The dynamics of mitral insufficiency

Abstract

By using specially constructed models, the hydrodynamic factors affecting the degree of mitral regurgitation were analyzed. Forward flow into the aorta is enhanced by increases in atrial pressure, ventricular filling, viscosity of the blood, celerity of ventricular contraction, and by lateral pressure effects on the regurgitant orifice. The tendency to mitral regurgitation is heightened by a rise in systemic arterial pressure, an increase in the size of the regurgitant orifice, or a decrease in the celerity of ventricular contraction. The proximity of the aortic orifice to the mitral opening operates to reduce reflux because of competition of the two valve areas for streamlines of flow. The role of pipe competition is examined and discussed. The relative contributions of each of the foregoing factors are reviewed in terms of findings on an integrated model of the circulation. The significance of these findings in clinical mitral insufficiency is discussed.