Wearable Cardioverter Defibrillator-Guided 6-Min Walk Test Performed at Home Is Accurate and Reliable: RESULTS OF THE TRENDS STUDY.

PURPOSE: The 6-min walk test (6MWT) is broadly used to evaluate the functional ability of patients with heart failure (HF). The purpose of this study was to evaluate the accuracy and reliability of the wearable cardioverter defibrillator (WCD)-guided 6MWT performed at home by patients with HF versus in-clinic testing. METHODS: Patients (n = 197) with HF and a low ejection fraction prescribed a WCD were randomized to 2 groups. Group 1 completed an in-clinic clinician-guided 6MWT while wearing the WCD; results were recorded by the clinician. Group 2 completed a WCD-guided 6MWT, also performed in the clinic; results were recorded by the WCD accelerometer. Both groups performed weekly unsupervised WCD-guided 6MWTs at home, with results recorded by the WCD. RESULTS: The initial in-clinic 6MWT showed no significant group difference in distance walked (group 1 = 306 m; group 2 = 297 m). For patients in group 2 who completed at least one 6MWT at home, there was a 15-step decrease between the in-clinic WCD-guided 6MWT and the first at-home 6MWT, 558 and 543 median steps (P = .001), respectively. Among patients with at least 8 weekly home WCD-guided 6MWTs (n = 70), there was no significant difference in the number of steps walked during the 6MWT from week to week. CONCLUSIONS: Results of the in-clinic 6MWT are similar between clinician-guided and WCD-guided patients across objective distances. Distances walked with a WCD-guided walk test were consistent whether conducted in the clinic or at home and were reliable over time.

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.

Oversensing of the wearable cardioverter defibrillator during bipolar ventricular stimulation.

The wearable cardioverter defibrillator (WCD) is a temporary treatment option for patients with potentially reversible risk of sudden cardiac death. This case demonstrates a pitfall during WCD usage in a pacemaker-dependent patient as well as a possible solution allowing continuation of WCD therapy. Bipolar stimulation may lead to double counting of the WCD detection algorithm resulting in false alarm or inappropriate therapy.