Effectiveness of upgrading to Left Bundle Branch Area Pacing compared with Biventricular Pacing in Patients with Right Ventricular Pacing-Induced Cardiomyopathy.

Background: Pacing-induced cardiomyopathy (PICM) occurs in some patients requiring high burden of right ventricular pacing (RVP).Whether left bundle branch area pacing (LBBAP) might be superior to biventricular pacing delivering cardiac resynchronization therapy (BiVP-CRT) remains unclear.

Objective: The present study aimed to evaluate the effectiveness of LBBAP compared with BiVP in patients with PICM.

Methods: This prospective, two-center observational study enrolled consecutive patients with PICM who underwent upgrading to either LBBAP or BiVP. LBBAP was further classified into left bundle branch pacing (LBBP) and left ventricular septal pacing (LVSP). The primary endpoint was the change in left ventricular ejection fraction (LVEF) from baseline to 6-month follow-up. Other echocardiographic parameters, NT-proBNP levels, New York Heart Association (NYHA) functional class, and clinical events (all-cause mortality, heart failure hospitalization, malignant ventricular arrhythmias) were evaluated during follow-up.

Results: Totally 78 patients were included into the final analysis (33% patients with LVEF<35%), including 40 patients with LBBAP (30 with LBBP and 10 with LVSP) and 38 patients with BiVP. At the 6-month follow-up, LVEF improvement was significantly greater in patients with LBBAP than those with BiVP (9.59±7.48% vs 4.91±7.73%; P=0.008), and higher in LBBP than LVSP (10.62±7.28% vs 6.47±7.57). During a mean follow-up duration of 20.5 ± 12.5 months, clinical outcomes did not differ between BiVP and LBBAP groups [26.3% vs 17.5%; adjusted HR=1.57(0.55-4.48), P=0.395] after adjustment for confounders.

Conclusions: PICM upgrading to LBBAP or BiVP demonstrated similar clinical outcomes, but upgrading to LBBAP was associated with greater improvement in LVEF.