INtra-procedural ultraSound Imaging During Pulmonary Veins Isolation

One of the biggest limitations of the currently used percutaneous techniques for Pulmonary Vein Isolation (PVI) in the setting of atrial fibrillation ablation is the lack of real-time information about the left atrial (LA) wall thickness and about its acute changes during energy delivery for ablation. This makes difficult to predict the achievement of transmural lesions, to identify the possible causes of ablation failure and also to avoid the occurrence of perforation and/or other collateral damage.

Computed tomography (CT) is a reliable technique for measurement of the LA wall thickness but it cannot be used during the ablation procedure and its extensive use is limited by the need of ionizing radiation. Preliminary data from animal studies support the accuracy of real-time ultrasound imaging modalities such as intracardiac echocardiography (ICE) or Intravascular Ultrasound (IVUS) imaging for measurement of LA wall thickness and monitoring of its acute changes related to catheter ablation.

The pilot study INSIDE PVs has been primarily designed to evaluate the feasibility and accuracy of intravascular imaging techniques for real-time imaging of the LA wall thickness during AF ablation.

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.

A total of 14 patients will finally be enrolled in the study. The end of the study for each patient will be the date of the telephone follow-up 1 week after the procedure.

For each patient the pre-procedural and post-procedural CT measurements of LA wall thickness and PVs ostial diameters will be compared with the corresponding IVUS or ICE measurements.

Eligibility Criteria:
* Inclusion Criteria

  * Males older than 40 years or females older than 40 and sterile or in post-menopausal age;
  * willing and able to give informed consent for participation in the study;
  * history of symptomatic and drug-refractory paroxysmal atrial fibrillation (AF);
  * planned AF ablation on a clinical basis.
* Exclusion Criteria

  * age less than 40 years and more than 80 years;
  * pregnancy, trying for a baby or breast feeding;
  * any other significant disease or disorder which, in the opinion of the investigator, may either put the participants at risk because of participation in the study, or may influence the result of the study, or the participant's ability to participate in the study;
  * documented allergy to iodinated contrast medium;
  * renal insufficiency (eGFR\<30);
  * weight exceeding the maximum load of the scanner (250kg).