Percent achieved of predicted peak exercise oxygen uptake and kinetics of recovery of oxygen uptake after exercise for risk stratification in chronic heart failure

To investigate whether percent achieved of predicted peak exercise oxygen uptake (%VO2 max) and recovery of oxygen consumption after exercise may provide prognostic information in chronic heart failure (CHF), we prospectively studied 196 patients with mild to moderate CHF. The following variables were examined: age, etiology of CHF, functional class, ejection fraction (EF), peak exercise oxygen uptake normalized for body weight (VO2 max), %VO2 max, time to reach 50% of the peak oxygen uptake after exercise (T1/2VO2 max), presence of nonsustained ventricular tachycardia (NSVT) and inability to take ACE-inhibitors. VO2 max was the most powerful predictor of cardiac death (P<0.0001). Other independent predictors of death were EF, T1/2VO2 max, NSVT and inability to take ACE-inhibitors. The discriminatory accuracy of VO2 max for cardiac death was not significantly greater than that of %VO2 max. In conclusion, the determination of %VO2 max does not enhance risk stratification in CHF whereas the kinetics of oxygen consumption after exercise can provide prognostic information.