Fusion pacing in patients with right bundle branch block who undergo cardiac resynchronization therapy.

PURPOSE: Patients with right bundle branch block (RBBB) are less likely to respond to cardiac resynchronization therapy (CRT). We aimed to assess whether patients with RBBB respond to CRT with biventricular fusion pacing. METHODS: Consecutive patients with RBBB at a single tertiary care center, who were implanted with a CRT device capable of biventricular fusion pacing using SyncAV programming, were assessed and compared to a historical cohort of CRT patients with RBBB. QRSd was measured and compared during intrinsic conduction, nominal CRT pacing and manual electrocardiogram-based optimized SyncAV programming. Left ventricular ejection fraction (LVEF) was also compared before and 6 months after CRT. RESULTS: We included 8 consecutive patients with RBBB (group 1) who were able to undergo SyncAV programming and 16 patients with RBBB (group 2) from a historical cohort. In group 1, compared to mean intrinsic conduction QRSd (155 ± 13 ms), mean nominally-paced QRSd was 156 ± 15 ms (ΔQRSd 1.3 ± 11.6; p = 0.77) and SyncAV-optimized paced QRSd was 135 ± 14 ms (ΔQRSd -20.0 ± 20.4; p = 0.03 and ΔQRSd -21.3 ± 16.3; p = 0.008; compared to intrinsic conduction and nominal pacing respectively). In group 2, mean QRSd with nominal pacing was 160 ± 24 ms (ΔQRSd 3.8 ± 33.4; p = 0.66 compared to intrinsic conduction). In group 1, baseline LVEF was 22.1 ± 11.5 and after 6 months of follow-up was 27.8 ± 8.6 (p = 0.047). In group 2, the baseline LVEF was 27.2 ± 10.6 and after 6 months of follow-up was 25.0 ± 10.0 (p = 0.45). CONCLUSIONS: CRT programed to allow biventricular fusion pacing significantly improved electrical synchrony and LVEF in patients with RBBB. Larger studies are required to confirm these findings.

Optimization of Chronic Cardiac Resynchronization Therapy Using Fusion Pacing Algorithm Improves Echocardiographic Response.

BACKGROUND: Whether reprogramming of cardiac resynchronization therapy (CRT) to increase electrical synchrony translates into echocardiographic improvement remains unclear. SyncAV is an algorithm that allows fusion of intrinsic conduction with biventricular pacing. We aimed to assess whether reprogramming chronically implanted CRT devices with SyncAV is associated with improved echocardiographic parameters. METHODS: Patients at a quaternary center with previously implanted CRT devices with a programmable SyncAV algorithm underwent routine electrocardiography-based SyncAV optimization during regular device clinic visits. This analysis included only patients who could be programmed to the SyncAV algorithm (i.e., in sinus rhythm with intrinsic atrioventricular conduction). Echocardiography was performed before and 6 months after CRT optimization. RESULTS: Of 64 consecutive, potentially eligible patients who underwent assessment, 34 who were able to undergo SyncAV programming were included. Their mean age was 74 ± 9 years, 41% were female, and 59% had ischemic cardiomyopathy. The mean time from CRT implant to SyncAV optimization was 17.8 ± 8.5 months. At 6-month follow-up, SyncAV optimization was associated with a significant increase in left ventricular ejection fraction (LVEF) (mean LVEF 36.5% ± 13.3% vs 30.9% ± 13.3%; P < 0.001) and a reduction in left ventricular end-systolic volume (LVESV) (mean LVESV 110.5 ± 57.5 mL vs 89.6 ± 52.4 mL; P < 0.001) compared with baseline existing CRT programming. CONCLUSION: CRT reprogramming to maximize biventricular fusion pacing significantly increased LVEF and reduced LVESV in patients with chronic CRT devices. Further studies are needed to assess if a continuous fusion pacing algorithm improves long-term clinical outcomes and to identify which patients are most likely to derive benefit.

CONTEXTE: On ignore si la reprogrammation du dispositif de resynchronisation cardiaque (DRC) afin d'améliorer la synchronisation électrique se traduit réellement par une amélioration échocardiographique. L'algorithme SyncAV permet de fusionner la conduction intrinsèque et la stimulation biventriculaire. Nous avons tenté de déterminer si la reprogrammation à l'aide de l'algorithme SyncAV d'un DRC implanté de façon permanente permet d'améliorer les paramètres échocardiographiques. MÉTHODOLOGIE: Les patients d'un centre de soins quaternaires porteurs d'un DRC doté d'un algorithme SyncAV programmable ont subi une optimisation électrocardiographique de routine de cet algorithme à l'occasion d'une consultation de suivi. L'analyse ne portait que sur les patients dont le dispositif pouvait être programmé au moyen de l'algorithme SyncAV (c.-à-d. en rythme sinusal avec conduction auriculoventriculaire intrinsèque). Une échocardiographie a été réalisée avant l'optimisation du DRC, puis 6 mois après. RÉSULTATS: Sur les 64 patients consécutifs potentiellement admissibles qui ont fait l'objet d'une évaluation, 34 sujets dont le DRC pouvait être programmé à l'aide de l'algorithme SyncAV ont été retenus. Les sujets avaient en moyenne 74 ± 9 ans; 41 % d'entre eux étaient des femmes, et 59 % présentaient une cardiomyopathie ischémique. Le temps écoulé entre l'implantation du DRC et l'optimisation au moyen de l'algorithme SyncAV était en moyenne de 17,8 ± 8,5 mois. Au moment du suivi à 6 mois, l'optimisation au moyen de l'algorithme SyncAV a été associée à une augmentation significative de la fraction d'éjection ventriculaire gauche (FEVG) (FEVG moyenne de 36,5 % ± 13,3 % vs 30,9 % ± 13,3 %; p < 0,001) et à une réduction du volume télésystolique ventriculaire gauche (VTSVG) (VTSVG moyen de 110,5 ± 57,5 mL vs 89,6 ± 52,4 mL; p < 0,001) comparativement à la programmation initiale du DRC. CONCLUSION: La reprogrammation du DRC afin de maximiser la stimulation biventriculaire par fusion a considérablement augmenté la FEVG et réduit le VTSVG chez les patients porteurs d'un DRC permanent. D'autres études sont nécessaires pour déterminer si un algorithme de stimulation par fusion en continu permet d'améliorer les résultats cliniques à long terme et pour établir le profil des patients les plus susceptibles de bénéficier d'une telle intervention.

Cardiac resynchronization therapy reprogramming to improve electrical synchrony in patients with existing devices.

BACKGROUND: Optimal programming of cardiac resynchronization therapy (CRT) has not yet been fully elucidated. A novel algorithm (SyncAV) has been developed to improve electrical synchrony by fusion of the triple wavefronts: intrinsic, right ventricular (RV)-paced, and left ventricular (LV)-paced. METHODS: Consecutive patients at a single tertiary care center with a previously implanted CRT device with SyncAV algorithm (programmable negative AV hysteresis) were evaluated. QRS duration (QRSd) was measured during 1) intrinsic conduction, 2) existing CRT pacing as chronically programmed by treating physician, 3) using the device-based QuickOpt™ algorithm for optimization of AV and VV delays, and 4) ECG-based optimized SyncAV programming. The paced QRSd was assessed and compared to intrinsic conduction and between the different modes of programming. RESULTS: Of 64 consecutive, potentially eligible patients who underwent assessment, 34 patients who were able to undergo SyncAV programming were included. Mean intrinsic conduction QRSd was 163 ±â€¯24 ms. In comparison, the mean QRSd was 152 ±â€¯25 ms (-11.1 ±â€¯19.0) during existing CRT pacing, 160 ±â€¯25 ms (-4.1 ±â€¯25.2) using the QuickOpt™ algorithm and 138 ±â€¯23 (-24.9 ±â€¯17.2) using ECG-based optimized SyncAV programming. SyncAV optimization resulted in significant reductions in QRSd compared to existing CRT pacing (P = 0.02) and QuickOpt™ (P < 0.001). Of the 32% of patients who did not have QRS narrowing with existing CRT, 72% experienced QRS narrowing with SyncAV. CONCLUSION: ECG-based atrio-ventricular delay optimization using SyncAV significantly improved electrical synchrony in patients with a previously implanted CRT. Further studies are needed to assess the impact on long-term outcomes.

Incidence and Predictors of Intracardiac Thrombus on Pre-electrophysiological Procedure Transesophageal Echocardiography.

BACKGROUND: Cerebral thromboembolism is a potentially devastating complication of atrial fibrillation (AF) and atrial flutter (AFl). The use of transesophageal echocardiogram (TEE) before electrophysiological procedures in anticoagulated patients is variable. Our objective was to determine the incidence and identify predictors of intracardiac left atrial appendage (LAA) thrombus on TEE in patients with AF/AFl before electrical cardioversion or ablation. METHODS: We reviewed TEEs of 401 patients undergoing an electrical cardioversion, AF, or AFl ablation from April 2013 to September 2015 at the McGill University Health Center. Clinical and echocardiographic variables were collected at the time of the TEE and follow-up visits. Multivariate logistic regression was used to determine predictors of LAA thrombus. RESULTS: Of 401 patients, 11.2% had LAA thrombus on TEE. The majority (87%) of patients were anticoagulated for at least 3 weeks before the TEE. The incidence of LAA thrombus was 21% (23/110) in patients taking warfarin vs 6.4% (15/236) in patients taking direct oral anticoagulants. Multivariate analysis identified prior stroke (odds ratio [OR], 2.7; 95% confidence interval [CI], 1.1-6.9) and heart failure (OR, 2.2; 95% CI, 1.0-4.7) as predictors of thrombus, whereas direct oral anticoagulant use (OR, 0.4; 95% CI, 0.2-0.8) was associated with reduced odds of thrombus. CONCLUSIONS: LAA thrombus was identified in a significant proportion of patients undergoing TEE before cardioversion or ablation of AF/AFl despite preprocedural anticoagulation. Patients at increased risk of LAA thrombus (heart failure and prior stroke) may benefit from TEE before cardioversion, AF, or AFl ablation.

INTRODUCTION: La thromboembolie cérébrale est une complication potentiellement dévastatrice de la fibrillation auriculaire (FA) et du flutter auriculaire. L'utilisation de l'échocardiographie transœsophagienne (ETO) avant les interventions en électrophysiologie chez les patients anticoagulés est variable. Notre objectif était de déterminer la fréquence et les prédicteurs des thrombi intracardiaques dans l'appendice auriculaire gauche (AAG) à l'ETO chez les patients atteints de FA ou de flutter auriculaire avant de procéder à une cardioversion électrique ou à une ablation. MÉTHODES: Nous avons passé en revue les ETO de 401 patients qui avaient subi une cardioversion électrique, ou une ablation de la FA ou du flutter auriculaire entre avril 2013 et septembre 2015 au Centre universitaire de santé McGill. Nous avons recueilli les variables cliniques et échocardiographiques au moment de l'ETO et des visites de suivi. Nous avons utilisé la régression logistique multivariée pour déterminer les prédicteurs de thrombus dans l'AAG. RÉSULTATS: Parmi les 401 patients, 11,2 % avaient un thrombus dans l'AAG à l'ETO. La majorité (87 %) des patients étaient anticoagulés au moins 3 semaines avant l'ETO. La fréquence des thrombus dans l'AAG était de 21 % (23/110) chez les patients qui prenaient de la warfarine vs 6,4 % (15/236) chez les patients qui prenaient des anticoagulants oraux directs. L'analyse multivariée a permis d'établir que l'accident vasculaire cérébral (AVC) antérieur (ratio d'incidence approché [RIA], 2,7; intervalle de confiance [IC] à 95 %, 1,1-6,9) et l'insuffisance cardiaque (RIA, 2,2; IC à 95 %, 1,0-4,7) étaient des prédicteurs de thrombus, alors que l'utilisation d'anticoagulants oraux directs (RIA, 0,4; IC à 95 %, 0,2-0,8) était associée une probabilité moindre de thrombus. CONCLUSIONS: Une proportion importante de patients qui avaient subi l'ETO avant la cardioversion, ou l'ablation de la FA ou du flutter auriculaire avaient un thrombus dans l'AAG en dépit de l'anticoagulation avant l'intervention. Les patients exposés à un risque accru de thrombus dans l'AAG (insuffisance cardiaque et AVC antérieur) peuvent bénéficier de l'ETO avant la cardioversion, ou l'ablation de la FA ou du flutter auriculaire.