[Intravenous magnesium in acute myocardial infarct]

The effects of magnesium (Mg) on the incidence of arrhythmias and on mortality were evaluated in 61 patients with documented acute myocardial infarction (AMI), in a randomized, double blind placebo controlled study. During the first 24 hours 31 patients received infusion of 1000 ml isotonic saline with 17 g MgSO4 and 30 ones received only equal volumes of saline as placebo. The baseline characteristics of the population including serum Mg and potassium were similar in the two groups. Severe arrhythmias were not as frequent in the Mg group (22%) as in the placebo one (36%), but the difference was not statistically significant (p = 0.05). There is no significant difference between the groups neither in mortality (3.2%; 0%) nor in conduction disturbances (3.2%; 3%). The adverse effects of Mg therapy were transient and therapy interruption was not required.

Although the trial is not an extensive one, and the results are nonsignificant, we consider intravenous Mg therapy to be simple and cheap with its place in the treatment of AMI in properly selected patients. According to available data it should be administered as soon as possible after the onset of AMI symptoms, before thrombolytic therapy, in 24-hrs. dose not exceeding 50-65 mmol probably through several days, but the optimal duration of therapy should be further investigated.