title: Characteristics of cavotricuspid isthmus-dependent atrial flutter after left atrial ablation of atrial fibrillation.
abstract: BACKGROUND
  Patients who have previously undergone ablation of atrial fibrillation may experience cavotricuspid isthmus (CTI)-dependent atrial flutter during follow-up. The effects of left atrial (LA) ablation on the characteristics of CTI-dependent flutter have not been described.
  
  
  RESULTS
  Fifteen patients underwent ablation of CTI-dependent flutter late after LA ablation of AF. The ECG, biatrial activation patterns, and LA voltage maps during flutter were analyzed. Thirty age- and gender-matched patients who underwent ablation of CTI-dependent flutter without prior LA ablation served as control subjects. Among the patients with prior LA ablation, mapping revealed counterclockwise activation around the tricuspid annulus in 12 of 15 patients (80%) and clockwise activation in 3 of 15 patients (20%). The flutter waves in the inferior leads were upright in 9 of the 15 patients (60%) with prior LA ablation and in none of the control subjects (P<0.001). The upright flutter waves in the inferior leads in patients with counterclockwise flutter corresponded to craniocaudal activation of the right atrial free wall. LA activation contributed little to the genesis of the flutter waves in these patients because of a significant reduction in bipolar LA voltage (0.44+/-0.20 versus 1.54+/-0.19 mV in patients with biphasic/negative flutter waves; P<0.001).
  
  
  CONCLUSIONS
  CTI-dependent flutter that occurs after LA ablation of atrial fibrillation often has atypical ECG characteristics because of altered LA activation. In patients presenting with atrial flutter after LA ablation, entrainment mapping should be performed at the CTI even if the ECG is uncharacteristic of CTI-dependent flutter.
authors.affiliation: Division of Cardiology, University of Michigan Hospitals, Ann Arbor, MI, USA. achugh@umich.edu
authors.forename: Aman
authors.initials: A
authors.lastname: Chugh
authors.forename: Rakesh
authors.initials: R
authors.lastname: Latchamsetty
authors.forename: Hakan
authors.initials: H
authors.lastname: Oral
authors.forename: Darryl
authors.initials: D
authors.lastname: Elmouchi
authors.forename: David
authors.initials: D
authors.lastname: Tschopp
authors.forename: Scott
authors.initials: S
authors.lastname: Reich
authors.forename: Petar
authors.initials: P
authors.lastname: Igic
authors.forename: Tammy
authors.initials: T
authors.lastname: Lemerand
authors.forename: Eric
authors.initials: E
authors.lastname: Good
authors.forename: Frank
authors.initials: F
authors.lastname: Bogun
authors.forename: Frank
authors.initials: F
authors.lastname: Pelosi
authors.forename: Fred
authors.initials: F
authors.lastname: Morady
mesh_terms: D001281:Atrial Fibrillation / Q000150:complications / Q000628:therapy*; D001282:Atrial Flutter / Q000209:etiology / Q000503:physiopathology*; D018780:Body Surface Potential Mapping; D017115:Catheter Ablation / Q000009:adverse effects*; D004562:Electrocardiography; D005260:Female; D006325:Heart Atria / Q000503:physiopathology; D006329:Heart Conduction System / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D014261:Tricuspid Valve / Q000503:physiopathology*