PREVENTION OF CARDIAC-ARRHYTHMIA BY DIETARY (N-3) POLYUNSATURATED FATTY-ACIDS AND THEIR MECHANISM OF ACTION

The role of marine fish oil (n-3) polyunsaturated fatty acids in the p revention of fatal ventricular arrhythmia has been established in expe rimental animals. Prevention of arrhythmias arising at the onset of is chemia and reperfusion is important because if untreated, they result in sudden cardiac death. Animals supplemented with fish oils in their diet developed little or no Ventricular fibrillation after ischemia wa s induced. Similar effects have also been observed in cultured neonata l cardiomyocytes. Several mechanisms have been proposed and studied to explain the antiarrhythmic effects of fish oil polyunsaturated fatty acids, but to date, no definite mechanism has been validated. The sequ ence of action of these mechanisms and whether more than one mechanism is involved is also not clear. Some of the mechanisms suggested to ex plain the antiarrhythmic action of fish oils include the incorporation and modification of cell membrane structure by (n-3) polyunsaturated fatty acids, their direct effect on calcium channels and cardiomyocyte s and their role in eicosanoid metabolism. Other mechanisms that are c urrently being investigated include the role of (n-3) polyunsaturated fatty acids in cell signalling mediated through phosphoinositides and their effect on various enzymes and receptors. This article reviews th ese mechanisms and the antiarrhythmic studies using (n-3) polyunsatura ted fatty acids.