PURPOSE: To evaluate the cardiopulmonary exercise testing (CPX) for the diagnosis of myopathies. METHODS: 27 patients with myopathy were submitted to CPX testing (symptom limited bike protocol). RESULTS: Dystrophic patients and patients with mitochondrial disease, compared with controls, showed significant differences for the power of work perfomed (watt) and the maximum oxygen consumption (VO2 max). Patients with mitochondrial disease presented significantly lower values of anaerobic threshold when compared to controls and elevation of exercise peak respiratory exchange ratio (RER) values when compared to the others groups. CONCLUSIONS: CPX testing may be useful in evaluating degree of physical limitation of patients with myopathy at inicial stage as well on follow-up examinations. Power of work performed, VO2 max, anaerobic threshold and RER at exercise peak may suggest the diagnosis of myopathy and its sub-types and therefore exclude psychologic causes of limitation.
neuromuscular diseases; exercise tolerance; mitochondrial myopathies
