THE EFFECT OF DIFFERENT DIETARY-LIPID SUPPLEMENTS ON THE NONESTERIFIED FATTY-ACID COMPOSITION OF NORMOXIC RAT HEARTS - A LINK BETWEEN NUTRITION AND CARDIAC-ARRHYTHMIA

In addition to changes in the fatty acid composition of cardiac membrane phospholipids, alterations in the dietary lipid intake of rats influence the composition but not the amount of myocardial non-esterified fatty acids (NEFA's). These changes are apparent in the relative proportions of arachidonic acid (AA) and those other polyunsaturated fatty acids (PUFA's) such as linoleic acid (LA) or docosahexaenoic acid (DHA) which are either substrates for or competitive inhibitors of the conversion of AA to the 2-series eicosanoids. In particular changes in the relative proportions of AA, LA and DHA in myocardial NEFA are associated with alterations in the production of myocardial thromboxane (TXA2) and the vulnerability of the heart to develop arrhythmia during partial ischaemia. These results suggest a link between the type of dietary fat intake, the composition of myocardial NEFA and the development of the lethal arrhythmias which are responsible for Sudden Cardiac Death.