title: Treatment of macro-re-entrant atrial tachycardia based on electroanatomic mapping: identification and ablation of the mid-diastolic isthmus.
abstract: OBJECTIVE
  This multicentre prospective study evaluated the ability of electroanatomic mapping (EAM) using a specific parameter setting to identify clearly the mid-diastolically activated isthmus (MDAI) and guide ablation of macro-re-entrant atrial tachycardia (MAT).
  
  
  RESULTS
  Consecutive patients with MAT, different from typical isthmus-dependent atrial flutter, were enrolled. EAM was performed using a specific setting of the window of interest, calculated to identify the MDAI and guide ablation of this area. Sixty-five patients exhibiting 81 MATs (mean cycle length 308 +/- 68 ms) were considered. Thirty-two (49.2%) had previous heart surgery. In 79 of 81 morphologies (97.5%), EAM reconstructed 95.9 +/- 4.3% of the tachycardia circuit and identified the MDAI; 23 of the 79 morphologies (29.1%) were double-loop re-entry. Mapping of two morphologies was incomplete due to MAT termination after catheter bumping. In 73 of 79 mapped morphologies (92.4%), abolition of the MAT was obtained by 13.2 +/- 12.4 applications. During the 14 +/- 4 month follow-up, MAT recurred in 4 of the successfully treated patients (6.8%).
  
  
  CONCLUSIONS
  EAM using a specific parameter setting proved highly effective at identifying the MDAI in MAT, even in patients with previous surgery and multiple re-entrant loops. Ablation of the MDAI yielded acute arrhythmia suppression with low rate of recurrence during follow-up.
authors.affiliation: Dipartimento di Scienze Cardiovascolari, Ospedale di Circolo e Fondazione Macchi, Università dell'Insubria, Viale Borri, 57. IT-21100 Varese, Italy. rdeponti@alice.it
authors.forename: Roberto
authors.initials: R
authors.lastname: De Ponti
authors.forename: Roberto
authors.initials: R
authors.lastname: Verlato
authors.forename: Emanuele
authors.initials: E
authors.lastname: Bertaglia
authors.forename: Maurizio
authors.initials: M
authors.lastname: Del Greco
authors.forename: Antonio
authors.initials: A
authors.lastname: Fusco
authors.forename: Nicola
authors.initials: N
authors.lastname: Bottoni
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Drago
authors.forename: Luigi
authors.initials: L
authors.lastname: Sciarra
authors.forename: Renato
authors.initials: R
authors.lastname: Ometto
authors.forename: Roberto
authors.initials: R
authors.lastname: Mantovan
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Salerno-Uriarte
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001282:Atrial Flutter / Q000503:physiopathology / Q000601:surgery*; D017115:Catheter Ablation; D002648:Child; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D018709:Statistics, Nonparametric; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000503:physiopathology / Q000601:surgery*