Effects of Pacemakers on Ventricular Functions and Early Variables Associated with Induced Cardiomyopathy

Right ventricular (RV) pacing can alter ventricular mechanics and may lead to ventricular dysfunction, even in patients with preserved baseline left ventricular ejection fraction (LVEF) and structurally normal hearts.

This study examines the hemodynamic effects of right ventricular pacing on left ventricular function and volume, and identifies early variables associated with pacemaker-induced left ventricular dysfunction and cardiomyopathy in patients with dual-chamber RV pacemakers.

The study enrolled patients undergoing dual-chamber RV pacemaker implantation without any structural abnormality of the heart. Data on biventricular functions, LV volumes, and global longitudinal strain (GLS) were collected with 2D, speckle tracking, and 3D echocardiography. Paired continuous variables were compared using two-sided tests with a significance level of 0.05.

Out of 75 patients, 20 experienced LV systolic dysfunction, 15 developed PIVD, and five developed PICM. In comparison to the control group, patients with PICM had lower GLS (17.02 vs. 19.27; p<0.05), wider QRS width (139.57 vs. 102.75; p < 0.05), and greater ventricular pacing percentage (VP%; 94.32 vs. 84.03; p = 0.06).

RV pacing resulted in a substantial decline in LV systolic function in the short and long term. Concurrently, RV functions declined over the long term (six months). Diminished GLS at seven days, a broader pre-implantation QRS complex, and an elevation in VP% are early indicators of PIVD and PICM. Routine patient monitoring for these indicators can be beneficial for timely intervention on a case-by-case basis.