788-3 Effect of Body Composition on Exercise Performance in Patients with Heart Failure

Changes in fat and skeletal muscle Volume may contribute to the exercise intolerance reported by patients with heart failure. To test this hypothesis, we measured hemodynamic and ventilatory responses to exercise in 65 patients with chronic heart failure. Body composition was determined by dual-energy x-ray absorptiometry. Peak exercise VO2 averaged 13.2±2.9ml/min/kg, peak exercise cardiac index 4.5±1.1 L/min/m2, lean body weight 55±12kg, lean leg weight 17.2±3.8kg and total fat 27±11kg. Thirty-eight (58%) of the patients were obese, as defined by a percentage fat >30%. Twenty-four patients (37%) exhibited lean body wt/height <300gm/cm, consistent with muscle atrophy. Peak exercise VO2 correlated closely with total leg muscle:There was no relationship between VO2/gm leg muscle and the lean body wt/height index, suggesting that muscle atrophy does not affect muscle performance/unit of muscle. VO2/kg muscle was higher in obese vs non-obese patients (72+14 vs 59+13 mllmin/kg (p<0.01) whereas peak VO2/kg body weight was similar (13.0+3.3 vs 13.2+2.6 mllmin/kg). since body weight inCludes fat. These findings suggest that skeletal muscle volume influences exercise capacity in patients with heart failure. Exercise capacity in obese patients is underestimated by normalizing for body weight