To characterize cardiac involvement in idiopathic hemochromatosis, clinical records and 2-dimensional (2-D) echocardiograms of 24 patients with idiopathic hemochromatosis were reviewed. The 17 men and 7 women were 24 to 80 years old (mean 48). Of 19 patients without valvular, ischemic, hypertensive or other known heart disease, 7 (37%) had structural and functional echocardiographic abnormalities attributed to idiopathic hemochromatosis (group 1) and 12 had normal echocardiographic findings (group 2). Age, gender and laboratory markers of iron overload did not differentiate patients with cardiac dysfunction (group 1) from those without cardiac dysfunction (group 2). In group 1, echocardiographic abnormalities included chamber dilatation and global systolic dysfunction. Increased wall thickness was not a feature of idiopathic hemochromatosis. All group 1 patients had abnormal electrocardiographic findings and cardiomegaly on radiography. Despite therapeutic phlebotomy, 4 patients in this group died, between 0.5 and 30 months after echocardiography, because of congestive heart failure. In conclusion, there is a spectrum of cardiac dysfunction in idiopathic hemochromatosis. In patients with idiopathic hemochromatosis and left ventricular dysfunction, absolute wall thickness is normal. Survival is poor in patients with idiopathic hemochromatosis and severe left ventricular dysfunction.