BackgroundLeft bundle branch area pacing (LBBAP) is an emerging pacing method that may prevent the deleterious effects of right ventricular pacing. The aim of this study is to compare the effects of LBBAP with right ventricular septal pacing (RVSP) in patients with advanced atrioventricular conduction abnormalities and preserved left ventricular ejection fraction. MethodsThe effect of pacing was evaluated by echocardiographic indices of dyssynchrony, including global myocardial work efficiency (GWE) and peak systolic dispersion (PSD). The primary endpoint was GWE postprocedural, at 3, 6, and 12 months after the procedure. ResultsTwenty patients received LBBAP and 18 RVSP. Complete follow-up was accomplished in 37 patients (97.4%) due to the death of a patient (RVSP arm) from nonrelated cause. GWE was significantly increased in the group of LBBAP compared to RVSP at all time points (90.8% in LBBAP versus 85.8% in RVSP group at 12 months, p = 0.01). PSD was numerically lower in the LBBAP arm at all time points, yet not statistically significant (56.4 msec in LBBP versus 65.1 msec in RVSP arm at 12 months, p = 0.178). The implantation time was increased (median 93 min in LBBAP versus 45 min in RVSP group, p < 0.01), along with fluoroscopy time and dose area product (DAP), in the arm of LBBAP. There were no severe perioperative acute complications in either group. ConclusionsLBBAP is an emerging and safe technique for patients with a pacing indication. Despite the longer procedural and fluoroscopy time, as well as higher DAP, LBBAP seems to offer better left ventricular synchrony compared to RVSP, according to GWE measurements.