Cardiol Young 2007; 17(Suppl. 2): 1–28 r Cambridge University Press ISSN 1047-9511 doi: 10.1017/S1047951107001138 Original Article The nomenclature, definition and classification of cardiac structures in the setting of heterotaxy Jeffrey P. Jacobs, 1 Robert H. Anderson, 2 Paul M. Weinberg, 3 Henry L. Walters III, 4 Christo I. Tchervenkov, 5 Danny Del Duca, 5 Rodney C. G. Franklin, 6 Vera D. Aiello, 7 Marie J. Be ´land, 8 Steven D. Colan, 9 J. William Gaynor, 10 Otto N. Krogmann, 11 Hiromi Kurosawa, 12 Bohdan Maruszewski, 13 Giovanni Stellin, 14 Martin J. Elliott 15 1 The Congenital Heart Institute of Florida, Division of Thoracic and Cardiovascular Surgery, All Children’s Hospital/Children’s Hospital of Tampa, University of South Florida College of Medicine, Cardiac Surgical Associates, Saint Petersburg and Tampa, Florida, United States of America; 2 Cardiac Unit, Institute of Child Health, Great Ormond Street Hospital for Children, London, United Kingdom; 3 Division of Pediatric Cardiology, The Children’s Hospital of Philadelphia, University of Pennsylvania School of Medicine, Pennsylvania, United States of America; 4 Children’s Hospital of Michigan, Wayne State University School of Medicine, Detroit, Michigan; 5 Division of Pediatric Cardiovascular Surgery, The Montreal Children’s Hospital of the McGill University Health Centre, Montre´al, Quebec, Canada; 6 Paediatric Cardiology Directorate, Royal Brompton & Harefield NHS Trust, Harefield, Middlesex, United Kingdom; 7 Heart Institute (InCor), Sao Paulo University School of Medicine, Sao Paulo, Brazil; 8 Division of Pediatric Cardiology, The Montreal Children’s Hospital of the McGill University Health Centre, Montre´al, Quebec, Canada; 9 Department of Cardiology, Children’s Hospital, Boston, Massachusetts, United States of America; 10 Cardiac Surgery, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America; 11 Paediatric Cardiology – CHD, Heart Center Duisburg, Duisburg, Germany; 12 Cardiovascular Surgery, Heart Institute of Japan, Tokyo Women’s Medical University, Tokyo, Japan; 13 The Children’s Memorial Health Institute, Department of Cardiothoracic Surgery, Warsaw, Poland; 14 Pediatric Cardiac Surgery Unit, University of Padova Medical School, Padova, Italy; 15 Cardiac Unit, Great Ormond Street Hospital for Children, London, United Kingdom Abstract In 2000, The International Nomenclature Committee for Pediatric and Congenital Heart Disease was established. This committee eventually evolved into the International Society for Nomenclature of Paediatric and Congenital Heart Disease. The working component of this international nomenclature society has been The International Working Group for Mapping and Coding of Nomenclatures for Paediatric and Congenital Heart Disease, also known as the Nomenclature Working Group. The Nomenclature Working Group created the International Paediatric and Congenital Cardiac Code, which is available for free download from the internet at [http://www.IPCCC.NET] . In previous publications from the Nomenclature Working Group, unity has been produced by cross- mapping separate systems for coding, as for example in the treatment of the functionally univentricular heart, hypoplastic left heart syndrome, or congenitally corrected transposition. In this manuscript, we review the nomenclature, definition, and classification of heterotaxy, also known as the heterotaxy syndrome, placing special emphasis on the philosophical approach taken by both the Bostonian school of segmental notation developed from the teachings of Van Praagh, and the European school of sequential segmental analysis. The Nomenclature Working Group offers the following definition for the term ‘‘heterotaxy’’: ‘‘Heterotaxy is synonymous with ‘visceral heterotaxy’ and ‘heterotaxy syndrome’. Heterotaxy is defined as an abnormality where the internal thoraco-abdominal organs demonstrate abnormal arrangement across the left-right axis of Correspondence to: Jeffrey P. Jacobs, MD, FACS, FACC, FCCP, Cardiovascular and Thoracic Surgeon, The Congenital Heart Institute of Florida (CHIF), Clinical Associate Professor, University of South Florida (USF), Cardiac Surgical Associates (CSA), 603 Seventh Street South, Suite 450, Saint Petersburg, FL 33701. Tel: (727) 822 6666; Cell Phone: (727) 235–3100; Fax: (727) 821 5994; E-mail: JeffJacobs@msn.com, http://www.heartsurgery-csa.com/, http://www.CHIF.us/