Quantitative histoenzymological characteristics of the myocardium in sudden cardiac death

Enzymes in the human myocardium following sudden death were examined for activity in a quantitative histoenzymological study, these were NAD-dependent dehadrogenases of succinate (SDG), lactate (LDG), beta-hydroxybutyrate (beta-HOBDG), alpha-glycerophosphate (alpha-GPDG), alcohol (ADG), glucoso-6-phosphate (G-6-PDG), and NAD-diaphorase (NADse), and catalase. Autopsies were performed within 3 h after death. beta-HOBDG and LDG were found to show an increase in activity in the cardiomyocytes of sudden death subjects with coronary heart disease without apparent changes. In the myocardium from death subjects with coronary heart disease and large postinfarct cardiosclerosis, the activity of the enzymes was directly related to the severity of myocardial hypertrophy and signs of chronic heart failure. As myocardial hypertrophy developed, the enzyme activity increased; when there appeared signs of chronic heart failure it decreased. The myocardium from sudden death subjects with alcoholic cardiomyopathy showed diminished redox enzyme activity and higher activity of the enzyme utilizing alcohol (ADG and catalase). The findings suggest that changes in the enzyme activity in the myocardium are of various type and depend on previous cardiac abnormalities.