title: Unmappable ventricular tachycardia after an old myocardial infarction. Long-term results of substrate modification in patients with an implantable cardioverter defibrillator.
abstract: OBJECTIVE
  The frequent occurrence of ventricular tachycardia can create a serious problem in patients with an implantable cardioverter defibrillator. We assessed the long-term efficacy of catheter-based substrate modification using the voltage mapping technique of infarct-related ventricular tachycardia and recurrent device therapy.
  
  
  METHODS
  The study population consisted of 27 consecutive patients (age 68 ± 8 years, 25 men, mean left ventricular ejection fraction 31 ± 9%) with an old myocardial infarction and multiple and/or hemodynamically not tolerated ventricular tachycardia necessitating repeated device therapy. A total of 31 substrate modification procedures were performed using the three-dimensional electroanatomical mapping system. Patients were followed up for a median of 23.5 (interquartile range 6.5-53.2) months before and 37.8 (interquartile range 11.7-71.8) months after ablation. Antiarrhythmic drugs were not changed after the procedure, and were stopped 6 to 9 months after the procedure in patients who did not show ventricular tachycardia recurrence.
  
  
  RESULTS
  Median ventricular tachycardias were 1.6 (interquartile range 0.7-6.7) per month before and 0.2 (interquartile range 0.00-1.3) per month after ablation (P = 0.006). Nine ventricular fibrillation episodes were registered in seven patients before and two after ablation (P = 0.025). Median antitachycardia pacing decreased from 1.6 (interquartile range 0.01-5.5) per month before to 0.18 (interquartile range 0.00-1.6) per month after ablation (P = 0.069). Median number of shocks decreased from 0.19 (interquartile range 0.04-0.81) per month before to 0.00 (interquartile range 0.00-0.09) per month after ablation (P = 0.001). One patient had a transient ischemic attack during the procedure, and another developed pericarditis. Nine patients died during follow-up, eight patients due to heart failure and one patient during valve surgery.
  
  
  CONCLUSIONS
  Catheter-based substrate modification using voltage mapping results in a long-lasting reduction of cardioverter defibrillator therapy in patients with multiple and/or hemodynamically not tolerated infarct-related ventricular tachyarrhythmia.
authors.affiliation: Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands. alzand@hotmail.com
authors.forename: B S N
authors.initials: BS
authors.lastname: Alzand
authors.forename: C C M M
authors.initials: CC
authors.lastname: Timmermans
authors.forename: H J J
authors.initials: HJ
authors.lastname: Wellens
authors.forename: R
authors.initials: R
authors.lastname: Dennert
authors.forename: S A M
authors.initials: SA
authors.lastname: Philippens
authors.forename: P J M
authors.initials: PJ
authors.lastname: Portegijs
authors.forename: L M
authors.initials: LM
authors.lastname: Rodriguez
mesh_terms: D000046:Academic Medical Centers; D000368:Aged; D018780:Body Surface Potential Mapping / Q000379:methods; D017115:Catheter Ablation / Q000379:methods*; D015331:Cohort Studies; D003131:Combined Modality Therapy; D017147:Defibrillators, Implantable; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications* / Q000175:diagnosis; D012008:Recurrence; D012189:Retrospective Studies; D018570:Risk Assessment; D018709:Statistics, Nonparametric; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000209:etiology / Q000628:therapy*; D013997:Time Factors; D016896:Treatment Outcome