Pacing-Induced Cardiomyopathy in Leadless and Traditional Pacemakers: A Single-Center Retrospective Analysis

Background: Pacing-induced cardiomyopathy (PICM) is a clinical syndrome that is characterized by a drop in the left ventricular ejection fraction (LVEF) due to chronic high-burden right ventricular (RV) pacing. It has been postulated that leadless pacemakers (LPs) cause decreased risk of PICM compared to transvenous pacemakers (TVPs), but the exact risk reduction is unknown. Methods: We performed a single-center retrospective analysis of adults who received an LP or TVP between January 1, 2014, and April 1, 2022, and had echocardiograms before and after the pacemaker implant. This study’s outcomes were the RV pacing percentage, change in EF, the need for cardiac resynchronization therapy (CRT) upgrade, and follow-up duration. A Wilcoxon rank-sum test calculated the change in EF. RV time, defined as the duration from pacemaker placement to the follow-up echocardiogram in months multiplied by the RV pacing percentage, served as a surrogate for how long the RV was paced. Results: A total of 614 patients were screened, and 198 patients were included in the study, where 72 received LP and 126 received TVP. The median follow-up was 480 days. The average of the reported RV percentage pacing was 63.43% for LP and 71.30% for TVP (p=0.14). The incidence of PICM and CRT upgrade was 44% and 9.7% in the LP group and 37% and 9.5% in the TVP group (p=0.3 and p>0.9), respectively. After accounting for age, sex, LP versus TVP, atrioventricular nodal ablation, RV pacing percentage, and follow-up duration, univariate analysis showed that RV time was significantly different between the two types of pacemakers (13.54 ± 14.21 months (LP) versus 9.26 ± 13.95 months (TVP), p=0.009). The difference in RV time between patients who underwent CRT upgrade and those who did not was statistically insignificant (12.11 ± 14.47 months (no CRT) versus 9.19 ± 12.00 months (CRT), p=0.5). Conclusions: This analysis demonstrated that the incidence of PICM was high in both groups (44% (LP) versus 37% (TVP)), despite significantly more RV time in patients with LP. There was no difference in CRT upgrade between LP and TVP.