Left Bundle Branch Versus Apical Pacing in Atrioventricular Block and Normal Cardiac Function Post-transcatheter...

There is currently no evidence of the best pacing mode for high-degree atrioventricular (AV) block occurring after transcatheter aortic valve implantation (TAVI). The objective of this pilot study was to compare a clinical combined endpoint achieved by left bundle branch pacing (LBBP) vs right ventricular (RV) pacing in patients with preserved left ventricular ejection fraction (LVEF) post-TAVI at 12-month follow-up.

Consecutive patients post-TAVI with high-degree AV block and LVEF ≥ 50% were randomized to LBBP or RV pacing. The primary endpoint was survival with an improvement of ≥ 1 point in New York Heart Association functional class or a ≥ 25% increase in distance covered on the 6-minute walking test. Secondary endpoints were change in LVEF, septal flash, mitral regurgitation, N-terminal pro-brain natriuretic peptide, heart failure hospitalization, score on symptoms, and QRS duration.

Twenty-four patients were included in the study, 12 in each arm. Both groups showed a similar incidence of the primary endpoint: 33.3% (n = 4) in the LBBP group vs 25% (n = 3) in the RV group (P = 1.0). In relation to secondary endpoints, significant shortening in the QRS was observed in the LBBP group compared with the RV group (median: -39 ms vs 0 ms, P < 0.001). Septal flash excursion was significantly lower for the LBBP group (median: 0 mm vs 2 mm, P = 0.03). There was no difference between groups on any other endpoint.

Similar midterm outcomes were obtained with LBBP and RV pacing in an elderly population with high-degree AV block and preserved LVEF after TAVI. The pilot Phys-TAVI trial showed the feasibility of LBBP in this population. Larger randomized clinical trials with longer follow-up are needed to test for differential clinical outcomes between pacing modalities.

NCT04482816.