title: Catheter ablation for hemodynamically unstable monomorphic ventricular tachycardia.
abstract: BACKGROUND
  Hemodynamic collapse precludes extensive catheter mapping to identify focal target regions in many patients with ventricular tachycardia (VT) associated with heart disease. This study tested the feasibility of catheter ablation of poorly tolerated VTs by targeting a region identified during sinus rhythm.
  
  
  RESULTS
  Ablation was attempted in five patients, ages 44 to 59 years, with left ventricular ejection fractions of 0.15 to 0.20 and poorly tolerated VT causing multiple implantable defibrillator therapies (6 to 30 episodes/month). VT was due to prior infarction in three patients and nonischemic cardiomyopathy in two. Target regions were sought that met the following criteria: (1) evidence of slow conduction from fractionated sinus rhythm electrograms and stimulus-QRS delays during pace mapping, and (2) evidence that the region contains the reentrant circuit exit from pace mapping. In 4 of 5 patients, a target region was identified and radiofrequency lesions applied. Ablation abolished all recurrences of VT in 3 of 4 patients during follow-up of 14 to 22 months. There were no complications.
  
  
  CONCLUSIONS
  Ablation of poorly tolerated VT is feasible in some patients by mapping during sinus rhythm and performing ablation over a region of identifiable scar that contains abnormal conduction and a presumptive VT exit.
authors.affiliation: Cardiovascular Division, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
authors.forename: K E
authors.initials: KE
authors.lastname: Ellison
authors.forename: W G
authors.initials: WG
authors.lastname: Stevenson
authors.forename: M O
authors.initials: MO
authors.lastname: Sweeney
authors.forename: D C
authors.initials: DC
authors.lastname: Lefroy
authors.forename: E
authors.initials: E
authors.lastname: Delacretaz
authors.forename: P L
authors.initials: PL
authors.lastname: Friedman
mesh_terms: D000328:Adult; D009202:Cardiomyopathies / Q000150:complications; D017115:Catheter Ablation; D004562:Electrocardiography; D004594:Electrophysiology; D005240:Feasibility Studies; D006329:Heart Conduction System / Q000503:physiopathology; D006339:Heart Rate; D006439:Hemodynamics; D006801:Humans; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications; D017180:Tachycardia, Ventricular / Q000188:drug therapy / Q000503:physiopathology* / Q000601:surgery*