Assessment of Left Ventricular (LV) synchronization according to Right ventricular (RV) pacing site and pacing mode

Background: Permanent pacing manages Bradyarrhythmias. RV pacing causes LV dyssynchrony and impair its function. RV septal pacing is thought to reduce LV dyssynchrony, enhancing contraction efficiency rather than RV apical pacing. Sequential RA-RV pacing with a two-chamber pacemaker offers more physiological depolarization than a single chamber pacemaker. Results: RVA and RVS groups (mean age 66.8±11.4 vs. 65±13.6 years) were compared, with similar gender distribution (P=0.266) and medical conditions (84.6% vs. 65.4%), The RVS group showed a significant shorter QRS timing (P=0.0001), with a difference of 161±19.6 ms in RVA group compared to 137 ± 19.1 ms in the RVS group. In the RVA group, the pacing mode was VVI (Single chamber, RV) in 15 (57.7%) patients, and DDD (Dual chambers, RA, RV) in 11 (42.3%) patients. In the RVS group, the VVI mode was used in eight (30.8%) patients, whereas the DDD mode was used in 18 (69.2%) patients. No statistically significant difference was found between groups regarding pacing mode (P = 0.051). Conclusions: RVS pacing reduced QRS time, provided better ventricular depolarization and function and had no considerable effect regarding pacing mode.