title: Anatomic and electrophysiologic differences between chronic and paroxysmal atrial flutter: intracardiac echocardiographic analysis.
abstract: BACKGROUND
  It remains unknown why atrial flutter (AFL) occurs as either a chronic or paroxysmal arrhythmia.
  
  
  OBJECTIVE
  The aim of the study was to compare intracardiac echocardiographic (ICE) images of the crista terminalis (CT) and transverse conduction properties of the CT between chronic and paroxysmal forms of common AFL.
  
  
  METHODS
  Chronic AFL (n = 7) was defined as non-self-terminating AFL lasting >1 month, and paroxysmal AFL (n = 8) was defined as an intermittent arrhythmia with symptomatic episodes of 24 hours maximum duration. ICE images of the right atrium were recorded with a 9 F 9-MHz intracardiac ultrasound catheter during pullback at 0.5-mm intervals from the superior vena cava to the inferior vena cava triggered by electrocardiogram and respiration. The two-dimensional image of the right atrium was reconstructed into a three-dimensional (3-D) image.
  
  
  RESULTS
  Three-dimensional images from patients with chronic AFL showed the CT to be thick and continuous, and conduction across the CT was blocked at a pacing rate just above sinus rhythm in all seven patients. In contrast, 3D images from paroxysmal AFL showed the CT to be thin and discontinuous, and conduction across the CT during midseptal pacing was observed in five of the eight patients.
  
  
  CONCLUSIONS
  The nature of AFL is determined, at least in part, by anatomic and electrophysiologic characteristics of the CT.
authors: Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Oyaguchi-kami, Itabashi-Ku,Tokyo, Japan.
authors: Kimie
authors: K
authors: Ohkubo
authors: Ichiro
authors: I
authors: Watanabe
authors: Yasuo
authors: Y
authors: Okumura
authors: Sonoko
authors: S
authors: Ashino
authors: Masayoshi
authors: M
authors: Kofune
authors: Kazunori
authors: K
authors: Kawauchi
authors: Takeshi
authors: T
authors: Yamada
authors: Tatsuya
authors: T
authors: Kofune
authors: Kenichi
authors: K
authors: Hashimoto
authors: Atsushi
authors: A
authors: Shindo
authors: Hidezou
authors: H
authors: Sugimura
authors: Toshiko
authors: T
authors: Nakai
authors: Satoshi
authors: S
authors: Kunimoto
authors: Satoshi
authors: S
authors: Saito
authors: Atsushi
authors: A
authors: Hirayama
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D001282:Atrial Flutter / Q000145:classification / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D018780:Body Surface Potential Mapping / Q000379:methods*; D002908:Chronic Disease; D019560:Echocardiography, Three-Dimensional / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018084:Ultrasonography, Interventional / Q000379:methods*