NONINVASIVE DETECTION OF MYOCYTE NECROSIS IN MYOCARDITIS AND DILATED CARDIOMYOPATHY WITH RADIOLABELED ANTIMYOSIN

The 'gold standard' for the diagnosis of myocarditis is endomyocardial biopsy. Although the specificity of this invasive method is good its sensitivity is questionable. Therefore, a non-invasive diagnostic meth od with greater sensitivity (even if it were overly sensitive) would c onstitute a useful screening tool for identification of patients who s hould under go endomyocardial biopsy. Antimyosin immunoscintigraphy fi ts such a criterion since it is highly sensitive and specific for diag nosis of myocardial necrosis, which is one of the two obligatory compo nents for the diagnosis of myocarditis. Therefore studies were perform ed on patients with clinical histories suggestive of myocarditis such as acute onset of dilated cardiomyopathy, myocarditis masquerading as acute myocardial infarction and patients presenting with unexplained l ife-threatening ventricular tachyarrhythmias In all these studies, ant imyosin imaging had higher sensitivity than endomyocaridal biopsy for the diagnosis of myocarditis. A rationale is provided for the increase d sensitivity and specificity of antimyosin antimyosin immunoscintigra phy for diagnosis of myocyte necrosis associated with myocarditis, rel ative to endomyocardial biopsy.