SERUM LACTIC DEHYDROGENASE ESTIMATIONS IN MYOCARDIAL INFARCTION

Abstract

A comparison of results obtained in 20 cases of myocardial infarction has been made, employing serum glutamic-oxalacetic transaminase (S.G.O[long dash]T) and serum lactic dehydrogenase (S.L.D.) estimations. The findings show that the results of American workers have been confirmed, and that S.L.D. estimation allows of greater latitude in sampling, due to its longer period of elevation. Its estimation by the method of the Sigma Co., using Sigma reagents is satisfactory for the purpose. Although it is raised in other conditions, it is doubtful if this represents a drawback to its use by discriminating workers as a test for myocardial infarction, as these other conditions are mostly clinically distinct from myocardial infarction. In doubtful cases, where the S.L.D. is not greatly elevated, one or two serial tests will usually resolve the difficulty, as the levels tend to remain static in conditions other than myocardial infarction over the short period of time involved, instead of following the typical course of rise and fall (Fig. 3). The explanation of this would appear to be that in myocardial infarction the enzyme is liberated from damaged cells, causing the serum enzyme activity to reach a peak, usually about 3-4 days after infarction, and then slowly to return to normal. Other conditions have raised S.L.D. activity, due to reasons explained but the serum level remains steady over the period involved, and is not usually so greatly raised.