An analysis on the opening behavior of a tilting disc heart valve using mock circulation

The dynamic behavior of prosthetic heart valves, which has an influence on blood flow adjacent to the valves is important from both clinical and hemodynamic viewpoints. In this experiment, the relationship between the mode of valve opening and flow pattern through the valve was analyzed. A Bjork Shiley Monostrut valve (sewing ring diameter: 23 mm) was incorporated in a mitral position of a mock circulatory system which contains a silastic left atrium and a rubber left ventricle driven by pneumatic pressure. Changes in valvular disc angle were measured at 500 frames per second using a high speed videocamera under two conditions in which the maxima flow rates were 15 and 20 L/min. The video data indicated that the valve opening motion was greatly influenced by a flow rate pattern in the early opening period from 0 to 20 msec. At this moment, a relationship between normal force as well as drug force applied to the disc is important to determine the initial movement of the disc.