Localization of the initial fibrillatory cycle in patients with paroxysmal atrial fibrillation.

BACKGROUND

Recent reports suggest the presence of conduction delay in the posterior septal region during sinus rhythm in patients with lone paroxysmal atrial fibrillation (AF).

OBJECTIVE

To explore the location of intra-atrial conduction delay associated with initiation of AF.

DESIGN

In 8 lone AF patients (51 +/- 10 years), 20 AF paroxysms were induced during electrophysiological examination. Bipolar electrograms were acquired from a 10-polar catheter in the coronary sinus (CS), a 4-polar His bundle catheter, and a 20-polar Halo catheter in the right atrium.

RESULTS

Induced AF paroxysms showed earliest registered atrial activity in interatrial septum (IAS) or proximal CS in 17 cases (85%). Conduction delay at the posterior IAS or proximal CS accompanied induction of 18 AF paroxysms (6 patients). Atrial activation sequence at the beginning of the AF paroxysms was stable and reproducible in six repeatedly induced AF episodes (3 patients).

CONCLUSION

In lone AF patients, induction of AF is associated with conduction disturbances in the IAS and proximal CS regions.