Pulmonary and cardiac function in advanced fibrodysplasia ossificans progressiva

Fibrodysplasia ossificans progressiva is a rare genetic disease characterized by heterotopic ossification in soft tissues. Severe disability results from progressive immobilization of the limbs, jaw, and chest wall. To determine whether cardiac function is altered in this disease, 25 patients ranging in age from 5 to 55 years (disease duration 1-51 years) were studied. History, physical examination, pulmonary functions, electrocardiography, and echocardiography were performed on each patient. Physical examination of the lungs and heart was unrevealing; no right sided ventricular gallops were heard, and no patient was found to have neck vein distention or peripheral edema. The patients had extremely limited chest expansion (1.9 +/- 0.8 inches), suggesting dependence on diaphragmatic breathing. Lung volumes were severely reduced (mean forced vital capacity 44% +/- 14% of predicted), but flow rates were relatively normal. All patients had normal capillary oxygen saturation. Echocardiography was technically difficult, but no abnormalities of left or right ventricular function were seen. Ten (40%) patients had electrocardiographic evidence of right ventricular dysfunction. Compared with patients without such evidence, these patients were older, had significantly longer disease duration, higher hemoglobin, and more impaired pulmonary function. The results of this study suggest that the presence of severely restrictive chest wall disease is associated with a high incidence of right ventricular abnormalities on electrocardiogram. Whether cor pulmonale will eventually occur remains to be determined.