Lactic dehydrogenase isoenzymes after electroshock treatment of cardiac arrhythmias

The serum enzyme concentrations measured in this study can be used to differentiate injury of heart muscle, skeletal muscle, lung and liver tissue. Serum lactic dehydrogenase (SLDH) isoenzymes, total SLDH, serum glutamic oxalacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT) were measured in 29 patients on the day before, the day of but before and the three days after treatment of atrial fibrillation by D.C. electroshock. All patients selected were men aged 50 or older with some evidence of atherosclerotic heart disease. Identical enzyme measurements were also made concurrently in a control group of 19 untreated subjects who were matched to the treated subjects by sex, age and disease. The SGOT levels increased significantly after D.C. electroshock in a minority of patients. These changes are statistically significant for the group as a whole ( p values < 0.02 and < 0.05). No significant changes occurred in SLDH alpha 1 and 2 and beta isoenzymes, in total SLDH, or in SGPT. No evidence was found that the enzyme changes observed after D.C. electroshock are due to myocardial injury. The statistically significant rise in SGOT appears to originate from tissues other than those of the heart. Reasons are presented for implicating the skeletal muscle of the chest wall as the source of these changes in serum enzyme concentrations.