Changes in ECG, plasma and myocardial lipids in experimental myocardial hypertrophy in rats

ECG, systolic blood pressure (BP), the ratio (R) of grams of myocardial mass/100 g of body mass, total lipids, cholesterol, triglycerides and phospholipids in blood plasma and the left ventricular myocardium, as well as the plasma free fatty acids, were investigated in 58 male Wistar rats 3, 30 and 180 days after operation, in a model of myocardial hypertrophy (MH) induced by experimental coarctation hypertension, after the method of Selye. An attempt was made to correlate some functional and metabolic indices which characterize the development of this type of MH. On a background of progressively rising BP and parallel increasing R, ECG changes were recorded. They were typical of the respective stage of arterial hypertension and MH and expressed mostly in a shifting of the electrical axis of the heart to the left and in essential repolarization disturbances. The most significant changes in the studied lipid fractions were found 30 days after the induction of hypertension. The pathological changes manifested on the 180th day are discussed in relation to age, the stage of hypertension and especially in relation to the developing hypoxic and ischaemic myocardial damage.