title: Electroanatomic characteristics of the mitral isthmus associated with successful mitral isthmus ablation.
abstract: OBJECTIVE
  The success of mitral isthmus (MI) ablation has been related to CT scan defined MI anatomy. We sought to correlate electroanatomical MI characteristics with MI ablation success in patients with perimitral flutter (PMF).
  
  
  RESULTS
  In 53 consecutive patients (46 males, 61 ± 10 years) with PMF, MI was ablated with endocardial ± coronary sinus (CS) linear radiofrequency (RF) ablation lesion. Acute (termination of PMF during ablation) and long-term procedural success were studied. Mitral isthmus characteristics (thickness--minimal endocardial to CS distance, length, maximal MI bipolar voltage), as well as MI ablation line length and width, RF duration, and delivered energy were analysed. In 43 of the 53 patients (81%), acute success was observed. This was more frequently achieved in patients with thinner MI (2.4 ± 3.1 vs. 7 ± 3.2 mm; P = 0.0009). Mitral isthmus thickness predicted ablation failure with a ROC area of 0.84. The best threshold to predict MI ablation failure was 8.3 mm with a sensitivity of 67% and a specificity of 97%. Left atrial size was of greater importance in failed cases (2D echo surface: 24.1 ± 2.5 vs. 32.5 ± 6.9 cm2, P = 0.005; electroanatomic volume: 124 ± 32 vs. 165 ± 23 mL, P = 0.02). None of the other electroanatomical characteristics were associated with outcome. After a mean follow-up of 28 ± 15 months, 21 patients (39%) had atrial fibrillation (AF) or atypical flutter (PMF recurrence in four).
  
  
  CONCLUSIONS
  Smaller MI thickness is associated with acute success in PMF ablation. Mitral isthmus electroanatomical characteristics might be used for decision-making on strategy during persistent AF ablation and for selecting the best location for interrupting PMF.
authors.affiliation: Cardiologie, Centre Hospitalier Princesse Grace, Avenue Pasteur, Monaco 98000, Monaco dglatcu@yahoo.com.
authors.forename: Decebal Gabriel
authors.initials: DG
authors.lastname: Latcu
authors.affiliation: Hospital of the University of Pennsylvania, 3400 Spruce St, Philadelphia, PA 19104, USA CHU Pasteur, 30 Avenue de la Voie Romaine, Nice 06000, France.
authors.forename: Fabien
authors.initials: F
authors.lastname: Squara
authors.affiliation: Cardiologie, Centre Hospitalier Princesse Grace, Avenue Pasteur, Monaco 98000, Monaco.
authors.forename: Youssef
authors.initials: Y
authors.lastname: Massaad
authors.affiliation: Cardiologie, Centre Hospitalier Princesse Grace, Avenue Pasteur, Monaco 98000, Monaco.
authors.forename: Sok-Sithikun
authors.initials: SS
authors.lastname: Bun
authors.affiliation: Cardiologie, Centre Hospitalier Princesse Grace, Avenue Pasteur, Monaco 98000, Monaco.
authors.forename: Nadir
authors.initials: N
authors.lastname: Saoudi
authors.affiliation: Hospital of the University of Pennsylvania, 3400 Spruce St, Philadelphia, PA 19104, USA.
authors.forename: Francis E
authors.initials: FE
authors.lastname: Marchlinski
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D001282:Atrial Flutter / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D017115:Catheter Ablation; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D008984:Monaco; D010414:Pennsylvania; D011237:Predictive Value of Tests; D012008:Recurrence; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D017211:Treatment Failure
keywords: Catheter ablation; Electroanatomic mapping; Perimitral flutter