Accelerated Bachmann bundle area pacing for atrial resynchronization in patients with non-obstructive hypertrophic cardiomyopathy and heart failure with preserved ejection fraction: A randomized crossover trial.

Background: Inter-atrial block (IAB) can contribute to the worsening of diastolic dysfunction in heart failure with preserved ejection fraction (HFpEF).

Objective: To determine the effects of accelerated Bachmann bundle area pacing (BBAP) in symptomatic patients with non-obstructive hypertrophic cardiomyopathy (nHCM), HFpEF, and IAB.

Methods: Prospective, randomized, patient-blinded crossover study in symptomatic patients with nHCM, HFpEF, and IAB. Patients were recruited during 2021-2024 for dual-chamber implantable cardioverter defibrillator (ICD) implantation. Patients with successful BBAP were randomized to dual-chamber rate-responsive pacing (DDDR 70/min) or no pacing (VVI 30/min) for 4 weeks. After a washout period of 4 weeks, they were crossed over to the other arm for 4 additional weeks. In addition, a historical cohort of nHCM patients with an atrial lead in the right atrial appendage pacing (RAAP) were programmed to DDDR 70/min for 12 weeks. The primary end point was a change in N-terminal pro-brain natriuretic peptide (NT-proBNP). Secondary end points included 6-minute walk distance, functional class, diastolic filling parameters, and daily diuretic requirement.

Results: Of 46 patients recruited, 42 patients had successful BBAP and were randomized (age 46.2 ± 7.2 years, 82.6% men). BBAP significantly reduced the N-terminal pro-brain natriuretic peptide (NT-proBNP), compared with no pacing (-116.4 ± 22.1 vs -8.1 ± 6.2, P = .008) and RAAP (-116.4 ± 22.1 vs -27.1 ± 12.6, P = .021). BBAP also led to an improvement in all the secondary end points. Compared with the historical cohort of RAAP, BBAP was associated with a significant reduction in NT-proBNP levels (-116.4 ± 22.1 vs -27.1 ± 12.6, P = .021) and all secondary end points.

Conclusion: Among patients with nHCM, HFpEF, and an IAB, accelerated BBAP was found to reduce the NT-proBNP and was accompanied by an improvement in the diastolic function and exercise capacity.