Effect of a Decrease in Aortic Compliance on the IsovolumicRelaxation Period of the Left Ventricle in Man

Abstract

A decrease in aortic compliance can modify the loading sequence to the left ventricular ejection in the elderly. To determine whether a decreased aortic compliance influences the left ventricular relaxation in man, 83 healthy volunteers, aged 34-87 years, were studied. The left ventricular relaxation was characterized by the isovolumic relaxation period (IRP) of the left ventricle. The aortic compliance was characterized by the aortic pulse wave velocity (AoPWV). The loading sequence to left ventricular ejection was classified into three groups by carotid pulse contour; type A, dominant tidal wave; type B, percussion wave almost equal to the tidal wave; type C, dominant percussion wave. IRP and AoPWV increased with age. The mean arterial pressure was unrelated to age. IRP was significantly related to AoPWV and mean arterial pressures. Multiple regression analysis, correlating IRP with AoPWV and mean arterial pressure, demonstrated that only AoPWV was an independent factor to explain IRP. IRP was longer in type A than in type C, and AoPWV was faster in type A than in type C volunteers. The prominent tidal wave in type A may reflect a more rapid transmission of arterial wave reflection which can result in a change of the loading sequence to the left ventricular ejection. These results reveal that a decrease in aortic compliance with aging can affect left ventricular relaxation through the change of the loading sequence in man.