title: Aggregate national experience with the wearable cardioverter-defibrillator: event rates, compliance, and survival.
abstract: OBJECTIVE
  The purpose of this study was to determine patient compliance and effectiveness of antiarrhythmic treatment by the wearable cardioverter-defibrillator (WCD).
  
  
  BACKGROUND
  Effectiveness of the WCD for prevention of sudden death is dependent on event type, patient compliance, and appropriate management of ventricular tachycardia/ventricular fibrillation (VT/VF).
  
  
  METHODS
  Compliance and events were recorded in a nationwide registry of post-market release WCDs. Survival, using the Social Security Death Index, was compared with survival in implantable cardioverter-defibrillator (ICD) patients.
  
  
  RESULTS
  Of 3,569 patients wearing the WCD (age 59.3+/-14.7 years, duration 52.6+/-69.9 days), daily use was 19.9+/-4.7 h (>90% of the day) in 52% of patients. More days of use correlated with higher daily use (p<0.001). Eighty sustained VT/VF events occurred in 59 patients (1.7%). First-shock success was 76 of 76 (100%) for unconscious VT/VF and 79 of 80 (99%) for all VT/VF. Eight patients died after successful conversion of unconscious VT/VF (89.5% survival of VT/VF events). Asystole occurred in 23 (17 died), pulseless electrical activity in 2, and respiratory arrest in 1 (3 died), representing 24.5% of sudden cardiac arrests. During WCD use, 3,541 of 3,569 patients (99.2%) survived overall. Survival occurred in 72 of 80 (90%) VT/VF events and 78 of 106 (73.6%) for all events. Long-term mortality was not significantly different from first ICD implant patients but highest among patients with traditional ICD indications.
  
  
  CONCLUSIONS
  Compliance was satisfactory with 90% wear time in >50% of patients and low sudden death mortality during use. Survival was comparable to that of ICD patients. However, asystole was an important cause of mortality in sudden cardiac arrest events.
authors.affiliation: Department of Cardiovascular Medicine, Cleveland Clinic, Cleveland, Ohio 44195, USA. chungm@ccf.org
authors.forename: Mina K
authors.initials: MK
authors.lastname: Chung
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Szymkiewicz
authors.forename: Mingyuan
authors.initials: M
authors.lastname: Shao
authors.forename: Edwin
authors.initials: E
authors.lastname: Zishiri
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Niebauer
authors.forename: Bruce D
authors.initials: BD
authors.lastname: Lindsay
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Tchou
mesh_terms: D016757:Death, Sudden, Cardiac / Q000517:prevention & control; D047548:Defibrillators; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D017180:Tachycardia, Ventricular / Q000401:mortality / Q000517:prevention & control; D014693:Ventricular Fibrillation / Q000401:mortality / Q000517:prevention & control