SKELETAL-MUSCLE CONTRACTILE CHARACTERISTICS AND FATIGUE RESISTANCE INPATIENTS WITH CHRONIC HEART-FAILURE

Whole muscle contractile characteristics and fatigue resistance were s tudied in male patients with chronic heart failure (n=6) and in health y control subjects (n=6). Maximum voluntary isometric strength in the major muscle groups of leg (plantar flexors and knee extensors) and ar m (elbow extensors and elbow flexors), was found to be similar for bot h groups of subjects. However, a faster isometric twitch time course w as observed in the plantar flexor and knee extensor muscles of heart f ailure chronic patients. The poor resistance to fatigue in the knee ex tensors of chronic heart failure patients was confirmed in the present study, but using twitch interpolation this was shown nor to be due to poor activation. The plantar flexors of chronic heart failures patien ts also showed a tendency to be less resistant to fatigue, even when t he muscle was activated by direct electrical stimulation. The present study shows that independent of muscle strength patients with chronic heart failure may possess muscles that are faster to contract and less resistant to fatigue. However, it seems this increased fatigability i s not due to pool muscle activation.