Maximal Instantaneous Mitral Valve Velocities Measured with a Digital Echocardiographic Tracking System

Analysis of the motion of various cardiac structures is attaining increasing clinical significance. By coupling a digital tracking system to a commercially available echocardiograph, continuous position and velocity data from selected intracardiac structures were obtained. This tracking system, which employs a dynamic range gate, has been designed to isolate and lock on to a selected target within the heart. Position of the target is calculated every 8 ms; velocity is obtained by determining the difference between consecutive positions. This system has been used to study mitral valve motion in 20 normal subjects. Maximal instantaneous velocities of the anterior leaflet of the mitral valve were recorded. These instantaneous velocities are to be distinguished from the average velocities obtained by manually measuring the slopes of the curve segments. This system demonstrates a new technique for obtaining more detailed information about the dynamic characteristics of selected cardiac structures.