Efficacy on resynchronization and longitudinal contractile function comparing His-bundle pacing to conventional biventricular pacing. - A substudy to the His-alternative study

Eur Heart J Cardiovasc Imaging. 2023 Jul 25:jead181. doi: 10.1093/ehjci/jead181. Online ahead of print.


Aims: His-bundle pacing has emerged as a novel method to deliver cardiac resynchronization therapy (CRT). However, there are no data comparing conventional Biventricular (BiV)-CRT to His-CRT with regards to effects on mechanical dyssynchrony and longitudinal contractile function.

Methods and results: Patients with symptomatic heart failure, left ventricular ejection fraction (LVEF) ≤ 35% and left bundle branch block (LBBB) by strict ECG criteria were randomized 1:1 to His-CRT or BiV-CRT. Two-dimensional strain echocardiography was performed prior to CRT implantation and at six months after implantation. Differences in changes in mechanical dyssynchrony (standard deviation of time-to-peak in 12 midventricular and basal segments) and regional longitudinal strain in the six left ventricular walls were compared between the BiV-CRT and His-CRT groups.In the on treatment analysis 31 received BiV-CRT and 19 His-CRT. In both groups mechanical dyssynchrony was significantly reduced after six months (BiV-group from 120 ms [±45] to 63 ms [±22], P < 0.001, His-group from 116 ms [±54] to 49 ms [±11], P < 0.001), but no significant differences in changes could be demonstrated between groups (-9.0 ms [-36; 18], P = 0.50). GLS improved in both groups (BiV-group from -9.1% [±2.7] to -10.7% [±2.6], P = 0.02, and His-group from -8.6% [±2.1] to -11.1% [±2.0], P < 0.001) but no significant differences in changes could be demonstrated from baseline to follow-up (-0.9 [-2.4; -0.6], P = 0.25) between groups. There were no regional differences between groups (P < 0.05, all).

Conclusions: In heart failure patients with LBBB, BiV-CRT and His-CRT have comparable effects with regards to improvements in mechanical dyssynchrony and longitudinal contractile function.

Keywords: 2D speckle tracking; His bundle pacing; biventricular pacing; cardiac resynchronization therapy; heart failure; left bundle branch block.