Impact of a Practice-wide Switch from Traditional Right Ventricular Pacing to Left Bundle Branch Area Pacing.

Left bundle branch area pacing (LBBAP) may mitigate pacing-induced cardiomyopathy (PICM) and is increasingly favored over traditional right ventricular pacing (RVP). We sought to evaluate the impact of a practice-wide switch from RVP to LBBAP. We switched practice from RVP to primarily LBBAP at our center in 2020. A retrospective review was conducted to compare patients who underwent LBBAP from 2020-2023 with controls who underwent RVP from 2018-2019. The LBBAP (n = 288; age, 73.3 ± 10.7 years; left ventricular ejection fraction [LVEF], 56.9% ± 11.4%) and RVP (n = 172) groups were similar in terms of age, body mass index, hypertension, diabetes, and LVEF. The LBBAP group as compared to the RVP group had fewer women (38% vs. 51%; P = .006) and longer intrinsic conducted QRS durations (117 ± 28 vs. 110 ± 30 ms; P = .04). LBBAP devices required longer implant (102 vs. 67 min) and fluoroscopy (9.3 vs. 6.9 min) times but resulted in shorter paced QRS durations (122 ± 20 vs. 145 ± 24 ms; all P < .0001). At 3 months, LBBAP patients had higher sensing (13.8 ± 6.1 vs. 12.0 ± 5.6 mV; P = .007), lower pacing impedance (543 ± 98 vs. 576 ± 150 Ω; P = .008), and similar capture threshold (0.78 ± 0.24 vs. 0.76 ± 0.35 V; P = .5) values. Device-related adverse events were similar between the groups (LBBAP 8.7% vs. RVP 8.8%; P = 1.0), which included ventricular lead dislodgement (2.1% vs. 0.6%; P = .3). There were no differences in hazard rates of all-cause mortality (P = .5) or heart failure (HF) hospitalizations (P = .07). In a subgroup of patients with ≥20% ventricular pacing, the average LVEF change during follow-up in the LBBAP group as opposed to the RVP group was +1.6% ± 12.9% versus -3.8% ± 12.0% (P = .03), the average left ventricular internal diameter at end-diastole change was -0.18 ± 0.73 cm versus +0.16 ± 0.45 cm (P = .006), and there were no differences in the hazard rate of all-cause mortality (P = .6) or HF hospitalizations (P = 1.0). Our results suggest there were no adverse consequences of the practice-wide switch from RVP to LBBAP. LBBAP was associated with longer procedure and fluoroscopy times but resulted in narrower paced QRS durations and less PICM.