Investigation of the vascular system using ultrasonic Doppler-shift techniques is rapidly attracting clinical attention. Frequently the technique is used to provide a sophisticated form of stethoscope with a rather non-specific indication of blood flow-velocity, or less frequently for the production of flowvelocity pulse wave shapes. Detailed analysis of these pulse wave shapes has not been reported. However it is known that partial obstruction of the arterial pathway and the presence of collateral vessels produces damping of the pulse

CARDIAC catheterization to evaluate myocardial or valvular function should not be used in the seriously ill patient and is difficult in the infant1. Furthermore, its use is justified for neither periodic screening examinations nor for routine monitoring at surgery. The clinical value of continuous monitoring of a parameter closely related to myocardial efficiency during and immediately after surgery cannot be over-emphasized. The social implications of the ability to screen for valvular disorders and decreased myocardial efficiency before infarction are more difficult to predict.