These 3 video clips with fluoroscopic ( X-Ray ) imaging are from recent ablation  cases. First clip ( below ) shows cryoballoon inflated in the left superior pulmonary vein. Distal to balloon is a spiral catheter for recording of electrical potentials in the pulmonary vein before and after ablation.
It is important to monitor for phrenic nerve damage during ablation of right pulmonary veins.  2 clips demonstrates phrenic nerve stimulation during freezing of right superior and right inferior pulmonary veins. Note contractions of diaphragm from pacing. Freezing is immediately terminated if diaphragmatic contraction ceases or decreases. Still , phrenic nerve damage can occur, fortunately nerve function comes back to normal in majority of the patients over time.