Ventricular Remodeling During Long-Term Right Ventricular Pacing Following His Bundle Ablation

To investigate ventricular remodeling during long-term right ventricular (RV) pacing after His bundle ablation (HBA) in patients with atrial arrhythmias, a retrospective analysis was performed on echocardiographic data from 45 patients (mean age 57 ± 11 years) with atrial arrhythmias who underwent HBA and pacemaker implantation (HBA-PI) to control ventricular rate. Echocardiography was performed 1 year before HBA-PI, and up to 7 ± 2 years of follow-up was conducted. An inverse linear relation was found between the relative increase of left ventricular (LV) end-diastolic diameter (EDD) during long-term RV pacing and LVEDD before HBA-PI (r = −0.61, p <0.001). Patients were divided into 2 groups: those with LVEDDs smaller than the mean LVEDD of 50 mm (group I, 46 ± 2 mm, n = 28) and those with LVEDDs >50 mm (group II, 56 ± 4 mm, n = 17). Before HBA-PI, patients in group I had significantly smaller LV weights (167 ± 44 vs 238 ± 56 g) and LV end-systolic diameters (30 ± 2 vs 42 ± 7 mm) and higher LV ejection fractions (64 ± 5% vs 49 ± 12%) than those in group II. In group I, long-term RV pacing increased LVEDD, LV end-systolic diameter, LV weight, and left atrial diameter; increased mitral regurgitation; and decreased the LV ejection fraction and LV fractional shortening. No significant changes were observed during long-term RV pacing in group II. In conclusion, long-term RV pacing after HBA adversely affects LV structure and function in patients with initially normal LV dimensions and function.