HIS bundle pacing as good as CRT, the "catch" is higher thresholds, HIS-Alternative study.

Procedure time was longer in the His-CRT group (137 vs 102 min; P < 0.01), with no differences in fluoroscopy time or radiation dose.

In the intention-to-treat analysis, both types of pacing improved QRS duration, LVEF (increasing to about 45%), LV end-systolic volume (decreasing by about 35%), NT-proBNP level, 6-minute walk distance, and NYHA class after 6 months, with no differences between trial arms.

Pacing thresholds were higher in the His-CRT versus biventricular-CRT group at baseline (1.8 vs 1.2 V) and at 6 months (2.3 vs 1.4 V; P < 0.05 for both), indicating that His-CRT will drain batteries more quickly and require more-frequent device changes, Vinther said.

Vinther acknowledged that His-pacing is not yet ready to be considered as a first-line therapy in clinical practice, noting that the required tools are not yet optimal, that failure to implant the leads will be more frequent, and that thresholds will be higher.

"We can hope that with better tools and maybe also better leads or maybe even other pacemakers, we could overcome that in the future," Vinther noted.

The trial was limited by its small size (50 patients) and its conduct at a single center, but "we are confident to say that His-CRT holds promise as an alternative to biventricular pacing in selected heart failure patients," Vinther concluded. "And we hope that our study, among others, can pave the way for a larger randomized study that can establish the position of His-CRT as either superior or noninferior to BiV-CRT and establish its place in the guidelines."

• Source: JACC Electrophysiology Vinther M, Risum N, Svendsen JH, et al. A randomized trial of His pacing versus biventricular pacing in symptomatic heart failure patients with left bundle branch block (His-Alternative). J Am Coll Cardiol EP. 2021;Epub ahead of print.