Anatomical Basis for the Cardiac Interventional Electrophysiologist

Figure 1

(a) The heart is viewed in attitudinally appropriate position. As can be seen, the right atrium lies anterior to its alleged left-sided counterpart. Note the arrangement of the sulcus terminalis and the atrioventricular or coronary groove (blue broken line). (b) The right atrium is shown in right anterior oblique projection. The terminal crest (yellow broken line) arches anterior to the orifice of the superior caval vein and extends toward the inferior caval vein. (b, c) Spatial relationship of the atrial structures. Right posterior (b) and superior (c) views of volume rendered CT angiographies are shown. The right atrium (RA) body (sinus venarum) is shown extending between the SCV and ICV. The right atrial appendage (RAA) is large with a wide neck compared to the left atrial appendage (LAA). Note prominent pectinate muscles of the RAA. The terminal groove (green arrows) is seen between the RAA and the venous part of the RA. The left atrium (LA) is located superior and posterior to the right atrium. (e, f) Endocardial aspects of the lateral wall of the right atrium opened. Note in (e) that the pectinate muscles have a uniform parallel alignment almost without crossovers between them. In contrast, the pectinate muscles in (f) have a nonuniform arrangement with abundant interlacing trabeculations between them. Ao = aorta, CSO = coronary sinus orifice, ICV = inferior cava vein, LA = left atrium, LAA = left atrial appendage, LI = left inferior pulmonary vein, LS = left superior pulmonary vein, OF = oval fossa, PM = pectinate muscles, PT = pulmonary trunk, RAA = right atrial appendage, RCA = right coronary artery, RI = right inferior pulmonary vein, RPA = right pulmonary artery, RS = right superior pulmonary vein, RVOT = right ventricle outflow tract, SCV = superior cava vein, TC = terminal crest, and TV = tricuspid valve.

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