Clinical Outcomes Following PM Implantation: A 3-Year Comparative Study of Sick Sinus Syndrome and Atrioventricular Block

Abstract Background Permanent pacemaker implantation is an established treatment for both sick sinus syndrome (SSS) and atrioventricular block (AVB), yet limited data exist comparing long-term clinical outcomes and cardiac remodeling patterns between these distinct bradyarrhythmic etiologies. Objectives To compare three-year clinical outcomes and cardiac structural changes between SSS and AVB patients following permanent pacemaker implantation. Methods This retrospective observational study enrolled 192 adult patients (65 SSS, 127 AVB) who underwent pacemaker implantation between January 2018 and December 2020. Demographic data, echocardiographic parameters, pacemaker-recorded data, and clinical outcomes were assessed at baseline, one month, six months, one year, and three years. Primary outcomes included changes in cardiac structure and function, symptomatic improvement, new-onset atrial fibrillation, rehospitalization, and all-cause mortality. Results Both groups demonstrated significant declines in left ventricular ejection fraction over three years (SSS: 57.2±6.0% to 54.3±8.3%, p