Effects of free fatty acids on electrophysiological properties of ventricular myocardium

Several metabolic factors have been regarded as a cause of ventricular tachyarrhythmias in cardiac ischemia, i.e. hypoxia, acidosis, intracellular potassium loss, local catecholamine release as well as an increased catecholamine concentration and an evaluation of serum free fatty acids. The arrhythmogenic properties of anoxia and hypoxic acidosis, catecholamines as well as potassium depletion are well known. However, the relationship between elevated free fatty acids concentration and the occurrence of ventricular arrhythmias remain obscure. The micro-electrode technique was applied to examine the electrophysiological effects of free fatty acids in papillary heart muscle fibres. Both linoleate and palmitate cause a concentration-dependent decrease of action potential duration and a corresponding shortening of the functional refractory period in the presence of sufficient oxygen supply. The results suggest that a high concentration of free fatty acids may play an additional role in the genesis of ventricular tachyarrhythmias in cardiac ischemia.