Efficacy of the implantable cardioverter-defibrillator in the elderly

Objectives. We sought to assess the effect of advanced age on the outcome of patients with an implantable cardioverter-defibrillator (ICD). Background ICDs are effective in preventing sudden cardiac death in susceptible patients, but their beneficial effect on survival is attenuated by the high rate of nonsudden cardiac death in those treated. Although advanced age is an important variable in determining cardiovascular mortality, its impact on the outcome of patients with an ICD has been inadequately studied. Methods. We performed multivariate analysis of a data base consisting of 769 consecutive patients with an ICD. Seventy-four patients greater than or equal to 75 years old at ICD implantation (Group 1) were compared with the remaining 695 patients (Group 2). Results. The two groups were similar in clinical presentation, left ventricular function and gender distribution. The mean follow-up time was 29 and 42 months, respectively, for patients in Group 1 and Group 2, Actuarial survival at 4 years was 57% in Group 1 versus 78% in Group 2 (p = 0.0001). This difference was primarily due to a higher rate of nonsudden cardiac death in Group 1. On multivariate analysis, age greater than or equal to 75 years, New York Heart Association functional class III, left ventricular ejection fraction <30% and appropriate shocks during follow-up were independently associated with increased mortality (odds ratio 3.56, 1.8, 1.6 and 1.39, respectively). Conclusions. Among patients with similar functional class and ejection fraction, the mortality risk is increased threefold in those greater than or equal to 75 years old at the time of ICD implantation. Extrapolation of results from younger patients is likely to overestimate ICD benefit in the elderly. (C) 1997 by the American College of Cardiology.