Right ventricular septal pacing upgrade improves left ventricular performance and functional capacity in patients with previous permanent right Ventricular Apical Pacing Independent Of Ventricular Dyssynchrony

Abstract

INTRODUCTION: Right ventricular apical pacing (RVA) results in abnormal left ventricular (LV) electrical and mechanical activation and is associated with an increased risk of developing heart failure. Chronic right ventricular septal pacing (RVS) has been shown to be superior to RVA pacing in newly-implanted patients (pts). However, whether RVS pacing can reverse the deleterious effects of RVA pacing remains unclear. METHODS: We evaluated the effects of RVS pacing on LV performance and functional capacity before and at 6-9 months after device replacement in 12 pts (age: 67±16 yrs, 8F) with previous permanent RVA pacing (>90% pacing, duration of pacing 15±7 yrs). Tissue Doppler imaging (DTI) to measure magnitude of systolic longitudinal displacement (SCS) at time of aortic valve closure, time to peak displacement (T-Pk), peak systolic velocity, and standard deviation of the times of peak systolic velocities (Ts-SD) using an 8 segments method from apical 2 and 4 chamber views was used to determine LV performance and synchrony. Six minutes hallwalk (6MHW) was performed to evaluate functional capacity. RESULTS: After a mean of 270±97 days of RVS pacing, there was a significant decrease in pacing QRS duration (165±13 to 156±10 ms, P=0.03), and increase in LV ejection fraction (53±6 to 59±8 %, P0.05), there was a significant regional improvement in SCS after RVS pacing at the mid-ventricular level (4.8±1.6 to 6.3±2.5 mm, P= 0.027) with the greatest improvement at the mid anterior and mid septal regions and a trend for improvement in global SCS (7.0±1.4 to 8.31±2.49 mm, P = 0.056). CONCLUSIONS: RVS pacing improves regional LV contraction and global ejection fraction, and functional capacity in pts with previous permanent RVA pacing. These findings suggest that RVS pacing can reverse the deleterious effects of longstanding RVA pacing, which appears to be independent of LV dyssynchrony.