Background The clinical relevance of myocardial cell damage in dilated cardiomyopathy is uncertain.Myocardial uptake of Indium-111 monoclonal antimyosin antibodies (MAA) was used to study myocardial damage in patients with idiopathic (IDC) and alcoholic (ADC) dilated cardiomyopathy and to assess its prognostic implications.1.87 were associated with increased risk of death or transplantation.Conclusions In patients with IDC, variations of MAA uptake are detected in patients who present acutely but not in those with chronic stable disease.In patients with ADC, MAA uptake mainly depends on alcohol consumption. In both situations, reduction of uptake correlates with improvement of ventricular function. Higher intensities of MAA uptake are associated with a worse outcome. The intensity of antibody uptake, along with other clinical and functional variables, may be helpful in risk stratification of patients with dilated cardiomyopathy. (Circulation. 1994;89:2054-2061.)