title: Limitations and late complications of third-generation automatic cardioverter-defibrillators.
abstract: BACKGROUND
  This study examines the limitations and complex management problems associated with the use of tiered-therapy, implantable cardioverter-defibrillators (ICDs).
  
  
  RESULTS
  The study group comprises the first 154 patients undergoing implantation of tiered-therapy ICDs at our institution. Pulse generators from three different manufacturers were used. In 39 patients, a complete nonthoracotomy lead system was used. The perioperative mortality was 1.3%. Of these 154 patients, 37% experienced late postoperative problems. Twenty-one patients required system revision within 36.5 months (mean, 8.57 +/- 11.3) of surgery. Reasons for revision were spurious shocks due to electrode fractures (3) or electrode adapter malfunction (2), inadequate signal from endocardial rate-sensing electrodes (3), superior vena cava or right ventricular coil migration (5), failure to correct tachyarrhythmias due to a postimplant rise in defibrillation threshold (5), or pulse generator failure (3). One of these patients required system removal for infection after revision of an endocardial lead. A further 32 patients received inappropriate shocks for atrial fibrillation with a rapid ventricular response or sinus tachycardia. Two of these patients also received shocks for ventricular tachycardia initiated by antitachycardia pacing triggered by atrial fibrillation. Ventricular pacing for bradycardia was associated with inappropriate shocks due to excessive autogain in 2 patients.
  
  
  CONCLUSIONS
  Despite the major diagnostic and therapeutic advantages of tiered-therapy ICDs, a significant proportion of patients continue to experience hardware-related complications or receive inappropriate shocks.
authors.affiliation: Cardiac Arrhythmia Service, Harvard Medical School, Boston, MA, USA.
authors.forename: S O
authors.initials: SO
authors.lastname: Nunain
authors.forename: M
authors.initials: M
authors.lastname: Roelke
authors.forename: T
authors.initials: T
authors.lastname: Trouton
authors.forename: S
authors.initials: S
authors.lastname: Osswald
authors.forename: Y H
authors.initials: YH
authors.lastname: Kim
authors.forename: G
authors.initials: G
authors.lastname: Sosa-Suarez
authors.forename: D R
authors.initials: DR
authors.lastname: Brooks
authors.forename: B
authors.initials: B
authors.lastname: McGovern
authors.forename: M
authors.initials: M
authors.lastname: Guy
authors.forename: D F
authors.initials: DF
authors.lastname: Torchiana
mesh_terms: D000465:Algorithms; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D001281:Atrial Fibrillation; D016757:Death, Sudden, Cardiac / Q000453:epidemiology; D017147:Defibrillators, Implantable / Q000009:adverse effects; D004562:Electrocardiography; D004567:Electrodes, Implanted / Q000009:adverse effects; D004867:Equipment Design; D004868:Equipment Failure; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D016019:Survival Analysis; D013616:Tachycardia, Sinus; D017180:Tachycardia, Ventricular / Q000453:epidemiology / Q000628:therapy*; D013997:Time Factors; D014693:Ventricular Fibrillation / Q000453:epidemiology / Q000628:therapy*
chemical_list: D000889:Anti-Arrhythmia Agents