After a single procedure of circumferential ablation with PVI and noninducibility, 82% patients did not have recurrence of AF. The inducibility of AF was related to the recurrence of AF. The atrial substrate affected the outcome of the inducibility.

Significant dilation of both superior PVs with simultaneous LA enlargement was demonstrated i

Atrial substrate remodeling with a progressive decrease in the left atrial voltage was demonstrated in patients with recurrent AF.

Focal PV stenosis is observed frequently after RF catheter ablation applied within the vein, but usually is without clinical significance. However, ablation within multiple PVs might cause pulmonary hypertension and should be considered a limiting factor in this procedure.

Structural remodeling of the superior PVs and LA can be reversible after successful ablation without AF recurrence; however, late recurrence of AF is associated with progressive LA dilation.

The right atrial foci played an important role in the very late recurrence of AF, whereas the left atrial foci (the majority were PVs) were the major origin of the late recurrence of AF after the catheter ablation of paroxysmal AF.

The LA voltage was lower than the RA, and the atrial voltage correlated with the TAT. Electroanatomical remodeling of the atria could be crucial to the maintenance of AF. The LA substrate properties may play an important role in the recurrence of AF after catheter ablation of AF.

The incidence of very late recurrent AF after ablation of paroxysmal AF is very low, and the clinical outcome of patients with very late recurrent AF is benign.