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



  • Presented in part at the 51st Annual Scientific Session of the American College of Cardiology, Atlanta, Georgia, March 2002.

  • Heilman and S.J. Szymkiewicz are employed by LIFECOR, Inc. and have an equity interest in the company.

  • Received March 3, 2003; revised May 8, 2003; accepted July 17, 2003.

Address for reprints: Arthur M. Feldman, M.D., Ph.D., Magee Professor of Medicine and Chairman of the Dept., Jefferson Medical College, 1025 Walnut St., Room 822, Philadelphia PA, 19107-5083. E-mail:


The automatic ICD improves survival in patients with a history of sudden cardiac arrest. However, some patients do not meet the guidelines for ICD implantation or are unable to receive an implantable device. This study tested the hypothesis that these patients could benefit from a wearable cardioverter defibrillator. Patients with symptomatic heart failure and an ejection fraction of <0.30 (WEARIT Study) or patients having complications associated with high risk for sudden death after a myocardial infarction or bypass surgery not receiving an ICD for up to 4 months (BIROAD Study) were enrolled into two studies. After a total of 289 patients had been enrolled in the trial (177 in WEARIT and 112 in BIROAD), prespecified safety and effectiveness guidelines had been met. Six (75%) of eight defibrillation attempts were successful. Six inappropriate shock episodes occurred during 901 months of patient use (0.67% unnecessary shocks per month of use). Twelve deaths occurred during the study 6 sudden deaths: 5 not wearing and 1 incorrectly wearing the device). Most patients tolerated the device although 68 patients quit due to comfort issues or adverse reactions.The results of the present study suggest that a wearable defibrillator is beneficial in detecting and effectively treating ventricular tachyarrhythmias in patients at high risk for sudden death who are not clear candidates for an ICD and may be useful as a bridge to transplantation or ICD in some patients. (PACE 2004; 27:4–9)