Abstract
Objectives. Magnesium (Mg) physiologically antagonizes calcium (Ca) and inhibits it from flowing into cells. Mg sulfate was given to patients with acute myocardial infarction (AMI) who were receiving coronary reperfusion therapy. The effectiveness of this treatment in inhibiting reperfusion problems was evaluated.
Methods. Twenty-two patients (20 males, 2 females, average age 64 yrs) treated with coronary reperfusion therapy within six hours after the onset of symptomswere randomly allocated to either the magnesium group which received intravenous Mg sulfate 0.27mmol·kg-1 prior to therapy, or the control (C) group which did not receive Mg. Mg2+ and IL-6 blood concentrations were measured with an ion selective electrode and the ELISA method in succession (normal values, Mg2+ 0.54±0.05 (SD) mmol·l-1, IL-6<5pg·ml-1). Adverse effects of the therapy which occurred within one hour of coronary reperfusion were chest pain aggravation, increased ST elevation a 12-lead electrocardiogram, and reappearance of arrhythmia (3 PVCs, premature ventricular contraction; VT, ventricular tachycardia; Vf, ventricular fibrillation; AIVR, accelerated idioventricular rhythm; IIIAV block, complete atrioventricular block).
Results. The occluded coronary arteries were recanalized in 20 cases (9 in the Mg group and 11 in the C group). The blood concentration of Mg2+ in the Mg group was 0.39±0.08mmol·l-1 before treatment, 1.04±0.10mmol·l-1 after therapy, and returned to baseline six hours after therapy. The incidence of arrhythmia after reperfusion was 11% (1 case) in the Mg group and 82% (9 cases) in the C group (P=0.002). ST change after reperfusion was 2.4±2.2mm in the Mg group, and 4.6±3.4mm in the C group(P=0.09). No marked difference was noted in the incidence of chest pain aggravation between the two groups. The IL-6 peak value in the blood was 44±27pg·ml-1 in the Mg group and 102±80pg·ml-1 in the C group (P=0.04).
Conclusion. Increased blood Mg2+ may inhibit the reappearrance of arrhythmia after reperfusion, as well as IL-6 production and myocardial lesions caused by Ca overload in the cells. Treating AMI patients with magnesium sulfate before coronary reperfusion therapy may be effective for preventing reperfusion injury.
