Clinical Briefs

Defibrillators in the Elderly

Source: Panotopoulos PT, et al. J Am Coll Cardiol 1997;29:556-560.

Implantable cardioverter-defibrillators (icds) have been shown to be effective for preventing sudden cardiac death. Because they are now smaller and more technologically advanced, their use has increased markedly. Their effect on total mortality is more problematic because most patients with life-threatening cardiac arrhythmias have advanced heart disease. This concern is especially relevant in the elderly. Thus, Panotopoulos et al compared 74 patients over age 75 to 695 less than 75 years old at ICD implantation. Perioperative mortality was less than 2%, and freedom from sudden death was 98% and 97% (P = NS). Actuarial survival at four years follow-up was 57% in the elderly and 78% in the younger patients (P < 0.001). Freedom from cardiac death was 76% and 87% (P < 0.001), and freedom from noncardiac death was 75% and 91% (P < 0.01). Thus, the mortality differences were largely due to non-sudden deaths in the older patients. Multivariate analysis showed that age greater than 75 (odds ratio, 3.6), functional class III (1.8), ejection fraction less than 0.30 (1.6), and appropriate shocks during follow-up (1.4) were predictive of increased mortality. The authors conclude that mortality is three fold higher post-ICD implantation in patients over age 75 vs. those less than 75 years, despite the near elimination of sudden cardiac death in both groups. The major limitation of the study is the retrospective design. Selection bias may have influenced decision making in elderly patients, but one would expect the more robust to be selected for this expensive therapy, making the results more striking. For these reasons, many have suggested that only a randomized trial looking at total mortality can determine the benefits of ICD placement in the elderly, but no such trial is currently being contemplated. Also, drug treatment of arrhythmias and heart failure were not considered in this trial even though some patients received them. Although this might be an important omission, changes in drug therapy recommendations over the time of this study would make analysis difficult. Therefore, as in all treatment decisions, age, concomitant disease, and natural life expectancy must be taken into consideration when deciding on ICD implantation.—mhc