A method using induced waves to study pressure propagation in human arteries.

THE observation that small pressure disturbances could be induced in the brachial artery and readily detected on radial arterial pressure records prompted the study of induced waves of two general types, impact transients' and forced sinusoidal waves. This report describes the method we have used to study "impact" waves and indicates the general nature of our findings. The interpretation of pulse wave transmission has been based upon the concepts of wave propagation in an ideal elastic thin walled tube. These principles were first developed and applied to the arterial pulse by Thomas Young and have been further formulated by many others. While the qualitative nature of such an interpretation seems to be acceptable, the quantitative aspects of pulse wave propagation remain open to question. Some of the limitations to quantitative interpretation of conventional pulse wave velocity are imposed by the methods of measurement, while additional difficulty arises from the fact that a living artery resembles a thin walled ideal elastic cylindrical tube only as a first approximation. Previous methods for the study of arterial wave propagation in living human subjects have utilized the wave produced by cardiac systole. Direct, i.e., intra-arterial pressure records, have been obtained in only a few instances. In all cases the pulse wave transmission time is calculated from the delay in the inscription of "corresponding" points on the pulse contour. The fact that the pulse form