Resting muscle sympathetic nerve activity and peak oxygen uptake in heart failure and normal subjects

Aims Exercise intolerance and increased efferent vasoconstrictor traffic to muscle are two characteristics of heart failure that have not been explicitly linked. We tested the hypothesis that peak oxygen consumption is inversely related to resting muscle sympathetic nerve activity in heart failure. Methods and Results We recorded peroneal muscle sympathetic nerve activity in 17 treated heart failure patients (16 men,1 woman; mean ejection fraction of 26·0±3·2% (SE)) and 17 age-matched healthy subjects (16 men, 1 woman). Oxygen consumption was measured during cycle ergometry to maximal effort. In heart failure and normal subjects, mean peak oxygen consumption was 20·6±1·7 vs 32·2±2·6ml.kg−1.min−1(P