Malignant arrhythmia in relation to serum potassium in acute myocardial infarction.

Several studies of patients with acute myocardial infarction have shown an association between hypokalemia, including mild hypokalemia, and increased occurrence of cardiac arrhythmia. Hypokalemia in acute myocardial infarction is significantly associated with diuretic therapy before or during the infarction. In a study of 1,074 patients with acute myocardial infarction, ventricular fibrillation occurred in 17.2% of 122 hypokalemic patients and in 7.5% of 952 normokalemic patients (p less than 0.01). The association of hypokalemia and ventricular fibrillation was not specifically related to poor left ventricular function. Recent studies indicate that hypokalemia is an independent risk factor of ventricular arrhythmia early in acute myocardial infarction, but a definite causal role of potassium remains to be shown. The importance of catecholamines versus serum potassium levels in occurrence of arrhythmia has not been clarified.