Regional characteristics of the harmonic components of the pressure pulse wave in the atherosclerotic aorta of the Kurosawa and Kusanagi-hypercholesterolemic (KHC) rabbit

We investigated the relationship between the severity and extent of atherosclerotic lesion and harmonic components of the pressure pulse waves at different aortic regions in the Kurosawa and Kusanagi-hypercholesterolemic (KHC) rabbit aged 10∼12 months. Frequency spectra of the pressure pulse waves recorded at nine positions from the ascending aorta to the left iliac artery were obtained for the first (Hc1) to fifteenth (Hc15) harmonic components with fast Fourier transformation. The amplitudes of Hc1, Hc2 and Hc3 progressively increased with distance along the aorta from the heart as observed in the normal rabbit, whereas the amplitudes of Hc4 to Hc6 were very slightly increased towards the peripheral aortic position. At any given aortic position, Hc1 and Hc2 showed higher amplitude in the KHC rabbit than in the normal rabbit except at the aortic region between the ascending aorta and the proximal thoracic aorta, in which sclerotic lesion was more severe and extensive than in any other aortic regions. These results suggest that the increased amplitude of the pressure pulse wave `peaking', apparent in the peripheral aortic region of the KHC rabbit, was mainly caused by the increase in the amplitudes of Hc1 and Hc2 of the pulse wave, and that the decrease in the amplitudes of Hc2 and Hc3 in the aortic arch was related to the severity and extent of atherosclerotic lesion.