The present study is designed as a observational prospective, multicentre, international. The main aim of this study is to evaluate the safety and feasibility of SVC isolation with the CB in a prospective manner.

Consecutive patients programmed for cryoballoon ablation (CBA) for PAF will be prospectively enrolled in our study. After PVI is obtained and proven by entrance- and exit block, the SVC will be mapped for potentials. If the SVC exhibits electrical activity, isolation will be attempted performing a single maximum 180 seconds balloon application. A single 180 seconds application is known to produce a durable lesion. Performing a combined approach (PVI together with SVC isolation) using the same cryoballoon requires no additional vascular access. Therefore no significant raise in complications is to be expected. During a second generation CBA the described rate of complications is to be estimated around 2%. Transient phrenic nerve palsy in 7.2 %, but reversible in virtually all patients within the end of the procedure.

To prevent nervous injury the phrenic nerve (PN) will be tested during ablation of the SVC, in the same fashion as performed systematically during ablation of the right sided pulmonary veins.

Inclusion Criteria:

1. Written informed consent
2. Consecutive patients programmed for cryoballoon ablation (CBA) for PAF will be prospectively enrolled in our study

Exclusion Criteria:

1. Age younger than 18 years
2. Severe valve disease (MI or AI > ¾)
3. Uncontrolled heart failure,
4. Contraindication to general anaesthesia/ deep procedural sedation
5. Left atrial thrombus at the pre-procedural transesophageal echocardiogram (TEE)

Patients programmed for cryoballoon ablation (CBA) for PAF