Exercise limitation in patients with polymyositis.

To examine the hypothesis that patients with inflammatory muscle disease have impairments in cardiac and/or pulmonary function that are masked by peripheral muscle weakness, complete PFTs, echo/Doppler studies and exercise testing were performed in 11 patients with polymyositis. Maximal inspiratory and expiratory pressures and expiratory flow rates were normal. One patient had evidence of restrictive lung disease; two had a reduced Dsb. Seven patients had evidence of pulmonary hypertension. Only three patients had normal aerobic capacity; VO2 max in the other 8 patients was 46 +/- 8 percent of predicted when they stopped exercising. Four patients had a normal O2 pulse; seven patients had a reduced O2 pulse while five of seven patients exceeded 85 percent of their target heart rate. We conclude that while asymptomatic impairments in pulmonary function are uncommon in polymyositis, the incidence of pulmonary hypertension is high, but symptoms may be masked by the peripheral muscle weakness.