Indium-111 monoclonal antimyosin cardiac scintigraphy in men with idiopathic dilated cardiomyopathy

This study examined the prognostic value and the evolution of the heart-to- lung ratio of monoclonal antimyosin antibody (MAA) uptake in patients with a diagnosis of idiopathic dilated cardiomyopathy (IDC). Uptake of indium-11 1-labeled MAA occurs when the myocytes become irreversibly damaged. The stu dy included 29 men with IDC followed up For 3 years. The diagnosis was veri fied by endomyocardial biopsy in all patients. Patients who survived beyond 1 year were restudied. Baseline heart-to-lung ratio st MAA was 1.74 +/- 0. 22. Multivariate Cox regression analysis revealed that MAA and New York Hea rt Association class were independent predictors of late mortality, with a hazard ratio of 4.4 (95% confidence interval 1.1 to 17.9, p = 0.036) and 7. 5 (95% confidence interval 2.0 to 28.4, p 0.003), respectively, when heart- to-lung ratio of MAA uptake was >1.74 and New York Heart Association class was >II. When these patients were divided into those with chronic IDC (grou p I [n = 19]) and those with subacute IDC (group II [n = 10]), baseline hea rt-to-lung ratio was 1.7 +/- 0.2 and 1.86 +/- 0.25, respectively tp = NS). In the surviving patients, on restudy, the heart-to-lung ratio of MAA uptak e was unchanged in group I (1.64 +/- 0.20, p = NS), bur had decreased to th e level of group 1 (1.66 +/- 0.2 1 [p = 0.008]) in group II. Thus, men with IDC and a high heart-to-lung ratio of MAA uptake have a worse long-term pr ognosis than patients with ct lower ratio. The heart-to-lung ratio of MAA d ecreases comparably over time in subacute IDC and remains stable in chronic IDC. (C) 2000 by Excerpta Medica, Inc.