INtra-procedural ultraSound Imaging for DEtermination of Atrial Wall Thickness and Acute Tissue Changes During Isolation of the Pulmonary Veins

Patients scheduled for their first pulmonary vein (PV) isolation ablation for symptomatic, drug-refractory paroxysmal atrial fibrillation (AF), will be considered for inclusion in the study.

Potential subjects will initially be approached some weeks before their ablation procedure, in order to give the patients enough time to consider the information, to ask questions to the Investigator, their general practitioner (GP) or other independent parties to decide whether they wish to participate in the study or not.

For those interested in participation, a baseline assessment will be arranged to coincide with their standard pre-admission visit, for informed consent, screening and eligibility assessment. Moreover, a pre-operative imaging assessment with a cardiac computed tomography (CT) scan will be performed to define the left atrial (LA) and PV anatomy and to measure the baseline LA wall thickness and PVs ostial diameters.

All AF ablation procedures will be performed in a standard fashion by using radiofrequency (RF) energy, cryo-balloon or laser balloon ablation under general anaesthesia and with continuous oesophageal temperature monitoring. Ultrasound imaging by IVUS (Visions PV .018, 20 MHz digital probe, Volcano Corp) or ICE (Ultra ICE (9 MHz rotational transducer, Boston Scientific) will be performed at sites corresponding with the PV/LA junction at the beginning and the end of the procedure in order to measure acute changes in LA wall thickness and PV ostial diameters.

The cardiac CT will be repeated within 24 hours post-procedure. After the procedure, a pre-discharge review and a telephone follow-up at 1 week will be performed to identify any early and late complications related to the procedure.