Focal arrhythmia confined within the coronary sinus and maintaining atrial fibrillation.
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.
Knecht
Sébastien
S
Hôpital Cardiologique du Haut-Lévêque and the Université Victor Segalen Bordeaux II, Bordeaux, France. sebastien.knecht@chu-brugmann.be <sebastien.knecht@chu-brugmann.be>
O'Neill
Mark D
MD
Matsuo
Seiichiro
S
Lim
Kang-Teng
KT
Arantes
Leonardo
L
Derval
Nicolas
N
Klein
Georges J
GJ
Hocini
Mélèze
M
Jaïs
Pierre
P
Clémenty
Jacques
J
Haïssaguerre
Michel
M
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