Pulmonary vein electrophysiology during cryoballoon ablation as a predictor for procedural success.

BACKGROUND: Cryoballoon technique is an innovative alternative to radiofrequency ablation for atrial fibrillation (AF). However, with current cryoballoon application techniques, the operator has no access to electrical information for 300 s during the freezing cycle.
OBJECTIVE: The objective of this study is to investigate the novel approach of real-time monitoring of pulmonary vein (PV) potentials throughout freezing using a circular mapping catheter introduced into the central lumen of the cryoballoon catheter.
METHODS: Patients had paroxysmal or persistent AF. Standard balloon catheters (23 or 28 mm diameter, 10.5 F shaft) were used. A coaxial mapping catheter (shaft diameter 0.9 mm; 15 mm loop with six electrodes) was advanced through the lumen of the cryoballoon catheter, replacing the guide wire. The primary procedural end point was successful PV isolation and real-time PV potential recording. Secondary end points were procedural data, complications, and the time to successful PV isolation.
RESULTS: In 141 consecutively enrolled patients, balloon positioning and ablation were successful in 439/568 veins (77%). Real-time recording of PV conduction during the freeze cycle was possible in 235/568 PVs (41%). Main reasons for failure to obtain real-time PV recordings were a distal position of the circular mapping catheter or insufficient catheter-vessel wall contact during ablation. A cutoff value of 83 s to PV isolation was predictive of stable procedural PV isolation without reconduction. One minor hemoptysis was observed possibly related to the mapping catheter.
CONCLUSIONS: This study, the largest to date, showed that real-time monitoring of PV conduction during cryoballoon freezing can be safely performed with a circular mapping catheter. A cutoff time of 83 s to PV isolation was predictive of sustained procedural PV isolation success without reconduction.