Influence of High Plasma Concentrations of Free Fatty Acids on Heart Rhythm in Healthy Fasting Men

Abstract
Ten healthy male students in regular sinus rhythm fasted for 66 h. Their overnight fasting plasma concentration of free fatty acids (FFA) was 455 .+-. 104 .mu.mol/l (mean .+-. SEM [standard error of the mean], n = 7), the reference value of the laboratory, measured in another normal population of young men, being 344 .+-. 28 .mu.mol/l (n = 10). After 42 and 66 h of fasting, the plasma concentration of FFA rose to 1198 .+-. 181 (P < 0.01, n = 10) and 1471 .+-. 89 .mu.mol/l (P < 0.001, n = 10), respectively. During the last 24 h of fasting, the heart rhythm was monitored continuously by means of a Holter recorder and computer. No arrhythmias were observed; elevated plasma concentrations of FFA, exceeding those reported in patients with acute myocardial infarction, are well-tolerated by the healthy human myocardium.