The Echocardiographic Assessment of Subclinical Left Ventricular Dysfunction Due to Permanent Pacemaker Implantation Using Global Longitudinal Strain-An Observational Study

Background: Permanent pacemaker implantation is an established treatment for symptomatic bradyarrhythmias. However, chronic right ventricular (RV) pacing, particularly from the RV apex, may cause abnormal ventricular activation and mechanical dyssynchrony, leading to progressive left ventricular (LV) dysfunction. Conventional assessment using LV ejection fraction (LVEF) may remain normal during early myocardial impairment. Global longitudinal strain (GLS) assessed by two-dimensional speckle-tracking echocardiography can detect subtle myocardial dysfunction before a decline in LVEF becomes evident. The aim is to evaluate the effect of permanent pacemaker implantation on LV myocardial function using GLS and determine the occurrence of subclinical LV dysfunction following RV pacing. Material and Methods: A hospital-based, prospective observational study was conducted in the Department of Cardiology, IPGME&R and SSKM Hospital, Kolkata, over 18 months. Fifty-seven consecutive adults aged ≥18 years undergoing permanent pacemaker implantation for symptomatic bradyarrhythmias were included. LVEF, LVIDd, LVIDs, and GLS were assessed at baseline and after 3 months. Results: The mean age was 66.5 ± 6.2 years, with males comprising 61.4%. Complete heart block was the commonest indication (59.6%), while RV apical pacing predominated (91.2%). LVEF, LVIDd, and LVIDs showed no significant changes at 3 months (p>0.05). In contrast, GLS significantly worsened (p<0.001). Higher RV pacing burden, prolonged paced QRS duration, and RV apical pacing were significantly associated with greater GLS deterioration (p<0.001). ROC analysis showed good predictive performance for RV pacing burden (AUC=0.896) and paced QRS duration (AUC=0.845). Conclusion: GLS detected early subclinical LV dysfunction despite preserved LVEF following permanent RV pacing. Serial GLS assessment may enable earlier identification of patients at risk of pacing-related ventricular deterioration.

Keywords: Permanent pacemaker; Right ventricular pacing; Global longitudinal strain; Subclinical LV dysfunction; Echocardiography.