Echocardiographic changes following dual-chamber pacemaker implantation at a Malaysian tertiary heart center
Dual-chamber pacemaker implantation restores atrioventricular synchrony, but it might be associated with alterations in ventricular mechanics and valvular function. The echocardiographic effects of dual-chamber pacing in contemporary practice remain incompletely characterized. We conducted a retrospective single-center study of patients who underwent dual-chamber pacemaker implantation and had transthoracic echocardiography performed before and after implantation in 2022. Changes in left ventricular ejection fraction (LVEF), ventricular and atrial functional parameters, strain-derived measures, and tricuspid regurgitation (TR) severity were assessed using paired statistical analyses. In total, 57 patients were included. The mean LVEF declined from 59.6% before implantation to 55.8% after implantation (mean change, − 3.76%; 95% confidence interval [CI], − 7.45 to 0.08; P = 0.051). Among the strain-based measures, right ventricular global longitudinal strain (RVGLS) worsened by a mean of 3.10% (95% CI, 0.73 to 5.48; P = 0.012), and left atrial conduit strain (LAScd) declined by 3.74% (95% CI, 3.11 to 4.37; P = 0.032) following pacemaker implantation. Stuart-Maxwell testing showed no significant overall shift in TR severity following pacemaker implantation (χ2 = 24.94, P = 0.678). The left atrial volume index decreased significantly (38.98 ± 17.16 mL/m2 vs. 34.38 ± 12.65 mL/m2, P = 0.023), but it showed no correlation with LAScd at baseline (ρ = − 0.183, P = 0.265) or with changes in LAScd over time (ρ = 0.160, P = 0.350). In regression analyses, increasing age was independently associated with greater decline in LAScd (β = − 0.323 per year; 95% CI, − 0.494 to − 0.152; P < 0.001). A high pacing burden (> 20%) was not associated with changes in LVEF, LAScd, or RVGLS. Dual-chamber pacemaker implantation was associated with early deterioration in myocardial deformation, particularly RVGLS and LAScd, despite preserved conventional systolic parameters. These functional changes were not accompanied by structural remodeling and were independent of TR progression, supporting a mechanism related to pacing-induced dyssynchrony and altered ventricular-atrial coupling. Strain imaging could offer incremental value in detecting early subclinical dysfunction in this population.