title: Comparison of electroanatomic contact and noncontact mapping of ventricular scar in a postinfarct ovine model with intramural needle electrode recording and histological validation.
abstract: BACKGROUND
  Substrate-based ablation is useful for nonhemodynamically tolerated postinfarct ventricular tachycardia. We assessed the accuracy of the CARTO contact and EnSite noncontact systems at identifying scar in a chronic ovine model with intramural plunge needle electrode recording and histological validation.
  
  
  RESULTS
  Scar mapping was performed on 8 male sheep with previous percutaneous-induced myocardial infarction. Up to 20 plunge needles were inserted into the left ventricle of each animal in areas of dense scar, scar border, and normal myocardium. A simultaneous CARTO map and EnSite geometry were acquired using a single catheter, and needle electrode locations were registered. A dynamic substrate map was constructed using ratiometric 50% peak negative voltage. The scar percentage around each needle location was quantified histologically. Analysis was performed on 152 plunge needles and corresponding histological blocks. Spearman correlation with histology was 0.690 (P<0.001) for needle electrode peak-to-peak voltage (PPV), 0.362 (P<0.001) and 0.492 (P<0.001) for CARTO bipolar and unipolar PPV, and 0.381 (P<0.001) for EnSite dynamic substrate map (< or =40 mm from array). The area under the receiver operator characteristics curve (<50% and > or =50% scar) was 0.896 for needle electrode PPV, 0.726 and 0.697 for CARTO bipolar and unipolar PPV, and 0.703 for EnSite dynamic substrate map (< or=40 mm from array).
  
  
  CONCLUSIONS
  Both the CARTO contact and EnSite noncontact systems were moderately accurate in identifying postinfarct scar when compared with intramural electrodes and confirmed with histology. The EnSite dynamic substrate map was comparable to the CARTO contact bipolar PPV when points >40 mm from the array were excluded.
authors.affiliation: Cardiology Department, Westmead Hospital, Sydney, Australia.
authors.forename: Gopal
authors.initials: G
authors.lastname: Sivagangabalan
authors.forename: Jim
authors.initials: J
authors.lastname: Pouliopoulos
authors.forename: Kaimin
authors.initials: K
authors.lastname: Huang
authors.forename: Juntang
authors.initials: J
authors.lastname: Lu
authors.forename: Michael A
authors.initials: MA
authors.lastname: Barry
authors.forename: Aravinda
authors.initials: A
authors.lastname: Thiagalingam
authors.forename: David L
authors.initials: DL
authors.lastname: Ross
authors.forename: Stuart P
authors.initials: SP
authors.lastname: Thomas
authors.forename: Pramesh
authors.initials: P
authors.lastname: Kovoor
mesh_terms: D000818:Animals; D002908:Chronic Disease; D002921:Cicatrix; D004195:Disease Models, Animal; D022062:Electrophysiologic Techniques, Cardiac; D006352:Heart Ventricles / Q000473:pathology / Q000503:physiopathology; D008297:Male; D009203:Myocardial Infarction / Q000150:complications* / Q000473:pathology / Q000503:physiopathology; D009206:Myocardium / Q000473:pathology*; D012372:ROC Curve; D015203:Reproducibility of Results; D012756:Sheep; D012815:Signal Processing, Computer-Assisted; D017180:Tachycardia, Ventricular / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology