Apparent pulse wave velocity in the canine superior vena cava

In order to evaluate clinically recorded jugular vein pulses it is necessary to understand the transmission process of the right atrial pressure pulse through the caval veins up to the jugular veins. The transmission speed at distinct points of the venous pressure curve was studied in the superior vena cava of 20 anaesthetised dogs. Under control conditions the propagation velocities varied from 1.2 +/- 0.49 to 2.5 +/- 1.36 m . s-1. During increased preload of the heart propagation velocities rose significantly from 2.2 to 4.2 m . s-1 per kPa as a function of mean venous pressure and from 2.3 to 5.8 m . s-1 per kPa as a function of phasic pressures. Right atrial pacing (between 60 and 120 beats . min-1) did not influence the propagation velocity of the studied distinct points. It was found that the summits of the pressure pulse propagate at only a slightly higher speed than the nadirs.