Relation between mode of pacing and long-term survival in the very elderly

This study analyzes the relationship between pacing mode and long-term survival in a large group of very elderly patients (> or = 80 years old).

The relationship between pacing mode and long-term survival is not clear. Because the number of very elderly who are candidates for pacing is increasing, issues related to pacemaker (PM) use in the elderly have important clinical and economic implications.

We retrospectively reviewed 432 patients (mean age, 84.5+/-3.9 years) who received their initial PM (ventricular in 310 and dual chamber in 122) between 1980 and 1992. Follow-up was complete (3.5+/-2.6 years). Observed survival was estimated by the Kaplan-Meier method. Age- and gender-matched cohorts from the Minnesota population were used for expected survival. Log-rank test and Cox regression hazard model were used for univariate and multivariate analyses.

Patients with ventricular PMs appeared to have poor overall survival compared with those with dual-chamber PMs. Observed survival after PM implantation in high grade atrioventricular block (AVB) patients was significantly worse than expected survival of the age- and gender-matched population (p < 0.0001), whereas observed survival of patients with sinus node dysfunction was not significantly different from expected survival of the matched population (p = 0.413). By univariate analysis, ventricular pacing in patients with AVB appeared to be associated with poor survival compared with dual-chamber pacing (hazard ratio [HR] 2.08; 95% confidence interval [CI] 1.33 to 3.33). After multivariate analysis, this difference was no longer significant (HR 1.41; 95% CI 0.88 to 2.27). Independent predictors of all-cause mortality were number of comorbid illnesses, New York Heart Association functional class, left ventricular depression and older age at implant. Pacing mode was not an independent predictor of overall survival. Older age at implantation, diabetes mellitus, dementia, history of paroxysmal atrial fibrillation and earlier year of implantation were independent predictors of ventricular pacemaker selection.

After PM implantation, long-term survival among very elderly patients was not affected by pacing mode after correction of baseline differences. Selection bias was present in pacing mode in the very elderly, with ventricular pacing selected for sicker and older patients, perhaps partly explaining the apparent "beneficial impact on survival" observed with dual-chamber pacing.