Cardiac Wall Motion Analysis Using Videodensitometry: A Time-Modulated Vector Display for Evaluation of Cardiac Performance

A new display format for the examination and study of myocardial wall motion parameters such as displacement, velocity, and acceleration has been developed which is suitable for mass screening of patients with suspected wall motion abnormalities. The physiological data from the display comes from videotape recorded fluoroscopy and from the ECG which is recorded synchronously with the television image on one of the audio channels of the videotape. The wall motion signal is obtained from the recorded images with a videodensitometer and displayed in pairs with the ECG, ventricular pressure, and other wall motion signals on an X-Y vectorscopc. In addition, the display is intensity modulated at a known rate to encode time information. The complex Lisajous patterns formed by the display give an immediate graphical presentation of the correlation between the paired parameters being plotted. Since the video recordings are obtained during routine cardiac fluoroscopy and the analysis made without further patient participation, there is no additional radiation hazard to the patient.