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Use of a Wearable Defibrillator in Terminating Tachyarrhythmias in Patients at High Risk for Sudden Death


  • Multi-center clinical trial testing the efficacy and safety of the Wearable Cardioverter Defibrillator (WCD) and was the pivotal trial leading to FDA approval.
  • The results of this study led to improvements in the WCD that was made available commercially.


  • Patients ages 18-75 who were at high risk of sudden cardiac death (SCD) but did not meet eligibility criteria for an ICD or would not receive an ICD for several months.
  • The WEARIT study group enrolled NY Heart Association Class III or IV heart failure patients with an ejection fraction (EF) < 30%.
  • The BIROAD study group included post-MI CABG patients in whom the WCD could be used as a bridge for a period of at least four months until the possible use of an ICD.
  • The WEARIT and BIROAD studies were initially separate studies but were combined at the request of the FDA.

Key Results

  • After 289 patients were enrolled into either WEARIT (n=177) or BIROAD (n=112) groups of the study, the Data and Safety Monitoring Board informed the Steering Committee that the pre-specified safety and effectiveness guidelines had be met for trial termination.
  • Eight SCA events occurred. Two events were not treated due to incorrect placement of the therapy electrodes. (Improvements were made to the commercialized version of the LifeVest to prevent this from happening.)
  • All treated patients were successfully converted on the first shock.


  • In a group of patients at high risk for SCD, the WCD effectively and safely terminated rapid VT/VF.


Click here to read the full publication
Feldman AM, Klein H, Tchou P, et al. Use of a wearable defibrillator in terminating tachyarrhythmias in patients at high risk for sudden death: Results of the WEARIT/BIROAD. Pacing Clin Electrophysiol. 2004;27:4–9.  

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