EFFECTS OF INTRAVENOUS MAGNESIUM-SULFATE IN SUSPECTED ACUTE MYOCARDIAL-INFARCTION ON ACUTE ARRHYTHMIAS AND LONG-TERM OUTCOME

A total of 252 patients with suspected acute myocardial infarction wer e included in a double blind study and randomised to 50 mmol magnesium sulfate infusion under 20 h or corresponding placebo. Acute myocardia l infarction was verified in 117 patients and 59% of these had concomi tant treatment with thrombolysis. One-hundred ninety-four patients had Holter registrations during the first day in the coronary care unit, Intention-to-treat analysis showed an increase in long RR-intervals (> 3 s) in the magnesium treated group (P=0.006) and a tendency toward a reduction in episodes of ventricular premature complexes in triplets (P=0.09). During hospital stay and a mean of 22 months follow-up, 23 f atal events occurred in the magnesium allocated group and 31 fatal eve nts among the placebo allocated group (P=0.1). Mortality rate from car diac disease was reduced by 54% (95% C.I. 30-99%, P < 0.05). Subgroup analysis on acute myocardial infarction patients showed a 48% mortalit y risk reduction in the magnesium treated acute myocardial infarction group compared to the placebo treated acute myocardial infarction grou p (95% C.I. 23-104%, P=0.06), There was no significant interaction bet ween the effects of magnesium and thrombolytic treatment on total mort ality or cardiac events, This study supports the results of other smal l double blind placebo controlled studies regarding effects of magnesi um therapy on mortality in acute myocardial infarction, but are in dis cordance to the conclusion from the ISIS-4 study. The reasons for thes e discrepancies cannot be elucidated by our data.