Introduction:
Transvenous pacemaker (TVP) with right ventricular (RV) apical pacing over 40% has been associated with a 17-25% risk of Pacing-Induced Cardiomyopathy (PICM), defined as a decrease in ejection fraction (EF) by 10% or more. It’s been postulated that a septally placed Leadless Pacemaker (LP) causes less risk of PICM, but the exact incidence 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. 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 to 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 161 patients with RV percentage pacing for LP was 63.43% and TVP was 71.30% (p=0.14). The incidence of PICM and CRT upgrade in the LP group was 44% and 9.7% in LP and TVP was 37% and 9.5% in TVP (p=0.3 and p>0.9), respectively. After accounting for age, age, sex, LP vs TVP, atrioventricular nodal ablation, RV pacing percentage, and follow-up duration, univariate analysis showed that RV time was significantly different between pacemakers (LP 1,353.97 ± 1,420.56 months vs TVP 926.47 ± 1,395.17 months, p=0.009), but not with CRT (No CRT 1,211.37 ± 1,447.45 months vs CRT 919.34 ± 1,199.54 months, p=0.5).
Conclusions:
This analysis demonstrated that the incidence of PICM was high in both groups (LP 44% vs TVP 37%). Despite significantly more RV time in patients with LP, there was no difference in CRT upgrade.