Predictors of pacemaker dependence and pacemaker dependence as a predictor of mortality in patients with implantable cardioverter defibrillator.

BACKGROUND

The prevalence, predictors, and survival for the development of pacemaker dependence (PD) in patients implanted with an implantable cardioverter defibrillator (ICD) are unknown.

METHODS

This was a retrospective analysis of 1,550 consecutive patients with ICD implantation at a single center from 1996 to 2008 with a mean of 4.2 ± 3.4 years. Patients with implant intrinsic heart rates less than 40 beats/min (n = 48) and cardiac resynchronization therapy (n = 444) were excluded leaving 1,058 patients in this study. PD was defined as an intrinsic rhythm <40 beats/min after inhibiting the pacemaker, <50 beats/min with transient symptoms of dizziness relieved by resumption of pacing and right ventricle pacing despite algorithms to promote intrinsic conduction at the 3 monthly follow-up ICD clinic visits. Multivariate regression and Cox proportional hazard models were used for analysis.

RESULTS

The mean age was 64 ± 13 years; 79% were male with a primary indication for the ICD in 57%. PD occurred in 142 (13.4%) of patients, with a mean time to PD of 2.6 ± 1.9 years. PD was associated with a 48% increased odds for mortality versus non-PD ICD patients during the mean follow-up time of 4.2 ± 3.4 years (adjusted odds ratio = 1.48 [95% confidence interval 1.080-2.042]; P = 0.015). Older age, a history of atrial fibrillation, amiodarone use, and secondary prevention were the strongest predictors for the development of PD.

CONCLUSIONS

In this single-center ICD cohort, the development of PD was not uncommon and was associated with decreased survival.