Author + information
- Received December 15, 2009
- Revision received March 10, 2010
- Accepted April 13, 2010
- Published online July 13, 2010.
- Mina K. Chung, MD*,* (, )
- Steven J. Szymkiewicz, MD†,
- Mingyuan Shao, MS*,
- Edwin Zishiri, MD*,
- Mark J. Niebauer, MD, PhD*,
- Bruce D. Lindsay, MD* and
- Patrick J. Tchou, MD*
- ↵*Reprint requests and correspondence:
Dr. Mina K. Chung, Department of Cardiovascular Medicine, Cleveland Clinic, 9500 Euclid Avenue, Desk J2-2, Cleveland, Ohio 44195
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.
The data were obtained from a ZOLL database, but no additional support from ZOLL was obtained for this study. Statistical analysis was performed independently by Cleveland Clinic statisticians. All members of the Section of Cardiac Electrophysiology and Pacing at the Cleveland Clinic participate in industry-sponsored research with Medtronic, Inc., Boston Scientific, St. Jude Medical, and Biotronik(manufacturers of ICDs), as disclosed here. Dr. Chung participates in industry-sponsored research with Medtronic, Boston Scientific, St. Jude Medical, and Biotronikand receives research support from the National Institutes of Health(NIH R01 HL090620). Dr. Szymkiewicz is Vice President of Medical Affairs, employee of ZOLL Cardiac Management Solutions, manufacturer of the Wearable Cardioverter Defibrillator vest. Dr. Niebauer participates in industry-sponsored research with Medtronic, Boston Scientific, St. Jude Medical, Biotronik, and ZOLL; has received honoraria from ZOLL; and is a member of the Data Safety Managing Board for Medtronic, Inc.Dr. Lindsay participates in industry-sponsored research with Medtronic, Boston Scientific, St. Jude Medical, and Biotronik. Dr. Tchou participates in industry-sponsored research with Medtronic, Boston Scientific, St. Jude Medical, and Biotronik.
- Received December 15, 2009.
- Revision received March 10, 2010.
- Accepted April 13, 2010.
- American College of Cardiology Foundation