The idiopathic hyperkinetic heart syndrome: clinical course and long-term prognosis.

Nineteen of the originally reported 24 patients having the idiopathic hyperkinetic heart syndrome were followed for periods of 11 to 25 years. One patient died of complicating severe mitral stenosis. Of the remaining 18 patients, nine had complete physical examinations and ECG records. Only one of these patients was symptomatic at the time of reexamination. Murmurs originally present in eight of nine patients were present in only five of nine at reexamination; hyperkinetic circulation and heart, originally present in eight, were found in only two at follow-up; and systolic hypertension, present in seven at beginning of the study, was only present in four at follow-up. ECG abnormalities (usually left ventricular hypertrophy) regressed in the majority. Persistent elevation of cardial index and systolic ejection rate were found at repeat catheterization in the single symptomatic patient who had congestive cardiomyopathy. Uncomplicated idiopathic hyperkinetic heart syndrome appears to have an excellent long-term prognosis.