title: Sites of focal atrial activity characterized by endocardial mapping during atrial fibrillation.
abstract: OBJECTIVE
  The aim of the present study was to assess the feasibility of identifying sites of focal atrial activity by localized high-density endocardial mapping during atrial fibrillation (AF).
  
  
  BACKGROUND
  Sites of focal activity in the left atrium have been demonstrated by epicardial mapping during AF.
  
  
  METHODS
  Twenty-four patients (15 with paroxysmal, 3 with persistent, and 6 with permanent AF) underwent endocardial mapping during AF. A 20-pole catheter with five radiating spines was used to map both atria for 30 s in each of 10 pre-determined segments. A focal activity was defined as > or =3 atrial cycles with activation spreading from center to periphery of the mapping catheter. Catheter ablation was performed independent of the mapping results.
  
  
  RESULTS
  Spontaneous focal activities were observed in 13 sites in the left atrium (9%; anterior 1, roof 2, posterior 6, inferior 4) in 12 patients (9 paroxysmal, 3 persistent). Focal activity was observed continuously (two sites) or intermittently (11 sites, median 5 episodes), and associated with shortening of the cycle length (from 183 +/- 33 ms to 172 +/- 29 ms; p < 0.05). The mean duration of an intermittent episode was 1.5 s (range 0.4 to 7.1 s). Atrial fibrillation terminated without ablation at the foci in all of 12 patients, but in 2 of them, re-initiated arrhythmia was successfully ablated at these foci. Nine of these 12 patients (75%) were arrhythmia-free without antiarrhythmic drugs during a follow-up period of 7.0 +/- 3.1 months.
  
  
  CONCLUSIONS
  Termination of AF without ablation at the sites of atrial focal activity suggests that this activity may be triggered by impulses originating from other regions, such as the pulmonary veins.
authors.affiliation: Hôpital Cardiologique du Haut-Lévêque-Université Victor Segalen Bordeaux 2, Bordeaux, France. yoshihide.takahashi@wanadoo.fr
authors.forename: Yoshihide
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Mélèze
authors.initials: M
authors.lastname: Hocini
authors.forename: Mark D
authors.initials: MD
authors.lastname: O'Neill
authors.forename: Prashanthan
authors.initials: P
authors.lastname: Sanders
authors.forename: Martin
authors.initials: M
authors.lastname: Rotter
authors.forename: Thomas
authors.initials: T
authors.lastname: Rostock
authors.forename: Anders
authors.initials: A
authors.lastname: Jonsson
authors.forename: Frédéric
authors.initials: F
authors.lastname: Sacher
authors.forename: Jacques
authors.initials: J
authors.lastname: Clémenty
authors.forename: Pierre
authors.initials: P
authors.lastname: Jaïs
authors.forename: Michel
authors.initials: M
authors.lastname: Haïssaguerre
mesh_terms: D000328:Adult; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000503:physiopathology* / Q000628:therapy*; D017115:Catheter Ablation; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac / Q000295:instrumentation / Q000379:methods*; D004699:Endocardium; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006325:Heart Atria / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011667:Pulmonary Veins
chemical_list: D000889:Anti-Arrhythmia Agents