Shape vs Substrate in AF

NCT ID: NCT05993104

Last Updated: 2024-02-21

Basic Information

• Recruitment Status: WITHDRAWN
• Study Classification: OBSERVATIONAL
• Study Start Date: 2024-01-31
• Study Completion Date: 2026-09-30

Brief Summary

Atrial fibrillation (AF) is an abnormal heart rhythm which originates from the top two chambers (atria) of the heart. It can cause significant symptoms and have severe consequences such as stroke.

Catheter ablation is a treatment for AF. It is minimally invasive, involving thin tubes known as catheters, being inserted through a blood vessel in the groin and passed to the heart under X-ray guidance. Once in the heart, regions of tissue believed responsible for the abnormal heart rhythm can be identified, and hot or cold energy used to create scar at these areas, preventing the abnormal rhythm.

Identifying these regions is a key challenge in making the treatment as effective as possible. The investigators believe that there may be a change in the shape of a participant's atria in these regions and as such identifying and treating areas of abnormal shape may be beneficial.

To investigate this, the study team propose three phases. The first, uses previously collected data to make a model of what is average atrial geometry in AF. Investigators will then compare individual participants' atrial geometries to this average shape to identify areas of geometric abnormality and see how these correspond to areas of abnormal electrical activity. In the second phase, investigators will collect new data on how much atrial geometry changes during catheter ablation procedures. Finally, in the third phase, investigators will investigate whether including geometric assessment in the catheter ablation procedure is feasible from a work flow perspective.

Detailed Description

This study will utilise the AcQMap system (Acutus Medical). This is a combined multi-electrode and imaging mapping system, with intra chamber ultrasound used to create a surface mesh of a participant's atrial anatomy. Noncontact charge-density mapping using AcQMap is novel, in that it allows whole chamber conduction to be analysed during AF. This is a distinct advantage over traditional contact mapping techniques, which are unable to globally map the inherently unstable and changing activation patterns occurring in AF. The system's AcQTrack software identifies patterns of localised propagation which may represent AF drivers and displays these on the surface mesh. They are classified as one of three phenomena (localised irregular activation [LIA], localised rotational activity [LRA], focal firing [FF]). AcQMap is the ideal tool for our investigation, given its ability to capture both global AF maps and geometric data. It is utilised routinely in clinical practice and there is an existing rich local dataset of previous cases.

Study Phases:

1. A retrospective observational phase recruiting >50 participants, utilising data already collected as part of standard clinical care. Investigators will use statistical shape analysis methods to create a left atrial shape model for perAF and see how individuals' left atrial geometries differ from this model. Investigators will then assess whether areas of abnormal geometry correlate with areas of abnormal electrical propagation in AF.

2. A prospective single-arm phase recruiting 20 participants undergoing AcQMap guided ablation. As previously mentioned, temporal stability is a defining characteristic of suitable ablation targets. Atrial geometry is dynamic, being related to phase of ventricular contraction and is also affected by an individual's volume status. To investigate variation in geometry, individuals in this substudy will have additional ultrasound geometries collected during their ablation procedure.

3. A feasibility study in 10 participants will assess our ability to include shape analysis as part of the procedural workflow for AF ablation utilising the AcQMap system.

Conditions

Atrial Fibrillation; Atrial Fibrillation, Persistent

Study Design

• Observational Model Type: CASE_ONLY
• Study Time Perspective: OTHER

Study Groups

Retrospective observational

Retrospective observational arm recruiting \>50 participants, utilising data already collected as part of standard clinical care.

Statistical shape analysis

Intervention Type: OTHER

Statistical shape analysis tools used to investigate left atrial geometry

Prospective single-arm

Prospective single-arm recruiting 20 participants undergoing AcQMap guided ablation.

Intrachamber ultrasound

Intervention Type: DIAGNOSTIC_TEST

Ultrasound left atrial geometry collecting using AcQMap.

Feasibility study

Feasibility study recruiting 10 participants.

Statistical shape analysis

Intervention Type: OTHER

Statistical shape analysis tools used to investigate left atrial geometry

Interventions

Intrachamber ultrasound

Ultrasound left atrial geometry collecting using AcQMap.

Intervention Type: DIAGNOSTIC_TEST

Statistical shape analysis

Statistical shape analysis tools used to investigate left atrial geometry

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

Retrospective component:

• Participant gave consent for anonymised data being utilised for clinical research at time of procedure.
• Male or Female, aged 18 years or above.
• Previous AcQMap guided ablation for paroxysmal or persistent atrial fibrillation.

Prospective component:

• Participant is willing and able to give informed consent for participation in the study.
• Male or Female, aged 18 years or above.
• Diagnosed with paroxysmal or persistent atrial fibrillation and planned for an AcQMap guided catheter ablation procedure.

Exclusion Criteria

• Congenital cardiac abnormality.
• Any other significant disease or disorder which, in the opinion of the Investigator, may either put the participant at risk because of participation in the trial, or may influence the result of the trial, or the participant's ability to participate in the trial.

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Oxford University Hospitals NHS Trust

OTHER

Sponsor Role: lead

Responsible Party

Tim Betts MD MBChB FRCP

Associate Professor of Cardiovascular Medicine

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Tim Betts, MD MBChB FRCP

Role: PRINCIPAL_INVESTIGATOR

Oxford University Hospitals NHS Trust

Locations

John Radcliffe Hospital

Oxford, Oxfordshire, United Kingdom

Countries

United Kingdom

Other Identifiers

16749

Identifier Type: -

Identifier Source: org_study_id