Study Of The Wearable Cardioverter Defibrillator in Advanced Heart-Failure Patients (SWIFT)

Introduction: Patients hospitalized with decompensated heart failure (HF) have high morbidity and mortality during the early post-discharge period. The wearable cardioverter defibrillator (WCD) may allow stabilization until reassessment for an implantable cardioverter defibrillator (ICD) among high-risk HF patients. However, there is limited data on WCD benefit in acute decompensated HF setting.

Methods: The Study of the Wearable Cardioverter Defibrillator in Advanced Heart-Failure Patients (SWIFT) was a prospective observational clinical trial carried out at two medical centers. Patients hospitalized with advanced HF symptoms and reduced left ventricular function were enrolled and prescribed a WCD prior to discharge for a total of 3 months. Outcome measures included arrhythmic events, WCD discharge, and death.

Results: Study patients (n=75, mean age 51±14 years, 30% women) had a mean left ventricular ejection fraction (LVEF) of 21.5±10.4%. Non-ischemic and ischemic cardiomyopathies were present in 66% and 34% of patients, respectively. The median WCD wearing time was 59 (interquartile range 17-97) days, and 80% of the patients wore the device >50% of daily hours. WCD interrogations showed a total of 7 arrhythmic events in 5 patients (7%), including 3 non-sustained or self-terminating ventricular tachycardia (VT) events, and one polymorphic VT successfully terminated by the WCD. None of the patients died while wearing the device and no inappropriate device therapies occurred. Upon termination of treatment with the WCD, 21 patients (28%) received an ICD. At 3 years the cumulative death rate was 20% in the ischemic and 21% in non-ischemic cardiomyopathy patients.

Conclusions: A management strategy incorporating the WCD can be safely used to bridge the decision regarding the need for ICD implantation in high-risk patients with advanced HF.