BACKGROUND: Peak oxygen consumption (peak VO2) is one of the strongest predictors of mortality in patients with congestive heart failure (CHF). In contrast to measurements of peak VO2, which requires analysis of expired gases, heart rate recovery, defined as maximum heart rate minus heart rate at 1 minute after exercise, is easily obtained. The current study was undertaken to determine the association between peak VO2 and heart rate recovery in patients with CHF. METHODS: Retrospective data on VO2 and heart rate recovery were analyzed in 296 patients with CHF secondary to left ventricular systolic dysfunction (left ventricular ejection fraction [LVEF] <50%) who had undergone cardiopulmonary exercise testing (CPET). Patients exercised on a treadmill using a graded work rate protocol with the work increasing to a symptom-limited maximum. Peak oxygen consumption was defined as the highest value of oxygen uptake attained in the final 20 seconds of exercise when the respiratory exchange ratio was >1.0. RESULTS: Heart rate recovery and peak VO2 correlated moderately (r = 0.47, p < 0.001). The degree of correlation was similar in patients receiving beta-blockers (r = 0.47, p < 0.001) and those not receiving beta-blockers (r = 0.49, p < 0.001). CONCLUSIONS: Although heart rate recovery and peak VO2 correlated moderately, from a clinical standpoint, this finding is probably not strong enough to use heart rate recovery in lieu of peak VO2. This modest correlation of two independent predictors of outcome may suggest their usefulness when combined in a multivariate score.
BACKGROUND: Peak oxygen consumption (peak VO2) is one of the strongest predictors of mortality in patients with congestive heart failure (CHF). In contrast to measurements of peak VO2, which requires analysis of expired gases, heart rate recovery, defined as maximum heart rate minus heart rate at 1 minute after exercise, is easily obtained. The current study was undertaken to determine the association between peak VO2 and heart rate recovery in patients with CHF. METHODS: Retrospective data on VO2 and heart rate recovery were analyzed in 296 patients with CHF secondary to left ventricular systolic dysfunction (left ventricular ejection fraction [LVEF] <50%) who had undergone cardiopulmonary exercise testing (CPET). Patients exercised on a treadmill using a graded work rate protocol with the work increasing to a symptom-limited maximum. Peak oxygen consumption was defined as the highest value of oxygen uptake attained in the final 20 seconds of exercise when the respiratory exchange ratio was >1.0. RESULTS: Heart rate recovery and peak VO2 correlated moderately (r = 0.47, p < 0.001). The degree of correlation was similar in patients receiving beta-blockers (r = 0.47, p < 0.001) and those not receiving beta-blockers (r = 0.49, p < 0.001). CONCLUSIONS: Although heart rate recovery and peak VO2 correlated moderately, from a clinical standpoint, this finding is probably not strong enough to use heart rate recovery in lieu of peak VO2. This modest correlation of two independent predictors of outcome may suggest their usefulness when combined in a multivariate score.
Authors: Vera Kubrychtova; Thomas P Olson; Kent R Bailey; Prabin Thapa; Thomas G Allison; Bruce D Johnson Journal: Eur J Appl Physiol Date: 2008-09-17 Impact factor: 3.078