title: Crista Terminalis as the Anterior Pathway of Typical Atrial Flutter: Insights from Entrainment Map with 3D Intracardiac Ultrasound.
abstract: BACKGROUND
  The precise location of truly active reentry circuits of typical atrial flutter (AFL) has not been well identified. The purpose of this study was to verify our hypothesis that the posterior block line is located along the posteromedial right atrium (PMRA) and the crista terminalis (CT) is the anterior pathway of AFL, with real-time intracardiac echo (ICE).
  
  
  METHODS
  The entire right atrium (RA) three-dimensional activation and entrainment mapping were evaluated during AFL in 18 patients using CARTO sound.
  
  
  RESULTS
  The CT was clearly visualized by ICE and the local electrograms along the CT were single potentials in all the patients. The CT was recognized as the truly active anterior pathway based on entrainment mapping in all patients. Double potentials were recorded along the PMRA. Entire RA entrainment mapping could be performed in 16 patients. The reentry circuits were separated into three passages. The first was around the tricuspid annulus (TA), the second the anterior superior vena cava (SVC; AFL waves passed between the anterior SVC and RA appendage), and the last the posterior SVC (between the posterior SVC and upper limit of the PMRA). All three of these passages were active in four, around the TA and anterior SVC in eight, around the TA and posterior SVC in three, and around only the anterior SVC in one patient.
  
  
  CONCLUSIONS
  The CT functions as the anterior pathway of typical AFL, and the posterior block line was located along the PMRA. Dual or triple circuits were recognized in the majority of AFL patients.
authors: Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.
authors: Tomoyuki
authors: T
authors: Nakanishi
authors: Koji
authors: K
authors: Fukuzawa
authors: Akihiro
authors: A
authors: Yoshida
authors: Mitsuaki
authors: M
authors: Itoh
authors: Kimitake
authors: K
authors: Imamura
authors: Ryudo
authors: R
authors: Fujiwara
authors: Atsushi
authors: A
authors: Suzuki
authors: Soichiro
authors: S
authors: Yamashita
authors: Akinori
authors: A
authors: Matsumoto
authors: Hiroki
authors: H
authors: Konishi
authors: Hirotoshi
authors: H
authors: Ichibori
authors: Ken-Ichi
authors: K
authors: Hirata
mesh_terms: D000368:Aged; D001282:Atrial Flutter / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D004452:Echocardiography / Q000379:methods*; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006329:Heart Conduction System; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male
keywords: atrial flutter; crista terminalis; electrophysiology - clinical; intracardiac echo; mapping