title: Characterization of warm saline-enhanced radiofrequency ablation lesions in the infarcted porcine ventricular myocardium.
abstract: BACKGROUND
  Radiofrequency (RF) ablation of scar-mediated ventricular tachycardia is limited by the size of lesions achieved with conventional catheters. We examined the gross and histopathology characteristics of warm saline-enhanced radiofrequency (SERF) ablation delivered to left ventricular (LV) infarction scars via a novel catheter employing an extendable infusion needle electrode.
  
  
  RESULTS
  Yorkshire pigs (n = 14) underwent LV infarction by left anterior descending artery balloon occlusion. After 4-6 weeks, baseline hemodynamic data were obtained and endocardial electroanatomic mapping was performed in 13 surviving animals. Following single, 40 Watt SERF ablations delivered endocardially to the center of infarctions, 4 were examined the same day (day 0). The rest underwent repeat measurements and were sacrificed at 1 week (n = 6), and at 4 weeks (n = 3). Average lesion depth and diameter were: 1.85 ± 0.7 cm and 2.33 ± 0.7 cm at day 0, 0.91 ± 0.1 cm and 1.9 ± 0.4 cm after 1 week, and 1.0 ± 0.2 cm and 1.89 ± 0.76 cm after 4 weeks, respectively. Histopathology at 1 week showed that ablation lesions covered 41 ± 10.6% of the infarct area. SERF ablation lesions extended 100%, 90%, and 68% of the total wall thickness at day 0, 1 week, and 4 weeks, respectively. Hemodynamic parameters were unchanged. There were no myocardial wall perforations or aneurysms.
  
  
  CONCLUSIONS
  SERF ablation within myocardial infarct tissue produced large, near-transmural lesions, without evidence of myocardial perforation, wall thinning, or aneurysm formation. Ablations did not produce any negative hemodynamic effects in this small group of experiments.
authors.affiliation: Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA.
authors.forename: Roy M
authors.initials: RM
authors.lastname: John
authors.forename: John
authors.initials: J
authors.lastname: Connell
authors.forename: Paul
authors.initials: P
authors.lastname: Termin
authors.forename: Haley
authors.initials: H
authors.lastname: Houde-Walter
authors.forename: Gregory
authors.initials: G
authors.lastname: Eberl
authors.forename: Katharine M
authors.initials: KM
authors.lastname: Stohlman
authors.forename: Michael G
authors.initials: MG
authors.lastname: Curley
mesh_terms: D000818:Animals; D017115:Catheter Ablation / Q000379:methods*; D006358:Hot Temperature; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000601:surgery*; D012965:Sodium Chloride; D013552:Swine
chemical_list: D012965:Sodium Chloride
keywords: catheter ablation; ischemic myocardium; myocardial infarction; ventricular tachycardia