CHANGES OF IONIZED MAGNESIUM AND FREE FATTY-ACIDS IN SERUM AFTER ACUTE MYOCARDIAL-INFARCTION

The most feared early complications after an acute myocardial infarcti on are ventricular arrhythmias. These may be initiated by changed conc entrations of catecholamines and electrolytes. The present study shows a reduction of total serum magnesium after acute myocardial infarctio n which is normalized within a few days. Further, it could be shown th at a more significant decrease of ionized Mg2+ (iMg(2+)) takes place a t the day of acute myocardial infarction in the total group of myocard ial infarction patients (n = 36). A closer investigation reveals that iMg(2+) was considerably decreased in one third of the patients, where as two thirds showed minor changes of iMg(2+) in both directions. The pronounced decrease of iMg(2+) in the first sub-group can be explained by the time course of free fatty acids in serum. On the day of the my ocardial infarction free fatty acids in serum were increased. This is probably caused by beta-adrenergic-induced lipolysis due to catecholam ines released by the stressful situation of an acute myocardial infarc tion. The increased free fatty acids in serum bind Mg2+, thus reducing iMg(2+). AS long as a beneficial effect of a general Mg infusion in a ll acute myocardial infarction patients is controversial, iMg(2+) shou ld be measured and Mg infusion therapy should be applied only in patie nts with low iMg(2+).