title: Left ventricular catheter ablation using direct, intramural ethanol injection in swine.
abstract: BACKGROUND
  Limitations in lesion volume and particularly lesion depth may negatively effect the efficacy of catheter ablation procedures using radiofrequency energy. This study evaluated the safety and efficacy of myocardial ablation using direct intramural injection of ethanol with a novel injection catheter system.
  
  
  METHODS
  Left ventricular lesions were performed in 9 male swine (80-85 pounds); two animals were studied 6 weeks following anterior infarction produced by agarose gel embolization. An 8 Fr deflectable catheter equipped with a 27 gauge adjustable depth, retractable needle was directed to the LV using a retrograde aortic approach. Lesion deployment was guided by fluoroscopy and intracardiac echocardiography (ICE). Lesion characteristics were assessed with ICE imaging and pathologic analysis.
  
  
  RESULTS
  Ethanol lesions were confined to the tissue directly adjacent to the injection port. Lesions were intramural with no evidence of overlying thrombus. Lesions delivered with a single port injection needle in normal myocardium (n = 24) averaged 1910 +/- 1066 mm(3) with a depth of 8.9 +/- 3.3 mm. Lesions directed to infarct border zones (n = 4) averaged 929 +/- 882 mm(3) with a depth of 4.3 +/- 2.8 mm. Lesions were immediately evident on ICE imaging, and were visualized by increased echo density and tissue swelling. Pathological analysis revealed homogenous lesions with intramural hemorrhage and contraction band necrosis.
  
  
  CONCLUSIONS
  Myocardial catheter ablation using direct ethanol injection is feasible, and relatively large and deep intramural lesions can be delivered, even in the infarct border zone. This technique may prove useful in ablation of arrhythmia substrates that are deep to the endocardial surface.
authors.affiliation: Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, USA. david.callans@uphs.upenn.edu
authors.forename: David J
authors.initials: DJ
authors.lastname: Callans
authors.forename: Jian-Fang
authors.initials: JF
authors.lastname: Ren
authors.forename: Navneet
authors.initials: N
authors.lastname: Narula
authors.forename: Vickas
authors.initials: V
authors.lastname: Patel
authors.forename: John
authors.initials: J
authors.lastname: Michele
authors.forename: Anna
authors.initials: A
authors.lastname: Gelzer
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Dillon
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D017115:Catheter Ablation / Q000379:methods*; D004195:Disease Models, Animal; D004452:Echocardiography / Q000379:methods*; D000431:Ethanol / Q000494:pharmacology*; D006352:Heart Ventricles / Q000473:pathology / Q000601:surgery; D007150:Immunohistochemistry; D015552:Injections, Intralesional; D008297:Male; D009203:Myocardial Infarction / Q000503:physiopathology; D009206:Myocardium / Q000473:pathology; D011336:Probability; D012680:Sensitivity and Specificity; D013552:Swine; D017180:Tachycardia, Ventricular / Q000000981:diagnostic imaging / Q000601:surgery; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000601:surgery*
chemical_list: D000431:Ethanol