Rhythm and rate control strategies in patients with long-standing persistent atrial fibrillation treated with cardiac resynchronization: the results of the randomized Pilot-CRAfT study.

Background: Atrial fibrillation (AF) is common in cardiac resynchronization therapy (CRT) recipients. It is a marker of impaired CRT response mainly mediated by the reduction of effectively captured biventricular paced beats (BiVp). There are no randomized trials comparing strategies to maintain high BiVp percentage.

Objective: To compare the efficacy of rhythm vs rate control strategies in CRT recipients with long-standing persistent AF.

Methods: We performed a randomized trial including CRT recipients with persistent AF resulting in low BiVp%. All patients received amiodarone, the rhythm control group received external electrical cardioversion (EC), and the rate control group received atrioventricular node ablation, if needed. The primary end-point was 12-month BiVp% (NCT).

Results: 43 patients were included in the analysis. The mean age was 68.4 (SD: ± 8.3) years and the mean BiVp% 82.4% ± 9.7%. AF lasted 25 ± 19 months. The mean baseline left ventricular ejection fraction (LVEF), left atrium area, and the maximal oxygen uptake (VO2max) were: 30 ± 8%, 33 ± 7 cm², and 14 ± 5 mL/(kg*min), respectively. The EC success rate was 58%. 38% patients remained in sinus rhythm (SR) after 12 months. BiVp% increased similarly in both arms reaching 99% [95% CI 97.3-99.8] and 98% [94.0-99.0], P = 0.14 in rhythm and rate control groups, respectively. LVEF raised significantly only in the rhythm control group (ΔLVEF 4.1 (± 7.3), P = 0,018) which was driven by the patients who maintained SR. No differences in VO2max, QoL, clinical and safety end-points were observed.

Conclusion: Despite comparable BiVp% in both groups, only restoration of SR led to improved left ventricular ejection fraction in CRT patients with long-standing AF.

Trial registration: NCT01850277 registered on 22/04/2013.