Cardiac complications of polymyositis

We report 3 cases of polymyositis, confirmed by enzyme assay and muscle biopsy, complicated by serious cardiac disease. They showed progressive fascicular block, despite immunosuppressive therapy sufficient to control the skeletal muscle disease, culminating in complete heart block with syncope, requiring the implantation of a pacemaker. In addition, all 3 showed echocardiographic evidence of dilated cardiomyopathy.