Creatine phosphokinase and malate dehydrogenase isozymes in heart muscle of sudden death cases.

CPK and MDK isozyme patterns of the heart muscle in cases of sudden death were studied to investigate the relationship between their changes and the causes of death. In most of death cases from violence, asphyxia, natural disease and poisoning, the percentage of CPK-MB was about 23--34% of the total CPK, and that of MDHm was about 35--50% of the total MDH. In a few death cases of coronary sclerosis and hypertrophy of the heart, the percentages of CPK-MB and MDHm decreased. The percentages of CPK-MB and MDHm in neonates were less than those in adults and they were about 7--15% and 25--34% of the total CPK and MDH, respectively. In more than half of the cases of both cardiac death from unknown cause and cot death, the average percentages of CPK-MB and MDHm decreased significantly. The findings of CPK and MDH isozyme patterns in cases of cardiac death from unknown cause and cot death suggest that there are some similar changes in many other kinds of heart enzymes in these cases.