title: Focal arrhythmia confined within the coronary sinus and maintaining atrial fibrillation.
abstract: BACKGROUND
  The coronary sinus (CS) is a complex structure comprising a mesh of circumferential muscular fibers with oblique connections to both atria. We describe further evidence for the clinical importance of CS arrhythmogenicity in maintaining atrial fibrillation (AF) in humans.
  
  
  METHODS
  Since January 2004, following a sequential approach, the CS and the inferior left atrium were ablated in 144 patients with symptomatic drug refractory AF. Patients were included for analysis when this step resulted in the electrical dissociation of the CS from both atria with restoration of sinus rhythm, but with continued arrhythmic activity in the CS. The electrophysiologic mechanism of the confined arrhythmia was considered as focal activity (automaticity or triggered activity) by the presence of electrograms spanning less than 75% of the cycle length in the CS.
  
  
  RESULTS
  After restoration of sinus rhythm, four male patients (3% of the patients, three persistent and one permanent AF) were identified in whom arrhythmia continued within the CS. Repetitive activity confined to the disconnected CS was inconsistent in occurrence, as well as in duration (1 sec to 15 min) and cycle length (from 158 to 380 ms). For all four patients, electrogram mapping of the entire CS was compatible with a focal mechanism. In two patients, bursts alternating with slow dissociated activity suggested automaticity. In one patient, local activity consistently coupled to the previous sinus beat favored triggered activity.
  
  
  CONCLUSIONS
  This study provides evidence that the CS may be a potential source of focal rapid activity maintaining AF.
authors: Hôpital Cardiologique du Haut-Lévêque and the Université Victor Segalen Bordeaux II, Bordeaux, France. sebastien.knecht@chu-brugmann.be <sebastien.knecht@chu-brugmann.be>
authors: Sébastien
authors: S
authors: Knecht
authors: Mark D
authors: MD
authors: O'Neill
authors: Seiichiro
authors: S
authors: Matsuo
authors: Kang-Teng
authors: KT
authors: Lim
authors: Leonardo
authors: L
authors: Arantes
authors: Nicolas
authors: N
authors: Derval
authors: Georges J
authors: GJ
authors: Klein
authors: Mélèze
authors: M
authors: Hocini
authors: Pierre
authors: P
authors: Jaïs
authors: Jacques
authors: J
authors: Clémenty
authors: Michel
authors: M
authors: Haïssaguerre
mesh_terms: D000328:Adult; D001281:Atrial Fibrillation / Q000503:physiopathology* / Q000601:surgery; D017115:Catheter Ablation; D054326:Coronary Sinus / Q000503:physiopathology*; D022062:Electrophysiologic Techniques, Cardiac; D006801:Humans; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome