In an experimental canine model of acute mitral regurgitation, the mitral regurgitant area decreased monotonically to 59% of its initial value, closely paralleling the decrease in ventricular volume.
Does the mitral regurgitant area vary dynamically with ventricular volume during systole in acute mitral regurgitation?
In acute mitral regurgitation, the mitral regurgitant orifice area is not fixed but decreases dynamically in parallel with ventricular volume during systole.
We designed this study to test the hypothesis that in acute mitral regurgitation the mitral regurgitant area (MRA) is a dynamic quantity which varies with the time variation of ventricular volume. Mitral insufficiency was created in five open-chest dogs in which a portion of the anterior leaflet was excised. Phasic aortic and mitral flows were measured electromagnetically, along with left atrial and ventricular pressures. Filling, regurgitant, and stroke volumes, and systolic pressure gradient were determined by digital methods. MRA was calculated from the fluid dynamic equation of motion to give the temporal mean and the instantaneous value at three instants of time and at the time of peak flow (when inertia is negligible). Mean regurgitant fraction was 42 +/- 12% with no indication of left ventricular failure due to volume overload. MRA decreased monotonically with time to 59% of its initial value and closely paralleled the decrease in ventricular volume during systole. In a control study using a tilting-disc prosthesis with a hole 5 mm in diameter in the occluder, the calculated MRA was time invariant and equal to the measured area for regurgitation. We conclude that in acute mitral regurgitation the MRA is a function of ventricular volume.
Yellin et al. (Thu,) conducted a other in Acute mitral regurgitation (n=5). Acute mitral regurgitation (experimental model) vs. Control study using a tilting-disc prosthesis with a 5 mm hole was evaluated on Mitral regurgitant area (MRA) variation during ventricular ejection. In an experimental canine model of acute mitral regurgitation, the mitral regurgitant area decreased monotonically to 59% of its initial value, closely paralleling the decrease in ventricular volume.