Living Anatomy of the Atrioventricular Junctions. A Guide to Electrophysiologic Mapping A Consensus Statement from the Cardiac Nomenclature Study Group, Working Group of Arrhythmias, European Society of Cardiology, and the Task Force on Cardiac Nomenclature from NASPE Francisco G. Cosı ´o, MD; Robert H. Anderson, MD; Karl-Heinz Kuck, MD; Anton Becker, MD; Martin Borggrefe, MD; Ronald W.F. Campbell, MD²; Fiorenzo Gaita, MD; Gerard M. Guiraudon, MD; Michel Haı ¨ssaguerre, MD; Juan J. Rufilanchas, MD; Gaetano Thiene, MD; Hein J.J. Wellens, MD; Jonathan Langberg, MD; David G. Benditt, MD; Saroja Bharati, MD; George Klein, MD; Francis Marchlinski, MD; Sanjeev Saksena, MD Abstract—Current nomenclature for the atrioventricular (AV) junctions derives from a surgically distorted view, placing the valvar rings and the triangle of Koch in a single plane with antero-posterior and right-left lateral coordinates. Within this convention, the aorta is considered to occupy an anterior position, although the mouth of the coronary sinus is shown as being posterior. Although this nomenclature has served its purpose for the description and treatment of arrhythmias dependent on accessory pathways and atrioventricular nodal reentry, it is less than satisfactory for the description of atrial and ventricular mapping. To correct these deficiencies, a consensus document has been prepared by experts from the Working Group of Arrhythmias of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology. It proposes a new anatomically sound nomenclature that will be applicable to all chambers of the heart. In this report, we discuss its value for description of the AV junctions, establishing the principles of this new nomenclature. (Circulation. 1999;100:e31-e37.) Key Words: anatomic nomenclature  atrioventricular junctions  triangle of Koch  atrial mapping  accessory pathway ablation T he introduction of catheter ablation has revolutionized the approach to treatment of arrhythmias. In the 1970s, surgery developed as a very effective means of curing the Wolff-Parkinson-White syndrome. 1,2 The accessory path- ways responsible for preexcitation and tachycardias were identified by mapping, 3 and their structure was confirmed by pathologic observations. 4,5 The atrioventricular (AV) junc- tions, defined as the AV rings and surrounding structures, and including Koch’s triangle and the AV conduction tissues, were described in great detail. The nomenclature developed at that time, however, depicted the position of the AV rings and the aortic valve in one plane, which was described on the basis of antero-posterior and right-left lateral coordinates. In this plane, the aortic valve is represented as being anterior to the mouth of the coronary sinus, when in reality it is predominantly superior. Similarly, the coronary sinus itself, which becomes the main landmark in the presumed posterior part of the section, is properly described as being inferior. 6 Despite the obvious distortion introduced by this nomencla- ture, it served its purpose to permit communication between electrophysiologists and surgeons and was fundamental in the evolution of surgical and catheter ablation in the treatment of Wolff-Parkinson-White syndrome. But as AV nodal reentrant tachycardia became better known (and subject to surgical treatment), the same inaccurate nomenclature was applied to Koch’s triangle. 7–9 This resulted in definition of anterior and posterior approaches to the AV node, which again are inappropriate descriptions of the true anatomic orientation because during life, the apex of Koch’s triangle points up and not to the front. In contrast, those who have also considered the treatment of ventricular tachycardia have described their findings using appropriate anatomic coordinates. 10 Such discrepancies now achieve greater importance because, with the development of catheter ablation, treat- From the Cardiac Nomenclature Study Group Working Group of Arrhythmias, European Society of Cardiology (F.G.C., R.H.A., A.B., M.B., F.G., G.M.G., M.H., K.-H.K., J.J.R., G.T., H.J.J.W.) and the Nomenclature Expert Panel, North American Society of Pacing and Electrophysiology (J.L., D.G.B., S.B., W.J., G.K., F.M., S.S.) ²Dr Ronald W.F. Campbell is deceased. This article is also published in Eur Heart J. 1999;20:1068 –1075 and J Cardiovasc Electrophysiol. In press. Correspondence to Francisco G. Cosı ´o, MD, Chief Cardiology Service, Hospital Universitario de Getafe, Carretera de Toledo, km 12,5, 28905 Getafe, Madrid. © 1999 American Heart Association, Inc. Circulation is available at http://www.circulationaha.org 1 Current Perspective by guest on November 8, 2015 http://circ.ahajournals.org/ Downloaded from