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Interrelationship between magnesium and potassium in preventing myocardial ischemia-reperfusion arrhythmia
1Department of Cardiovascular Diseases, Tongji Hospital, Tongji Medical University, Wuhan.
Objective:
To assess the interrelationship between Mg2+ and K+ in preventing reperfusion arrhythmia (RA).
Material And Methods:
72 rat hearts were randomly divided into 6 equal groups, and perfused with various combinations of Mg2+ and K+ in the perfusate by Langendorff method. Each heart was subjected to coronary occlusion for 15 minutes followed by 12-minute reperfusion. The incidence of RA was recorded. The concentration of K+ and malondialdehyde (MDA) in the coronary effluent before and after reperfusion were measured with increasing concentrations of Mg2+ and fixed concentration of K+.
Results:
All forms of ventricular arrhythmias occurred after reperfusion but with decreased incidence by increasing Mg2+ and K+. When both Mg2+ and K+ were in high level, no VF appeared on reperfusion. However, when they were both in low level, 100% of hearts developed severe arrhythmia. The concentration of K+ and MDA in the coronary effluent was markedly increased compared with that before reperfusion, and the loss of K+ and malondialdehyde (MDA) decreased with increasing Mg2+.
Conclusions:
Mg2+ may prevent or reduce the incidence of RA by maintaining the integrity of intracellular K+ and by reducing the lipid peroxide reaction.