PRESENCE, EVOLVING CHANGES, AND PROGNOSTIC IMPLICATIONS OF MYOCARDIAL DAMAGE DETECTED IN IDIOPATHIC AND ALCOHOLIC DILATED CARDIOMYOPATHY BY IN-111 MONOCLONAL ANTIMYOSIN ANTIBODIES

Background The clinical relevance of myocardial cell damage in dilated cardiomyopathy is uncertain. Myocardial uptake of In-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. Methods and Results MAA and echocardiographic studies were performed in 117 patients. Intensity of antibody uptake was measured by heart-to-lung ratio (HLR) (normal <1.55). Studies were repeated in survivors and patients who did not receive a cardiac transplant. Follow-up extended up to 62 months (mean, 23+/-16 months). Eighty-eight patients with IDC showed a 77% prevalence of abnormal MAA. After acute-onset IDC, reduction of HLR (1.81+/-0.2 to 1.56+/-0.1) (P=.007) with improvement in ejection fraction (EF) (35+/-10% to 46+/-14%) (P=.018) was observed. No changes in HLR or EF were detected in patients with chronic stable IDC. Twenty-nine patients with ADC showed a lower prevalence (48%) of abnormal MAA studies than those with IDC (P=.003). HLR was higher in 13 active (1.78+/-0.3) than in 16 past consumers (1.49+/-0.2) (P=.019); in the former, HLR decreased to 1.44+/-0.2 (P=.012), and EF improved (35+/-14% to 53+/-18%) (P=.05) after abstention. Intensities of uptake HLR of >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.