Permanent left bundle branch area pacing for atrioventricular block: Feasibility, safety, and acute effect

Left bundle branch area pacing (LBBAP), a new pacing approach, lacks adequate evaluation. To assess the feasibility, safety, and acute effect of permanent LBBAP in patients with atrioventricular block (AVB). A total of 33 AVB patients with indications for ventricular pacing were recruited. Electrocardiograms, pacing parameters, echocardiographic measurements, and complications associated with LBBAP were evaluated perioperatively and at 3-month follow-up. Successful LBBAP was defined as a paced QRS morphology of right bundle branch block pattern in lead V1 and QRS duration (QRSd) less than 130 ms. LBBAP was successfully performed in 90.9% (30/33) of patients (mean age: 55.1 ± 18.5 years; 66.7% male). The mean capture threshold was similar during the procedure (0.76 ± 0.26 V at 0.4 ms) and at the 3-month follow-up (0.64 ± 0.20 V at 0.4 ms). The paced QRSd was 112.8 ± 10.9 ms during the procedure and 116.8 ± 10.4 ms at the 3-month follow-up. Baseline left or right bundle branch block was corrected (intrinsic QRSd 153.3 ± 27.8 ms vs paced QRSd 122.2 ± 9.9 ms) with a success rate of 68.7% (11/16). One ventricular septal lead perforation occurred soon after the procedure with characteristics of pacing failure, and lead revision was successful. Cardiac function and left ventricular synchronization by 2-dimensional echocardiographic strain imaging at the 3-month follow-up slightly improved compared with that at baseline. Permanent LBBAP yielded a stable threshold, a narrow QRSd, and preserved left ventricular synchrony with few complications. Our preliminary results indicate that LBBAP holds promise as an attractive physiological pacing strategy for AVB.