Preservation of exercise capacity and lack of peripheral changes in asymptomatic patients with severely impaired left ventricular function

Aims:To establish the extent, if any, of peripheral changes in asymptomatic patients with severe left ventricular dysfunction. Methods and Results: Nine asymptomatic and nine symptomatic patients with left ventricular ejection fraction, <25%, matched for age and left ventricular ejection fraction (asymptomatic vs symptomatic, age: 52±1·5 vs 55·9±2·5 years [Mean±SEM], left ventricular ejection fraction: 16±2 vs 19±2%P=0·23 and 0·48, respectively) were studied and compared with 26 age-matched normal controls. We assessed exercise capacity, leg blood flow (occlusion plethysmography), respiratory muscle strength, quadriceps maximal isometric strength, fatigue and CT cross-sectional muscle area at mid thigh. Fatigue was expressed as the percentage reduction in maximal strength following a 20min fatiguing protocol. There was a graded increase in peak oxygen consumption comparing symptomatic, asymptomatic and control groups (16·6±1·3 vs 27·1±1·6 vs 32·8±1·3ml.min−1.kg−1respectively, ANOVA P<0·0001). Between the three groups there was significant variation in muscle strength (P<0·0001), endurance (P=0·0002) and cross-sectional area (P=0·0003) and in peak blood flow (P=0·027) and respiratory muscle strength (P