Optimal Pacing Rate for Cardiac Resynchronization Therapy

Cardiac resynchronization therapy (CRT) after atrioventricular node (AVN) ablation for permanent atrial fibrillation (AF) has led to better outcomes in heart failure (HF) patients with reduced ejection fraction (HFrEF) and with preserved ejection fraction (HFpEF) compared to pharmacotherapy. Emerging evidence has demonstrated patients with HFpEF may benefit from a higher heart rate compared to standard heart-lowering therapies. The optimal pacing rate for CRT after AVN ablation in persistent AF and HFpEF remains unknown. This is a prospective, randomized crossover study. The objective of the study is to determine if a pacing rate of 80 beats per minute (bpm) improves exercise tolerance during the 6-minute walk test. The investigators will randomly assign half of the participants to a starting rate of 60 bpm and then switch them to a rate of 80 bpm for 3 months, and vice versa. Patient mortality and HF hospitalizations will be recorded at each phase. An electrocardiogram, echocardiogram, pacemaker interrogation, BNP and creatinine levels, KCCQ-12, six-minute walk test, and physical activity measure will be obtained at baseline, 3 months, and 6 months.