[Comparative analysis of enzyme activities in endomyocardial biopsy samples of patients with various cardiomyopathies]

41 patients have been investigated using invasive techniques including left ventricular endomyocardial biopsy. One of six specimens per patient was investigated biochemically. 8 pts. (group A) suffered from dilated cardiomyopathy (DCM), 13 (group B) from sarcoidosis of the lungs, 20 (group C) from so-called latent cardiomyopathy (LCM). The histological diagnoses were: normal (3 pts.), small vessel disease (4 pts.), unknown etiology (4 pts.), post myocarditis (6 pts.), residual myocarditis (12 pts.), active myocarditis (5 pts.), suspected toxic myocardial disease (6 pts.), Fabry's disease (1 pt.). The enzyme/isoenzyme activities of malate dehydrogenase (MDH), aspartate amino transferase (ASAT) and lactate dehydrogenase (LDH) were measured and compared in different hemodynamic and histologic groups. The enzyme activities from patients with impaired left ventricular function were increased. Independent from left ventricular function the activities of MDH, ASAT and LDH as well mitochondrial isoenzymes were decreased in active and residual myocarditis. The isoenzyme LDH M was increased significantly in active myocarditis and suspected toxic myocardial disease. The measurements of LDH enzyme/isoenzyme profile in myocardial tissue obtained by endomyocardial biopsy seem to support the histological diagnosis of active myocarditis.