[Magnesium and myocardial infarction. Brazilian aspects].

Most of the brazilian's territory is poor in magnesium (Mg) and an evaluation of urinary Mg indicated very low concentration of this cation in a normal population sample. The study of the behavior of plasmatic Mg in the acute phase of uncomplicated myocardial infarction permitted the following conclusions; a) during the first three days of the clinical course there is significant hypomagnesemia; b) magnesemia rises progressively during the three days of infarction, without however reaching normal levels. The lymphocytic magnesium also show the same behavior. Mg infusion in patients with acute myocardial infarction (four grams of MgSO4 during the first three days) reduced the incidences of arrhythmias, death and the size of infarction, in São Paulo. Another study in Bahia also showed reduction of mortality with infusion of 10 grams of MgSO4 in 24 hours. These studies about the protective role of Mg show potential limitations because the samples were small.