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

Background Peak oxygen consumption (VO₂) is an important criterion for listing patients for cardiac transplantation. β-Blockers improve survival without affecting peak VO₂. We questioned the value of peak VO₂ in predicting outcome in patients treated with β-blockers. Methods and results We reviewed the records of 127 patients who had peak VO₂ 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 (VO₂ hi) and ≤14 ml·kg·min (VO₂ lo). VO₂ hi had 109 patients and VO₂ lo had 18 patients. The combined end-point of death or cardiac transplantation was compared between groups. Mean peak VO₂ and left ventricular ejection fraction were lower in VO₂ lo versus VO₂ 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 VO₂ lo versus 79% in VO₂ 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 VO₂ cutoff does not predict survival without transplantation of patients who tolerate chronic treatment with β-blockers.