Clinical outcomes of left bundle branch area pacing in heart failure patients with typical or atypical left bundle branch block.

BACKGROUND

The impact of stricter definition of left bundle branch block (LBBB) on echocardiographic response of left bundle branch area pacing (LBBAP) and clinical outcomes remains unclear.

AIMS: This study aimed to compare the effects of LBBAP in heart failure (HF) patients with typical left bundle branch block (t-LBBB) versus atypical LBBB (a-LBBB).

METHODS

Ninety-seven patients with LBBB and left ventricular ejection fraction <50% who successfully underwent LBBAP were enrolled. Patients were categorized into a t-LBBB group (n = 82) and an a-LBBB group (n = 15) based on Strauss criteria. Baseline characteristics, pacing parameters, and clinical outcomes were compared between the two groups.

RESULTS

In the t-LBBB group, the left ventricular end-diastolic dimension decreased from 63.9 (8.3) mm to 53.5 (8.2) mm (P <0.001), and the left ventricular ejection fraction improved from 33.3 (8.1)% to 51.1 (11.1)% (P <0.001). Compared with the a-LBBB group, the t-LBBB group had a higher proportionof responders (91.5% vs. 33.3%; P <0.001) and hyper-responders (59.8% vs. 13.3%; P <0.001). Also, the t-LBBB group showed lower incidence of death from any cause (2.4% vs. 20.0%; log-rank P = 0.005), HF hospitalizations (6.1% vs. 46.7%; log-rank P <0.001), and the primary composite endpoint (8.5% vs. 60.0%; log-rank P <0.001).

CONCLUSIONS

Compared to HF patients with a-LBBB, LBBAP significantly reverses cardiac remodeling and improves clinical outcomes in those with t-LBBB.