Beyond Ventricular Pacing: Is Atrial Cardiomyopathy a Determinant of Clinical Outcome after Pacemaker Implantation?

The study “Clinical Outcomes Following Pacemaker Implantation: A 3-Year Comparative Study of Sick Sinus Syndrome and Atrioventricular Block” presents a relevant comparative analysis between patients with sick sinus syndrome (SSS) and atrioventricular block (AVB) who underwent permanent pacemaker implantation and were followed for three years. The main merit of the work lies in the clinical evaluation and assessment of cardiac remodeling, atrial fibrillation (AF) rates, readmissions, and mortality compared between the two groups.

Among the study’s strengths are the relatively long follow-up period, with serial echocardiographic evaluation, showing important differences between the patterns of cardiac remodeling. Patients with SSS showed a progressive increase in left atrial volume (LAV) and left ventricular end-diastolic diameter (LVDD), in addition to a significant worsening of mitral regurgitation (MR). In contrast, patients with left atrial block (LAB), even with a ventricular pacing load above 90%, showed relative stability in atrial and ventricular dimensions. Both groups had slight reductions in ejection fraction (EF), high rates of AF, hospitalizations, and mortality, without significant differences between the groups. These findings partially challenge the classic concept that right ventricular pacing alone is the main cause of cardiac remodeling.

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