title: Cardiac magnetic resonance and electroanatomical mapping of acute and chronic atrial ablation injury: a histological validation study.
abstract: OBJECTIVE
  To provide a comprehensive histopathological validation of cardiac magnetic resonance (CMR) and endocardial voltage mapping of acute and chronic atrial ablation injury.
  
  
  RESULTS
  16 pigs underwent pre-ablation T2-weighted (T2W) and late gadolinium enhancement (LGE) CMR and high-density voltage mapping of the right atrium (RA) and both were repeated after intercaval linear radiofrequency ablation. Eight pigs were sacrificed following the procedure for pathological examination. A further eight pigs were recovered for 8 weeks, before chronic CMR, repeat RA voltage mapping and pathological examination. Signal intensity (SI) thresholds from 0 to 15 SD above a reference SI were used to segment the RA in CMR images and segmentations compared with real lesion volumes. The SI thresholds that best approximated histological volumes were 2.3 SD for LGE post-ablation, 14.5 SD for T2W post-ablation and 3.3 SD for LGE chronically. T2-weighted chronically always underestimated lesion volume. Acute histology showed transmural injury with coagulative necrosis. Chronic histology showed transmural fibrous scar. The mean voltage at the centre of the ablation line was 3.3 mV pre-ablation, 0.6 mV immediately post-ablation, and 0.3 mV chronically.
  
  
  CONCLUSIONS
  This study presents the first histopathological validation of CMR and endocardial voltage mapping to define acute and chronic atrial ablation injury, including SI thresholds that best match histological lesion volumes. An understanding of these thresholds may allow a more informed assessment of the underlying atrial substrate immediately after ablation and before repeat catheter ablation for atrial arrhythmias.
authors.affiliation: Division of Imaging Sciences & Biomedical Engineering, Medical Engineering Centre, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, SE1 7EH London, UK Department of Cardiology, Guy's and St. Thomas' NHS Foundation Trust, London, UK james.harrison@kcl.ac.uk.
authors.forename: James L
authors.initials: JL
authors.lastname: Harrison
authors.affiliation: Department of Cardiology, Aarhus University Hospital Skejby, Aarhus, Denmark.
authors.forename: Henrik K
authors.initials: HK
authors.lastname: Jensen
authors.affiliation: Division of Imaging Sciences & Biomedical Engineering, Medical Engineering Centre, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, SE1 7EH London, UK.
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Peel
authors.affiliation: Division of Imaging Sciences & Biomedical Engineering, Medical Engineering Centre, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, SE1 7EH London, UK Department of Cardiology, Guy's and St. Thomas' NHS Foundation Trust, London, UK.
authors.forename: Amedeo
authors.initials: A
authors.lastname: Chiribiri
authors.affiliation: Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital Skejby, Aarhus, Denmark MR-Center, Aarhus University Hospital Skejby, Aarhus, Denmark.
authors.forename: Anne K
authors.initials: AK
authors.lastname: Grøndal
authors.affiliation: Department of Cardiology, Aarhus University Hospital Skejby, Aarhus, Denmark MR-Center, Aarhus University Hospital Skejby, Aarhus, Denmark.
authors.forename: Lars Ø
authors.initials: LØ
authors.lastname: Bloch
authors.affiliation: Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital Skejby, Aarhus, Denmark.
authors.forename: Steen F
authors.initials: SF
authors.lastname: Pedersen
authors.affiliation: Department of Cardiology, Aarhus University Hospital Skejby, Aarhus, Denmark Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
authors.forename: Jacob F
authors.initials: JF
authors.lastname: Bentzon
authors.affiliation: Division of Imaging Sciences & Biomedical Engineering, Medical Engineering Centre, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, SE1 7EH London, UK.
authors.forename: Christoph
authors.initials: C
authors.lastname: Kolbitsch
authors.affiliation: Division of Imaging Sciences & Biomedical Engineering, Medical Engineering Centre, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, SE1 7EH London, UK.
authors.forename: Rashed
authors.initials: R
authors.lastname: Karim
authors.affiliation: Division of Imaging Sciences & Biomedical Engineering, Medical Engineering Centre, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, SE1 7EH London, UK Department of Cardiology, Guy's and St. Thomas' NHS Foundation Trust, London, UK.
authors.forename: Steven E
authors.initials: SE
authors.lastname: Williams
authors.affiliation: Division of Imaging Sciences & Biomedical Engineering, Medical Engineering Centre, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, SE1 7EH London, UK Department of Cardiology, Guy's and St. Thomas' NHS Foundation Trust, London, UK.
authors.forename: Nick W
authors.initials: NW
authors.lastname: Linton
authors.affiliation: Division of Imaging Sciences & Biomedical Engineering, Medical Engineering Centre, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, SE1 7EH London, UK.
authors.forename: Kawal S
authors.initials: KS
authors.lastname: Rhode
authors.affiliation: Division of Imaging Sciences & Biomedical Engineering, Medical Engineering Centre, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, SE1 7EH London, UK Department of Cardiology, Guy's and St. Thomas' NHS Foundation Trust, London, UK.
authors.forename: Jaswinder
authors.initials: J
authors.lastname: Gill
authors.affiliation: Department of Cardiology, Guy's and St. Thomas' NHS Foundation Trust, London, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Cooklin
authors.affiliation: Division of Imaging Sciences & Biomedical Engineering, Medical Engineering Centre, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, SE1 7EH London, UK Department of Cardiology, Guy's and St. Thomas' NHS Foundation Trust, London, UK.
authors.forename: C A
authors.initials: CA
authors.lastname: Rinaldi
authors.affiliation: Division of Imaging Sciences & Biomedical Engineering, Medical Engineering Centre, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, SE1 7EH London, UK Department of Cardiology, Guy's and St. Thomas' NHS Foundation Trust, London, UK.
authors.forename: Matthew
authors.initials: M
authors.lastname: Wright
authors.affiliation: Department of Cardiology, Aarhus University Hospital Skejby, Aarhus, Denmark MR-Center, Aarhus University Hospital Skejby, Aarhus, Denmark.
authors.forename: Won Y
authors.initials: WY
authors.lastname: Kim
authors.affiliation: Division of Imaging Sciences & Biomedical Engineering, Medical Engineering Centre, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, SE1 7EH London, UK.
authors.forename: Tobias
authors.initials: T
authors.lastname: Schaeffter
authors.affiliation: Division of Imaging Sciences & Biomedical Engineering, Medical Engineering Centre, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, SE1 7EH London, UK.
authors.forename: Reza S
authors.initials: RS
authors.lastname: Razavi
authors.affiliation: Division of Imaging Sciences & Biomedical Engineering, Medical Engineering Centre, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, SE1 7EH London, UK Department of Cardiology, Guy's and St. Thomas' NHS Foundation Trust, London, UK.
authors.forename: Mark D
authors.initials: MD
authors.lastname: O'Neill
mesh_terms: D000208:Acute Disease; D000818:Animals; D057791:Cardiac Imaging Techniques / Q000379:methods; D017115:Catheter Ablation / Q000009:adverse effects*; D002908:Chronic Disease; D003287:Contrast Media; D004568:Electrodiagnosis / Q000379:methods*; D005260:Female; D006325:Heart Atria / Q000473:pathology; D006335:Heart Injuries / Q000473:pathology*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D009942:Organometallic Compounds; D013552:Swine; D013556:Swine, Miniature
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C090600:gadobutrol
keywords: Ablation; Atrial fibrillation; Electroanatomical mapping; Histology; Magnetic resonance