Background

Recurrence of atrial fibrillation due to pulmonary vein (PV) reconnection is still evident despite high efficacy of cryoballoon ablation (CBA) for PV isolation (PVI) in patients with paroxysmal atrial fibrillation (PAF). Recently the POLARx cryoablation system (PLX, Boston Scientific) was released. It provides features that may impact on a more durable PVI.

Purpose

To compare standard CBA using the arctic front advance pro catheter (AFP, Medtronic) with the novel PLX device regarding procedural parameters.

Methods

55 consecutive patients with PAF (45% male, mean age 64.1±9.2 years) were included. After 30 patients treatment was switched from AFP to PLX device. Procedural parameters were assessed in all patients and compared between AFP and PLX group.     

Results

Complete PVI was achieved in 99%. Total procedure time (AFP 101.7±18.2 vs. PLX 100.0±21.2 min), balloon in body time (AFP 40.9±7.4 vs. PLX 45.7±11.5 min) and radiation time (AFP 17.2±5.1 vs. PLX 15.4±5.6 min) were similar in both groups (n.s.). There was no significant difference in real-time PVI visualization (AFP 85% vs. PLX 77%, n.s.). Mean time to isolation (TTI) was shorter in PLX (AFP 51.9±33.9 s vs. PLX 41.9±30.0 s, p=0.046). A lower mean nadir temperature could be measured in the PLX group (AFP -49.0±5.6 °C vs. PLX -57.5±5.8, p < 0.001), but this had no impact on esophageal temperature (AFP 31.5±5.4 °C vs. PLX 29.8±8.0 °C, n.s.). Thawing time to 0°C (TT₀) was significantly prolonged in the PLX group (AFP 10.2±4.3 s vs. PLX 18.7±6.2 s, p<0.001) and there was a difference in TT₀ comparing superior with inferior PVs in AFP patients (12.0±4.5 s vs. 8.3±3.2 s, p<0.001) but not in PLX patients. One transient phrenic nerve palsy was seen in each group und one vascular complication occurred in the PLX group.    

Conclusion

CBA was feasible and save using AFP and PLX. A shorter TTI and a prolonged and more consistent TT₀ may improve durability of PVI in PAF patients treated with PLX.