Relation of left atrial V-wave/left ventricular systolic pressure ratio to mitral regurgitant volume

Evaluation of mitral regurgitation is difficult whether invasive or noninvasive methods are used. The determination of the regurgitant volume itself cannot be done in clinical practice with reasonable accuracy. In six sheep with chronic mitral regurgitation, left ventricular and left atrial pressures were recorded with high-fidelity catheters. The regurgitant volume was measured directly with electromagnetic flow probes positioned at the mitral annulus and around the ascending aorta, balanced against each other. A total of 24 hemodynamic states were obtained varying preload and afterload by fluid expansion and angiotensin infusion. On the basis of these studies, the pressure ratio of the V wave divided by the left ventricular systolic pressure is proposed as an index of regurgitant volume. A good correlation was found between this ratio and the regurgitant volume (r = 0.75). The ratio is easily recorded during routine heart catheterization.