The Second Sound-Mitral Opening Snap (A2-OS) Interval during Exercise in the Evaluation of Mitral Stenosis

Abstract

Cardiac catheterization and phonocardiography data were obtained from patients with mitral stenosis at rest and during exercise. There was a linear relationship between the percentage decrease of the interval from closure of the aortic valve to the mitral valve opening snap (A2-OS) and the percentage increase [see figure in the PDF file] of the left atrial mean pressure from rest to exercise. The duration of the A2-OS interval was an effective indicator of the level of the left atrial mean pressure during exercise. The duration of the A2-OS interval during exercise allowed separation of patients with mild stenosis from those with moderate or severe stenosis but could not be used to distinguish moderate stenosis from severe stenosis.