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The radial and digital arterial pulse is a superposition of several component pulses. At the temporal front of the pulse envelope is the primary pressure pulse that results from the contraction of the left ventricle. This arterial pressure pulse travels away from the heart through the arterial tree and is reflected at two major reflection sites, one in the region of the renal arteries where the aorta’s diameter decreases on the order of 17%, the other beyond the bifurcation of the iliac arteries [1]. Both reflection sites exhibit sufficiently large reflection coefficients, about 40% in the case of the iliac site, as to produce re-
Above is an example of the radial pulse of a 44 year old male and its various component pulses.
While the clinical evidence supporting the above model is conclusive so far, we present here just two simple physical supporting arguments:
1. The features of the reflected component pulses are too distinct, too sharp, as to be the convolution of different reflections originating from different sites with different time delays and different reflection coefficients, which would tend to broaden out specific pulse features.
2. The arrival times of the specific features of the radial pulse very much narrow the location possibilities of the reflection sites that gave rise to them. Using published arterial pulse propagation velocities for different arterial segments (see Figure on left) and the subject’s limb and torso dimensions one arrives at relative delay times very close to measured ones, such as are shown above in milliseconds.
1. The features of the reflected component pulses are too distinct, too sharp, as to be the convolution of different reflections originating from different sites with different time delays and different reflection coefficients, which would tend to broaden out specific pulse features.
2. The arrival times of the specific features of the radial pulse very much narrow the location possibilities of the reflection sites that gave rise to them. Using published arterial pulse propagation velocities for different arterial segments (see Figure on left) and the subject’s limb and torso dimensions one arrives at relative delay times very close to measured ones, such as are shown above in milliseconds.
