Magnesium deficiency in patients with recent myocardial infarction and provoked coronary artery spasm

This study sought to clarify the relationship between magnesium (Mg) defici ency and coronary artery spasm provoked by pharmacologic agents in patients with a recent acute myocardial infarction (AMI). Twenty-three consecutive patients suffering from AMI were investigated with a Mg retention test (Mg: 0.1 mmol/kg for 4h) in both the acute phase (within 1 week (3 +/-2 days) o f onset) and the subacute phase (3-4 weeks (24 +/-6 days) of the onset). Ea rly coronary arteriography was performed in all patients. Coronary stenosis in the infarct-related artery was less than 90% in all patients in the sub acute phase. The spasm provocation test was performed in the subacute phase and coronary spasm was defined as transient subtotal or total occlusion in association with angina or electrocardiographic ST-segment deviation. Coro nary artery spasm was provoked in only 13 of the 23 patients. Compared with the control subjects(12 patients without coronary artery disease or corona ry spasm), the 24-h Mg retention was significantly higher in patients with AMI (acute phase: 78 +/- 27%, subacute phase: 66 +/- 32%, vs control: 48 +/ - 12%, p<0.05). In the subacute phase, the 24-h Mg retention decreased in p atients without coronary spasm (43<plus/minus>26%), but a high level of Mg retention was still observed in patients with coronary spasm (84 +/- 25%). There was no difference in the serum concentrations of Mg, calcium and phos phorus between the 2 groups on both phases. In conclusion, both Mg deficien cy and provoked coronary artery spasm were noted in more than half of the J apanese patients with a recent AMI, suggesting a close association between Mg deficiency and AMI.