Antiarrhythmic fatty acids and antioxidants in animal and cell studies

From the animal and cellular studies that will be discussed in this review, it is apparent that dietary fatty acids and antioxidants play an important role in influencing the development of ventricular tachycardia and potentially lethal ventricular fibrillation. It is this latter disturbance to the rhythmic beating of the heart that is responsible for much of the mortality from coronary heart disease. It is now recognized that diets high in certain polyunsaturated fatty acids (PUFAs) and diets containing antioxidants can afford considerable protection to the heart with regard to the generation of disorders of contractile rhythmicity. The mechanism by which such dietary components confer their cardioprotective effects are now being intensively investigated, particularly with respect to their possible effects on the molecular mechanisms underlying the excitation-contraction coupling process of the myocardial cell. This overview will cover recent studies that have focused on the antiarrhythmic role of PUFAs, particularly those of the n-3 (or omega 3) class with emphasis on experiments performed using laboratory animals, isolated heart preparations, and isolated heart cells (cardiomyocytes). The role of free radicals (reactive oxygen species) and antioxidants in disorders of cardiac rhythm also will be addressed within the perspective of reperfusion injury to the myocardium following ischemia. Emphasis will be placed on the cardioprotective role of nutritional factors and components and the possible cellular mechanisms by which such components may act.