Long-term outcome of intravenous magnesium therapy in thrombolysis-ineligible acute myocardial infarction patients.

The aim of our study was to analyze the long-term survival and cardiac function in 194 consecutive, thrombolysis-ineligible acute myocardial infarction (AMI) patients receiving 48-hour intravenous magnesium sulfate (22 g) - 96 patients, compared with placebo - 98 patients. After a mean 4.8-year follow-up, all-cause mortality and cardiac mortality were significantly lower in the magnesium compared to the placebo group [(18 vs. 33 patients, p < 0.01) and (12 vs. 30 patients, p < 0.001), respectively]. Rest radionuclide ventriculography tests for left-ventricular ejection fraction (LVEF) were assessed in surviving patients up to completion of follow-up. Magnesium-treated patients had a significantly higher LVEF (0.51 +/- 0.10 vs. 0.44 +/- 0.14, p < 0.05) and a lower incidence of heart failure compared to placebo-treated patients (12 vs. 3 patients, p = 0.02). Beneficial effects of intravenous magnesium therapy in thrombolysis-ineligible AMI patients appeared to last for at least 4.8 years, concomitant with preserved LVEF, suggesting a favorable role for acute magnesium treatment in these patients.