One-year follow-up of the prospective registry of patients using the wearable defibrillator (WEARIT-II Registry)

Background: The WEARIT-II Registry demonstrated efficacy and safety of the wearable cardioverter defibrillator (WCD) for at-risk cardiac patients. However, 1-year outcomes in this population have not been reported. Methods: The WEARIT-II Registry enrolled 2,000 U.S. patients prescribed the WCD. One-year mortality data from start of WCD use were prospectively collected for 1,846 patients (93%). Outcome data were analyzed by disease etiology and implantable cardioverter defibrillator (ICD) implantation following WCD use. Results: During 12 months of follow-up, 73 patients died (4%). Kaplan-Meier survival analysis showed differences in all-cause mortality from WCD prescription between patients with ischemic versus nonischemic cardiomyopathy versus congenital/inherited heart disease (4% vs 3% vs 7%, P = 0.013). Patients with ventricular arrhythmia events during WCD use had a higher 1-year mortality (10% vs 3%, P = 0.042). Renal disease, increasing age, prior syncope, and nonbeta-blocker use predicted mortality. One-year mortality was similar in patients who did versus did not receive an ICD following WCD use in ischemic (3% vs 4%, P = 0.470) and nonischemic cardiomyopathy (3% vs 3%, P = 0.892). Patients with congenital/inherited heart disease with no implanted ICD had a trend toward a higher rate of mortality than those who received an ICD (8% vs 3%, P = 0.082). Multivariate models confirmed these findings. Conclusion: One-year follow-up from the WEARIT-II Registry shows an overall good survival in patients prescribed the WCD. Short-term use of WCD allows appropriate risk stratification for decision on an ICD implantation in at-risk ischemic and nonischemic cardiomyopathy patients. Congenital/inherited heart disease patients had a higher risk of 1-year mortality even without an implanted ICD post-WCD.