scholarly journals High Incidence of Inappropriate Alarms in Patients with Wearable Cardioverter-Defibrillators: Findings from the Swiss WCD Registry

2021 ◽  
Vol 10 (17) ◽  
pp. 3811
Author(s):  
Boldizsar Kovacs ◽  
Haran Burri ◽  
Andres Buehler ◽  
Sven Reek ◽  
Christian Sticherling ◽  
...  

Background: The wearable cardioverter defibrillator (WCD) uses surface electrodes to detect arrhythmia before initiating a treatment sequence. However, it is also prone to inappropriate detection due to artefacts. Objective: The aim of this study is to assess the alarm burden in patients and its impact on clinical outcomes. Methods: Patients from the nationwide Swiss WCD Registry were included. Clinical characteristics and data were obtained from the WCDs. Arrhythmia recordings ≥30 s in length were analysed and categorized as VT/VF, atrial fibrillation (AF), supraventricular tachycardia (SVT) or artefact. Results: A total of 10653 device alarms were documented in 324 of 456 patients (71.1%) over a mean WCD wear-time of 2.0 ± 1.6 months. Episode duration was 30 s or more in 2996 alarms (28.2%). One hundred and eleven (3.7%) were VT/VF episodes. The remaining recordings were inappropriate detections (2736 (91%) due to artefacts; 117 (3.7%) AF; 48 (1.6%) SVT). Two-hundred and seven patients (45%) had three or more alarms per month. Obesity was significantly associated with three or more alarms per month (p = 0.01, 27.7% vs. 15.9%). High alarm burden was not associated with a lower average daily wear time (20.8 h vs. 20.7 h, p = 0.785) or a decreased implantable cardioverter defibrillator implantation rate after stopping WCD use (48% vs. 47.3%, p = 0.156). Conclusions: In patients using WCDs, alarms emitted by the device and impending inappropriate shocks were frequent and most commonly caused by artefacts. A high alarm burden was associated with obesity but did not lead to a decreased adherence.

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
J Ehmsen ◽  
H Keller ◽  
C Stoellberger

Abstract Background The use of the Wearable Cardioverter Defibrillator (WCD) is recommended in national, European and American guidelines. However, there are almost exclusively data from the manufacturer's own data network. Independent data on the experience with the WCD are rare. Objective The aim of the retrospective study from one cardiologic department was to record efficiency, safety and compliance of the WCD. Patients and methods The study included all patients, to whom a WCD was described between 1.11.2010 and 1.5.2018 at one cardiologic department. Clinical data were obtained from the patients' records and the data about the WCD from the information network of the manufacturer. Results This study enrolled 66 patients, 51 males (77%) and 15 females (23%). The median age was 55 years (IQR: 45–63). They suffered from ischemic cardiomyopathy (n=33; 49%), dilated cardiomyopathy (n=12; 18%), myocarditis (n=7; 11%), explantation of an implantable cardioverter/defibrillator (ICD; n=5; 8%) and other indications (n=6; 9%). The median wearing time of the WCD was 73 days (interquartile range-IQR: 39–126), with median daily use of 22.91 h (IQR: 19.58–23.61). Among 38 patients with LVEF ≤35%, LVEF improved to ≥35% in 19 patients (50%) during WCD therapy. Over 1600 times the WCD detected a VT falsely. Four patients (8%) suffered from 212 non-sustained VT. One patient was successfully shocked because of ventricular fibrillation (appropriate shock rate: 1.5%). There were no inappropriate shocks. All patients, who wore the WCD, survived and one patient died when he did not wear the WCD. At the end of therapy 32 patients (48%) received an ICD. In terms of wearing time and events (shocks, arrhythmias, artifacts) there were no significant differences between patients receiving ICD and those who did not receive an ICD. Patients who received an ICD had a significantly lower LVEF after 3 months than patients who did not receive an ICD. Conclusion Our data confirm, that the WCD is safe and that the patients, who wear a WCD, have a high adherence. More than half of the patients with reduced LVEF improved their systolic function during WCD therapy, thus obviating the need for ICD implantation. Questions about the effectiveness of the detection algorithm remained open. Funding Acknowledgement Type of funding source: None


Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Madhurmeet Singh ◽  
Krishna Alluri ◽  
Andrew Voigt ◽  
Norman Wang ◽  
Sandeep Jain ◽  
...  

Introduction: The wearable cardioverter-defibrillator (WCD) is approved for prevention of sudden cardiac death in patients with newly diagnosed cardiomyopathy and LVEF < 35% who do not yet meet criteria for implantation of an implantable cardioverter-defibrillator (ICD). While there are some data supporting WCD use in patients with ischemic cardiomyopathy (ICM), data in patients with nonischemic cardiomyopathy (NICM) are lacking. Methods: This was a retrospective review of outcomes for all NICM patients prescribed a WCD at a large tertiary academic center from 6/2004 - 1/2014 for a newly diagnosed cardiomyopathy and no prior sustained ventricular arrhythmia. During this time period, 454 patients were prescribed a WCD, of whom we excluded 161 patients with ICM. Results: The 183 (40%) patients with NICM consisted of 70% men, aged 57 +/- 15 years old, with mean EF 23% +/- 8% and LV end-diastolic dimension 4.5 +/- 2.8 cm. DM and HTN were prevalent (20% and 51%, respectively). At NICM diagnosis, 21% had LBBB and 36% had known history of AF. Patients wore the WCD for 13,124 patient-days, each averaging 72 +/- 55 days and with fairly high compliance (18.3 +/- 5.7 hours/day). Medication use consisted of 90% beta-blockers, 88% ACE inhibitors, 85% diuretics, 16% digoxin, and 17% anti-arrhythmic drugs. NSVT was documented in 42% of patients prior to WCD prescription. During follow-up, 60 (33%) patients improved LVEF to > 35%, obviating an indication for ICD implantation, whereas 79 (43%) patients received an ICD. The remainder died (n=17), were lost to follow-up (n=20), refused ICD implant (n=5), or are still wearing the WCD (n=2). No appropriate WCD shocks were delivered in any NICM patient, yet 3 inappropriate shocks were delivered (1.6%). Based on estimated rental costs provided by the manufacturer, the total cost of WCD use in this population was $1,449,360. Conclusions: In this large, tertiary care center registry of patients with newly recognized NICM, no patient received an appropriate shock from the WCD whereas several inappropriate shocks were delivered, despite nearly one-half of patients having documented significant ventricular ectopy. Given the significant expense and inconvenience of the WCD, its use in this population requires prospective study.


2021 ◽  
Vol 17 ◽  
Author(s):  
Camilla Silva Araújo ◽  
Carla Liz Barbosa Silva ◽  
Antônio da Silva Menezes Júnior ◽  
Vinícius Araújo Barbosa ◽  
Tiago de Almeida Laranjeira ◽  
...  

Background/Objectives: Implantable cardioverter defibrillators are used to prevent sudden cardiac death. The subcutaneous implantable cardioverter defibrillator was newly developed to overcome the limitations of the conventional implantable cardioverter defibrillator-transvenous device. The subcutaneous implantable cardioverter defibrillator is indicated for young patients with heart disease, congenital heart defects, and poor venous access, who have an indication for implantable cardioverter defibrillator without the need for anti-bradycardic stimulation. We aimed to compare the efficacy and complications of subcutaneous with transvenous implantable cardioverter defibrillator devices. Methodology: A systematic review was conducted using different databases. The inclusion criteria were observational and clinical randomized trials with no language limits and no publication date limit that compared subcutaneous with transvenous implantable cardioverter defibrillators. The selected patients were aged > 18 years with complex ventricular arrhythmia. Results : Five studies involving 2111 patients who underwent implantable cardioverter defibrillator implantation were included. The most frequent complication in the subcutaneous device group was infection, followed by hematoma formation and electrode migration. For the transvenous device, the most frequent complications were electrode migration and infection. Regarding efficacy, the total rates of appropriate shocks were 9.04% and 20.47% in the subcutaneous and transvenous device groups, respectively, whereas inappropriate shocks to the subcutaneous and transvenous device groups were 11,3% and 10,7%, respectively. Conclusion: When compared to the transvenous device, the subcutaneous device had lower complication rates owing to lead migration and less inappropriate shocks due to supraventricular tachycardia; nevertheless, infection rates and improper shocks due to T wave oversensing were comparable for both devices


2019 ◽  
Vol 72 (7) ◽  
pp. 1243-1246
Author(s):  
Dariusz Jagielski ◽  
Dorota Zyśko ◽  
Klaudiusz Nadolny ◽  
Joanna Wizowska ◽  
Bartosz Biel ◽  
...  

Introduction: Inappropriate shocks in patients with an implantable cardioverter-defibrillator (ICD) are associated with significant psychological and physical consequences and increased long-term mortality. The aim: To assess predictors associated with inappropriate high-energy discharges of implantable cardioverter-defibrillators. Material and Methods: Retrospective data analysis of 150 patients aged 64.2±12.8 years (84.7% male) admitted to the Hospital Emergency Department due to at least one cardioverter-defibrillator discharge was performed. All of the discharges were inappropriate in the group of 33 patients, and in the group of 117 patients at least one discharge was appropriate. The following data: age, gender, concomitant diseases, type of ICD implantation (primary vs. secondary prevention), type of discharge, number of discharges, serum potassium, and sodium concentration were collected. Results: Patients with only inappropriate discharges were younger, significantly more often had chronic atrial fibrillation, a significantly higher number of discharges, and ischaemic cardiomyopathy. Logistic regression analysis revealed that the occurrence of only inappropriate discharges was related to the number of discharges over three, the age of patients below 60 years, the serum sodium concentration between 135 mEq/L and 142 mEq/L, and the primary type of prevention of sudden cardiac death. Conclusions: 1. Predictors of inappropriate discharges include: age, serum sodium concentration, and primary type of indications for cardioverter-defibrillator implantation. 2. Further research is necessary to determine the influence of disturbances in the sodium economy on the occurrence of appropriate and inappropriate interventions of implantable cardioverter-defibrillators.


EP Europace ◽  
2020 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
B Kovacs ◽  
S Reek ◽  
A Linka ◽  
P Ammann ◽  
A S Mueller ◽  
...  

Abstract OnBehalf Swiss WCD Registry Introduction  The wearable cardioverter-defibrillator (WCD) has established itself as a temporary protection from sudden arrhythmogenic death in selected patients at risk. However, it is still of debate which patients and for what duration benefit from its use. Therefore, appropriate patient selection is key. Purpose: This study reports the results of the Swiss WCD registry with an emphasis on implantable cardioverter-defibrillator (ICD) implantation rate and ICD therapies. Methods  We retrospectively reviewed the indications, baseline characteristics and administered therapies in patients prescribed a WCD at 12 participating centers rom 2014 until 2018 in Switzerland. Further data on medical therapy, WCD therapy adherence, and ICD implantation rates were collected.  Results  456 patients were included in our study comprising of 66% of all Swiss patients prescribed a WCD in the examined time period. The mean age was 57 ±14 years, 18% were female and the mean ejection fraction (EF) was 32% ± 13. Indications for WCD use and appropriate shock rate are shown in the figure. Patients wore the WCD over a median of 58 days (range 1-455) with a median daily average wear-time of 22.6 hours (range 0.6-23.8). 17 appropriate therapies were administered by the WCD to a total of 12 patients leading to a therapy rate of 2.6% over a median wear-time of 16 days (range 2-79) and to a therapy rate of 3.9% in patients with ischemic cardiomyopathy (ICM) with an EF ≤35%. ICM with an EF ≤35% and bridging to ICD-implantation or heart transplantation as indication for WCD prescription were significantly associated with an appropriate therapy (p = 0.046 and 0.003, respectively). One patient with non-ischemic cardiomyopathy (NICM) received an appropriate therapy (0.8%). The mean EF in patients receiving an appropriate therapy by the WCD was also significantly lower (p = 0.04). No patient with wearing the WCD for congenital/inherited heart disease or risk stratification with an EF &gt;35% had a therapy administered by the WCD. There were no inappropriate therapies during the investigated time period. After cessation of WCD use EF improved to 38% ±13; ultimately, 212 patients (46%) were implanted with an ICD. During a follow-up of 476 days (range 7-2347) 22 (9.8%) patients received an appropriate therapy by their ICD. Four of the 22 had prior appropriate therapy by the WCD. Conclusions  ICM with severely reduced EF was the most common indication for WCD use leading to a high rate of appropriate therapy by the WCD. This, however, did not translate in a higher rate of appropriate ICD-therapies during follow-up in this subpopulation possibly due to significant improvements in their ejection fractions. Patients with NICM or congenital/inherited heart disease seldom had an appropriate therapy by the WCD. Abstract Figure. Indications for WCD use and therapy rate


Author(s):  
C Fielder Camm ◽  
Kim Rajappan ◽  
Mark Curson ◽  
Lindsey Tilling

Abstract Background Subcutaneous implantable cardioverter-defibrillators (S-ICDs) are increasingly used in patients at risk of fatal cardiac arrhythmias. Twiddler’s syndrome is a condition in which a device is manipulated by the patient after implantation leading to lead twisting and retraction. Device manipulation has been reported multiple times in transvenous pacing systems and occasionally leads to inappropriate discharges from implanted defibrillators. However, little has been reported about device manipulation in S-ICD devices. Case summary We present the case of a 16-year-old who underwent insertion of an S-ICD for idiopathic dilated cardiomyopathy. He represented for a pacing check following a discharge from the device. This showed a significant change in the sensed vectors. Chest radiographs confirmed lead retraction and suggested device manipulation. The device was turned off to prevent further inappropriate shocks. The patient underwent successful reimplantation of a S-ICD device. Discussion This case highlights that twiddler’s syndrome can occur in those with an S-ICD and lead to an inappropriate device discharge. The patient in this case had a number of risk factors that have been previously associated with twiddler’s syndrome.


Author(s):  
Rajesh Chelliah ◽  
Raj Khiani

This chapter covers the principles of implantable cardioverter defibrillators (ICDs). Indications and potential problems for insertion of an ICD are described, including the evidence base for insertion based on randomized trials. International clinical guidelines are summarized. The mechanism and components of an ICD are defined, including diagrams to show the pulse generator, electrodes, and a section on which lead to choose. Arrhythmia detection, sensitivity, oversensing, and rate determination are all discussed. Supraventricular tachycardia (SVT) discriminators, pacing for anti-tachycardia and bradycardia, anti-tachycardia pacing (ATP) delivery, defibrillation, and configuration of shock vector are covered. The importance of avoiding inappropriate shocks is briefly outlined, and strategies for home monitoring are featured.


2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
U Rohrer ◽  
M Manninger ◽  
T Odeneg ◽  
C Ebner ◽  
D Moertl ◽  
...  

Abstract Background The wearable cardioverter-defibrillator (WCD) is a treatment option for patients at high risk for ventricular arrhythmia, either if the risk is potentially reversible or if an implantable cardioverter defibrillator (ICD) implantation is currently not possible. Methods We performed a retrospective analysis of all alarms in the cohort of the Austrian WCD registry between 2010 and 2018. Type of arrhythmias was assessed by independent review of two cardiologists. Results 25.540 automatically recorded ECGs in 605 patients (68%) were analyzed. 1125 ECGs showed sustained ventricular arrhythmias in 117 patients, 65 ECGs showed non sustained VTs. 24.415 ECGs in 488 patients showed inadequate alarms Reasons for inadequate alarms were artefacts (97%), pacemaker or t-wave oversensing (0,3%) and in 2,3% atrial fibrillation or SVTs. 5860 manually recorded ECGs in 608 patients (68%) were analyzed. 298 (5%) of these ECGs showed following arrhythmias: atrial fibrillation (34,7%), SVTs (28%), sinustachycardia (10,7%), non sustained VTs (12%) and sustained VTs or sustained slow VTs (6,7%), premature ventricular beats or bradycardia was identified in 8%. The remaining 5562 ECGs (95%) showed normal sinus rhythm. Of the 895 patients (60±14 years, 20% female), 34 (3,8%) received a total of 65 automatically triggered shocks (median 2; range 1–5). 31/895 (3.5%) patients received 57 appropriate shocks (median 1, range 1–5) for 49 arrhythmic events, whereas 7/895 (0.8%) patients received 8 inappropriate shocks (median 1, range 1–2). 44 events were successfully terminated with the first shock (85,7%) and 4 events were terminated with the second shock. In one patient, a shock treatment for VF was not successful. The time from event onset to shock was median 60 [40; 1187] sec. The median time from WCD prescription to a shock event was 8 days [1–151]. 23/ 34 patients (68%) received their first WCD shock within 30 days. Seven patients (0.8%) received a total of nine inappropriate shocks due to different reasons: artefacts (2 inappropriate shocks), non-shockable rhythms (asystole, weak action, 3 shocks) and atrial fibrillation with a bundle branch block in two cases. In one patient VF terminated spontaneously before the WCD treatment was delivered. Conclusion The WCD is an effective treatment option in patients with a high SCD risk but it also triggers a significant amount of alarms. Although many inadequate alarms occurred, adequate alarms led to arrhythmia detection such as in VT/VF events which were successfully terminated by the WCD in 3,4% of patients.


2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
V Kutyifa ◽  
K Vermilye ◽  
W Zareba ◽  
S McNitt ◽  
I Goldenberg

Abstract Background The use of the wearable cardioverter-defibrillator (WCD) in patients with non-ischemic cardiomyopathy has been less characterized. Objective We aimed to characterize WCD use and outcomes for patients with ischemic or non-ischemic cardiomyopathy, enrolled in the WEARIT-II Registry. Methods In WEARIT-II, we stratified 1,732 patients into ischemic (n=805) and non-ischemic etiology (n=927). WCD wear time, arrhythmia events during WCD use, and implantable cardioverter-defibrillator (ICD) implantation rates, or ejection fraction (EF) improvement at the end of WCD were evaluated for etiology subgroups. Results The WCD median wear time was higher in patients with non-ischemic cardiomyopathy (93 vs. 87 days, p=0.003), however daily use was similar (22.4 vs. 22.6 hours, p=0.07). There were 24 ischemic patients (3%) with sustained VT/VF events compared to 10 patients (1%) with non-ischemic cardiomyopathy (p=0.013). About 2/3 of these events were treated with WCD shock in ischemic patients, half of them in the non-ischemic group (1.9% vs. 0.4%). Atrial arrhythmias were frequent in both groups (3.1% vs. 3.1%, p=0.06). At the end of WCD use, 36% of the non-ischemic patients were implanted with an ICD compared to 42% in ischemic (p=0.01), likely due to the lower rate of sustained ventricular arrhythmias (Figure). Figure 1 Conclusions In WEARIT-II, patients with non-ischemic cardiomyopathy had longer WCD use than ischemic patients with good compliance. The rate of sustained ventricular arrhythmia events was lower in non-ischemic patients avoiding the need for an ICD implantation in more patients compared to ischemic, following a time period of risk stratification. Acknowledgement/Funding WEARIT-II was funded by an unrestricted research grant from ZOLL Inc.


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