Myocardial bioptic findings in correlation with TL-201 imaging and hemodynamic parameters in patients with latent cardiomyopathies suspected of having myocarditis.

Sixty-eight patients (24 males, 44 females, mean age 37.2 years) belonging to NYHA classes I and II were investigated. All patients had a nondilated ventricle as well as hemodynamic criteria of "latent cardiomyopathy." In 78% of the patients, a high susceptibility to infection, frequent angina, or possible myocarditis were found. In 75.5%, the mean pulmonary artery pressure was abnormal. T1-201 scintigraphy revealed perfusion defects in 78%. Dyskinesia or hypokinesia were found in 52%. The left ventricular ejection fraction was normal in 74%. On biopsy, pathologic findings were detected in 60.9% of patients with a high frequency of hypertrophy and fibrosis (50%). In two patients, lymphocytic infiltrates were found. Immunohistologically, deposits of complement, IgG, IgM, and gammaglobulin, mainly in the sarcolemma, could be identified in 19.1% of cases. The myocardium was normal in 39.1%; insufficient material was found in 5.9% of patients. Morphologic, scintigraphic, and hemodynamic findings could not be correlated but the combination of two pathologic parameters permitted diagnosis. Biopsy was the most effective diagnostic method in myocarditis.