In patients with congestive cardiomyopathy, increased myocardial LDH5 correlates with worse hemodynamics, suggesting a shift toward anaerobic metabolism as disease severity increases.
Endomyocardial biopsy samples from patients suffering from congestive cardiomyopathy of unknown etiology (COCM) were analyzed for lactate dehydrogenase (LDH) isoenzyme distribution by microisoelectric focusing. In addition, the concentration of collagen in the biopsy samples was estimated by determination of hydroxyproline and proline. The results were correlated with the clinical and hemodynamic data of the patients. Increased activities of total LDH and LDH5--the worse the hemodynamic parameters, the higher the concentration of LDH5--indicate an enhanced anaerobic glycolysis in the myocardium of COCM patients. The close correlation between the hemodynamic data and the LDH isoenzyme pattern suggests an association between severity of COCM and impairment of aerobic metabolism. The results of the alteration in the LDH isoenzyme pattern were not influenced by the collagen content in the myocardial biopsy samples. Varying isoenzyme patterns in the different parts and wall layers of the normal heart show the necessity of analyzing biopsy samples only from comparable localizations.
Schultheiß et al. (Wed,) studied this question.