title: Surface electrocardiographic characteristics of right and left atrial flutter.
abstract: BACKGROUND
  There is little information about the surface expression of non-cavotricuspid isthmus (CTI)-dependent right atrial (RA) or left atrial (LA) flutter circuits.
  
  
  RESULTS
  We retrospectively evaluated 32 episodes (in 26 patients) of atypical RA and 22 episodes (in 21 patients) of LA flutter. The surface ECG of 13 patients with lower-loop reentry was similar to that of their pattern during counterclockwise (CCW) CTI atrial flutter (AFL), except for decreased amplitude of the terminal forces in the inferior leads. In 11 of 24 episodes characterized by high or multiple breaks over the crista, the ECG showed changes that depended on the initial activation sequence of the LA. In 7 of 8 episodes of upper-loop reentry, the ECG pattern completely mimicked that for clockwise (CW) CTI AFL. All 11 patients with an LA septal circuit showed a typical ECG pattern characterized by prominent forces in lead V1 with flat deflections in the other surface leads. Eleven patients with other LA circuits had a more variable pattern but showed decreased voltage in the inferior leads compared with that of a group with CCW-CTI AFL (1.6+/-1 vs 2.68+/-0.7 mV, respectively; P<0.05).
  
  
  CONCLUSIONS
  The RA surface-ECG patterns different from those of CCW or CW-CTI could still be CTI dependent. In contrast, a typical CW-CTI surface pattern was always seen in patients with upper-loop reentry, which was non-CTI dependent. LA AFL circuits had either flat or low-amplitude forces in the inferior leads.
authors.affiliation: Cardiovascular Research Institute and Section of Cardiac Electrophysiology, University of California, San Francisco 94143-1354, USA.
authors.forename: Andres
authors.initials: A
authors.lastname: Bochoeyer
authors.forename: Yanfei
authors.initials: Y
authors.lastname: Yang
authors.forename: Jie
authors.initials: J
authors.lastname: Cheng
authors.forename: Randall J
authors.initials: RJ
authors.lastname: Lee
authors.forename: Edmund C
authors.initials: EC
authors.lastname: Keung
authors.forename: Nassir F
authors.initials: NF
authors.lastname: Marrouche
authors.forename: Andrea
authors.initials: A
authors.lastname: Natale
authors.forename: Melvin M
authors.initials: MM
authors.lastname: Scheinman
mesh_terms: D000368:Aged; D001282:Atrial Flutter / Q000175:diagnosis / Q000503:physiopathology* / Q000601:surgery; D018780:Body Surface Potential Mapping; D017115:Catheter Ablation; D004562:Electrocardiography / Q000379:methods; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006325:Heart Atria / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity