Anatomical Basis for the Cardiac Interventional Electrophysiologist

Figure 14

(a, b) These two halves of a heart are bisected longitudinally to show the three aortic sinuses and the papillary muscles of the mitral valve. Note that the muscular subpulmonary infundibulum of the right ventricular outflow tract abuts the right and left coronary sinuses. (c) The kidney-shaped vestibule of the mitral valve is shown from the atrial side. The commissure between the leaflets of the mitral valve and the fibrous continuity between the aortic leaflet of the mitral valve and left coronary and noncoronary of the aortic sinuses are shown. There is no muscular infundibulum in the left ventricle. Note the coronary sinus (blue broken line) next to the left atrioventricular groove surrounding the mitral valve from behind. (d) The aortic root has been opened through the left coronary aortic sinus showing the musculature in the depth of the sinus and the area of fibrous continuity between the leaflets of the aortic and mitral valves. It is photographed by transillumination from behind to show the three sinuses showing the left aortic sinus (L), the right aortic sinus (R), and the posterior or noncoronary aortic sinus (N). Two of the three interleaflet fibrous triangles are shown (). Note that the right fibrous trigone is continuous with the membranous septum, the two fibrous structures together forming the so-called central fibrous body (the brightest area by transillumination, black broken line). The specialized atrioventricular conduction axis penetrates through this fibrous area and left bundle branch. (e) Short-axis view from atria side, after removal of the epicardium and coronary vessels, shows the relationship of the aortic valve and the right (blue asterisk) and left (red asterisk) fibrous trigones. Pulmonary sinuses are named according to their relationship to the heart (nonattitudinal), including anterior (A), left posterior (LP), and right posterior (RP) pulmonary sinus. (f) Cross-histological section stained with Masson’s trichrome through the left and the right atria. Note the anatomic relation of the right ventricular outflow tract with the subaortic outflow. Note that while all of the leaflets of the pulmonary valve are supported by infundibular musculature, only two of the leaflets of the aortic valve have muscular support. Ao = aorta, CS = coronary sinus, MV = mitral valve, LVOT = left ventricle outflow tract, PT = pulmonary trunk, RVOT = right ventricle outflow tract, and TV = tricuspid valve.

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