[Hypokalemia in acute heart infarct]

Serum potassium in 20 patients with acute myocardial infarction (AMI) measured 2 to 6 hours after the beginning of chest pain was 3.8 +/- 0.4 mmol/l. This was lower than the value of 4.1 +/- 0.2 mmol/l of 29 controls admitted for elective evaluation of coronary heart disease. In patients with AMI there was a negative linear correlation between serum potassium and lymphocyte count. The hypothesis that AMI induces a decrease in potassium concentration by accompanying epinephrine secretion is supported by this correlation. In addition, respiratory alkalosis may play a role because it also induces hypokalemia and lymphocytosis. In view of the arrhythmogenic effect of hypokalemia, measures which reduce the epinephrine increase and hyperventilation, such as analgesic therapy and sedation, should be of potential antiarrhythmic value.