Unexplained features of the left ventricular pressure pulse

¹ Department of Physiology, Medical College of Georgia, Augusta, Georgia

An accurate record of the left ventricular pressure pulse in the dog is difficult to register, and often cannot be recognized unless a comparison with a simultaneously recorded pulse from the ascending aorta is made. What seem reliable records usually indicate a transient pressure excess over the aortic level when ejection presumably is beginning. Hence, there is a lag of some 5 msec. between the time when the ventricular pressure reaches the aortic diastolic pressure level and the start of the aortic pulse. The timing of the latter is coincident with an inflection on the slope of ventricular pressure rise. The start of the pulse requires little, if any, transmission lag for the first part of the ascending aorta, but does for the descending aorta. The incisura, in contrast, shows a propagation delay from the very mouth of the aorta. The initial steep slope of the aortic pulse, and the height of the inflection, are not necessarily related to the slope of the ventricular pulse, or the excess ventricular pressure height-initiating ejection.