Cardiac abnormality in polymyositis.

Thirteen patients with polymyositis were investigated for the presence of cardiac disease by clinical examination, chest x-ray, electrocardiogram, and systolic time intervals. 5 patients had evidence of cardiac involvement. Compared with the other 8 patients, their polymyositis was more long-standing, more severe, and had remained active. Electrocardiogram usually showed arrhythmias and conduction disturbances, and 4 of the 5 patients had abnormal systolic time intervals indicating left ventricular dysfunction. Left ventricular involvement in polymyositis is more frequent than previously recognized and systolic time intervals are a simple, noninvasive method of detecting this.