Pulmonary vein tachycardia after pulmonary vein isolation in patients with atrial fibrillation.

BACKGROUND: Pulmonary vein (PV) isolation has been developed to treat patients with atrial fibrillation (AF), and the electrophysiological endpoint of PV isolation is the disappearance or dissociation of pulmonary vein potentials (PVPs). Pulmonary vein tachycardia (PVT) is the dissociated PV rhythm with a rapid rate. However, the characteristics and significance of PVT after pulmonary vein isolation in patients with AF remains unclear. METHODS: From June 2003 to June 2005, a total of 285 consecutive patients with drug refractory AF were included in this study, and they underwent segmental pulmonary vein ablation (SPVA) or circumferential pulmonary vein ablation (CPVA). PV isolation was the initial endpoint for both approaches with documenting disappearance or dissociation of PVPs. PVT was characterized as dissociated activities within PVs with a circle length (CL) of < 300 ms, and was classified into organized PVT or disorganized PVT according to the variance of CL. Systematic follow-up was conducted after initial procedures. Continuous variables were analyzed by Student's t test and categorical variables were analyzed by chi-square test. RESULTS: Three hundred and fifteen PVs were ablated in 85 patients underwent SPVA approach, 400 circular lesions surrounding ipsilateral PVs (including 790 PVs) were produced in the rest of 200 patients received CPVA approach. Electrical isolation was achieved in all of these PVs. Of these, PVPs were abolished in 89.8% (992/1105) of the ablated PVs, dissociated PV rhythms were documented in the rest 10.2 % (113/1105) of the treated PVs. Among the 113 dissociated PV rhythms, 28 met the criteria of PVT with mean CL of (155 +/- 43) ms (2 PVTs in 2 patients received SPVA, 26 PVTs in 18 patients underwent CPVA). PVT was more frequently documented in patients underwent CPVA approach [9.0% (18/200) vs 2.3% (2/85), P = 0.04]. During the 6-month follow-up, it was indicated that no significant difference existed in AF free rate between patients with PVT and those without PVT (P = 0.75). CONCLUSIONS: PVT dissociated from LA activations can be documented after PV isolation, especially in patients underwent CPVA approach. However, PVT does not affect the follow-up results.