title: Clinical experience with antitachycardia pacing and improved detection algorithms in a new implantable cardioverter-defibrillator.
abstract: OBJECTIVE
  This study was conducted to assess the effectiveness of antitachycardia pacing modes and detection algorithms in patients with a new third-generation implantable cardioverter-defibrillator.
  
  
  METHODS
  Twenty-three of 42 consecutive patients had coronary artery disease, 14 had dilated cardiomyopathy, 2 had prior valve replacement and 3 had arrhythmogenic right ventricular dysplasia. The mean ejection fraction was 41 +/- 14%; there were 31 men (74%) and 11 women, with a mean age of 53 years. On the basis of preoperative and postoperative electrophysiologic studies, in 28 patients antitachycardia pacing was postoperatively programmed randomly as "burst" (66%) or autodecremental "ramp" (34%) stimulation with a first coupling interval of 81% of tachycardia cycle length and up to 8 sequences with 3 to 10 stimuli.
  
  
  RESULTS
  During a follow-up interval of 6.3 +/- 2.2 months, 15 patients were treated by antitachycardia pacing for a median of 6 (range 1 to 59) hemodynamically stable ventricular tachycardias (175 +/- 12 beats/min). In 5 patients, 22 ventricular tachycardias (9%) were not terminated by antitachycardia pacing but by cardioversion. Seven (3%) of these episodes accelerated (> 50 ms) during antitachycardia pacing. Syncope did not occur during these episodes. In seven patients initial antitachycardia pacing in cases of supraventricular tachycardias delayed charging and redetection prevented inappropriate discharges. Additional detection algorithms were programmed only after inappropriate therapy. The sudden "onset" and "sustained rate duration" criteria were programmed in three patients and the cycle length "stability" criteria in six patients, respectively. After activation of these detection algorithms only two of the seven patients had further inappropriate device discharges.
  
  
  CONCLUSIONS
  Thus, antitachycardia pacing by this implantable cardioverter-defibrillator effectively and appropriately terminated 91% of hemodynamically stable ventricular tachycardias. Inappropriate device discharges were prevented in some patients by antitachycardia pacing and additional detection algorithms.
authors.affiliation: Hospital of the Westfälische-Wilhelms University of Münster, Department of Cardiology and Angiology, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Wietholt
authors.forename: M
authors.initials: M
authors.lastname: Block
authors.forename: F
authors.initials: F
authors.lastname: Isbruch
authors.forename: D
authors.initials: D
authors.lastname: Böcker
authors.forename: M
authors.initials: M
authors.lastname: Borggrefe
authors.forename: M
authors.initials: M
authors.lastname: Shenasa
authors.forename: G
authors.initials: G
authors.lastname: Breithardt
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D002304:Cardiac Pacing, Artificial; D017147:Defibrillators, Implantable; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D017180:Tachycardia, Ventricular / Q000188:drug therapy / Q000503:physiopathology / Q000628:therapy*; D014693:Ventricular Fibrillation / Q000628:therapy
chemical_list: D000889:Anti-Arrhythmia Agents