Left Bundle Branch Area Pacing Compared to Right Ventricular Outflow Tract Septal Pacing: Mid-term Results and Learning Curve.

Our study evaluated the efficacy and feasibility of left bundle branch area pacing (LBBAP) compared to right ventricular outflow tract septal pacing (RVOSP). We conducted a prospective, single-center, observational study involving 200 consecutive patients who required pacemaker implantation. The patients were divided into two groups (LBBAP and RVOSP), with 100 patients in each group. We aimed to compare the safety and efficacy, as well as the procedure and fluoroscopy times, between the two groups. Additionally, we aimed to describe the learning curve for the LBBAP group. The success and acute complication rates were similar (P = .56 vs. P = .65). The procedure time was longer in the LBBAP group compared to the RVOSP group (18 [13-28] vs. 11 [7-17] min; P < .001), while the fluoroscopy time was shorter in the LBBAP group compared to the RVOSP group (2.8 [1.3-3.7] vs. 3.1 [2-5.9] min; P = .02). The paced QRS interval was narrower in the LBBAP group (123.77 ± 10.25 vs. 159.79 ± 17.0 ms; P = .001). There were no significant differences in pacing parameters like R-wave sensing (9.6 ± 5.2 vs. 9.1 ± 4.7 mV; P = .91), bipolar impedance (685.9 ± 151.8 vs. 686.5 ± 158.6 Ω; P = .98), or pacing threshold (0.70 ± 0.29 vs. 0.64 ± 0.26 V @ 0.4 ms; P = .63). In the LBBAP group, both the procedure time (12 [10.5-15] vs. 32 [28.5-38.5] min; P < .001) and the fluoroscopy time (2 [1-4.6] vs. 5.1 [3.4-12] min; P < .01) were shorter in the last quartile (Q4) compared to the first quartile (Q1). The procedure time was similar between LBBAP Q4 and RVOSP (12 [10.5-15] vs. 11 [7-17] min; P = .33). LBBAP is as safe as RVOSP and achieves a narrower paced QRS compared to RVOSP. After a rapid learning curve, a shorter fluoroscopy time and a similar procedure time can be achieved.