Predictors of implantation failure in left bundle branch area pacing using a lumenless lead in patients with bradycardia

BackgroundLeft bundle branch area pacing (LBBAP) is a novel conduction system pacing technique. In this multicenter study, we aimed to evaluate the procedural success, safety, and preoperative predictors of procedural failure of LBBAP. MethodsLBBAP was attempted in 285 patients with pacemaker indications for bradyarrhythmia, which were mainly atrioventricular block (AVB) (68.1%) and sick sinus syndrome (26.7%). Procedural success and electrophysiological and echocardiographic parameters were evaluated. ResultsLBBAP was successful in 247 (86.7%) patients. Left bundle branch (LBB) capture was confirmed in 54.7% of the population. The primary reasons for procedural failure were the inability of the pacemaker lead to penetrate deep into the septum (76.3%) and failure to achieve shortening of stimulus to left ventricular (LV) activation time in lead V6 (18.4%). Thickened interventricular septum (odds ratio [OR], 2.48; 95% confidence interval [CI], 1.15-5.35), severe tricuspid regurgitation (OR, 8.84; 95% CI, 1.22-64.06), and intraventricular conduction delay (OR, 8.16; 95% CI, 2.32-28.75) were preoperative predictors of procedural failure. The capture threshold and ventricular amplitude remained stable, and no major complications occurred throughout the 2-year follow-up. In patients with ventricular pacing burden >40%, the LV ejection fraction remained high regardless of LBB capture. ConclusionsSuccessful LBBAP was affected by abnormal cardiac anatomy and intraventricular conduction. LBBAP is feasible and safe as a primary strategy for patients with AVB, depending on ventricular pacing.