Peak oxygen consumption and outcome in heart failure patients chronically treated with beta-blockers.

Background: Peak oxygen consumption (VO(2)) is an important criterion for listing patients for cardiac transplantation. Beta-blockers improve survival without affecting peak VO(2). We questioned the value of peak VO(2) in predicting outcome in patients treated with beta-blockers.
Methods and Results: We reviewed the records of 127 patients who had peak VO(2) measured at baseline and were subsequently treated with beta-blockers for at least 3 months. We divided the patients into 2 groups with peak oxygen consumption >14 (VO(2) hi) and < or =14 ml.kg.min (VO(2) lo). VO(2) hi had 109 patients and VO(2) lo had 18 patients. The combined end-point of death or cardiac transplantation was compared between groups. Mean peak VO(2) and left ventricular ejection fraction were lower in VO(2) lo versus VO(2) hi: 12.4+/-1.4 ml.kg.min versus 19.1+/-3.9 ml.kg.min and 17+/-8% versus 21+/-9%, respectively. At 30 months, the percentage of patients who did not reach the combined end-point was 94% in VO(2) lo versus 79% in VO(2) hi (P=.47). In multivariate analysis, only changes in heart rate and LVEF from baseline to follow-up were predictive of survival.
Conclusions: Current peak VO(2) cutoff does not predict survival without transplantation of patients who tolerate chronic treatment with beta-blockers.