title: Nonsurgical transthoracic epicardial approach in patients with ventricular tachycardia and previous cardiac surgery.
abstract: BACKGROUND
  The subxyphoid pericardial mapping approach can be used to facilitate catheter ablation of postmyocardial-infarction ventricular tachycardia (post-MI VT), but the presence of dense adhesions is thought to preclude this approach in patients who have previously undergone open-chest cardiac surgery.
  
  
  OBJECTIVE
  This study reports the first use of a nonsurgical transthoracic epicardial approach in patients with scar-related VT and previous cardiac surgery.
  
  
  METHODS
  Five patients with a mean age of 67 +/- 10 years, left ventricular ejection fraction (LVEF) of 40 +/- 4.3%) and recurrent VT occurring 7 months to 10 years after cardiac surgery underwent combined endocardial and epicardial mapping and ablation during the same session. Because pericardial adhesions were anticipated to be denser in the anterior wall, the nonsurgical transthoracic epicardial puncture was directed to the inferior wall of the left ventricle. Failure to interrupt VT with radio frequency (RF) energy pulses delivered at the best endocardial or epicardial site prompted changing from one approach to the other.
  
  
  RESULTS
  During the epicardial puncture procedure, the contrast medium accumulated in the inferior wall instead of spreading around the cardiac silhouette. The pericardial sac could be entered in all patients, and mapping of the inferolateral epicardial wall of the left ventricle was feasible. Fourteen VTs were induced, of which 8 could not be mapped because of poor hemodynamic tolerance. Three of the remaining 6 mappable VTs were eliminated by endocardial ablation, 2 required an epicardial RF pulse to be rendered noninducible, and 1 VT was not eliminated. No intra- or postprocedural complications were noted despite full heparinization.
  
  
  CONCLUSIONS
  Nonsurgical transthoracic epicardial catheter mapping and ablation of epicardial VT related to the inferolateral left ventricular wall are feasible in patients who have previously undergone open- cardiac surgery.
authors.affiliation: Unidade Clinica de Arritmia, Heart Institute (InCor), University of São Paulo Medical School, São Paulo, SP, Brazil. sosa@incor.usp.br
authors.forename: Eduardo
authors.initials: E
authors.lastname: Sosa
authors.forename: Mauricio
authors.initials: M
authors.lastname: Scanavacca
authors.forename: André
authors.initials: A
authors.lastname: D'Avila
authors.forename: José
authors.initials: J
authors.lastname: Antônio
authors.forename: Franchine
authors.initials: F
authors.lastname: Ramires
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D018780:Body Surface Potential Mapping; D001938:Brazil; D006348:Cardiac Surgical Procedures; D017115:Catheter Ablation; D017147:Defibrillators, Implantable; D004452:Echocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D005500:Follow-Up Studies; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D010496:Pericardium / Q000000981:diagnostic imaging / Q000601:surgery*; D017180:Tachycardia, Ventricular / Q000000981:diagnostic imaging / Q000628:therapy*; D016896:Treatment Outcome