Bundle branch block

Cardiology

Cardiac resynchronization therapy

Ventricular pacing

Heart failure

Cardiac pacing

Internal medicine

Electrocardiography

Left bundle branch block

Medicine

Ejection fraction

Randomized controlled trial

JACC. Clinical electrophysiology

This study sought to compare 2 ways of achieving cardiac resynchronization.Cardiac resynchronization therapy (CRT) in patients with symptomatic heart failure and left bundle branch block (LBBB) can be achieved with His-bundle pacing correcting the bundle branch block (His-CRT). The present study is the largest randomized study comparing His-CRT and biventricular pacing (BiV-CRT) to date.Fifty patients with symptomatic heart failure, left ventricular ejection fraction (LVEF) ≤35% and LBBB according to electrocardiography were randomized 1:1 to His-CRT or BiV-CRT and followed for 6 months. At implantation, 7 patients crossed over from His-pacing to LV-pacing in the His-CRT group and 1 patient crossed over from LV-pacing to His-pacing in the BiV-CRT group.His-corrective pacing was achieved in 72% of the patients in the His-CRT group. Intention-to-treat 6-month follow-up LVEF increased by 16 ± 7% in the His-CRT group compared with 13 ± 6% in the BiV-CRT group (nonsignificant) and improvements were seen in clinical and physical parameters in both treatment arms with no significant differences between the groups. Pacing thresholds were higher for His-CRT compared with BiV-CRT both at implantation (1.8 ± 1.2 V vs. 1.2 ± 0.8 V; p < 0.01) and at 6-month follow-up (2.3 ± 1.4 V vs. 1.4 ± 0.5 V; p < 0.01). The per-protocol LVEF was significantly higher at 6 months (48 ± 8% vs. 42 ± 8%; p < 0.05) and the end-systolic volume was lower (65 ± 22 ml vs. 83 ± 27 ml; p < 0.05) in His-CRT patients compared with BiV-CRT.In heart failure patients with LBBB, His-CRT provided similar clinical and physical improvement compared with BiV-CRT at the expense of higher pacing thresholds.

A Randomized Trial of His Pacing Versus Biventricular Pacing in Symptomatic HF Patients With Left Bundle Branch Block (His-Alternative)