SKELETAL-MUSCLE MASS AND EXERCISE PERFORMANCE IN STABLE AMBULATORY PATIENTS WITH HEART-FAILURE

The purpose of this study was to determine whether skeletal muscle atr ophy limits the maximal exercise capacity of stable ambulatory patient s with heart failure. Body composition and maximal exercise capacity w ere measured in 100 stable ambulatory patients with heart failure. Bod y composition was assessed by using dual-energy X-ray absorption. Peak exercise oxygen consumption (Vo(2peak)) and the anaerobic threshold w ere measured by using a Naughton treadmill protocol and a Medical Grap hics CardioO(2) System. Vo(2peak) averaged 13.4 +/- 3.3 ml . min(-1). kg(-1) or 43 +/- 12% of normal. Lean body mass averaged 52.9 +/- 10.5 kg and leg lean mass 16.5 +/- 3.6 kg. Leg lean mass correlated linearl y with Vo(2peak) (r= 0.68, P < 0.01), suggesting that exercise perform ance is influenced by skeletal muscle mass. However, lean body mass wa s comparable to levels noted in 1,584 normal control subjects, suggest ing no decrease in muscle mass. Leg muscle mass was comparable to leve ls noted in 34 normal control subjects, further supporting this conclu sion. These findings suggest that exercise intolerance in stable ambul atory patients with heart failure is not due to skeletal muscle atroph y.