INtra-procedural ultraSound Imaging During Pulmonary Veins Isolation

Completed

Conditions: Atrial Fibrillation

Registration Number: NCT03372798

Lead Sponsor: Oxford University Hospitals NHS Trust

Brief Summary: 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.

Detailed Description: 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.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 14

Inclusion Criteria

Not provided

Exclusion Criteria

Not provided

Study & Design

Study Type: OBSERVATIONAL

Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Measurement of LA Wall Thickness on CT Scans	1 day	Left atrial wall thickness at the PV ostia, measured as Wall Thickness Index % = \[(vessel area - lumen area)/vessel area\] x 100
Measurement of Left Atrial (LA) Wall Thickness on ICE/IVUS Frames	Day 1	Left atrial wall thickness at the PV ostia, measured as Wall Thickness Index % = \[(vessel area - lumen area)/vessel area\] x 100

Secondary Outcome Measures

Name	Time	Method
Mean Time Required for ICE/IVUS for Real Time Imaging of the Left Atrial (LA) Wall Thickness During AF Ablation	Day 1	Mean time required to image the left atrium for measurement of left atrial wall thickness with intracardiac echo (ICE) or with intravascular ultrasound (IVUS)
Number of ICE/IVUS Cases of Good Quality	Day 1	Number of intracardiac echo (ICE) cases and number of intravascular ultrasound (IVUS) cases of good quality, allowing a precise measurement of the left atrial (LA) wall thickness The imaging quality of each PV cross-section was defined as good quality if the vessel contour was visible in all 4 quadrants.