Revaluation of the Significance of Demonstrable Exit Block After Radiofrequency Pulmonary Vein Isolation

Background: Demonstration of exit block from the pulmonary vein (PV) to the left atrium after PV isolation (PVI) is not always possible after demonstration of entrance block. We examined factors associated with demonstrable exit block and the relationship between demonstrable exit block and subsequent PV reconnection. Methods and Results: The subjects consisted of 227 patients (908 PV; mean patient age, 59.2±10.8 years; 72.2% male) who underwent radiofrequency PVI, 49 of whom proceeded to the second session after a mean duration of 563.4±456.3 days after the first session. In the first session, exit block was demonstrated in 73.1% of PV, and the predictors were superior PV, longitudinal diameter of the PV, and spontaneous activity in the PV. In the second session (n=49), exit block was demonstrated in 51.0% (33.1% in PV without reconnection vs. 79.7% in PV with reconnection, P<0.0001). Spontaneous activity (OR, 2.74; 95% CI: 1.12–7.03, P=0.0272) and use of a contact force-sensing catheter (OR, 0.42, 95% CI: 0.20–0.85, P=0.0151) were independent predictors of PV reconnection, but demonstrable exit block was not (OR, 1.58; 95% CI: 0.74–3.46, P=0.2377). Conclusions: Inability to demonstrate exit block was not associated with increased risk of future PV reconnection.