Clinical Outcome After Permanent Pacemaker Implantation in Patients With a High Percentage of Ventricular Pacing.

Previous reports have suggested that right ventricular apical pacing may lead to cardiac dysfunction. Septal pacing is thought to be superior to apical pacing in the prevention of cardiac dyssynchrony, however, there have been no reports on the contribution of septal pacing to improving clinical outcome.We retrospectively evaluated factors associated with cardiac events in patients with right ventricular pacing.The study population consisted of 256 consecutive patients newly implanted with permanent pacemakers and followed-up for 29 ± 18 months. Cardiac events, consisting of cardiac death or heart failure requiring hospitalization, occurred in 22 patients. Kaplan-Meier curves revealed that patients with a high percentage of ventricular pacing (> 90%, n = 101, group H) had a higher incidence of cardiac events than patients with a low percentage of ventricular pacing (< 10%, n = 83, group L) (P = 0.002). In group H, multivariate analysis showed that age (HR: 1.174, 95%CI: 1.066-1.291, P = 0.001), ejection fraction (EF) (HR: 0.898, 95%CI: 0.836-0.964, P = 0.003), QRS duration during cardiac pacing (HR: 1.059, 95%CI: 1.017-1.103, P = 0.006), and existing basal cardiac diseases (HR: 13.080, 95%CI: 2.463-69.479, P = 0.003) were significant predictors of cardiac events, although pacing site had no significant association with prognosis (P = 0.56).Higher age, lower EF, longer QRS duration during cardiac pacing, and existing basal cardiac diseases are associated with poor prognosis in patients with a high percentage of ventricular pacing.