CHANGES IN FATTY-ACID COMPOSITIONS OF MYOCARDIAL LIPIDS IN RATS WITH HEART-FAILURE FOLLOWING MYOCARDIAL-INFARCTION

Changes in fatty acid composition of myocardial lipids were examined i n rats with heart failure following myocardial infarction. Left ventri cular systolic pressure (LVSP) was decreased and left ventricular end- diastolic pressure (LVEDP) was elevated 24 h, 1 and 12 weeks after lef t coronary artery ligation (GAL), suggesting the development of heart failure at these periods in this model. Hearts were isolated 24 h, 1 w eek and 12 weeks after the operation, Myocardial lipids in the infarct ed scar tissue, non-infarcted remaining left ventricle including inter septum and right ventricle were separated into phospholipid (PL), tria cylglycerol (TG), diacylglycerol (DAG) and free fatty acid (FFA) fract ions, In the scar tissue PL content markedly decreased whereas TG, DAG and FFA contents increased 24 h after GAL. Despite a marked decrease in constituted fatty acids of PL fraction in the scar tissue the perce ntage of arachidonic acid in PL was elevated 12 weeks after GAL, sugge sting that release of arachidonic acid during PL degradation was suppr essed. In the non-infarcted viable left ventricle PL content remained unchanged throughout the experiment whereas TG, DAG and FFA contents w ere elevated 24 h after GAL. Despite no changes in PL and other lipid contents in the non-infarcted tissue the percentage of linoleic acid i n PL was reduced and that of docosahexaenoic acid in pi, was elevated 12 weeks after GAL. Our findings showed that myocardial lipid composit ion of the non-infarcted left ventricle was altered only in an early s tage of the development of heart failure and fatty acid compositions o f PL was exchanged in a late stage of the development of heart failure . The exchange may be related to cardiac dysfunction or myocardial rem odelling in the rat with heart failure.