Analysis of Prosthetic Cardiac Valve Performance by use of Combined Audio and Ultrasonic Techniques

The most effective and precise noninvasive diagnostic technique for measuring prosthetic valve performance and detecting early malfunction is a hard-copy multichannel simultaneous recording of valve sound, the echocardiogram of the prosthetic valve and the electrocardiogram. The measurement criteria include velocity and timing measurements as well as ultrasonic pattern analysis. These criteria were established on the basis of results obtained from in vitro studies of ultrasonic beam patterns - prosthetic valve interactions, acoustic focusing properties of prosthetic poppets and chemical characteristics of prosthetic valve materials as they relate to normal and malfunctioning valves. The clinical reliability of this technique has been confirmed by its applications to a series of more than 100 prosthetic valve patients. The results were corroborated by cardiac catheterization open heart surgery or post mortem examination.