Intracellular cations and diuretic therapy following acute myocardial infarction.

In a controlled, prospective, randomized study of the effects of diuretic therapy on serum, lymphocyte, and erythrocyte potassium, magnesium, and calcium concentrations, 155 patients were followed up for six months after experiencing acute myocardial infarction. Of these, 48 patients received furosemide and potassium; 37 patients received hydrochlorothiazide and amiloride hydrochloride; and 70 patients did not require diuretics. Lymphocyte and erythrocyte cation concentrations were all statistically significantly lower in the furosemide-treated patients when compared with the patients in the nondiuretic-therapy group or the hydrochlorothiazide-amiloride-treated group, with no change in serum levels. Since the combination of low intracellular potassium and magnesium concentrations in patients with recent myocardial infarction may be of importance in the cause of arrhythmias, we suggest that potassium- (and magnesium-) sparing diuretics be used in the treatment of patients, when necessary, unless their diuretic needs cannot be met by such agents.