Left Atrial and Left Ventricular Sound and Pressure in Mitral Stenosis

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Abstract
Left atrial and left ventricular pressure and sound were recorded at the time of mitral commissurotomy in 18 patients with severe, isolated, noncalcific mitral stenosis and sinus rhythm. Catheter tip micromanometers were used, and in eight studies, two equisensitive micromanometers were employed to examine pressure crossover relationships. Analysis of the left atrial and left ventricular sound and pressure crossover relationships is presented; viewed in the perspective provided by cineangiographic studies and surgical observations, a unifying concept of the auscultatory events in mitral stenosis is proposed. Beginning with left ventricular pressure rise, the left ventricle drives the mitral complex through its ascent (or eversion) phase toward the left atrium, clearing the anterior leaflet from the left ventricular outflow tract. The ascent (eversion) terminates abruptly at the first heart sound (S 1 ). Following systole, left ventricular and left atrial pressure fall together after v peak, during and after pressure crossover, until the point where left atrial pressure fall ceases abruptly (opening snap notch), left atrial pressure exceeding that in the left ventricle, and the mitral opening snap occurs. During this interval, the mitral valve complex descends or inverts toward the left ventricle and terminates abruptly with the mitral opening snap. Thus, the mitral opening snap may be considered as the reciprocal of the delayed, accentuated S 1 , in noncalcific mitral stenosis in sinus rhythm.