Aggregate national experience with the wearable cardioverter-defibrillator: event rates, compliance, and survival.
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.
Chung
Mina K
MK
Department of Cardiovascular Medicine, Cleveland Clinic, Cleveland, Ohio 44195, USA. chungm@ccf.org
Szymkiewicz
Steven J
SJ
Shao
Mingyuan
M
Zishiri
Edwin
E
Niebauer
Mark J
MJ
Lindsay
Bruce D
BD
Tchou
Patrick J
PJ
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