Mitral valve (M-mode echocardiogram)
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An M-mode echocardiogram from the parasternal long axis, with the m-mode pick directed through the mitral valve leaflets. One may appreciate the approximated mitral valve leaflets at the beginning of diastole (D) swing apart, with the cephalad and anterior excursion of the anterior leaflet contacting the septum at its peak excursion (E). As the pressure gradient between the left atrium and left ventricle begins to decline towards diastasis, the valves return toward their nuclear position (F). Their path is then reversed by atrial contraction (A), and thereafter trend toward one another until ventricular systole forces rapid coaptation.
Anatomy is labeled as RVOT (right ventricular outflow tract), IVS (interventricular septum), LV (left ventricle), and LVPW (left ventricular posterior wall).
This M-mode examination was performed from the parasternal long axis, with the m mode pick placed through the leaflets of the mitral valve. Historically, the E-F and A-C slopes were sought as barometers of left ventricular function. Mitral stenosis would classically decrease the E-F slope in the context of an enlarged left atrium, while the latter would be interrupted by a positive deflection ("B bump") in the presence of elevated left ventricular filling pressures 1.
While the aforementioned parameters are no longer used routinely, E point septal separation (EPSS), the distance between the anterior MV leaflet at its most anterior opening excursion (the E point) and the interventricular septum is a reproducible, quick, and highly sensitive measure of severe left ventricular systolic dysfunction. Indeed, both the diastolic excursion of the mitral leaflets and the subsequent degree of closure during systole are intimately related to the vigor of left ventricular systole 2.
Key learning points:
- left ventricular systolic dysfunction may result in a decreased mitral valve diastolic opening, measured as a pathologically elevated (>8 mm) EPSS
- in the correct clinical context, this EPSS < 0 mm would support the preservation of left ventricular radial contraction