title: A comparison of the output characteristics of several implantable cardioverter-defibrillators.
abstract: BACKGROUND
  Implantable cardioverter-defibrillators (ICDs) are effective for primary and secondary prevention of sudden cardiac death due to ventricular arrhythmias. However, despite wide clinical use, there are no generally accepted standardized protocols to characterize and report the output capabilities of ICDs.
  
  
  OBJECTIVE
  The objective of this study was to measure and compare the output characteristics of standard-output and high-output ICDs from several manufacturers under a common set of conditions.
  
  
  METHODS
  The output characteristics of ICDs randomly selected from hospital stock were measured. The energy delivered for each shock to a range of fixed loads (25-75 Omega) was computed from the voltage waveform and the corresponding load.
  
  
  RESULTS
  Delivered energy varied by approximately 4 J over the range of loads tested and varied between devices (high-output 33.8-35 J; standard-output 26.7-28.6 J, at 50 Omega). Leading-edge voltage varied by approximately 6% over the range of loads tested and varied between devices (high-output 738-792 V; standard-output 593-797 V, at 50 Omega). Pulse width varied by a factor of approximately 3 over the range of loads tested and varied between devices (high-output 10-14.5 ms; standard-output 9-12.2 ms, at 50 Omega). Observed variations between devices and with load were significant (P <.001).
  
  
  CONCLUSIONS
  Potentially important differences in output characteristics of different ICD systems exist and merit further clinical investigation. The reporting of ICD output characteristics should be standardized. Additionally, it is recommended that manufacturers report output characteristics as a function of load over the typical range of patient loads clinically encountered.
authors.affiliation: Department of Biomedical Engineering, Boston University, Massachusetts 02215, USA.
authors.forename: Apiradee
authors.initials: A
authors.lastname: Thammanomai
authors.forename: Michael O
authors.initials: MO
authors.lastname: Sweeney
authors.forename: Solomon R
authors.initials: SR
authors.lastname: Eisenberg
mesh_terms: D016757:Death, Sudden, Cardiac / Q000517:prevention & control*; D017147:Defibrillators, Implantable / Q000592:standards; D004553:Electric Conductivity; D004867:Equipment Design; D006801:Humans