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

Peak oxygen consumption (VO 2) is an important criterion for listing patients for cardiac transplantation. β-Blockers improve survival without affecting peak VO 2. We questioned the value of peak VO 2 in predicting outcome in patients treated with β-blockers. We reviewed the records of 127 patients who had peak VO 2 measured at baseline and were subsequently treated with β-blockers for at least 3 months. We divided the patients into 2 groups with peak oxygen consumption >14 (VO 2 hi) and ≤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. Current peak VO 2 cutoff does not predict survival without transplantation of patients who tolerate chronic treatment with β-blockers.