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.

Predicting response to cardiac resynchronization therapy: Use of strict left bundle branch block criteria.

BACKGROUND: Cardiac resynchronization therapy (CRT) reduces morbidity and mortality in heart failure with reduced ejection fraction (HFrEF). CRT efficacy is greater in left bundle branch block (LBBB). This study aimed to determine if strict LBBB criteria predict an improved QRS duration and left ventricular ejection fraction (LVEF) response after CRT. METHODS: HFrEF patients who received a CRT device at a single quaternary center were included. Patients were divided into three groups based on baseline QRS morphology. Group 1 consisted of patients with strict LBBB. Group 2 had conventional LBBB, and group 3 had non-LBBB morphology. Outcomes assessed included change in QRS duration after CRT, change in LVEF, and all-cause mortality. RESULTS: In 231 patients, 56% of patients were in group 1, 29% were in group 2, and 15% were in group 3. Patients with strict LBBB had a significant reduction in QRS duration (-20.9 ± 12.4 ms) compared to conventional LBBB (6.7 ± 19.4 ms; P < 0.0001) and non-LBBB (3.9 ± 29.3 ms; P < 0.0001). Patients with strict LBBB had a significant increase in LVEF (19.5 ± 10.2) compared to conventional LBBB (5.3 ± 12.6; P < 0.0001) and non-LBBB (-1.3 ± 10.9; P < 0.0001). There was moderate negative correlation between changes in QRS duration and LVEF (correlation coefficient = -0.63, P < 0.0001). Strict LBBB criteria were associated with a significant reduction in mortality compared to conventional LBBB (odds ratio 0.49, 95% confidence interval 0.24 to 0.99; P = 0.046). CONCLUSIONS: Strict LBBB predicted a reduction in QRS duration and an increase in LVEF compared to conventional LBBB and non-LBBB morphology in patients with HFrEF who received CRT.

Prognostic value of atrial fibrillation inducibility after right atrial flutter ablation.

BACKGROUND: Patients with typical right atrial flutter (AFL) may also have underlying atrial fibrillation (AF) or be at high risk of developing AF. Inducibility of AF among patients undergoing AFL ablation may be an important predictor of future occurrence of AF and may be useful in guiding management of this patient population. OBJECTIVE: This study aimed to determine whether inducibility of AF at the time of AFL ablation is independently associated with the risk of future AF. METHODS: Attempt at induction of AF by burst pacing was performed in consecutive patients who underwent AFL ablation. Time to incidence of AF after AFL ablation was examined using multivariable Cox proportional hazards models. All analyses were stratified by a history of AF. RESULTS: A total of 175 patients were retrospectively evaluated over a median follow-up period of 482 days. In patients without a documented history of AF (n = 93), the incidence of AF after AFL ablation was 18.7 per 100 person-years. In these patients, inducible AF was strongly associated with the future development of AF (adjusted hazard ratio 15.99; 95% confidence interval 5.10-50.12). In contrast, in patients with a documented history of AF (n = 82), the incidence of AF after AFL ablation was 59.3 per 100 person-years and inducible AF was not associated with the future development of AF (adjusted hazard ratio 1.26; 95% confidence interval 0.74-2.14). CONCLUSION: Inducibility of AF after AFL ablation is strongly and independently associated with the risk of future AF among patients without a history of AF but not among patients with a history of AF.

Psychological impact of surveillance in patients with a defibrillator lead under advisory: a prospective evaluation.

BACKGROUND: Implantable cardioverter defibrillator (ICD) leads are subject to technical failures and the impact of the resulting public advisories on patient welfare is unclear. The psychological status of patients who received an advisory for their Medtronic Fidelis ICD lead (Medtronic Inc., Minneapolis, MN, USA) and followed either by self-surveillance for alarm or home monitoring with CareLink was evaluated prospectively and compared to patients with ICDs not under advisory. METHODS: One hundred sixty consecutive consenting patients (90 alarms, 24 Carelinks, 46 controls) were recruited within 1.5 years of advisory notification. Advisory patients were seen immediately before being told that the automatic lead surveillance utilized since the advisory had been inadequate in warning of impending fracture, as well as 1 and 6 months after programming was optimized. Depression, anxiety, quality of life (QoL), and ICD-related concerns were assessed. RESULTS: Symptoms of depression and state anxiety were experienced by 31% and 48% of patients, respectively. QoL was impaired on all subscales. No significant group differences in distress and ICD-related concerns emerged at baseline or at follow-up. At baseline, alarm patients reported greater limitations because of body pain compared to controls (P < 0.05). All patients showed a significant reduction in body pain-related QoL at the final versus first two evaluations (P < 0.001). Advisory patients were significantly less satisfied with surveillance at follow-up than at baseline (P < 0.05). CONCLUSIONS: There was limited evidence for worse psychosocial functioning in those at risk for ICD lead fracture, irrespective of surveillance method. However, many control and advisory patients experienced chronic distress for which counseling may prove beneficial.

Improved Flutter Ablation Outcomes Using a 10mm-tip Ablation Catheter.

INTRODUCTION: Radiofrequency(RF) ablation has become the first line of therapy for atrial flutter(AFL). Advances in catheter and mapping technologies have led to better understanding and different approaches for treating this arrhythmia. We describe the results of different approaches to ablate this arrhythmia. MATERIALS AND METHODS: A cohort of 198 patients with isthmus dependent AFL. The techniques used were: 10mm-tip catheter with power set to 100w, 8mm-tip catheter with power set to 60W and irrigated tip catheter. RESULTS: 212 procedures, including redos were done in 198 consecutive patients. We used irrigated tip catheters in 14 procedures, 8mm-tip in 55 procedures, and 10mm-tip in 143 procedures. Bidirectional block was achieved in 97.6% of cases with all techniques, with no difference among them. Procedure time was shorter in the 10mm-tip versus 8mm-tip(69.6±30.6min vs.105±43min) or irrigated tip(180±90min) (P<0.05). Fluoroscopy time was also shorter in the 10mm-tip versus 8mm-tip (24±18min vs. 37±23min) or irrigated tip (110±25min)(P<0.05). The cumulative incidence of failure during follow-up was 1.2%/year in the 10mm, 10.1%year in the 8mm and 6.9%year in the irrigated tip. The survival free of a new procedure was significantly higher among 10mm patients. CONCLUSIONS: In our series we found a high rate of acute success with the use of different techniques for AFL ablation. Procedure and fluoroscopic times were shorter with the use of 10mm-tip as compared with the others techniques. The long-term risk of recurrence was lower when we used the 10mm-tip catheter and the survival free of a second procedure was higher among patients treated with this catheter.

Patterns and predictors of warfarin use in patients with new-onset atrial fibrillation from the FRACTAL Registry.

Warfarin is underused for stroke prevention in atrial fibrillation (AF). Previous studies addressing this have lacked longitudinal assessment. This study sought to characterize contemporary warfarin use in new-onset AF and evaluate its change over time. It was hypothesized that AF recurrence has an important influence on warfarin use patterns. One thousand five adults from 17 centers in the United States and Canada were enrolled into a prospective observational registry after their first documented episodes of AF. Detailed demographic, clinical history, and management data were collected on all subjects at enrollment, including medication use. Patients were followed at regular intervals for interim events and changes in AF management. Warfarin use at baseline and last follow-up (mean 25 +/- 8 months) after enrollment was modeled using multivariate analysis. Initially, 65% of subjects were prescribed warfarin, but only 44% were taking it at 30 months. Even in "ideal" candidates for warfarin, the rate of warfarin prescription decreased from 70% at baseline to 50% at 30 months. Stroke risk factors, including hypertension, congestive heart failure, valvular heart disease, and previous stroke or transient ischemic attack were significant predictors of warfarin prescription at baseline. At last follow-up, the relation between AF recurrence and warfarin use (odds ratio 2.3, 95% confidence interval 1.6 to 3.1) was stronger than that for any individual stroke risk factor. In conclusion, predictors of warfarin use in patients with AF include AF recurrence and selected stroke risk factors. The discontinuation of warfarin in a large number of patients with AF over time is a cause for concern in light of data from recent clinical trials.