[The syndrome of "muscle deconditioning" in chronic cardiac insufficiency]

Fatigue, that cardinal symptom of heart failure, expresses muscle deconditioning and is becoming the main complaint of our patients. Dyspnoea also is, at least partially, a consequence of muscle deconditioning; however, the wide use of diuretics which reduce water and salt retention has improved the "pump" function an therefore dyspnoea. The "muscle deconditioning" syndrome in heart failure has two causes: reduction of the nutritive blood flow in skeletal muscle, and specific alteration of mitochondrial oxidative metabolism. The syndrome appears only after a lasting reduction of physical activities. Its anatomical substrate is a mild muscular fibrosis and, mainly, reduced area of oxidative mitochondrial cristae. It remains for approximately three months, which accounts for the delayed improvement of exercise tolerance under vasodilatator treatment with angiotensin-converting enzyme inhibitors. This syndrome explains the success of retraining techniques which, in ou opinion, should become part of our therapeutic armamentarium.