Heart Sounds Research Lab
Mitral Regurgitation (MR)
The Heart Sounds and Murmurs Laboratory | 6560 Fannin St, Suite 1836| Houston, Texas 77030 | 832-355-2937
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Mitral valve regurgitation, also called mitral valve insufficiency, is a regurgitant systolic murmur. In a patient with mitral
regurgitation, the murmur begins with the onset of isovolemic systole and continues throughout systole as a relatively flat,
holosystolic murmur that ends with the declining period of isovolemic relaxation of the left ventricle. The murmur of mitral
regurgitation is usually blowing in character. The murmur accordingly begins with, and frequently obscures, S1 and continues
beyond aortic valve closure, so that S2 may likewise be obscured. It is best heard at the apex, the sound usually radiating to the
axilla and to the tip of the scapula. When the volume of mitral regurgitation is more severe, the return of this regurgitant
volume with the next diastole results in a filling sound, a third heart sound (S3), and an inflow diastolic rumble, a flow rumble
(FR). The S3 and flow rumble are both low frquency events and are best heard with the bell of the stethoscope placed over the
apex of the heart.