A computerized system for video analysis of the aortic valve

A technique was developed to study the dynamic behavior of the porcine aortic valve in an isolated heart preparation. Under the control of a personal computer, a video frame grabber board continuously acquired and digitized images of the aortic valve, and an analog-to-digital (A/D) converter read four channels of physiological data (flow rate, aortic and ventricular pressure, and aortic root diameter). The valve was illuminated with a strobe light synchronized to fire at the field-acquisition rate of the CCD (charge-coupled device) video camera. Using the overlay bits in the video board, the measured parameters were superimposed over the live video as graphical tracing, and the resultant composite images were recorded online to video tape. The overlaying of the valve images with the graphical tracings of acquired data allowed the data tracings to be precisely synchronized with the video images of the aortic valve. This technique enabled the authors to observe the relationship between aortic root expansion and valve function.