Aggregate National Experience With the Wearable Cardioverter-Defibrillator

• Published in: Journal of the American College of Cardiology 2010-07, Vol.56 (3), p.194-203
• Main Authors: Chung, Mina K., MD, Szymkiewicz, Steven J., MD, Shao, Mingyuan, MS, Zishiri, Edwin, MD, Niebauer, Mark J., MD, PhD, Lindsay, Bruce D., MD, Tchou, Patrick J., MD
• Format: Article
• Language: English
• Subjects: Cardiovascular; compliance; implantable cardioverter-defibrillator; Internal Medicine; outcomes; wearable cardioverter-defibrillator
• ISSN: 0735-1097; 1558-3597
• DOI: 10.1016/j.jacc.2010.04.016

Objectives 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.