Keshan disease is an endemic cardiomyopathy in China. Morphologically, the condition is characterized by multifocal necrosis and replacement fibrosis of the myocardium, resulting in acute or chronic heart failure. Some patients with Keshan disease show the clinical features of congestive (dilated) cardiomyopathy, but the pathologic features of the two conditions are different. The etiology of Keshan disease remains unknown. It is likely that numerous agents work synergistically to cause the disease.