Mitral Regurgitation

Mitral regurgitation is the backflow of blood from the LV into the LA during systole due to improper closure of the mitral valve. Over time, this can lead to increased LA volume and pressure, LA dilation, and eventually LV dysfunction.

Primary MR: Caused by structural pathology of the mitral valve itself (ie mitral valve prolapse, rheumatic heart disease, infective endocarditis, congenital ie Marfans).
Secondary MR = Normal valve with MR secondary to LV remodelling (ie from Ischemic cardiomyopathy (post-MI), no ischemic dilated cardiomyopathy).
On physical exam, MR classically presents as a holosystolic murmur at the apex, radiating to the axilla. On POCUS, the presence and severity of MR can be roughly estimated using colour doppler by comparing the jet regurgitant area to LA area.

Steps for Image Acquisition:

Obtain A4C view: Place probe at apex, center LV and LA with a straight septum. Assess mitral valve for thickening, calcification, vegetations, perforation, or prolapse.
Turn On Colour Doppler: Adjust box to cover the entire LA and extend beyond the mitral valve
Freeze image: Capture images during systole
Estimate MR severity: Assess the regurgitant jet area relative to the LA.

Interpretation:

The video shown has no features of aortic regurgitation.
Check out UBC's video of eccentric mitral regurgitation: https://www.ubcimpocus.com/new-gallery/2019/4/23/mvp-eccentric-mr-a4c

⚠️ Tips

Large regurgitant jet with LA/LV dilation and abnormal valve morphology should trigger suspicion for severe MR, even if jet area alone seems borderline.

Abnormal Valve Morphology

Mitral valve prolapse: bulging of the valve leaflets into the LA during systole.
Flail leaflet: incomplete closure from ruptured chordae or papillary muscle
Mitral annular calcification: thickening and stiffening of the valve annulus

Regurgitant Jets

Central jets produce direct backward flow into the LA. In contrast, Eccentric jets hug the LA wall, often underestimating severity if judged by the jet area alone. This is due to the Coanda effect (tendency of a fluid jet to cling to a convex surface; it will hug wall of atrium making the jet appear smaller). If an eccentric jet is suspected, always confirm in multiple views.