RELATION BETWEEN SERUM-FREE-FATTY-ACIDS AND ARRHYTHMIAS AND DEATH AFTER ACUTE MYOCARDIAL INFARCTION

Abstract

Serum-free-fatty-acid (F.F.A.) levels measured in 200 patients during the first forty-eight hours after an acute myocardial infarction have been related to the prevalence of arrhythmias detected by continuous monitoring of the electrocardiogram, to the clinical state of the patients, and to serum-enzyme and blood-glucose levels. Maximum elevation of serum F.F.A. occurred within four to eight hours in most patients after acute myocardial infarction. Those with a striking elevation (above 1200 μeq. per litre) had an increased prevalence of serious arrhythmias and disorders of conduction. Both early and late deaths were more frequent among these patients compared with those with less elevated levels. There was no correlation between serum-F.F.A. and the clinical state of the patients, except for cardiogenic shock; nor between serum-F.F.A. and serum-creatine-kinase or serum-aspartate-aminotransferase levels; nor between these serum-enzyme levels and the prevalence of arrhythmias. Serum-F.F.A. and blood-glucose levels did not show significant correlation, except in cardiogenic shock. It is concluded that measurement of serum-F.F.A. is a new and valuable early predictive index of the vulnerability of patients with acute myocardial infarction to serious arrhythmias. This relationship between serum-F.F.A. levels and arrhythmias could result from increased catecholamine activity, particularly that of noradrenaline, or it could be due directly to an increase in myocardial oxygen consumption caused by the utilisation of F.F.A. as the major energy substrate. Both mechanisms would intensify myocardial hypoxia in an already ischæmic heart.