The challenging right inferior pulmonary vein: A systematic approach for successful cryoballoon ablation

Pulmonary vein isolation (PVI) using cryoballoon ablation is widely used for rhythm control in patients with paroxysmal atrial fibrillation. This technique has a steep learning curve, and PVI can be achieved quickly in most patients. However, the right inferior pulmonary vein (RIPV) is often challenging to occlude and isolate.

We aimed to analyse the efficacy of RIPV ablation using a systematic approach.

Consecutive patients referred for cryoballoon ablation of paroxysmal atrial fibrillation were enrolled prospectively. A systematic approach was used for RIPV cryoablation. The primary endpoint was acute RIPV isolation during initial freeze.

A total of 214 patients were included. RIPV isolation during initial freeze occurred in 179 patients (82.2%). Real-time PVI could be observed in 72 patients (33.6%), whereas cryoballoon stability required pushing the Achieve™ catheter inside the RIPVs in the remaining patients. The rate of unsuccessful or aborted first freeze as a result of insufficient minimal temperature was significantly higher in patients with real-time pulmonary vein potential recording (16.7% vs. 6.3%; P=0.031). To overcome this issue and obtain both stability and real-time PVI, a dedicated "whip technique" was developed. Twelve patients (5.6%) required a redo ablation; only two of these had a reconnected RIPV.

A systematic approach to RIPV cryoablation can lead to a high rate of first freeze application. Operators should not struggle to visualize pulmonary vein potentials before ablation, as this may decrease cryoapplication efficacy. Thus, stability should be preferred over real-time PVI for RIPV ablation. Both stability and real-time PVI can be obtained using a "whip technique".