Em. Antman et al., MAGNESIUM IN ACUTE MYOCARDIAL-INFARCTION - CLINICAL BENEFITS OF INTRAVENOUS MAGNESIUM THERAPY, Magnesium-Bulletin, 18(3), 1996, pp. 74-76
Intravenous magnesium therapy for acute myocardial infarction has been
a focus of research over the past decade. Meta-analyses of data from
randomized trials revealed a benefit of magnesium therapy in reducing
mortality of patients with acute myocardial infarction. The most compe
lling confirmation was provided by the Second Leicester Intravenous Ma
gnesium Intervention Trial (LIMIT-2) which reported a 24% mortality re
duction with magnesium treatment. Recent data from the Forth Internati
onal Study of Infarct Survival (ISIS-4), however, caused major controv
ersies about clinical benefits of intravenous magnesium therapy. This
large-scale trial of over 58 000 patients with suspected acute myocard
ial infarction showed no mortality benefit of magnesium administration
. Differences in results between ISIS-4 and previous trials, however,
may be attributed to differences in trial design and patient character
istics. Late initiation of intravenous magnesium therapy as was perfor
med in ISIS-4 may be accounted for therapy failure, since experimental
data suggest that the beneficial effects of magnesium in acute myocar
dial ischemia are mediated by attenuation of reperfusion injury. Furth
ermore, the average mortality risk in ISIS-4 was relatively low in com
parison to previous trials. A regression model using pooled data from
randomized trials prior to ISIS-4, however, suggest a relationship bet
ween the baseline mortality risk of patients and the expected benefit
of magnesium therapy. In summary, the clinical benefit of magnesium th
erapy in acute myocardial infarction still awaits complete elucidation
and needs further well-designed trials with special attention to timi
ng of magnesium administration.