title: Three-dimensional atrial wall thickness maps to inform catheter ablation procedures for atrial fibrillation.
abstract: OBJECTIVE
  Transmural lesion formation is critical to success in atrial fibrillation ablation and is dependent on left atrial wall thickness (LAWT). Pre- and peri-procedural planning may benefit from LAWT measurements.
  
  
  RESULTS
  To calculate the LAWT, the Laplace equation was solved over a finite element mesh of the left atrium derived from the segmented computed tomographic angiography (CTA) dataset. Local LAWT was then calculated from the length of field lines derived from the Laplace solution that spanned the wall from the endocardium or epicardium. The method was validated on an atrium phantom and retrospectively applied to 10 patients who underwent routine coronary CTA for standard clinical indications at our institute. The Laplace wall thickness algorithm was validated on the left atrium phantom. Wall thickness measurements had errors of <0.2 mm for thicknesses of 0.5-5.0 mm that are attributed to image resolution and segmentation artefacts. Left atrial wall thickness measurements were performed on 10 patients. Successful comprehensive LAWT maps were generated in all patients from the coronary CTA images. Mean LAWT measurements ranged from 0.6 to 1.0 mm and showed significant inter and intra patient variability.
  
  
  CONCLUSIONS
  Left atrial wall thickness can be measured robustly and efficiently across the whole left atrium using a solution of the Laplace equation over a finite element mesh of the left atrium. Further studies are indicated to determine whether the integration of LAWT maps into pre-existing 3D anatomical mapping systems may provide important anatomical information for guiding radiofrequency ablation.
authors.affiliation: Department of Imaging Sciences and Biomedical Engineering King's College London, London SE1 7EH, UK.
authors.forename: Martin
authors.initials: M
authors.lastname: Bishop
authors.affiliation: Department of Imaging Sciences and Biomedical Engineering King's College London, London SE1 7EH, UK Department of Cardiac Computed Tomography, Guy's and St Thomas' NHS Foundation Trust, London SE1 7EH, UK Department of Cardiology, Guy's and St Thomas' NHS Foundation Trust, London SE1 7EH, UK.
authors.forename: Ronak
authors.initials: R
authors.lastname: Rajani
authors.affiliation: Institute of Biophysics, Medical University of Graz, Graz, Austria Oxford e-Research Centre, University of Oxford, Oxford, UK.
authors.forename: Gernot
authors.initials: G
authors.lastname: Plank
authors.affiliation: Department of Imaging Sciences and Biomedical Engineering King's College London, London SE1 7EH, UK.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Gaddum
authors.affiliation: Department of Imaging Sciences and Biomedical Engineering King's College London, London SE1 7EH, UK Department of Cardiac Computed Tomography, Guy's and St Thomas' NHS Foundation Trust, London SE1 7EH, UK Department of Cardiology, Guy's and St Thomas' NHS Foundation Trust, London SE1 7EH, UK.
authors.forename: Gerry
authors.initials: G
authors.lastname: Carr-White
authors.affiliation: Department of Imaging Sciences and Biomedical Engineering King's College London, London SE1 7EH, UK Department of Cardiology, Guy's and St Thomas' NHS Foundation Trust, London SE1 7EH, UK.
authors.forename: Matt
authors.initials: M
authors.lastname: Wright
authors.affiliation: Department of Imaging Sciences and Biomedical Engineering King's College London, London SE1 7EH, UK Department of Cardiology, Guy's and St Thomas' NHS Foundation Trust, London SE1 7EH, UK mark.oneill@kcl.ac.uk.
authors.forename: Mark
authors.initials: M
authors.lastname: O'Neill
authors.affiliation: Department of Imaging Sciences and Biomedical Engineering King's College London, London SE1 7EH, UK.
authors.forename: Steven
authors.initials: S
authors.lastname: Niederer
mesh_terms: D000200:Action Potentials; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery; D017115:Catheter Ablation / Q000379:methods*; D000072226:Computed Tomography Angiography / Q000295:instrumentation; D017023:Coronary Angiography / Q000295:instrumentation / Q000379:methods*; D004562:Electrocardiography; D005260:Female; D020342:Finite Element Analysis; D006325:Heart Atria / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery; D006339:Heart Rate; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D019047:Phantoms, Imaging; D011237:Predictive Value of Tests; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D012189:Retrospective Studies
keywords: Ablation; Atrial fibrillation; Cardiac computed tomography; Finite element modelling; Left atrial wall thickness; Mapping
references.citation: Europace. 2015 Nov;17 (11):1700-7
references.pmid: 25736723
references.citation: J Interv Card Electrophysiol. 2006 Nov;17(2):127-32
references.pmid: 17226084
references.citation: Europace. 2012 Aug;14 (8):1104-11
references.pmid: 22417722
references.citation: J Cardiovasc Electrophysiol. 2008 Jul;19(7):689-92
references.pmid: 18284501
references.citation: J Cardiovasc Electrophysiol. 2005 Nov;16(11):1172-9
references.pmid: 16302900
references.citation: Clin Anat. 2009 Jan;22(1):52-63
references.pmid: 18470938
references.citation: J Cardiovasc Electrophysiol. 2011 Nov;22(11):1232-6
references.pmid: 21615817
references.citation: Front Physiol. 2011 Apr 09;2:14
references.pmid: 21516246
references.citation: Circulation. 2005 Sep 6;112(10):1400-5
references.pmid: 16129790
references.citation: Circulation. 1998 Sep 8;98(10):946-52
references.pmid: 9737513
references.citation: J Am Coll Cardiol. 2012 Aug 14;60(7):628-36
references.pmid: 22818076
references.citation: J Cardiovasc Electrophysiol. 2004 Jul;15(7):809-12
references.pmid: 15250867
references.citation: Am J Med. 2002 Oct 1;113(5):359-64
references.pmid: 12401529
references.citation: Int J Cardiol. 2014 Apr 1;172(3):e411-3
references.pmid: 24439855
references.citation: Cardiovasc Res. 2012 Apr 1;94(1):48-57
references.pmid: 22227155
references.citation: Int J Cardiol. 2011 Apr 14;148(2):139-47
references.pmid: 19906452
references.citation: J Electrocardiol. 2003;36 Suppl:69-74
references.pmid: 14716595
references.citation: J Am Coll Cardiol. 2009 May 12;53(19):1798-803
references.pmid: 19422987
references.citation: JAMA. 2001 May 9;285(18):2370-5
references.pmid: 11343485