Serum magnesium in propranolol-treated patients with acute myocardial infarction.

A rise in free fatty acids (FFA) and a concomitant decrease in serum magnesium levels were found soon after acute myocardial infarction (AMI) in a group of 5 patients. Magnesium and FFA returned to normal levels within 3 days. No changes in serum FFA and magnesium levels were found in the postinfarction period in 5 patients who were under treatment with propranolol during the time they developed AMI. The linear model, magnesium = f(time, FFA), was investigated according to the stepwise regression-forward selection system. It was found that the magnesium level in AMI is best predicted by the FFA level (inverse correlation). In the period of 0-72 h after infarction, an inverse linear correlation was found to exist between the FFA level and the period of time after infarction.