Abstract 12637: Utility of the Wearable Cardioverter-Defibrillator for Patients With Newly Diagnosed Non-Ischemic Cardiomyopathy?

Abstract

Introduction: The wearable cardioverter-defibrillator (WCD) is approved for prevention of sudden cardiac death in patients with newly diagnosed cardiomyopathy and LVEF < 35% who do not yet meet criteria for implantation of an implantable cardioverter-defibrillator (ICD). While there are some data supporting WCD use in patients with ischemic cardiomyopathy (ICM), data in patients with nonischemic cardiomyopathy (NICM) are lacking. Methods: This was a retrospective review of outcomes for all NICM patients prescribed a WCD at a large tertiary academic center from 6/2004 - 1/2014 for a newly diagnosed cardiomyopathy and no prior sustained ventricular arrhythmia. During this time period, 454 patients were prescribed a WCD, of whom we excluded 161 patients with ICM. Results: The 183 (40%) patients with NICM consisted of 70% men, aged 57 +/- 15 years old, with mean EF 23% +/- 8% and LV end-diastolic dimension 4.5 +/- 2.8 cm. DM and HTN were prevalent (20% and 51%, respectively). At NICM diagnosis, 21% had LBBB and 36% had known history of AF. Patients wore the WCD for 13,124 patient-days, each averaging 72 +/- 55 days and with fairly high compliance (18.3 +/- 5.7 hours/day). Medication use consisted of 90% beta-blockers, 88% ACE inhibitors, 85% diuretics, 16% digoxin, and 17% anti-arrhythmic drugs. NSVT was documented in 42% of patients prior to WCD prescription. During follow-up, 60 (33%) patients improved LVEF to > 35%, obviating an indication for ICD implantation, whereas 79 (43%) patients received an ICD. The remainder died (n=17), were lost to follow-up (n=20), refused ICD implant (n=5), or are still wearing the WCD (n=2). No appropriate WCD shocks were delivered in any NICM patient, yet 3 inappropriate shocks were delivered (1.6%). Based on estimated rental costs provided by the manufacturer, the total cost of WCD use in this population was $1,449,360. Conclusions: In this large, tertiary care center registry of patients with newly recognized NICM, no patient received an appropriate shock from the WCD whereas several inappropriate shocks were delivered, despite nearly one-half of patients having documented significant ventricular ectopy. Given the significant expense and inconvenience of the WCD, its use in this population requires prospective study.