Cardiac arrhythmias following acute myocardial infarction: associations with the serum potassium level and prior diuretic therapy.

The relationship between the initial serum potassium level and the incidence of cardiac arrhythmias following myocardial infarction has been reviewed in a coronary care unit setting. The incidence of arrhythmias in general, and ventricular fibrillation, ventricular tachycardia and frequent ventricular ectopic beats in particular, were inversely related to the initial serum potassium level. Hyperkalaemia was also significantly associated with ventricular fibrillation and ventricular tachycardia. Hypokalaemia was significantly more common in patients previously treated with diuretics, though most patients with hypokalaemia had not been so treated. The occurrence of an acute hypokalaemic syndrome, independent of, but exacerbated by, diuretic therapy, is further supported by these results.