An ultrasonic system for visualizing the dynamics of the left ventricle has been developed that utilizes a catheter-borne array of four transducers spaced 90° apart in a plane normal to the axis of the catheter. The transducers (transceivers) are pulsed sequentially at the rate of 1000/second and the data are collected over a period of about 8 seconds. The cardiac cycle is arbitrarily divided into 24 equal increments or frames depicting the contour of the left ventricle at various stages during the cardiac cycle. The display phase commences upon completion of the data acquisition. Compensation for the motion of the catheter within the heart and determination of the angular orientation of the catheter tip were major problems that had to be dealt with in the development of this instrumentation. The fact that data are not acquired in the same order in which they can be displayed necessitates the use of the computer for sorting and storage of echo-ranging data. The resulting views of the inner wall of the left ventricle are proving to be useful information, which should lead to a better understanding of the dynamic events of the cardiac cycle.
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