Background: The rate in which heart rate recovers from exercise has recently been shown to be a strong predictor of mortality in patients suspected of having coronary disease, but its prognostic value in patients with heart failure (HF) has not been explored. We sought to assess the prognostic utility of heart rate recovery (HRR) in patients with HF.
Methods: Eighty-seven subjects diagnosed with compensated HF underwent cardiopulmonary exercise testing (CPX). Mean age and ejection fraction were 50.0 (+/-13.9) years and 28.1% (+/-13.6%), respectively. Heart rate at 1-minute post-CPX was subtracted from maximal heart rate during the exercise test to produce a measure of HRR1 in beats per minute. Subjects were followed for a combined death/hospitalization end point for 1-year after CPX.
Results: The mean peak respiratory exchange ratio, peak oxygen consumption (VO2), minute ventilation/carbon dioxide production (VE/VCO2) slope, and HRR1 were 1.06 (+/-0.11), 14.8 (+/-4.7) mL.kg(-1).min(-1), 36.6 (+/-8.6), and 11.0 (+/-10.4) beat/min, respectively. Although all three variables were significant univariate predictors of the composite end point (P < .001), multivariate Cox regression analysis only retained the VE/VCO2 slope (chi2 = 33.5, P < .001) and HRR1 (residual chi2 = 15.0, P < .001) in the equation. The hazard ratio for subjects having both an abnormal VE/VCO2 slope (> 34.4) and HRR1 (< 6.5 beat/min) value was 9.2 (95% CI 4.5-18.5, P < .0001).
Conclusions: These results indicate that HRR provides additional prognostic information in patients with HF undergoing CPX. Moreover, given the independent prognostic value of HRR, this variable alone may provide valuable clinical information when ventilatory expired gas analysis is not available.