S3 and left ventricular dysfunction in AR vs MR

S3 and left ventricular dysfunction in AR vs MR

Abstract: S3 can occur in mitral regurgitation without left ventricular dysfunction while presence of S3 in aortic regurgitation indicates left ventricular dysfunction.

Conventional teaching is that an S3 can occur in mitral regurgitation without left ventricular dysfunction while presence of S3 in aortic regurgitation indicates left ventricular dysfunction. Horn RA and colleagues explored this aspect using quantitative Doppler echocardiography and the data was published as an abstract in the Journal of American College of Cardiology in 1996.¹ They evaluated three hundred and forty patients with a third heart sound.

They found that S3 in aortic regurgitation was associated with decreased left ventricular function and increased end systolic volume index. In the case of mitral regurgitation, S3 was associated with severe mitral regurgitation and left ventricular enlargement. They had measured end diastolic volume index, end systolic volume index, ejection fraction and regurgitant fraction for the study. Regurgitant fraction was measured by a combination two dimensional echocardiography and quantitative Doppler echocardiography.

Reference

1. Horn RA, Sarano ME, Seward JB. The significance of an audible S3 is different in aortic regurgitation, mitral regurgitation and LV dysfunction: A quantitative doppler echocardiography study. J Am Coll Cardiol. 1996;27(2s1):115-116.