Abstract 17740: Can Adaptive Cardiac Resynchronization Therapy Reduce Atrial Fibrillation Risk?
Background: Little evidence exists regarding cardiac resynchronization therapy (CRT) reducing the risk for atrial fibrillation (AF). We investigated the impact on AF risk using the Adaptive CRT (aCRT) ambulatory algorithm which continually adjusts CRT to heart rhythms and minimizes right ventricular (RV) pacing when normal intrinsic atrio-ventricular conduction exists.
Methods: The global Adaptive CRT Trial randomized CRT-defibrillator indicated patients (2:1) to receive either aCRT or conventional bi-ventricular pacing (BiV). The risk of AF was assessed by a) time to at least 48 consecutive hours in AF or b) at least 7 consecutive days in AF (persistent) as detected by the device and was compared between the groups using Cox regression and log-rank tests. Patient adverse events due to untoward occurrence of new onset or worsening AF condition were also compared. Patients in permanent AF at baseline (n=2) were excluded from the AF analyses.
Results: Study patients (n=478) were mostly male (69%), NYHA Class III (95%), with LBBB (77%). History of AF (17.6% vs 18.8%; p=0.80), mean left atrial size (23.3 ± 6.6 vs 22.8 ± 6.4 cm2; p=0.43), and other baseline characteristics were well-balanced between aCRT and BiV groups. Over a mean follow-up of 20.2 ± 5.9 months, total percent atrial pacing (28.8 ± 32.7%; p=0.78) and ventricular pacing (95.0 ± 8.5%; p=0.36) were similar between groups, but aCRT reduced RV pacing by an absolute 35.3 ± 37.1% (p<0.0001). Compared to BiV patients, aCRT patients were at lower risk of 48 or more hours in AF (HR 0.54 [95% CI 0.31-0.93]; p=0.03, figure). In patients without prior history of AF, aCRT patients were less likely to develop persistent AF (HR 0.44 [95% CI 0.19-1.03]; p=0.05). Adverse events related to AF were less common with Adaptive CRT (HR 0.39 [95% CI 0.19-0.79]; p=0.01).
Conclusions: Patients receiving aCRT experienced a reduced risk of AF compared to conventional CRT, potentially through a more physiological therapy that minimizes RV pacing.
- © 2013 by American Heart Association, Inc.