Author + information
- Helmut U. Klein, MD,
- Wojciech Zareba, MD, PhD and
- Valentina Kutyifa, MD, PhD∗ ()
- ↵∗Heart Research Follow-up Program, University of Rochester Medical Center, 265 Crittenden Boulevard, Box 653, Rochester, New York 14642
The recently published paper by Singh et al. (1) about the experience using the wearable cardioverter-defibrillator (WCD) for patients with newly diagnosed cardiomyopathies has caught our interest, and we believe that some comments on the authors’ results and conclusions are necessary. During a 10-year period, the WCD was prescribed for 639 patients; however, retrospective analysis was reported only on 525 patients, hospitalized with newly diagnosed cardiomyopathy, 254 with nonischemic cardiomyopathy (NICM) and 271 with ischemic cardiomyopathy (ICM). Patients with NICM did not experience any appropriate shock delivery, whereas 6 patients (2.2%) with ICM had tachyarrhythmic events with WCD shocks. The authors conclude that the WCD is of “limited utility” for patients with NICM and that there is a “disconnection between the clinician-perceived risk and the actual risk of SCD.”
Trying to understand the authors’ conclusion, we believe that they are subject to misunderstanding of the true value of the WCD. The WCD is neither a competitor to nor a replacement for the implantable cardioverter-defibrillator (ICD). The WCD is most helpful for risk stratification in patients with a presumed but not yet confirmed arrhythmic risk, to better select patients for primary prevention ICD therapy and to avoid unnecessary ICD implantation. The value of the WCD cannot be entirely assessed by the number of appropriately delivered shocks.
We would like to point out that in this study, during protection from sudden cardiac death, almost 40% of the 100 newly diagnosed NICM patients improved their left ventricular ejection fraction >35%, thus obviating ICD implantation. This demonstrates the real value of using the WCD in NICM as well as ICM patients.
There are certain significant limitations of the current report. The authors do not report on episodes of nonsustained ventricular tachycardia (VT) or self-terminating sustained VT episodes. Further, the article does not report on the precise intention of WCD prescription or the clinical heart failure status, and we do not learn what the authors mean by “newly diagnosed cardiomyopathy”?
We (2,3) agree with Dr. Epstein (4), the author of the accompanying editorial comment, that most likely the absence of VT/ventricular fibrillation events during the 70 days of WCD use was the “play of chance” in NICM patients. We support the authors’ request that better risk stratification in NICM is greatly needed. However, this is best studied separately with prospective randomized trials among the various underlying etiologies. The WCD will be a useful tool to perform such important studies.
Please note: Dr. Klein has received research grant support from ZOLL and lecture honoraria from ZOLL and Boston Scientific. Dr. Zareba has received research grant support from ZOLL, Boston Scientific, and Gilead Sciences. Dr. Kutyifa has received research grants support from ZOLL and Boston Scientific.
- 2016 American College of Cardiology Foundation
- Singh M.S.,
- Wang N.C.,
- Jain S.,
- Voigt A.H.,
- Sabir S.,
- Adelstein E.C.
- Kutyifa V.,
- Moss A.J.,
- Klein H.,
- et al.
- Epstein E.C.