Abstract
Employing the logarithmic phonocardiograph, significant apical diastolic murmurs which were exceedingly faint were recorded. Nearly one-half of 100 curves showed an abnormal delay in the onset of the max. vibrations of the 1st heart sound and a series of high frequency vibrations at the time of a-v openings. The occurrence of these features indicates mitral stenosis although usually there is no auscultatory evidence of its presence. When diastolic vibrations occur without a late 1st heart sound and without an opening snap it seems probable that there is no mitral stenosis.