Effects of magnesium deficiency on the pathogenesis of myocardial infarction.

The death rate due to myocardial infarction appears to vary with dietary consumption of Mg. This could be due to effects on atherosclerosis, coronary artery spasm, altered pathogenesis of myocardial infarction, increased vulnerability to arrhythmia, or some combination of these. Mg deficiency (MD) has been found to increase the severity of a coronary occlusive event in terms of the amount of necrosis produced by a given occlusion. MD is also associated with increased likelihood of arrhythmia development. In addition, reduced extracellular magnesium concentration (Mgo) is associated with contraction of vascular smooth muscle that may be the equivalent of arterial spasm. In hamsters, MD leads to fibrinoid necrosis thought to be secondary to Ca overload. These 3 effects: coronary artery spasm, cardiac arrhythmia, and increased vulnerability to myocardial necrosis following coronary occlusion, may all be dependent on changes in myocardial and vascular smooth muscle electrolyte metabolism that follow from the reduced Mgo that is associated with MD.