Cardiac manifestations of Rocky Mountain spotted fever.

An increasing incidence of Rocky Mountain spotted fever is being noted across the United States. From 1955 to 1978 80 children with this disease were seen in a children's hospital. Autopsies were performed in six of the nine fatal cases, and cardiac lesions were seen in each. Multifocal myocarditis with petechiae was present in four cases, and in two of them there were areas of myocardial necrosis. In four of the necropsied cases there were electrocardiographic changes and cardiac enlargement on chest roentgenogram. Among survivors five patients manifested at least one cardiac abnormality. ST-T changes were noted in two patients, atrioventricular conduction disturbance in two, and severe left ventricular hypertrophy in one patient. Cardiomegaly was observed in three patients, and one had severe cardiac failure that responded to medical management. Cardiac involvement is frequently present in Rocky Mountain spotted fever, and close observation seems to be warranted.