title: Focal atrial tachycardia arising from the cavotricuspid isthmus with saw-tooth morphology on the surface ECG: electrocardiographic and electrophysiologic characteristics.
abstract: BACKGROUND
  Limited information is available about focal atrial tachycardia (AT) arising from cavotricuspid isthmus (CTI).
  
  
  OBJECTIVE
  The purpose of this study is to evaluate the electrocardiographic and electrophysiologic characteristics of a focal AT arising from the CTI.
  
  
  METHODS
  From a consecutive series of 92 patients undergoing radiofrequency catheter ablation (RFCA) for focal AT, three (4.4%) patients (three men) with a focal AT arising from the CTI were studied.
  
  
  RESULTS
  The median age was 71 years (range, 50 to 81 years). None of the patients had a history of CTI-dependent atrial flutter. The electrocardiogram (ECG) of a focal AT showed a significant negative F-wave in the inferior leads. Focal AT could be reproducibly initiated and terminated with programmed stimulation. The focus of the tachycardia was localized to the central isthmus in two and the paraseptal isthmus in one patient. The median tachycardia cycle length was 275 ms (range, 260 to 310 ms). In two patients, the focal AT was adenosine insensitive. In all of the patients, tachycardia was entrained from multiple right atrial sites, including the earliest activation site. RFCA was acutely successful in all patients. Long-term success was achieved in all patients over the median follow-up of 18 months (range, 6 to 33 months).
  
  
  CONCLUSIONS
  Cavotricuspid isthmus is an uncommon site of origin for focal AT. This focal AT has unique electrocardiographic characteristics such as saw-tooth morphology on ECG and is suggested to be caused by a focal reentrant circuit located at the CTI. Long-term success is achieved with focal ablation.
authors: Division of Cardiology, Sendai City Hospital, Wakabayashi-ku, Shimizukouji3-1, Sendai, Japan.
authors: Hirokazu
authors: H
authors: Sato
authors: Tetsuo
authors: T
authors: Yagi
authors: Akio
authors: A
authors: Namekawa
authors: Akihiko
authors: A
authors: Ishida
authors: Yoshihiro
authors: Y
authors: Yamashina
authors: Takashi
authors: T
authors: Nakagawa
authors: Manjirou
authors: M
authors: Sakuramoto
authors: Eiji
authors: E
authors: Sato
authors: Tomoyuki
authors: T
authors: Yambe
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001282:Atrial Flutter / Q000150:complications / Q000175:diagnosis* / Q000601:surgery*; D018780:Body Surface Potential Mapping / Q000379:methods*; D017115:Catheter Ablation / Q000379:methods*; D015331:Cohort Studies; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D018570:Risk Assessment; D013612:Tachycardia, Ectopic Atrial / Q000175:diagnosis* / Q000209:etiology* / Q000601:surgery; D016896:Treatment Outcome; D014261:Tricuspid Valve / Q000503:physiopathology*