Value of Exercise Capacity and Heart Rate Recovery in Older People

OBJECTIVES: To evaluate the prognostic value in older adults of two predictors of mortality: impaired functional capacity and an attenuated heart rate recovery. SETTING: Academic medical center. DESIGN: Prospective study with mean 3.7 years follow-up. PARTICIPANTS: Seven thousand three hundred fifty-four adults aged 65 and older consecutively referred for exercise testing between 1990 and 1999. Patients with heart failure, valvular disease, atrial fibrillation, and pacemakers were excluded. MEASUREMENTS: The primary endpoint was all-cause mortality. Impaired functional capacity was defined as the peak exercise workload in the lowest quintile of metabolic equivalents achieved according to prespecified strata of age and sex. Heart rate recovery was defined as the fall in heart rate during the first minute after exercise and was abnormal if 12 or fewer beats per minute, except for patients undergoing stress echocardiography, in which case 18 or fewer beats per minute was abnormal. RESULTS: There were 842 deaths. Patients with impaired functional capacity were at increased risk for death (23% vs 9%, hazard ratio (HR) = 2.7, 95% confidence interval (CI) = 2.2-3.1, P <.0001) as were patients with an abnormal heart rate recovery (17% vs 9%, HR = 2.0, 95% CI = 1.8-2.3, P <.0001). After adjusting for age, sex, coronary history, and other confounders, impaired functional capacity (adjusted HR = 2.1, 95% CI = 1.8-2.4) and an abnormal heart rate recovery (adjusted HR = 1.5, 95% CI = 1.3-1.7) independently predicted death. No interactions between these two variables with age were noted. CONCLUSIONS: In older patients, impaired functional capacity and heart rate recovery were independent predictors of death.