Risk factors of pacing‐induced cardiomyopathy—Insights from lead position

Background Mid-right ventricular septum (mid-RVS) pacing is challenging to implant a lead in the intended position, and its effective-ness for preventing pacing-induced cardiomyopathy (PICM) remains controversial. This study aimed to elucidate the predictors of PICM among the patients with the confirmed lead position. Methods This retrospective multicenter observational study enrolled patients who underwent pacemaker implantation with lead in right ventricular apex (RVA) or mid-RVS and underwent follow-up transthoracic echocardiography (TTE). The position of mid-RVS leads were confirmed by computed tomography. PICM was defined as a left ventricular ejection fraction decrease to <40% at the follow-up TTE. We investigated the predictors of PICM among those patients. Results Among 172 enrolled patients (76 +/- 11 years and 88 men), 18 (10.5%) experienced PICM. The paced QRS duration of the mid-RVS pacing was significantly shorter than that of the RVA pacing (RVAP; 140 +/- 12 ms vs. 158 +/- 18 ms, P<.001); however, there was no significant difference in the incidence of PICM between the two groups (log-rank test, P = .17). The preoperative left ventricular end-systolic diameter (pre-LVESD) and paced QRS duration were independent predictors of PICM in multivariate analyses (hazard ratio, 1.12; 95% confidence interval, 1.03-1.22; P = .01 and hazard ratio 1.03; 95% confidence interval 1.004-1.06; P = .02, respectively). Conclusion Mid-RVS pacing reduced the QRS duration compared with RVAP, but the lead position was not a predictor of PICM. The paced QRS duration and pre-LVESD may be useful indicators for predicting PICM.