title: Factors affecting error in integration of electroanatomic mapping with CT and MR imaging during catheter ablation of atrial fibrillation.
abstract: OBJECTIVE
  Integration of 3-D electroanatomic mapping with Computed Tomographic (CT) and Magnetic Resonance (MR) imaging is gaining acceptance to facilitate catheter ablation of atrial fibrillation. This is critically dependent on accurate integration of electroanatomic maps with CT or MR images. We sought to examine the effect of patient- and technique-related factors on integration accuracy of electroanatomic mapping with CT and MR imaging of the left atrium.
  
  
  METHODS
  Sixty-one patients undergoing catheter-based atrial fibrillation (AF) ablation procedures were included. All patients underwent cardiac CT (n = 11) or MR (n = 50) imaging, and image integration with real-time electroanatomic mapping of the aorta and left atrium (LA). CARTO-Merge software (Biosense-Webster) was used to calculate the overall average accuracy of integration of electroanatomic points with the CT and MR-derived reconstructions of the LA and aorta.
  
  
  RESULTS
  There was a significant correlation between LA size assessed by electroanatomic mapping (112 +/- 31 ml) and average integration error (1.9 +/- 0.6 mm) (r = 0.46, p = 0.0003). There was also greater integration error for patients with LA volume >/= 110 ml (n = 31) versus < 110 ml (n = 30) (p = 0.004). In contrast, there was no significant association between average integration error and paroxysmal versus persistent AF, left ventricular ejection fraction, days from imaging to electroanatomic mapping, or images derived from CT versus MR.
  
  
  CONCLUSIONS
  Patients with larger LA volume may be prone to greater error during integration of electroanatomic mapping with CT and MR imaging. Strategies to reduce integration error may therefore be especially useful in patients with large LA volume.
authors.affiliation: Cardiac Arrhythmia Service and Cardiac Unit, Massachusetts General Hospital, Gray 109, 55 Fruit St, Boston, MA, 02114, USA.
authors.forename: E Kevin
authors.initials: EK
authors.lastname: Heist
authors.forename: Jianping
authors.initials: J
authors.lastname: Chevalier
authors.forename: Godtfred
authors.initials: G
authors.lastname: Holmvang
authors.forename: Jagmeet P
authors.initials: JP
authors.lastname: Singh
authors.forename: Patrick T
authors.initials: PT
authors.lastname: Ellinor
authors.forename: David J
authors.initials: DJ
authors.lastname: Milan
authors.forename: Andre
authors.initials: A
authors.lastname: D'Avila
authors.forename: Theofanie
authors.initials: T
authors.lastname: Mela
authors.forename: Jeremy N
authors.initials: JN
authors.lastname: Ruskin
authors.forename: Moussa
authors.initials: M
authors.lastname: Mansour
mesh_terms: D016477:Artifacts; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000601:surgery*; D018780:Body Surface Potential Mapping / Q000379:methods*; D017115:Catheter Ablation / Q000379:methods*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique; D025321:Surgery, Computer-Assisted / Q000379:methods*; D018511:Systems Integration; D014057:Tomography, X-Ray Computed / Q000379:methods*