Regionalization of the atria for 3D electroanatomical mapping, cardiac imaging, and computational modelling: a clinical consensus statement of the European Heart Rhythm Association and the European Association of Cardiovascular Imaging of the ESC

Abstract

This clinical consensus document proposes standardized atrial segments for 3D imaging, electroanatomical mapping and computational modelling, based on anatomical, electrophysiological and clinical considerations, with precise definitions of regional borders allowing for reproducible and automated regionalization. 3D imaging and high-resolution electroanatomical mapping have become an integral part of cardiac electrophysiology and the management of patients with arrhythmias. However, to perform regional quantitative analyses and intra- and inter-individual, as well as cross-modality comparisons, a universal definition of atrial regions and their boundaries is required. While for the left ventricle there is already an established standardized regionalization (AHA 17-segment model), there is no such consensus for the atria. In a multi-disciplinary writing group consisting of cardiologists, cardiac electrophysiologists, cardiovascular imaging specialists, and anatomists as well as specialists in computational cardiac modelling from European Heart Rhythm Association and European Association of Cardiovascular Imaging, a standardized regionalization based on a 15-segment bi-atrial model was elaborated. This clinical consensus document will enable consistent regional analyses and homogeneous data acquisition across different centres and modalities, and may thus have a significant impact on atrial arrhythmia research and personalized treatment approaches based on individual arrhythmia patterns and phenotypes.

Keywords: Atrial fibrillation; Atrial regions; Cardiac imaging; Catheter ablation; Electroanatomical mapping; Segmentation.

Graphical Abstract

Figure 1

Standard axes and planes. (A) Body axes and corresponding planes. Directions are indicated according to the standard attitudinal terminology, with anterior, posterior, superior, inferior, left and right corresponding to ventral, dorsal, cranial, caudal, left and right direction, respectively. (B) Cardiac axis and corresponding planes. The cardiac axis is defined by the line connecting the aortic root and cardiac apex. The cardiac axis indicates the apical and basal direction, respectively.

Figure 2

Clock model indicating specific locations at the left and right atrioventricular junction in a left anterior oblique view. SVC, superior caval vein; RSPV, right superior pulmonary vein; LSPV, left superior pulmonary vein; LIPV, left inferior pulmonary vein.

Figure 3

The image is a frontal section through the atrial chambers of a human foetus at 9 weeks of development. It is possible to recognize the developmental origins of the components of both atrial chambers. Each atrium possesses a body, which is the remains of the atrial component of the primary heart tube. The vestibules are derived from the atrioventricular canal myocardium of the primary tube. The appendages are chamber myocardium, formed by the process of ballooning from the body on each side. Each atrium now possesses its venous sinus, with the venous valves still recognizable to show the boundaries of the systemic venous sinus of the right atrium. The primary atrial septum forms the floor of the oval fossa, with its antero-inferior buttress formed by muscularization of the vestibular spine and mesenchymal cap of the primary septum. The superior margin of the fossa is clearly seen to be an infolding between the atrial walls.

Figure 4

Gross anatomy of the right atrium. (A) The morphologically right atrium has been opened by making an incision within the systemic venous sinus parallel to the terminal groove, and reflecting the appendage laterally. The heart is viewed from a lateral projection that corresponds to a right posterior oblique view. It is possible to recognize all the anatomical components that make up the atrial chamber. The appendage is characterized by its pectinated walls. The smooth vestibule separates the appendage from the hinges of the leaflets of the tricuspid valve in the right atrioventricular junction. The remnants of the embryonic right venous valve, seen as the Eustachian and Thebesian valves guarding the mouths of the inferior caval vein and coronary sinus respectively, delineate the lateral border between the venous sinus and the appendage. In this heart, the remnant of the left venous valve can also be seen, making it possible to recognize the small part of the atrial body interposed between the valvular remnants and the septal surface. The depression on the septal surface shows the location of the true septum. It is not possible to identify the paraseptal areas. (B) The image shows the en-face septal aspect of the cavity of the morphologically right atrium. The endocardium has been removed to show the ‘grain’ produced by the parallel aggregation of the individual cardiomyocytes. It is possible to recognize the rims and floor of the oval fossa. Only the area adjacent superior to the tendon of Todaro is a true second septal component over and above the flap valve forming the floor of the fossa. The dissection also shows the boundaries of the triangle of Koch along with the locations of the cavotricuspid and septal isthmuses.

Figure 5

Gross anatomy of the left atrium. (A) The morphologically left atrium from the same heart as used to prepare Figure 4 has been opened by making cuts in its lateral wall, and reflecting the wall to show its cavity. It is possible to recognize the tubular appendage by virtue of the pectinated nature of its walls. The remaining walls are all smooth, but these are made up of the vestibule, the body, and the pulmonary venous component. Note that the venous component forms the superior wall of the chamber, or its dome. The posterior wall is made up of the body and the vestibule. The flap valve of the septum is adherent to the rims of the oval fossa, better seen from the right side (A). It is possible to recognize the myocardial sleeves of the left pulmonary veins, which come together to form the left pulmonary venous antrum. The orifices of the right antrum cannot be seen. Note the coronary sinus within the inferior atrioventricular groove. (B) The image shows the lateral wall of the morphologically left atrium as viewed from the septal aspect. The superior and inferior pulmonary veins are seen entering the left antrum of the venous sinus, separated by the venous carina. The left lateral ridge, part of the body of the atrium, interposes between the orifices of the left pulmonary veins, and the mouth of the appendage. It is possible to recognize the mitral isthmus, between the pulmonary venous orifices and the hinge of the mural leaflet of the mitral valve, and the second, narrower, isthmus formed between the mouth of the left appendage, and the hinge of the mitral valvular leaflet. The latter isthmus is formed by the atrial vestibule, whereas both the vestibule and the lateral wall of the body of the atrium make up the mitral isthmus.

Figure 6

(Central illustration): 15-segment bi-atrial model. Illustrated visualization of the 15 left and right atrial segments in different views (A–C), and head-to-head comparison with anatomical sections (D–F) as well as electroanatomical mapping clinical routine CT-imaging (G–I) and electroanatomical mapping clinical routine CT-imaging (J–L) in the correspondent views. Left column: posterior-anterior view; middle column: left anterior oblique view; right column: right anterior oblique view. CS, coronary sinus; IVC, inferior vena cava; LAA, left atrial appendage; LIPV, left inferior pulmonary vein; LSPV, left superior pulmonary vein; MA, mitral annulus (left atrioventricular junction); RAA, right atrial appendage; RIPV, right inferior pulmonary vein; RSPV, right superior pulmonary vein; SVC, superior vena cava; TA, tricuspid annulus (right atrioventricular junction).

Figure 7

Segment 1 (left pulmonary antrum). Illustration of segment 1 in a postero-anterior view (A) and a superior view (B). (C) Clinical routine electroanatomical map visualizing segment 1 in a postero-anterior view. LSPV, left superior pulmonary vein; LIPV, left inferior pulmonary vein; RSPV, right superior pulmonary vein; RIPV, right inferior pulmonary vein.

Figure 8

Segment 2 (right pulmonary venous antrum). Illustration of segment 2 in a postero-anterior view (A) and a right anterior oblique view (B). (C) Clinical routine electroanatomical map visualizing segment 2 in a postero-anterior view. RIPV, right inferior pulmonary vein; RSPV, right superior pulmonary vein; LIPV, left inferior pulmonary vein; LSPV, left superior pulmonary vein.

Figure 9

Segment 3 (left atrial posterior wall). Illustration of segment 3 in a postero-anterior view (A) and clinical routine electroanatomical map visualizing segment 3 in the same view (B). RIPV, right inferior pulmonary vein; RSPV, right superior pulmonary vein; LIPV, left inferior pulmonary vein; LSPV, left superior pulmonary vein.

Figure 10

Segment 4 (left atrial anterior wall). Illustration of segment 4 in a left anterior oblique view (A) and a superior view (B). (C) Clinical routine electroanatomical map visualizing segment 4 in a left anterior oblique view. IVC, inferior vena cava; LAA, left atrial appendage; LIPV, left inferior pulmonary vein; LSPV, left superior pulmonary vein; RSPV, right superior pulmonary vein; SVC, superior vena cava.

Figure 11

Segment 5 (left atrial appendage). Illustration of segment 5 in a left anterior oblique view (A) and a clinical routine electroanatomical map visualizing segment 5 in the same view (B). LIPV, left inferior pulmonary vein; LSPV, left superior pulmonary vein; MA, mitral annulus (left atrioventricular junction); RSPV, right superior pulmonary vein.

Figure 12

Segment 6 (left atrial lateral wall). Illustration of segment 6 in a left lateral view (A), a left posterior oblique view (B), and a superior view (C). (D) Clinical routine electroanatomical map visualizing segment 6 in a left lateral view. IVC, inferior vena cava; LAA, left atrial appendage; LSPV, left superior pulmonary vein; MA, mitral annulus (left atrioventricular junction) RSPV, right superior pulmonary vein; RIPV, right inferior pulmonary vein; SVC, superior vena cava.

Figure 13

Segment 7 (left atrial inferior wall). Illustration of segment 7 in an inferior view (A) and a clinical routine electroanatomical map visualizing segment 7 in the same view (B). LAA, left atrial appendage; LIPV, left inferior pulmonary vein; LSPV, left superior pulmonary vein; MA, mitral annulus (left atrioventricular junction); RIPV, right inferior pulmonary vein; RSPV, right superior pulmonary vein.

Figure 14

Segment 8 (left atrial septal wall). Illustration of segment 8 in a right anterior oblique view (A), and a clinical routine electroanatomical map visualizing segment 8 in the same view (B). LSPV, left superior pulmonary vein; LAA, left atrial appendage RIPV, right inferior pulmonary vein; RSPV, right superior pulmonary vein.

Figure 15

Segment 9 (right atrial septal wall). Illustration of segment 9 in a left posterior oblique view (A) and a left anterior oblique view (B). (C) Clinical routine electroanatomical map visualizing segment 9 in a left posterior oblique view. CS, coronary sinus; IVC, inferior vena cava; SVC, superior vena cava; TA, tricuspid annulus (right atrioventricular junction).

Figure 16

Segment 10 (right atrial posterior venous wall). Illustration of segment 10 in a right posterior oblique view (A) and a clinical routine electroanatomical map visualizing segment 10 in the same view (B). IVC, inferior vena cava; RAA, right atrial appendage; SVC, superior vena cava.

Figure 17

Segment 11 (right atrial appendage and lateral wall). Illustration of segment 11 in a right anterior oblique view (A), a left anterior oblique view (B), and a right lateral view (C). (D) Clinical routine electroanatomical map visualizing segment 11 in a right anterior oblique view. IVC, inferior vena cava; SVC, superior vena cava.

Figure 18

Segment 12 (right atrial lateral vestibule). Illustration of segment 12 in an antero-posterior view (A) and a clinical routine electroanatomical map visualizing segment 12 in the same view (B). IVC, inferior vena cava; SVC, superior vena cava; TA, tricuspid annulus (right atrioventricular junction).

Figure 19

Segment 13 (right atrial anterior wall). Illustration of segment 13 in a left anterior oblique view (A) and a clinical routine electroanatomical map visualizing segment 13 in the same view (B). CS, coronary sinus; IVC, inferior vena cava; SVC, superior vena cava; TA, tricuspid annulus (right atrioventricular junction).

Figure 20

Segment 14 (cavotricuspid isthmus). Illustration of segment 14 in an inferior view (A), and a clinical routine electroanatomical map visualizing segment 14 in the same view (B). CS, coronary sinus; IVC, inferior vena cava; TA, tricuspid annulus (right atrioventricular junction).

Figure 21

Segment 15 (Koch's triangle). Illustration of segment 15 in a left posterior oblique view (A), and a clinical routine electroanatomical map visualizing segment 15 in the same view (B). CS, coronary sinus; IVC, inferior vena cava; RAA, right atrial appendage; SVC, superior vena cava; TA, tricuspid annulus (right atrioventricular junction).