xml: <clinical_study>
    <!-- This xml conforms to an XML Schema at:
      https://clinicaltrials.gov/ct2/html/images/info/public.xsd -->
    <required_header>
      <download_date>ClinicalTrials.gov processed this data on September 20, 2023</download_date>
      <link_text>Link to the current ClinicalTrials.gov record.</link_text>
      <url>https://clinicaltrials.gov/ct2/show/NCT05993104</url>
    </required_header>
    <id_info>
      <org_study_id>16749</org_study_id>
      <nct_id>NCT05993104</nct_id>
    </id_info>
    <brief_title>Shape vs Substrate in AF</brief_title>
    <official_title>Investigating the Interplay of Left Atrial Geometry With Abnormal Propagation Patterns in Atrial Fibrillation</official_title>
    <sponsors>
      <lead_sponsor>
        <agency>Oxford University Hospitals NHS Trust</agency>
        <agency_class>Other</agency_class>
      </lead_sponsor>
    </sponsors>
    <source>Oxford University Hospitals NHS Trust</source>
    <oversight_info>
      <is_fda_regulated_drug>No</is_fda_regulated_drug>
      <is_fda_regulated_device>No</is_fda_regulated_device>
    </oversight_info>
    <brief_summary>
      <textblock>
        Atrial fibrillation (AF) is an abnormal heart rhythm which originates from the top two&#xD;
        chambers (atria) of the heart. It can cause significant symptoms and have severe consequences&#xD;
        such as stroke.&#xD;
  &#xD;
        Catheter ablation is a treatment for AF. It is minimally invasive, involving thin tubes known&#xD;
        as catheters, being inserted through a blood vessel in the groin and passed to the heart&#xD;
        under X-ray guidance. Once in the heart, regions of tissue believed responsible for the&#xD;
        abnormal heart rhythm can be identified, and hot or cold energy used to create scar at these&#xD;
        areas, preventing the abnormal rhythm.&#xD;
  &#xD;
        Identifying these regions is a key challenge in making the treatment as effective as&#xD;
        possible. The investigators believe that there may be a change in the shape of a&#xD;
        participant's atria in these regions and as such identifying and treating areas of abnormal&#xD;
        shape may be beneficial.&#xD;
  &#xD;
        To investigate this, the study team propose three phases. The first, uses previously&#xD;
        collected data to make a model of what is average atrial geometry in AF. Investigators will&#xD;
        then compare individual participants' atrial geometries to this average shape to identify&#xD;
        areas of geometric abnormality and see how these correspond to areas of abnormal electrical&#xD;
        activity. In the second phase, investigators will collect new data on how much atrial&#xD;
        geometry changes during catheter ablation procedures. Finally, in the third phase,&#xD;
        investigators will investigate whether including geometric assessment in the catheter&#xD;
        ablation procedure is feasible from a work flow perspective.&#xD;
      </textblock>
    </brief_summary>
    <detailed_description>
      <textblock>
        This study will utilise the AcQMap system (Acutus Medical). This is a combined&#xD;
        multi-electrode and imaging mapping system, with intra chamber ultrasound used to create a&#xD;
        surface mesh of a participant's atrial anatomy. Noncontact charge-density mapping using&#xD;
        AcQMap is novel, in that it allows whole chamber conduction to be analysed during AF. This is&#xD;
        a distinct advantage over traditional contact mapping techniques, which are unable to&#xD;
        globally map the inherently unstable and changing activation patterns occurring in AF. The&#xD;
        system's AcQTrack software identifies patterns of localised propagation which may represent&#xD;
        AF drivers and displays these on the surface mesh. They are classified as one of three&#xD;
        phenomena (localised irregular activation [LIA], localised rotational activity [LRA], focal&#xD;
        firing [FF]). AcQMap is the ideal tool for our investigation, given its ability to capture&#xD;
        both global AF maps and geometric data. It is utilised routinely in clinical practice and&#xD;
        there is an existing rich local dataset of previous cases.&#xD;
  &#xD;
        Study Phases:&#xD;
  &#xD;
          1. A retrospective observational phase recruiting &gt;50 participants, utilising data already&#xD;
             collected as part of standard clinical care. Investigators will use statistical shape&#xD;
             analysis methods to create a left atrial shape model for perAF and see how individuals'&#xD;
             left atrial geometries differ from this model. Investigators will then assess whether&#xD;
             areas of abnormal geometry correlate with areas of abnormal electrical propagation in&#xD;
             AF.&#xD;
  &#xD;
          2. A prospective single-arm phase recruiting 20 participants undergoing AcQMap guided&#xD;
             ablation. As previously mentioned, temporal stability is a defining characteristic of&#xD;
             suitable ablation targets. Atrial geometry is dynamic, being related to phase of&#xD;
             ventricular contraction and is also affected by an individual's volume status. To&#xD;
             investigate variation in geometry, individuals in this substudy will have additional&#xD;
             ultrasound geometries collected during their ablation procedure.&#xD;
  &#xD;
          3. A feasibility study in 10 participants will assess our ability to include shape analysis&#xD;
             as part of the procedural workflow for AF ablation utilising the AcQMap system.&#xD;
      </textblock>
    </detailed_description>
    <overall_status>Not yet recruiting</overall_status>
    <start_date type="Anticipated">September 2023</start_date>
    <completion_date type="Anticipated">September 2026</completion_date>
    <primary_completion_date type="Anticipated">September 2026</primary_completion_date>
    <study_type>Observational</study_type>
    <has_expanded_access>No</has_expanded_access>
    <study_design_info>
      <observational_model>Case-Only</observational_model>
      <time_perspective>Other</time_perspective>
    </study_design_info>
    <primary_outcome>
      <measure>Regional deformation between participant left atrial geometry and SSM (study phase 1).</measure>
      <time_frame>1 year.</time_frame>
      <description>Left atria will be partitioned into 6 segments: anterior, posterior, inferior, roof, septal and lateral. Regional deformation is defined by the mean proximity of these segments from their respective closest locations on the SSM.</description>
    </primary_outcome>
    <primary_outcome>
      <measure>Location of AF drivers defined by AcQTrack (study phase 1).</measure>
      <time_frame>1 year.</time_frame>
      <description>Location defined using 6 segment model as described above (outcome 1).</description>
    </primary_outcome>
    <primary_outcome>
      <measure>Frequency of AF drivers defined by AcQTrack (study phase 1).</measure>
      <time_frame>1 year.</time_frame>
      <description>Frequency of AcQTrack phenomena reported as #/s.</description>
    </primary_outcome>
    <primary_outcome>
      <measure>Regional change in AcQMap left atrial geometry during ablation procedure (study phase 2).</measure>
      <time_frame>2 years.</time_frame>
      <description>Regional change defined using 6 segments as per outcome 1. Calculated as mean proximity of these segments during repeated geometry collection from their respective closest locations during initial geometry collection.</description>
    </primary_outcome>
    <primary_outcome>
      <measure>Completion of additional shape analysis (study phase 3).</measure>
      <time_frame>3 years.</time_frame>
    </primary_outcome>
    <primary_outcome>
      <measure>Additional procedure time (study phase 3).</measure>
      <time_frame>3 years.</time_frame>
    </primary_outcome>
    <number_of_groups>3</number_of_groups>
    <enrollment type="Anticipated">80</enrollment>
    <condition>Atrial Fibrillation</condition>
    <condition>Atrial Fibrillation, Persistent</condition>
    <arm_group>
      <arm_group_label>Retrospective observational</arm_group_label>
      <description>Retrospective observational arm recruiting &gt;50 participants, utilising data already collected as part of standard clinical care.</description>
    </arm_group>
    <arm_group>
      <arm_group_label>Prospective single-arm</arm_group_label>
      <description>Prospective single-arm recruiting 20 participants undergoing AcQMap guided ablation.</description>
    </arm_group>
    <arm_group>
      <arm_group_label>Feasibility study</arm_group_label>
      <description>Feasibility study recruiting 10 participants.</description>
    </arm_group>
    <intervention>
      <intervention_type>Diagnostic Test</intervention_type>
      <intervention_name>Intrachamber ultrasound</intervention_name>
      <description>Ultrasound left atrial geometry collecting using AcQMap.</description>
      <arm_group_label>Prospective single-arm</arm_group_label>
    </intervention>
    <intervention>
      <intervention_type>Other</intervention_type>
      <intervention_name>Statistical shape analysis</intervention_name>
      <description>Statistical shape analysis tools used to investigate left atrial geometry</description>
      <arm_group_label>Feasibility study</arm_group_label>
      <arm_group_label>Retrospective observational</arm_group_label>
    </intervention>
    <eligibility>
      <study_pop>
        <textblock>
          Participants with atrial fibrillation referred to a tertiary hospital (John Radcliffe,&#xD;
          Oxford) for ablation.&#xD;
        </textblock>
      </study_pop>
      <sampling_method>Non-Probability Sample</sampling_method>
      <criteria>
        <textblock>
          Inclusion Criteria:&#xD;
  &#xD;
          Retrospective component:&#xD;
  &#xD;
            -  Participant gave consent for anonymised data being utilised for clinical research at&#xD;
               time of procedure.&#xD;
  &#xD;
            -  Male or Female, aged 18 years or above.&#xD;
  &#xD;
            -  Previous AcQMap guided ablation for paroxysmal or persistent atrial fibrillation.&#xD;
  &#xD;
          Prospective component:&#xD;
  &#xD;
            -  Participant is willing and able to give informed consent for participation in the&#xD;
               study.&#xD;
  &#xD;
            -  Male or Female, aged 18 years or above.&#xD;
  &#xD;
            -  Diagnosed with paroxysmal or persistent atrial fibrillation and planned for an AcQMap&#xD;
               guided catheter ablation procedure.&#xD;
  &#xD;
          Exclusion Criteria:&#xD;
  &#xD;
            -  Congenital cardiac abnormality.&#xD;
  &#xD;
            -  Any other significant disease or disorder which, in the opinion of the Investigator,&#xD;
               may either put the participant at risk because of participation in the trial, or may&#xD;
               influence the result of the trial, or the participant's ability to participate in the&#xD;
               trial.&#xD;
        </textblock>
      </criteria>
      <gender>All</gender>
      <minimum_age>18 Years</minimum_age>
      <maximum_age>N/A</maximum_age>
      <healthy_volunteers>No</healthy_volunteers>
    </eligibility>
    <overall_official>
      <last_name>Tim Betts, MD MBChB FRCP</last_name>
      <role>Principal Investigator</role>
      <affiliation>Oxford University Hospitals NHS Trust</affiliation>
    </overall_official>
    <overall_contact>
      <last_name>Alexander J Sharp, MBBS BSc</last_name>
      <phone>+44(0)1865 220255</phone>
      <email>alex.sharp@ouh.nhs.uk</email>
    </overall_contact>
    <location>
      <facility>
        <name>John Radcliffe Hospital</name>
        <address>
          <city>Oxford</city>
          <state>Oxfordshire</state>
          <zip>OX3 9DU</zip>
          <country>United Kingdom</country>
        </address>
      </facility>
      <contact>
        <last_name>Alexander J Sharp, MBBS BSc</last_name>
        <email>alex.sharp@ouh.nhs.uk</email>
      </contact>
      <investigator>
        <last_name>Tim Betts, MD MBChB FRCP</last_name>
        <role>Principal Investigator</role>
      </investigator>
      <investigator>
        <last_name>Alexander J Sharp, MBBS BSc</last_name>
        <role>Sub-Investigator</role>
      </investigator>
    </location>
    <location_countries>
      <country>United Kingdom</country>
    </location_countries>
    <verification_date>August 2023</verification_date>
    <study_first_submitted>July 5, 2023</study_first_submitted>
    <study_first_submitted_qc>August 7, 2023</study_first_submitted_qc>
    <study_first_posted type="Actual">August 15, 2023</study_first_posted>
    <last_update_submitted>August 7, 2023</last_update_submitted>
    <last_update_submitted_qc>August 7, 2023</last_update_submitted_qc>
    <last_update_posted type="Actual">August 15, 2023</last_update_posted>
    <responsible_party>
      <responsible_party_type>Principal Investigator</responsible_party_type>
      <investigator_affiliation>Oxford University Hospitals NHS Trust</investigator_affiliation>
      <investigator_full_name>Tim Betts MD MBChB FRCP</investigator_full_name>
      <investigator_title>Associate Professor of Cardiovascular Medicine</investigator_title>
    </responsible_party>
    <condition_browse>
      <!-- CAUTION:  The following MeSH terms are assigned with an imperfect algorithm            -->
      <mesh_term>Atrial Fibrillation</mesh_term>
    </condition_browse>
    <!-- Results have not yet been posted for this study                                          -->
  </clinical_study>
  
  
text: download date: ClinicalTrials.gov processed this data on September 20, 2023
  link text: Link to the current ClinicalTrials.gov record.
  url: https://clinicaltrials.gov/ct2/show/NCT05993104
  org study id: 16749
  nct id: NCT05993104
  lead sponsor: 
  is fda regulated drug: No
  is fda regulated device: No
  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.
  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.
  observational model: Case-Only
  time perspective: Other
  measure: Regional deformation between participant left atrial geometry and SSM (study phase 1).
  time frame: 1 year.
  description: Left atria will be partitioned into 6 segments: anterior, posterior, inferior, roof, septal and lateral. Regional deformation is defined by the mean proximity of these segments from their respective closest locations on the SSM.
  measure: Location of AF drivers defined by AcQTrack (study phase 1).
  time frame: 1 year.
  description: Location defined using 6 segment model as described above (outcome 1).
  measure: Frequency of AF drivers defined by AcQTrack (study phase 1).
  time frame: 1 year.
  description: Frequency of AcQTrack phenomena reported as #/s.
  measure: Regional change in AcQMap left atrial geometry during ablation procedure (study phase 2).
  time frame: 2 years.
  description: Regional change defined using 6 segments as per outcome 1. Calculated as mean proximity of these segments during repeated geometry collection from their respective closest locations during initial geometry collection.
  measure: Completion of additional shape analysis (study phase 3).
  time frame: 3 years.
  measure: Additional procedure time (study phase 3).
  time frame: 3 years.
  arm group label: Retrospective observational
  description: Retrospective observational arm recruiting >50 participants, utilising data already collected as part of standard clinical care.
  arm group label: Prospective single-arm
  description: Prospective single-arm recruiting 20 participants undergoing AcQMap guided ablation.
  arm group label: Feasibility study
  description: Feasibility study recruiting 10 participants.
  intervention type: Diagnostic Test
  intervention name: Intrachamber ultrasound
  description: Ultrasound left atrial geometry collecting using AcQMap.
  arm group label: Prospective single-arm
  intervention type: Other
  intervention name: Statistical shape analysis
  description: Statistical shape analysis tools used to investigate left atrial geometry
  arm group label: Feasibility study
  arm group label: Retrospective observational
  study pop: 
  sampling method: Non-Probability Sample
  criteria: 
  gender: All
  minimum age: 18 Years
  maximum age: N/A
  healthy volunteers: No
  last name: Tim Betts, MD MBChB FRCP
  role: Principal Investigator
  affiliation: Oxford University Hospitals NHS Trust
  last name: Alexander J Sharp, MBBS BSc
  phone: +44(0)1865 220255
  email: alex.sharp@ouh.nhs.uk
  facility: 
  contact: 
  investigator: 
  investigator: 
  country: United Kingdom
  responsible party type: Principal Investigator
  investigator affiliation: Oxford University Hospitals NHS Trust
  investigator full name: Tim Betts MD MBChB FRCP
  investigator title: Associate Professor of Cardiovascular Medicine
  mesh term: Atrial Fibrillation