Normal M-mode echocardiographic base-to-apex scan. The leaflets of the boxlike aortic valve (AoV) open widely in systole, whereas in diastole they coapt and are midway between the anterior and posterior aortic walls. The aorta (Ao) and left atrium (LA) are equal in size. There are normal anterior continuity between the anterior aortic wall and the interventricular septum (VS) and normal posterior continuity between the posterior aortic wall and the anterior mitral leaflet (AML). The mitral valve has a characteristic M-shaped anterior leaflet and W-shaped posterior leaflet (PML). Onset of mitral valve opening is designated by the letter D, full opening of the anterior leaflet by E, middiastolic closure by F, atrial systole by A, and valve closure by C. RVW, right ventricular wall; RVOT, right ventricular out flow tract,; Ch, chordae tendineae; LV, left ventricle.
J.M. Felner, R.P. Martin, The Echocardiogram, The Hurst's The Heart, 8th ed., p 382.