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

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.

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.

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.

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.

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.