Measurements of Velocity Wave Forms in the Dog Aorta

Abstract

Hot film needle and catheter probes were used to measure the velocity waves in the dog aorta between the aortic valve and the iliac bifurcation. The forms of the waves were found to be of two types, those in which there was a reverse flow, following systole, everywhere along the centerline of the aorta and those for which there was no flow reversal in the regions below the diaphragm. Energy spectra were measured before and after the administration of a cardiac stimulant. Except for a shift to higher frequencies, no significant change in the form of the spectra was observed. Characteristic times developed for the mean flow and the decay of a fully developed turbulence suggest that it is difficult to sustain small scale turbulence which might be initiated during peak systole.