Dyssynchrony: A Novel Principle to Identify Candidates for Cardiac Resynchronization Therapy (CRID–CRT)", which was registered at clinicaltrials.gov (identifier NCT02525185). The ability of peak systolic strain by echocardiography and glucose metabolism by FDG-PET to identify transmural LV lateral and septal scar in CRT candidates compared to LGE-CMR, illustrated in three representative patients. LGE-CMR (left images) allows for direct scar identification independent of wall motion, and was used as reference standard for scar. Peak systolic strain by echocardiography (middle images) was generally inconclusive of scar, but absolute strain >10% in the LV lateral wall implies that transmural scar in this region is unlikely. Glucose metabolism by FDG-PET (right images) accurately identified transmural LV lateral wall scar, but was unable to distinguish transmural septal scar from septal hypo-metabolism due to left bundle branch block in itself. FDG-PET = 18F-fluorodeoxyglucose Positron Emission Tomography; LV = left ventricular; CRT = cardiac resynchronization therapy; LGE = late gadolinium enhancement; CMR = cardiac magnetic resonance. [Display omitted] • FDG-PET is a good alternative to CMR to identify transmural left ventricular lateral wall scars in patients referred for CRT. • Strain by echocardiography is only moderately accurate, but relatively preserved strain (>10%) in the lateral wall strain means that transmural scar in this region is unlikely. • Contrary to preserved strain, reduced strain in the lateral wall is inconclusive with regard to scar. • Neither FDG-PET nor echocardiographic strain identifies septal scar. [ABSTRACT FROM AUTHOR]

Background: Impaired cardiac sympathetic activity and mechanical dyssynchrony (MD) are associated with poor prognosis in patients with heart failure (HF) after cardiac resynchronization therapy (CRT). The study aims to assess the significance of scintigraphic evaluation of cardiac sympathetic innervation and contractility in predicting response to CRT in patients with ischemic and non-ischemic chronic HF. Methods and results: The study includes 58 HF patients, who were referred for CRT. Prior to CRT all patients underwent 123I-metaiodobenzylguanidine (123I-MIBG) imaging and gated myocardial perfusion imaging (MPI) using a cadmium-zinc-telluride (CZT) SPECT/CT device. At a one-year follow-up post-CRT, the delayed heart-to-mediastinum 123I-MIBG uptake ratio was an independent predictor of CRT response in non-ischemic HF patients (OR 1.469; 95% CI 1.076-2.007, p =.003). In ischemic HF patients the MD index histogram bandwidth (HBW) obtained by CZT-gated MPI had a predictive value (OR 1.06, 95% CI 1.001-1.112, p =.005) to CRT response. Conclusion: CRT response can be predicted by cardiac 123I-MIBG scintigraphy, specifically by the heart-to-mediastinum ratio in non-ischemic HF and by the MD index HBW in ischemic HF. These results suggest the value of a potentially useful algorithm to improve outcomes in HF patients who are candidates for CRT. [ABSTRACT FROM AUTHOR]

Cardiac resynchronization therapy (CRT) has become a valuable addition to the treatment options for heart failure, in particular for patients with disturbances in electrical conduction that lead to regionally different contraction patterns (dyssynchrony). Dyssynchronous hearts show extensive molecular and cellular remodeling, which has primarily been investigated in experimental animals. Evidence showing that at least several miRNAs play a role in this remodeling is increasing. A comparison of results from measurements in plasma and myocardial tissue suggests that plasma levels of miRNAs may reflect the expression of these miRNAs in the heart. Because many miRNAs released in the plasma are included in extracellular vesicles (EVs), which protect them from degradation, measurement of myocardium-derived miRNAs in peripheral blood EVs may open new avenues to investigate and monitor (reverse) remodeling in dyssynchronous and resynchronized hearts of patients. [ABSTRACT FROM AUTHOR]

Although PVCs commonly lead to degraded cine cardiac MRI (CMR), patients with PVCs may have relatively sharp cine images of both normal and ectopic beats ("double beats") when the rhythm during CMR is ventricular bigeminy, and only one beat of the pair is detected for gating. MRI methods for directly imaging premature ventricular contractions (PVCs) are not yet widely available. Localization of PVC site of origin with images may be helpful in planning ablations. The contraction pattern of the PVCs in bigeminy provides a "natural experiment" for investigating the potential utility of PVC imaging for localization. The purpose of this study was to evaluate the correlation of the visually assessed site of the initial contraction of the ectopic beats with the site of origin found by electroanatomic mapping. Images from 7 of 86 consecutive patients who underwent CMR prior to PVC ablation were found to include clear cine images of bigeminy. The visually apparent site of origin of the ectopic contraction was determined by three experienced, blinded CMR readers and correlated with each other, and with PVC site of origin determined by 3D electroanatomic mapping during catheter ablation. Blinded ascertainment of visually apparent initial contraction pattern for PVC localization was within 2 wall segments of PVC origin by 3D electroanatomic mapping 76% of the time. Our data from patients with PVCs with clear images of the ectopic beats when in bigeminy provide proof-of-concept that CMR ectopic beat contraction patterns analysis may provide a novel method for localizing PVC origin prior to ablation procedures. Direct imaging of PVCs with use of newer cardiac imaging methods, even without the presence of bigeminy, may thus provide valuable data for procedural planning. [ABSTRACT FROM AUTHOR]

Background: SPECT myocardial perfusion imaging (MPI) provides an assessment of LV mechanical dyssynchrony (LVMD) which correlates with CVD outcomes in diverse populations including those awaiting renal transplant (RT). The current study examines the association of LVMD on pre-transplant MPI with long-term CVD mortality post RT. Methods: We identified consecutive patients who underwent RT at the University of Alabama at Birmingham between 2008 and 2012 from our prospectively collected database. 675 patients in the database underwent MPI and had images amenable for phase analysis. A blinded investigator retrieved the studies and derived LVMD indices including histogram bandwidth (BW), standard deviation (SD), phase peak, phase skewness, and phase kurtosis. The primary outcome was CVD death after RT. Results: The study cohort had a median age of 54 years, 56% were men, 43% had diabetes, and 7% had prior myocardial infarction. Patients were on dialysis for a median of 3.4 years prior to RT and 34% received living donor transplants. During a median follow-up time after RT of 4.7 years (IQR 3.5 to 6.3 years) 59 patients (9%) succumbed to CVD death. Patients with wider BW, wider SD, lower skewness, and lower kurtosis had an increased risk of CVD death. On multivariate adjustment, BW and skewness remained as independent predictors of CVD deaths. Conclusions: LVMD by phase analysis of gated SPECT MPI is associated with increased risk of CVD death after RT. This association is independent of demographics, comorbidities, and traditional findings on MPI and added incremental prognostic information. Assessment of LVMD should be considered for risk stratification in these patients. [ABSTRACT FROM AUTHOR]

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Background: In this review, we introduce the displacement encoding with stimulated echoes (DENSE) method for measuring myocardial dyssynchrony using cardiovascular magnetic resonance (CMR) imaging. We provide an overview of research findings related to DENSE from the past two decades and discuss other techniques used for dyssynchrony evaluation. Additionally, the review discusses the potential uses of DENSE in clinical practice. Methods: A search was conducted to identify relevant articles published from January 2000 through January 2023 using the Scopus, Web of Science, PubMed and Cochrane databases. The following search term was used: (DENSE OR ‘displacement encoding with stimulated echoes’ OR CURE) AND (dyssynchrony* OR asynchron* OR synchron*) AND (MRI OR ‘magnetic resonance’ OR CMR). Results: After removing duplicates, researchers screened a total of 174 papers. Papers that were not related to the topic, reviews, general overview articles and case reports were excluded, leaving 35 articles for further analysis. Of these, 14 studies focused on cardiac dyssynchrony estimation with DENSE, while the remaining 21 studies served as background material. The studies used various methods for presenting synchronicity, such as circumferential uniformity ratio estimate (CURE), CURE-singular value decomposition (SVD), radial uniformity ratio estimate (RURE), longitudinal uniformity ratio estimate (LURE), time to onset of shortening (TOS) and dyssynchrony index (DI). Most of the dyssynchrony studies concentrated on human heart failure, but congenital heart diseases and obesity were also evaluated. The researchers found that DENSE demonstrated high reproducibility and was found useful for detecting cardiac resynchronisation therapy (CRT) responders, optimising CRT device settings and assessing right ventricle synchronicity. In addition, studies showed a correlation between cardiac fibrosis and mechanical dyssynchrony in humans, as well as a decrease in the synchrony of contraction in the left ventricle in obese mice. Conclusions: DENSE shows promise as a tool for quantifying myocardial function and dyssynchrony, with advantages over other cardiac dyssynchrony evaluation methods. However, there remain challenges related to DENSE due to the relatively time-consuming imaging and analysis process. Improvements in imaging and analysing technology, as well as possible artificial intelligence solutions, may help overcome these challenges and lead to more widespread clinical use of DENSE.

Abstract Background Mitral regurgitation after transcatheter aortic valve implantation (TAVI) can be caused by various etiologies. Case presentation An 81-year-old woman with mild mitral regurgitation and complete right bundle branch block was scheduled to undergo TAVI under general anesthesia. After the deployment of the prosthetic valve, electrocardiography depicted a wide QRS wave and bradycardia, suggestive of complete atrioventricular block. Although there was no lesion indicative of tissue injury to the valve itself, worsening of mitral regurgitation was identified on transesophageal echocardiography. The hemodynamic condition was stable, and no additional procedure was performed. Electrocardiography depicted a return to a narrow QRS wave 3 days after surgery, and the mitral regurgitation appeared comparable to the preoperative grade. We assumed that the worsening of mitral regurgitation was caused by dyssynchrony in the left ventricle due to the conduction disorder. Conclusions Mitral regurgitation after TAVI needs observation, including the determination of the etiology and treatment principle.

Abstract We present a 66‐year‐old male patient with heart failure, mid‐range ejection fraction and QRS widening suffering from recurrent hospitalization due to acute heart failure. We measured intra‐cardiac pressure by cardiac catheterization to clearly demonstrate the augmentation of afterload by a vasoconstricting drug induced increase of left ventricular end‐diastolic blood pressure and pulmonary capillary wedge pressure with pulmonary arterial V‐wave augmentation (indicator of worsening of mitral regurgitation). Because the patient was considered as refractory to optimal medication, cardiac resynchronization therapy (CRT) was performed. After CRT implantation, these factors were improved, and the patient has not experienced recurrent hospitalization for >2 years.

Biventricular endocardial (BIV-endo) pacing and left bundle pacing (LBP) are novel delivery methods for cardiac resynchronization therapy (CRT). Both pacing methods can be delivered through leadless pacing, to avoid risks associated with endocardial or transvenous leads. We used computational modelling to quantify synchrony induced by BIV-endo pacing and LBP through a leadless pacing system, and to investigate how the right-left ventricle (RV-LV) delay, RV lead location and type of left bundle capture affect response. We simulated ventricular activation on twenty-four four-chamber heart meshes inclusive of His-Purkinje networks with left bundle branch block (LBBB). Leadless biventricular (BIV) pacing was simulated by adding an RV apical stimulus and an LV lateral wall stimulus (BIV-endo lateral) or targeting the left bundle (BIV-LBP), with an RV-LV delay set to 5 ms. To test effect of prolonged RV-LV delays and RV pacing location, the RV-LV delay was increased to 35 ms and/or the RV stimulus was moved to the RV septum. BIV-endo lateral pacing was less sensitive to increased RV-LV delays, while RV septal pacing worsened response compared to RV apical pacing, especially for long RV-LV delays. To investigate how left bundle capture affects response, we computed 90% BIV activation times (BIVAT-90) during BIV-LBP with selective and non-selective capture, and left bundle branch area pacing (LBBAP), simulated by pacing 1 cm below the left bundle. Non-selective LBP was comparable to selective LBP. LBBAP was worse than selective LBP (BIVAT-90: 54.2 ± 5.7 ms vs. 62.7 ± 6.5, p < 0.01), but it still significantly reduced activation times from baseline. Finally, we compared leadless LBP with RV pacing against optimal LBP delivery through a standard lead system by simulating BIV-LBP and selective LBP alone with and without optimized atrioventricular delay (AVD). Although LBP alone with optimized AVD was better than BIV-LBP, when AVD optimization was not possible BIV-LBP outperformed LBP alone, because the RV pacing stimulus shortened RV activation (BIVAT-90: 54.2 ± 5.7 ms vs. 66.9 ± 5.1 ms, p < 0.01). BIV-endo lateral pacing or LBP delivered through a leadless system could potentially become an alternative to standard CRT. RV-LV delay, RV lead location and type of left bundle capture affect leadless pacing efficacy and should be considered in future trial designs.

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A significant number of right bundle branch block (RBBB) patients receive cardiac resynchronization therapy (CRT), despite lack of evidence for benefit in this patient group. His bundle (HBP) and left bundle pacing (LBP) are novel CRT delivery methods, but their effect on RBBB remains understudied. We aim to compare pacing-induced electrical synchrony during conventional CRT, HBP, and LBP in RBBB patients with different conduction disturbances, and to investigate whether alternative ways of delivering LBP improve response to pacing. We simulated ventricular activation on twenty-four four-chamber heart geometries each including a His-Purkinje system with proximal right bundle branch block (RBBB). We simulated RBBB combined with left anterior and posterior fascicular blocks (LAFB and LPFB). Additionally, RBBB was simulated in the presence of slow conduction velocity (CV) in the myocardium, left ventricular (LV) or right ventricular (RV) His-Purkinje system, and whole His- Purkinje system. Electrical synchrony was measured by the shortest interval to activate 90% of the ventricles (BIVAT-90). Compared to baseline, HBP significantly improved activation times for RBBB alone (BIVAT-90: 66.9 ± 5.5 ms vs. 42.6 ± 3.8 ms, p < 0.01), with LAFB (69.5 ± 5.0 ms vs. 58.1 ± 6.2 ms, p < 0.01), with LPFB (81.8 ± 6.6 ms vs. 62.9 ± 6.2 ms, p < 0.01), with slow myocardial CV (119.4 ± 11.4 ms vs. 97.2 ± 10.0 ms, p < 0.01) or slow CV in the whole His-Purkinje system (102.3 ± 7.0 ms vs. 75.5 ± 5.2 ms, p < 0.01). LBP was only effective in RBBB cases if combined with anodal capture of the RV septum myocardium (BIVAT-90: 66.9 ± 5.5 ms vs. 48.2 ± 5.2 ms, p < 0.01). CRT significantly reduced activation times in RBBB in the presence of severely slow RV His-Purkinje CV (95.1 ± 7.9 ms vs. 84.3 ± 9.3 ms, p < 0.01) and LPFB (81.8 ± 6.6 ms vs. CRT: 72.9 ± 8.6 ms, p < 0.01). Both CRT and HBP were ineffective with severely slow CV in the LV His-Purkinje system. HBP is effective in RBBB patients with otherwise healthy myocardium and Purkinje system, while CRT and LBP are ineffective. Response to LBP improves when LBP is combined with RV septum anodal capture. CRT is better than HBP only in patients with severely slow CV in the RV His-Purkinje system, while CV slowing of the whole His-Purkinje system and the myocardium favor HBP over CRT. [ABSTRACT FROM AUTHOR]