Indications for and outcome in patients with the wearable cardioverter-defibrillator in a nurse-based training programme: results of the Austrian WCD Registry.

Background: The wearable cardioverter-defibrillator is a treatment option for patients at temporarily high risk of sudden cardiac death or in whom implantation of a cardioverter-defibrillator is temporarily not possible. Objectives: The aim of this study was to provide real-world data on patients receiving this therapy in a nurse-based wearable cardioverter-defibrillator training programme. Methods: A registry including all patients prescribed with a wearable cardioverter-defibrillator in Austria between 2010 and 2016. Overall, 448 patients received a wearable cardioverter-defibrillator in 48 centres. Patients received structured nurse-based wearable cardioverter-defibrillator educational initial training followed by remote monitoring. Results: Main indications were: severe non-ischaemic cardiomyopathy (21%); recent myocardial infarction and percutaneous coronary intervention (20%); and stable coronary artery disease with percutaneous coronary intervention/coronary artery bypass grafting (14%). Eleven patients (2.5%) received 22 appropriate wearable cardioverter-defibrillator shocks. Two patients (0.4%) received three inappropriate shocks. The risk of sudden cardiac death varied between different aetiologies. Eight out of 11 (73%) patients received their first wearable cardioverter-defibrillator shock within 30 days. The main reasons for termination of the wearable cardioverter-defibrillator therapy were implantable cardioverter-defibrillator implantation (55.5%) and improvement of left ventricular ejection fraction to more than 35% (33%). Conclusion: The wearable cardioverter-defibrillator is an effective and safe treatment option in patients at either transiently elevated risk of ventricular tachycardia/ventricular fibrillation or mandated postponed implantable cardioverter-defibrillator implantation, with a 2.5% shock rate over a median 54 days wearable cardioverter-defibrillator treatment period. However, both the wearable cardioverter-defibrillator shock rate and implantable cardioverter-defibrillator implantation rate vary widely depending on the wearable cardioverter-defibrillator indication. Nurse-based wearable cardioverter-defibrillator training is associated with high patient adherence, with a median wearing duration per day of 23.5 (1-24) hours.