Echographic evaluation of acquired valvular diseases of the heart.

Abstract

The mitral valve is one of the easiest structures to identify echographically. The valve is located along the left sternal border at the third to fifth intercostal space. The normal mitral valve follows a characteristic motion pattern during ventricular diastole (Fig. 1). Although the anterior mitral leaflet echo is most prominent, the posterior leaflet may also be detected ultrasonically and shows a pattern opposite in direction to that of the anterior leaflet. At the onset of ventricular diastole, there is a rush of blood across the valve that results in a peak excursion that terminates at point e of the mitral valve echogram depicted in Fig. 1. Following rapid ventricular filling, the mitral valve coasts toward a position of closure at point f and then reopens (point a) with atria1 systole. The mitral valve echogram thus reflects phasic flow across its orifice.14 When rheumatic fever results in mitral stenosis, the slope of the anterior leaflet from point e-f is reduced below the normal range of 80-150 mm/set, the response to atria1 systole is obliterated, and the posterior leaflet tends to follow the anterior in diastole (Fig. 2).3*7 M-mode echocardiography has been of limited value in assessing severity of mitral stenosis; the abnormal echographic pattern may also be found in patients with left ventricular failure and pulmonary hypertension.” The newer two-dimensional