Po-05-045 left bundle branch area pacing electrical synchronization performance compared to conventional biventricular pacing

Long-term right ventricular (RV) pacing has been shown to induce desynchrony and left ventricular (LV) dysfunction. Accordingly, some of those patients may need upgrade for resynchronization therapy (CRT). Left bundle branch area pacing (LBBAP) is increasingly recognized as an attractive alternative for conventional pacing, by preserving LV synchrony. We aimed to 1) describe the procedural characteristics of patients submitted to LBBAP; and 2) to compare final QRS duration with patients undergoing biventricular CRT (BiV-CRT) for RV apical pacing induced LV dysfunction. Single-center cohort including consecutive patients submitted to LBBAP since November 2021. Pacing lead was implanted deep on the interventricular septum, aiming to a right bundle brunch pacing pattern and LV activation time (LVAT) < 90ms. Feasibility, procedure, and fluoroscopy times, electrical synchrony assessed by QRS duration immediately after implantation, and periprocedural complications were assessed. Procedure characteristics were compared to a group of consecutive patients undergoing BiV-CRT due to RV pacing induced cardiomyopathy. A total of 50 patients were submitted to LBBAP (aged 76±13 years, 62% male, 18% with LV ejection fraction < 50%). The most common indication was high-degree atrioventricular block (n = 25, 50%), and in 5 cases (10%) LBBAP was implanted due to failed BiV-CRT. Median LVAT was 86ms (IQR 80-92) and no cases of electrode dislocation or perforation were reported at discharge. LBBAP resulted in a pacing QRS immediately after implantation of 112ms (IQR 105-125), similar across LVEF categories. When compared to a group of patients undergoing BiV-CRT upgrade (n = 43), LBBAP pacing QRS complex duration was significantly lower than pacing QRS before (172ms [IQR 154-184]; p<0.001) and after the upgrade (125ms [IQR 114-138]; p=0.002) (Figure). Furthermore, procedure (63min [IQR 53-79] vs. 112min [IQR 94-140], p<0.001) and fluoroscopy times (4.1min [IQR 3.4-6.4] vs. 19.3min [IQR 11.6-33.6], p<0.001) were significantly shorter in the LBBAP group compared to BiV-CRT upgrade, respectively. In this series of patients undergoing LBBAP, greater electrical synchronization was achieved when compared to BiV-CRT. LBBAP seems a safe and feasible alternative pacing strategy to preserve synchrony. Further studies are needed to understand its role as first-line therapy in patients with indication for ventricular pacing to prevent desynchrony-related cardiomyopathy.