title: Generator replacement is associated with an increased rate of ICD lead alerts.
abstract: BACKGROUND
  Lead malfunction is an important cause of morbidity and mortality in patients with an implantable cardioverter-defibrillator (ICD). We have shown that the failure of recalled high-voltage leads significantly increases after ICD generator replacement. However, generator replacement has not been recognized as a predictor of lead failure in general.
  
  
  OBJECTIVE
  The purpose of this study is to assess the effect of ICD generator exchange on the rate of ICD lead alerts.
  
  
  METHODS
  A time-dependent Cox proportional hazards model was used to analyze a database of remotely monitored ICDs. The model assessed the impact of generator exchange on the rate of lead alerts after ICD generator replacement.
  
  
  RESULTS
  The analysis included 60,219 patients followed for 37 ± 19 months. The 5-year lead survival was 99.3% (95% confidence interval 99.2%-99.4%). Of 60,219 patients, 7458 patients (12.9%) underwent ICD generator exchange without lead replacement. After generator replacement, the rate of lead alerts was more than 5-fold higher than in controls with leads of the same age without generator replacement (hazard ratio 5.19; 95% confidence interval 3.45-7.84). A large number of lead alerted within 3 months of generator replacement. Lead alerts were more common in patients with single- vs dual-chamber ICDs and in younger patients. Sex was not associated with lead alerts.
  
  
  CONCLUSIONS
  Routine generator replacement is associated with a 5-fold higher risk of lead alert compared to age-matched leads without generator replacement. This suggests the need for intense surveillance after generator replacement and the development of techniques to minimize the risk of lead damage during generator replacement.
authors: Division of Cardiology, Emory University School of Medicine, Atlanta, Georgia.
authors: Joshua D
authors: JD
authors: Lovelock
authors: Division of Cardiology, Emory University School of Medicine, Atlanta, Georgia.
authors: Cesar
authors: C
authors: Cruz
authors: Division of Cardiology, Emory University School of Medicine, Atlanta, Georgia.
authors: Michael H
authors: MH
authors: Hoskins
authors: Boston Scientific, Marlborough, Massachusetts.
authors: Paul
authors: P
authors: Jones
authors: Division of Cardiology, Emory University School of Medicine, Atlanta, Georgia.
authors: Mikhael F
authors: MF
authors: El-Chami
authors: Division of Cardiology, Emory University School of Medicine, Atlanta, Georgia.
authors: Michael S
authors: MS
authors: Lloyd
authors: Division of Cardiology, Emory University School of Medicine, Atlanta, Georgia.
authors: Angel
authors: A
authors: Leon
authors: Division of Cardiology, Emory University School of Medicine, Atlanta, Georgia.
authors: David B
authors: DB
authors: DeLurgio
authors: Division of Cardiology, Emory University School of Medicine, Atlanta, Georgia,. Electronic address: jlangbe@emory.edu.
authors: Jonathan J
authors: JJ
authors: Langberg
mesh_terms: D001145:Arrhythmias, Cardiac / Q000401:mortality / Q000628:therapy*; D017147:Defibrillators, Implantable; D004867:Equipment Design; D004868:Equipment Failure; D019544:Equipment Failure Analysis; D005500:Follow-Up Studies; D006801:Humans; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends; D013997:Time Factors; D014481:United States / Q000453:epidemiology
keywords: Generator replacement; ICD malfunction; Risk factor for ICD lead failure