title: Scar-related right atrial macroreentrant tachycardia in patients without prior atrial surgery: electroanatomic characterization and ablation outcome.
abstract: BACKGROUND
  Few descriptions of right atrial macroreentrant atrial tachycardia involving regions of spontaneous "scar" have been reported.
  
  
  OBJECTIVE
  We describe the electrocardiographic, electrophysiologic, and electroanatomic characteristics of an unusual RA macroreentrant atrial tachycardia in eight patients with spontaneous RA scarring.
  
  
  METHODS
  Eight of 286 patients with macroreentrant atrial tachycardia treated with radiofrequency ablation had RA spontaneous scarring and underwent conventional electrophysiologic studies and electroanatomic mapping.
  
  
  RESULTS
  Eight patients (age 53 +/- 12 years) had symptoms for 58 +/- 62 months and had not responded to 2.5 +/- 0.8 antiarrhythmic drugs and 1.0 +/- 0.9 DC cardioversions. All patients had overall normal systolic function, and five had mild atrial enlargement. Scarring was present in the posterolateral wall extending from the crista terminalis toward the tricuspid annulus. The proportion of RA classified as scar was 31% +/- 14% (range 11%-46%). Stable circuits were around scar in seven patients, through a "channel" within the scar in four, and typical cavotricuspid isthmus-dependent flutter in five. Radiofrequency ablation sites included the cavotricuspid isthmus; between the inferior vena cava, superior vena cava, or crista terminalis and scar; or a channel in the scar. ECG morphology of the RA free wall tachycardias varied, depending upon whether cavotricuspid isthmus block was present. Radiofrequency ablation of all inducible circuits was successful in six patients and of all clinical circuits in seven. At follow-up of 20 +/- 13 months, six patients are free from macroreentrant atrial tachycardia, one has infrequent nonsustained macroreentrant atrial tachycardia, and one is controlled with previously ineffective medication. Five had sinus node dysfunction requiring permanent pacemaker implant.
  
  
  CONCLUSIONS
  Extensive spontaneous scarring of the RA is an unusual cause of macroreentrant atrial tachycardias, both cavotricuspid isthmus dependent and independent in the same patient. Radiofrequency ablation is an effective treatment. Sinus node dysfunction requiring permanent pacemaker is common. The cause is unknown.
authors.affiliation: Department of Cardiology, Royal Melbourne Hospital, University of Melbourne, Melbourne, Australia.
authors.forename: Irene H
authors.initials: IH
authors.lastname: Stevenson
authors.forename: Peter M
authors.initials: PM
authors.lastname: Kistler
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Spence
authors.forename: Jitendra K
authors.initials: JK
authors.lastname: Vohra
authors.forename: Paul B
authors.initials: PB
authors.lastname: Sparks
authors.forename: Joseph B
authors.initials: JB
authors.lastname: Morton
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Kalman
mesh_terms: D017115:Catheter Ablation; D002921:Cicatrix / Q000503:physiopathology; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000503:physiopathology / Q000601:surgery*; D016896:Treatment Outcome