Temporal change in right ventricular pacing ratio and its association with cardiac function and arrhythmia: A linear...

Right ventricular pacing (RVP) induces electrical and mechanical dyssynchrony, possibly influencing left ventricular (LV) dysfunction and heart failure (HF). However, the impact of temporal increases in the RVP ratio (RVP%) on LV remodeling and arrhythmia remains unclear.

This study aimed to evaluate the association between longitudinal changes in RVP% and subsequent adverse LV remodeling and arrhythmia occurrence.

We conducted a retrospective longitudinal cohort study of patients who underwent RVP implantation between May 2013 and December 2024. Patients with ≥6 months of follow-up and serial RVP% data were included. The annual RVP% change rate (slope, %/y) was estimated using linear regression; a slope of ≥10%/y was used to define those in the elevation group, whereas the stable group comprised those with a slope of <10%/y. Primary outcomes were changes in LV ejection fraction and LV end-diastolic dimension. Secondary outcomes included device-detected atrial fibrillation, ventricular tachyarrhythmia (ventricular tachycardia/ventricular fibrillation), and HF hospitalization.

Among 148 patients (median follow-up 1825 days), 37 (25%) were in the elevation group. RVP% increased significantly over time (interaction P < .001). LV ejection fraction declined faster (-3.33%/y vs -1.81%/y; P = .028), with LV end-diastolic dimension progressively enlarging (+1.19 mm/y vs -0.19 mm/y; P < .001). The elevation group showed higher ventricular tachycardia/ventricular fibrillation risk (hazard ratio 6.48; 95% confidence interval 3.44-12.2; P < .001), confirmed by joint modeling (P = .0002), with no association with atrial fibrillation (P = .33). Hospitalization for HF was more frequent (adjusted hazard ratio 3.41; 95% confidence interval 1.42-8.20; P = .006).

Progressive RVP% increase is independently associated with adverse LV remodeling and arrhythmic events, serving as a potential clinical risk marker.