Coupling of left ventricular and aortic volume elasticity in the rabbit

Changes in volume elasticity (VE) of the left ventricle and aorta could be important for blood flow. A procedure is presented to rapidly assess VE of the left ventricle and aorta by analyzing changes in the eigenfrequency. Si x control rabbits and 11 rabbits with atheromatosis (12 wk of high-choleste rol feeding) were studied. In control rabbits, during the first half of the systole, left ventricular VE continuously increased to +43% (P< 0.05). The n VE gradually declined to an end-diastolic minimum (20% of the average sys tolic levels, P< 0.05). Aortic VE changes were in the opposite direction to the ventricle. Aortic VE continuously decreased throughout the systole; th e last value was 20% lower than at the beginning of the systole (P< 0.05). Conversely, diastolic VE of the aorta took on greater values. This inverse time course between ventricle and aorta may reduce energy requirements for conveying blood. High cholesterol-fed rabbits did not reveal the inverse be havior of ventricular and aortic VE, e.g., aortic VE increased during the s ystole (119%, P< 0.05).