176-57: Impact of Detected Arrhythmias on further Therapy Decision in Patients with Wearable Cardioverter Defibrillators

Background: Patients (pts) with reduced left ventricular function often suffer from fatal cardiac arrhythmias. Cardioverter Defibrillator implantation (ICD) is recommended after risk stratification and/ or a period of optimized pharmacological and/ or coronary interventional treatment. Wearable cardioverter defibrillator (WCD) have been invented to bridge this period, providing both, cardiac rhythm monitoring and defibrillation therapy delivery. As there are only few data about further therapy decision in WCD pts, we present a single centre experience. Methods: 84 pts (64 male, 64 ± 14 years) with reduced left ventricular function (EF 33.5 ± 12.9 %) received a WCD (LifeVest®, ZOLL, Pittsburgh, PA, USA). 46 pts suffered from dilative cardiomyopathy or non-ischemic cardiomyopathy, 21 pts from ischemic heart disease post coronary intervention or from CABG operation (n = 3), 6 pts from acute myocarditis, 4 pts from ICD explantation, and 4 from other reasons. Results: Pts wore WCD 48.5 ± 32.6 days and 20.3 ± 3.8 hours per day. During that time, 2065 events were registered, ranging from 1 to 222 events per pt. 1592 events were automatically detected, 366 events were manually activated and 99 were due to initiating the system. Out of the automatically detected events, 1586 were tachycardia and 6 were bradycardia or asystole. The latter was in all patients due to disconnected systems. Out of the manually detected events, only 8 arrhythmias were “true”, i.e. sustained VT (n = 2), non-sustained VT (n = 2), bradycardia (n = 1), and atrial fibrillation (n = 3). In 3 pts. arrhythmia detection led to an adequate and successful shock delivery. Non of these patients showed VT/VF before or after this event. All data were transferred automatically by the device remote system. After WCD therapy, 33 pts (39.3%) received an ICD due to persistence of left ventricular EF reduction and/or persistence of high degree of ventricular ectopy. In 51 pts (60.7%), an ICD implantation could be avoided. Conclusion: Among patients with reduced left ventricular function and high risk of ventricular arrhythmia, the use of WCD was feasible and showed a high acceptance rate. In these pts, WCD allowed a high detection rate and shock application, if necessary. As decision for ICD implantation was based on arrhythmias detected by WCD only in few patients, the impact of arrhythmias on ICD implantation seems to be low in these patients.