[Analysis of arterial pulse propagation time variability for studying wave transmitting properties of arteries]

Propagation time of arterial pulse waves was studied concerning intervals R-R and intervals of corresponding peaks of differential radial arterial pressure. These signals were detected by an ECG monitor LIFESCOPE 6 (NIHON KOHDEN) and a tonometric arterial pressure detector JENTOW 7700 (NIHON COLIN), and are simultaneously recorded by a data-recorder. The cyclic variations in arterial propagation time and heart rate fluctuations were analyzed by means of fast Fourier transform (FFT) using a personal computer PC-9801RX (NEC). Apparently, they resembled each other in their power spectra. Therefore, an index for assessment of wave transform characteristics was induced as follows: Magnitude of variation can be calculated by sigma(power x frequency) = sigma PF, where the power means a square root of amplitude of power spectrum by FFT. Then, sigma PFRR and sigma PFRP were defined as the variation in arterial pulse wave propagation time and variation in heart rate fluctuations, respectively. Furthermore, they were normalized by their mean values (mRR, mRP), respectively, as sigma PFRR was found proportionate to mRR. The components of low (0.05-0.075Hz) and mid (0.075-0.15Hz)-frequency bands of heart rate variability are considered from pressure-derived-fluctuation dependent on the vasomotor tone and the baroreceptor reflex of arteries. On the other hand, high frequency (0.15-0.45Hz) component of the heart rate fluctuation with respiratory cycle is decreased by arterial elasticity and is induced to propagation time variation directly. Therefore, (sigma PFRP.mRP-1)/(sigma PFRR.mRR-1) in high frequency band was proposed as an index for assessment of wave transform characteristics.(ABSTRACT TRUNCATED AT 250 WORDS)