title: Risks of developing supraventricular and ventricular tachyarrhythmias after implantation of a cardioverter-defibrillator, and timing the activation of arrhythmia termination therapies.
abstract: The clinical courses of 39 consecutive recipients (mean age 61 +/- 12 years, and mean left ventricular ejection fraction 0.32 +/- 0.15) of an automatic implantable cardioverter-defibrillator (ICD) were examined to determine the risks of developing ventricular tachycardia (VT) and supraventricular tachyarrhythmias (SVT) after surgery, with ventricular response rates fulfilling ICD detection criteria. ICD system leads were implanted by thoracotomy in 25 patients and by using nonthoracotomy lead systems in 14. Six patients (18%) developed SVT after surgery, whereas 14 (36%) developed sustained VT. The median times to the development of both SVT and VT were 2 days. By actuarial analysis, the probability of developing VT after surgery was significantly greater than that of SVT during hospitalization (p = 0.04). This significant excess of postoperative VT over SVT was most marked in patients aged < or = 61 years, those who received nonthoracotomy rather than epicardial lead systems, those who presented with VT rather than ventricular fibrillation, and those who received > 20 intraoperative defibrillation shocks. These observations recommend the activation of ICD therapies immediately after implantation.
authors.affiliation: Department of Medicine, Foothills Medical Center, Calgary, Alberta, Canada.
authors.forename: J T
authors.initials: JT
authors.lastname: Hii
authors.forename: A M
authors.initials: AM
authors.lastname: Gillis
authors.forename: D G
authors.initials: DG
authors.lastname: Wyse
authors.forename: R S
authors.initials: RS
authors.lastname: Sheldon
authors.forename: H J
authors.initials: HJ
authors.lastname: Duff
authors.forename: L B
authors.initials: LB
authors.lastname: Mitchell
mesh_terms: D000367:Age Factors; D000368:Aged; D000638:Amiodarone / Q000627:therapeutic use; D001145:Arrhythmias, Cardiac / Q000628:therapy*; D017147:Defibrillators, Implantable / Q000009:adverse effects*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011336:Probability; D013617:Tachycardia, Supraventricular / Q000453:epidemiology / Q000209:etiology*; D017180:Tachycardia, Ventricular / Q000453:epidemiology / Q000209:etiology*; D013997:Time Factors
chemical_list: D000638:Amiodarone