Wearable Defibrillator Research Articles

Computational Model for Therapy Optimization of Wearable Cardioverter Defibrillator: Shockable Rhythm Detection and Optimal Electrotherapy.

Wearable cardioverter defibrillator (WCD) is a life saving, wearable, noninvasive therapeutic device that prevents fatal ventricular arrhythmic propagation that leads to sudden cardiac death (SCD). WCD are frequently prescribed to patients deemed to be at high arrhythmic risk but the underlying pathology is potentially reversible or to those who are awaiting an implantable cardioverter-defibrillator. WCD is programmed to detect appropriate arrhythmic events and generate high energy shock capable of depolarizing the myocardium and thus re-initiating the sinus rhythm. WCD guidelines dictate very high reliability and accuracy to deliver timely and optimal therapy. Computational model-based process validation can verify device performance and benchmark the device setting to suit personalized requirements. In this article, we present a computational pipeline for WCD validation, both in terms of shock classification and shock optimization. For classification, we propose a convolutional neural network-“Long Short Term Memory network (LSTM) full form” (Convolutional neural network- Long short term memory network (CNN-LSTM)) based deep neural architecture for classifying shockable rhythms like Ventricular Fibrillation (VF), Ventricular Tachycardia (VT) vs. other kinds of non-shockable rhythms. The proposed architecture has been evaluated on two open access ECG databases and the classification accuracy achieved is in adherence to American Heart Association standards for WCD. The computational model developed to study optimal electrotherapy response is an in-silico cardiac model integrating cardiac hemodynamics functionality and a 3D volume conductor model encompassing biophysical simulation to compute the effect of shock voltage on myocardial potential distribution. Defibrillation efficacy is simulated for different shocking electrode configurations to assess the best defibrillator outcome with minimal myocardial damage. While the biophysical simulation provides the field distribution through Finite Element Modeling during defibrillation, the hemodynamic module captures the changes in left ventricle functionality during an arrhythmic event. The developed computational model, apart from acting as a device validation test-bed, can also be used for the design and development of personalized WCD vests depending on subject-specific anatomy and pathology.

When is a wearable defibrillator indicated?

ABSTRACT Introduction Wearable cardioverter-defibrillator (WCD) is a novel tool that may be of interest in situations with atransient risk of sudden cardiac death. It offers a temporary and easy to remove protection against malignant ventricular arrhythmias. In this review, the authors describe evidence in literature and different international guidelines and consensus. Areas covered The authors searched PubMed, Cochrane Central Register of controlled trials, and Google Scholar for relevant studies and comments. Expert Opinion If a WCD is indicated, the observance must be as perfect as possible. Thus, patients need proper education in wearing the WCD. The temporary use of a WCD is reasonable in patients with a high risk for SCD, even with a low level of evidence with only one randomized clinical trial (VEST), as its disadvantages are limited to a transitory impairment in quality of life and a low risk of inappropriate shock. Indications are now well accepted: ischemic cardiomyopathy with LVEF below 35% before reassessment, recent onset of NICM or presumed myocarditis with LVEF ≤35% before reassessment, after ICD explant until reimplantation (e.g. infection), and bridge to transplant. Future guidelines on WCD in the prevention of SCD may be warranted to harmonize clinical practice especially in debated indications..

Feasibility and First Results of Heart Failure Monitoring Using the Wearable Cardioverter-Defibrillator in Newly Diagnosed Heart Failure with Reduced Ejection Fraction.

The wearable cardioverter–defibrillator (WCD) is used in patients with newly diagnosed heart failure and reduced ejection fraction (HFrEF). In addition to arrhythmic events, the WCD provides near-continuous telemetric heart failure monitoring. The purpose of this study was to evaluate the clinical relevance of additionally recorded parameters, such as heart rate or step count. We included patients with newly diagnosed HFrEF prescribed with a WCD. Via the WCD, step count and heart rate were acquired, and an approximate for heart rate variability (HRV5) was calculated. Multivariate analysis was performed to analyze predictors for an improvement in left ventricular ejection fraction (LVEF). Two hundred and seventy-six patients (31.9% female) were included. Mean LVEF was 25.3 ± 8.5%. Between the first and last seven days of usage, median heart rate fell significantly (p < 0.001), while median step count and HRV5 significantly increased (p < 0.001). In a multivariate analysis, a delta of HRV5 > 23 ms was an independent predictor for LVEF improvement of ≥10% between prescription and 3-month follow-up. Patients with newly diagnosed HFrEF showed significant changes in heart rate, step count, and HRV5 between the beginning and end of WCD prescription time. HRV5 was an independent predictor for LVEF improvement and could serve as an early indicator of treatment response.

Wearable Cardioverter-Defibrillator Used as a Telemonitoring System in a Real-Life Heart Failure Unit Setting.

Background: In patients with reduced left ventricular ejection fraction (LVEF) who are at risk of sudden cardiac death, a wearable cardioverter-defibrillator (WCD) is recommended as a bridge to the recovery of LVEF or as a bridge to the implantation of a device. In addition to its function to detect and treat malignant arrhythmia, WCD can be used via an online platform as a telemonitoring system to supervise patients’ physical activity, compliance, and heart rate. Methods: We retrospectively analyzed 173 patients with regard to compliance and heart rate after discharge. Results: Mean WCD wearing time was 59.75 ± 35.6 days; the daily wearing time was 21.19 ± 4.65 h. We found significant differences concerning the patients’ compliance. Men showed less compliance than women, and younger patients showed less compliance than patients who were older. Furthermore, we analyzed the heart rate from discharge until the end of WCD prescription and found a significant decrease from discharge to 4, 8, or 12 weeks. Conclusion: WCD can be used as a telemonitoring system to help the involved heart failure unit or physicians attend to and adjust the medical therapy. Furthermore, specific patient groups should be educated more intensively with respect to compliance.

Abstract 9719: Structured Patient Education Improves Adherence with Wearable Cardiac Defibrillators

Background: The wearable-cardioverter defibrillator (WCD) tradename LifeVest has emerged as a temporary alternative to implantable cardioverter-defibrillator therapy. However, patient adherence can be variable. We sought to investigate if standardized device education and patient follow-up phone calls could lead to increased adherence. Methods: Patients prescribed a WCD from July 2017 to July 2018 comprised the pre-intervention group. The initial post-intervention group from January 2019 to May 2019 enrolled 32 patients. Each patient received standardized device education using a video presentation, and we sought to call each patient within 7 days of discharge to answer questions and administer a questionnaire. 14 patients comprised the second post-intervention group from March 2020 to May 2020, which received refined education with both a video presentation and 30-minute, standardized, hands-on training with the LifeVest representative, as well as similar follow-up phone calls for all patients within 7 days of discharge. Results: The pre-intervention group had a median wear time of 19.46 hours/day. In the first post-intervention group, all patients received standardized education; however, only 17 patients were contacted via phone due to time constraints. Patients with standardized education-only had a median wear time 21.55 hours/day, while patients who received both interventions had a median wear time of 23.01 hours/day. The increase in median wear time in pre-intervention compared to post-intervention groups was statistically significant (p= 0.0056) There was no significant difference between the two post-intervention groups (p=0.5485). In the second intervention group, median wear time significantly increased to 22.00 hours/day compared to the pre-intervention group (p=0.0244). Conclusions: Implementing standardized device education can improve median WCD wear time. The addition of post-discharge follow-up phone call did lead to improved mean and median wear times, but this was not statistically significant. Similar strategies could be cheaply and easily adopted at other centers in an effort to improve WCD adherence.

Abstract 9209: Type 1 Brugada Syndrome Diagnosed in a Patient With an Unaffected Identical Twin

Introduction: Brugada syndrome is a rare arrhythmia disorder due to a cardiac channelopathy with a predisposition to ventricular arrhythmias or SCD. It is characterized by an ECG pattern of complete or incomplete right bundle branch block and ST segment elevation in leads V1-V3. It is normally inherited in an autosomal dominant pattern however environmental factors such as viral infections and inflammation may create myocardial cell damage that may induce an ECG pattern consistent with the diagnosis of Brugada syndrome. Case: A 39-year-old male with no significant past medical history presented to the hospital for two weeks of intermittent dizziness and nocturnal symptoms of being “jolted” awake. ECG on admission was suggestive of a Type 2 Brugada pattern. He denied a family history of first-degree relatives with cardiac disease, SCD or unexplained syncope but did note that he had an identical twin brother. Given symptoms and ECG findings, he was given 400 mg of oral flecainide for a sodium blockade challenge. Four hours after administration of flecainide he developed an overt Type 1 Brugada pattern. Due to issues with the MRI, a cardiac CTA was performed to assess for ARVD. Cardiac CTA showed a mild amount of fat in the apex of the right ventricular wall but was otherwise unremarkable. He was discharged with a wearable external defibrillator and outpatient follow up with EP. During outpatient follow up he reported resolution of symptoms. Interrogation of the defibrillator did not reveal any arrhythmias. An ECG was done on his identical twin brother which did not show evidence of a Type 1 Brugada pattern. He completed a cardiac MRI that showed normal morphology and motion of the right ventricle without evidence of fat dysplasia or late gadolinium enhancement. Given resolution of his symptoms with a normal cardiac MRI and an unremarkable ECG from his identical twin, he was diagnosed with an acquired Brugada syndrome likely due to a viral myocarditis. Conclusion: While Brugada syndrome is normally an inherited genetic disorder, there are instances of acquiring the syndrome through environmental factors. As demonstrated by our case of identical twin brothers with the same genetic makeup, one was diagnosed with Brugada syndrome while the other had an unremarkable ECG.

Rate of Recovery of Left Ventricular Ejection Fraction in a Real-World Population of Patients Receiving a Wearable Cardioverter Defibrillator

Background: This study aimed to investigate the rate of early improvement in ejection fraction (EF) within 21 - 60 days among patients with cardiomyopathy who were provided with a wearable cardioverter defibrillator (WCD). Methods: This was a retrospective study of patients who received a WCD at our institution to determine the rate of improvement in left ventricular EF (LVEF) to ? 35-40%. Among 990 patients who received a WCD during the study period, 101 had an echocardiogram performed during the subsequent 21 - 60 days. Patients were stratified according to their initial EF, as well as age, gender, number of heart failure medications, and ischemic vs. nonischemic cardiomyopathy. Multivariate logistic regression analysis was performed to assess the influence of these variables on the subsequent improvement in EF. Results: There were 39 patients who had improvement in their EF to ? 35-40%. The only significant predictor of EF recovery was the initial EF. There was a direct correlation between initial EF category and the likelihood of improvement in EF. For every unit increase in initial EF category, the odds of improvement increased 1.73 times (95% confidence interval (CI): 1.22 - 2.45). Age (P = 0.20), gender (P = 0.10), ischemic cardiomyopathy (P = 0.40), and number of heart failure medications at the time of WCD placement (P = 0.26) were not significant predictors of improved LVEF. Conclusions: This study showed a rate of improvement in EF to ? 35-40% of 39% within 21 - 60 days of placement of a WCD among patients with both ischemic and nonischemic cardiomyopathy. The only significant clinical predictor of EF improvement was initial EF. Cardiol Res. 2021;000(000):000-000 doi: https://doi.org/10.14740/cr1325

Rate of Recovery of Left Ventricular Ejection Fraction in a Real-World Population of Patients Receiving a Wearable Cardioverter Defibrillator.

BackgroundThis study aimed to investigate the rate of early improvement in ejection fraction (EF) within 21 - 60 days among patients with cardiomyopathy who were provided with a wearable cardioverter defibrillator (WCD).MethodsThis was a retrospective study of patients who received a WCD at our institution to determine the rate of improvement in left ventricular EF (LVEF) to ≥ 35-40%. Among 990 patients who received a WCD during the study period, 101 had an echocardiogram performed during the subsequent 21 - 60 days. Patients were stratified according to their initial EF, as well as age, gender, number of heart failure medications, and ischemic vs. nonischemic cardiomyopathy. Multivariate logistic regression analysis was performed to assess the influence of these variables on the subsequent improvement in EF.ResultsThere were 39 patients who had improvement in their EF to ≥ 35-40%. The only significant predictor of EF recovery was the initial EF. There was a direct correlation between initial EF category and the likelihood of improvement in EF. For every unit increase in initial EF category, the odds of improvement increased 1.73 times (95% confidence interval (CI): 1.22 - 2.45). Age (P = 0.20), gender (P = 0.10), ischemic cardiomyopathy (P = 0.40), and number of heart failure medications at the time of WCD placement (P = 0.26) were not significant predictors of improved LVEF.ConclusionsThis study showed a rate of improvement in EF to ≥ 35-40% of 39% within 21 - 60 days of placement of a WCD among patients with both ischemic and nonischemic cardiomyopathy. The only significant clinical predictor of EF improvement was initial EF.

Increased Quality of Life Among Newly Diagnosed Patients With Heart Failure With Reduced Ejection Fraction in the Months After Initiation of Guideline-Directed Medical Therapy and Wearable Cardioverter Defibrillator Prescription.

The patient experience of heart failure involves a multi-impact symptom response with functional limitations, psychological changes, and significant treatment burden. The aim of this study was to examine the change in patient-reported outcomes in newly diagnosed patients with heart failure and reduced ejection fraction (HFrEF) prescribed a wearable cardioverter defibrillator. Adults hospitalized for new-onset heart failure, due to ischemic or nonischemic cardiomyopathy, and prescribed a wearable cardioverter defibrillator within 10 days post discharge were approached for inclusion. Participants completed the Kansas City Cardiomyopathy Questionnaire at 3 time points: baseline, day 90, and day 180. A total of 210 patients (26% female) were included. All Kansas City Cardiomyopathy Questionnaire subscales (physical limitation, symptom frequency, quality of life, and social limitation) showed improvement from baseline to day 90 (all Ps < .001). Only quality of life continued to improve from day 90 to day 180 (P < .001). By day 90, nearly 70% of patients showed an improvement in quality of life (67.9%, n = 91), and by day 180, more than 80% (82.8%, n = 111) reported a net improvement. Five patients (3.7%) reported a net decrease, and 18 patients (13.4%) had no net change in quality of life during the 180-day period. Patient-reported quality of life improved significantly among patients newly diagnosed with HFrEF and prescribed a wearable cardioverter defibrillator. These results suggest that pursuing guideline-directed medical therapy for HFrEF, while being protected by the wearable cardioverter defibrillator, is likely to provide symptom relief and improve quality of life.

Real-world experience with the wearable cardioverter defibrillator: clinical effectiveness and wear-time adherence in patients at high risk for sudden cardiac death.

Previous studies established arole for the wearable cardioverter defibrillator (WCD) to effectively and safely bridge temporary risk for sudden cardiac death (SCD) in patients with advanced heart failure. The prognostic relevance of the WCD remains controversial. The authors investigated adherence to, as well as the safety and effectiveness of, WCD use in areal-world cohort of patients at high risk for SCD. All consecutive patients (n = 83) receiving aWCD at aGerman tertiary care hospital between April 2012 and December 2019 were retrospectively included in this analysis. Patient characteristics were collected at the time of the index hospitalization. Using the Zoll® lifeVest® (ZOLL Medical Corporation, Chelmsford, MA, USA) network database, two separate investigators evaluated adherence to the WCD as well as arrhythmic events during WCD wear time. During 3680 wearing days (mean WCD wear time, 44days) with amedian daily wear time of 23.1 h, three arrhythmic events of relevance (sustained ventricular tachycardia, VT) occurred, one of which was sufficiently terminated by WCD shock. Another patient died from sudden cardiac death while pausing his WCD. Right bundle branch block correlated significantly with sustained VT occurrence (r = 0.3315; 95% CI -0.1265 to 0.3014; p = 0.0022). In 30patients (36.1%) acardioverter/defibrillator was implanted. In areal-life clinical setting, the use of WCD in patients at high risk for sudden cardiac death is effective and safe and adherence to the device is high. The event rate for VA was lower than in comparable patient cohorts. Adherence remains acrucial issue as one patient in the present series died while not wearing the device.

Wearable Cardioverter-Defibrillator-Measured Step Count for the Surveillance of Physical Fitness during Cardiac Rehabilitation.

Background: The wearable cardioverter–defibrillator (WCD) has a built-in accelerometer, which allows tracking of patients’ physical activity by remote monitoring. It is unclear whether WCD-measured physical activity, step count, and heart rate correlate with established tools for the assessment of cardiopulmonary fitness such as the 6-min walk test (6MWT). Objective: To correlate measurements of patient physical activity through the WCD with a supervised 6MWT during in-patient cardiac rehabilitation (CR) and to allow their use as surrogate parameters of cardiopulmonary fitness in an out-patient setting. Methods: Consecutive patients with a history of WCD use treated at our center and an in-patient CR following an index hospitalization were included. Baseline characteristics, measurements of WCD accelerometer (median daily step count, median daily activity level), median daily heart rate, and clinically supervised 6MWT at admission and discharge of CR were obtained. Results: Forty-one patients with a mean age of 55.5 (±11.5) years were included. Thirty-five patients (85.4%) were male and 28 patients (68%) had a primary prophylactic WCD-indication. The most common underlying heart diseases were ischemic heart disease (24 patients 58.6%) and dilated cardiomyopathy (13 patients, 31.7%). Median CR duration was 20 (IQR 19.75–26.25) days. 6MWT distance increased from a mean of 329 m (±107) to 470 m (±116) during CR (p < 0.0001). The median daily step count and activity level increased significantly, from 5542 steps (IQR 3718–7055) to 8778 (IQR 6229–12,920, p < 0.0001) and median 117 × 106 (IQR 96 × 106–142 × 106) threshold value exceedance (TVE) to 146 × 106 TVE (IQR 110 × 106–169 × 106, p < 0.0001), respectively. The median heart rate was 74.9 bpm (IQR 65.8–84.5) and 70.2 (IQR 64.1–77.3, p = 0.09) at admission and discharge, respectively. Of all three parameters, median daily step count showed the best correlation to the results of the 6MWT at admission and discharge (r = 0.32, p = 0.04 and 0.37, p = 0.02, respectively). Conclusions: Remote monitoring of median daily step count as assessed by the WCD’s accelerometer showed positive correlation with the 6MWT and could serve as a surrogate for cardiopulmonary exercise capacity. Assessment of daily step count and activity level measured remotely by the WCD could help to tailor optimal exercise instruction for patients not attending CR.

High incidence of inappropriate alarms in patients with wearable cardioverter-defibrillators: findings from the swiss WCD registry

Abstract Introduction The wearable cardioverter defibrillator (WCD) uses surface electrodes built into the vest to detect underlying arrhythmia before initiating a treatment sequence. However, it is also prone to inappropriate detection due to artefacts. Purpose The aim of this study was to assess the alarm burden in patients and its possible impact on clinical outcomes. Methods The Swiss WCD Registry is a nationwide, retrospective, observational registry. Patients were included from December 2011 until February 2018. Clinical characteristics and data from the WCDs, including alarm burden were analysed. Recordings ≥30 seconds of length were analysed and categorized as VT/VF, atrial fibrillation (AF), supraventricular tachycardia or artefact. Results A total of 10'653 device alarms were documented in 324 of 456 patients (71.1%) over a mean WCD wear-time of 2.0±1.6 months. Among these, the episode duration was 30 seconds or more in 2996 (28.2%). One hundred and eleven (3.7%) were VT/VF episodes. The remaining recordings were inappropriate arrhythmia detections (2736 (91%) due to artefacts; 117 (3.7%) AF; 48 (1.6%) supraventricular tachycardia). Two-hundred and seven patients (45.0%) had 3 or more alarms per month, whereas 49 patients (10.7%) had 1 or more alarms per day. Body mass index (BMI) was significantly higher in patients with 3 or more alarms per month (p=0.002, 25.6 vs. 27.3 kg/m2) High alarm burden was not associated with a lower average daily wear time (20.8 hours vs 20.7 hours, 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 did not lead to a decreased adherence, as determined by average daily wear-times. Obesity was significantly associated with a higher alarm burden. Funding Acknowledgement Type of funding sources: None.

Extended follow-up after wearable cardioverter-defibrillator period: the PROLONG-II study.

AimThe wearable cardioverter‐defibrillator (WCD) is used for temporary protection from sudden cardiac death (SCD) in patients with newly diagnosed heart failure with reduced ejection fraction before considering an implantable cardioverter‐defibrillator (ICD). However, the prognostic significance of the WCD remains controversial due to conflicting evidence. The aim of the present study was to evaluate prognosis of patients receiving life‐saving WCD shocks.Methods and resultsAll patients receiving a WCD at Hannover Medical School for heart failure with reduced ejection fraction between 2012 and 2017 were included. Data were acquired at baseline, at 3 months and at last available follow‐up (FU). Three hundred and fifty‐three patients were included (69% male; age 56 ± 15 years; left ventricular ejection fraction 25 ± 8%). FU after the WCD was 2.8 ± 1.5 years with a maximum of 6.8 years. Daily WCD wear time was 22 ± 4 h. Fourteen patients (4%) received appropriate WCD shocks. Two patients (0.6%) died during the WCD period. Thirty patients (9%) died during extended FU. Mean estimated survival after the WCD was similar between patients with and without WCD shocks. Patients without an ICD recommendation after WCD prescription did not experience SCD during FU.ConclusionsPatients with WCD shocks showed a favourable survival. Patients without an ICD recommendation after WCD prescription had no SCD during FU. These findings support the practice of careful risk stratification before considering an ICD and the use of the WCD for temporary protection from SCD.

The wearable cardiac defibrillator: the meeting point between the latest scientific evidence and clinical applicability

The use of the wearable cardioverter-defibrillator, already widely used in the United States and other European countries, is rapidly spreading in Italy. The population of patients who may benefit from this type of device is very heterogeneous, but they share the transient risk of sudden cardiac death, for which temporary, automatic and non-invasive protection is required. By interpreting the latest scientific evidence and clinical experiences reported in the registries, it is clear that this type of tool is safe, effective and could have an important impact on the reduction of arrhythmic and total mortality in certain patient subsets. Starting from the clinical conditions for which even the guidelines have recognized the usefulness of the device, new opportunities open up where the wearable cardiac defibrillator can be used with the double benefit of protecting the patient from the risk of sudden cardiac death in safety and allows clinicians to have the right time to make the most appropriate long-term therapeutic decisions.

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

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.

Cost-minimization analysis of a wearable cardioverter defibrillator in adult patients undergoing ICD explant procedures: Clinical and economic implications.

AimsPatients with permanently increased risk of sudden cardiac death (SCD) can be protected by implantable cardioverter defibrillators (ICD). If an ICD must be removed due to infection, for example, immediate reimplantation might not be possible or indicated. The wearable cardioverter defibrillator (WCD) is an established, safe and effective solution to protect patients from SCD during this high‐risk bridging period. Very few economic evaluations on WCD use are currently available.MethodsWe conducted a systematic review to evaluate the available evidence of WCD in patients undergoing ICD explant/lead extraction. Additionally, a decision model was developed to compare use and costs of the WCD with standard therapy (in‐hospital stay). For this purpose, a cost‐minimization analysis was conducted, and complemented by a one‐way sensitivity analysis.ResultsIn the base case scenario, the WCD was less expensive compared to standard therapy. The cost‐minimization analysis showed a cost reduction of €1782 per patient using the WCD. If costs of standard care were changed, cost savings associated with the WCD varied from €3500 to €0, assuming costs for standard care of €6800 to €3600.ConclusionAfter ICD explantation, patients can be safely and effectively protected from SCD after hospital discharge through WCD utilization. Furthermore, the use of a WCD for this patient group is cost saving when compared to standard therapy.

B-PO02-180 HIGH BURDEN OF INAPPROPRIATE ALARMS BY THE WEARABLE CARDIOVERTER-DEFIBRILLATOR IN OBESE PATIENTS - FINDINGS FROM THE SWISS WCD REGISTRY

The wearable cardioverter-defibrillator (WCD) uses surface electrodes built into the vest to detect underlying arrhythmia before initiating a treatment sequence. Before a shock is administered an alarm consisting of vibratory and auditory signals is emitted to warn the patient. Some patients frequently experience alarms. The aim of this study is to assess the alarm burden in patients and its possible impact on clinical outcomes. The aim of this study is to assess the alarm burden in patients and its possible impact on clinical outcomes. The Swiss WCD Registry is a nationwide retrospective registry including patients with a history of WCD use. Patients were included since 2011 until February 2018. Baseline characteristics and data on WCD usage were analysed. As sustained ventricular tachycardia or fibrillation (VT/VF) requires arrhythmia duration of ≥30s, only recordings ≥30s of length were analysed and categorized as appropriate (VT/VF), or inappropriate (atrial fibrillation, supraventricular tachycardia and artefact). A total of 10’653 alarms were documented in the total registry including 456 patients over a mean WCD wear-time of 2 months (±1.6). One hundred and thirty-two patients (28.9%) had zero alarms. A recording with a length ≥30s was present in 2996. One hundred and eleven (3.7%) of these were VT/VF episodes. The remaining recordings were inappropriate arrhythmia detections: 2736 artefacts (91%), 117 atrial fibrillation episodes (3.7%) and 48 supraventricular tachycardia episodes (1.6%). Two-hundred and seven patients (45%) had ≥3 alarms per months, and 49 patients (10.7%) had ≥1 alarm per day. BMI ≥30kg/m2 was significantly associated with ≥3 alarms per month (p=0.002), and increasing BMI correlated with increasing total number of alarms (p<0.001). ≥3 alarms per months were not associated with a lower average daily wear time (20.8 vs 20.7 hours, p=0.785) or a decreased ICD implantation rate after stopping WCD use (48 vs 47.3%, p=0.156). Inappropriate alarms emitted by the WCD are frequent and significantly associated with obesity. They did not lead to a decreased adherence to WCD therapy.

JCS/JHRS 2019 guideline on non-pharmacotherapy of cardiac arrhythmias.

JCS/JHRS 2019 guideline on non-pharmacotherapy of cardiac arrhythmias.

Wearable Cardioverter Defibrillator (WCD) in Italy: results from the nationwide multicenter registry WEAR-ITA

Abstract Funding Acknowledgements Type of funding sources: None. BACKGROUND The Wearable Cardioverter Defibrillators (WCD) has been used extensively in Italy since 2015, following long years of experience in other countries. This technology provides temporary protection from Sudden Cardiac Death (SCD) for patients with an evolving risk profile that may not yet be eligible for an Implantable Cardioverter Defibrillator (ICD). Collecting national data on use of the device can help build a picture that will enable an understanding on how to use the WCD appropriately in the future. PURPOSE Our purpose has been to investigate WCD usage on a nationwide level. This is in terms of target population, average wear time, patient compliance, diagnosed and treated arrhythmic events and patient outcome once they stopped wearing the device. METHODS WEAR-ITA is a nationwide, multi-centre retrospective observational project. Patient data was retrospectively collected from the Italian hospitals that agreed to take part in the data collection for all patients fitted with a WCD between April 2015 to May 2018. All data refers to the range from the first day of wear until the end of use. RESULTS We collected data for 411 patients from 15 (75%) Italian regions. WCD use among the different regions was heterogeneous with a median of 0.5 (0.2-1.2) WCD wore/105 inhabitants. The mean age of the population was 55(±14) and the majority of patients were male (79%). Main WCD indication was non-ischemic cardiomyopathy with reduced ejection fraction (51%), ischemic etiology with severe systolic dysfunction (31%), uncertain or unidentified diagnosis (10%) that then revealed to be predominantly channelopathies or myocarditis and after ICD extraction (8%). Patients wore the WCD for a median of 59 (33-90) days and the median daily weartime was 23 (22,7-23,8) hours. In 15 patients (4%), the WCD recorded non sustained ventricular tachycardia (VT), 10 patients (2%) had hemodynamically well-tolerated sustained VT not needing a shock. 8 patients (2%) received effective appropriate shocks. Time to episodes were respectively 61 (14-61) days for non-sustained VT and 28 (19-70) days for VT/VF. 2 patients (0.5%) received inappropriate shocks for sinus tachycardia and atrial fibrillation (AF) respectively. WCD recorded new onset of supra ventricular tachycardia episodes in 12 patients (3%) and of atrial fibrillation (AF) in 7 patients (2%). 7 patients (2%) died while wearing WCD; none of them from SCD. At the end of the WCD use, 195 patients (47%) did not receive an ICD while 209 patients (51%)were implanted. CONCLUSIONS WCD is an effective therapy for the treatment of SCD with a very low complication rates. The indication and penetration in Italy is quite heterogeneous. The patient’s compliance is high over time. The incidence of appropriate shock is not negligible; only half of patients, who wore WCD, received an ICD. There is however still a requirement to conduct further randomized trials to understand which patients could most benefit from the use of WCD. Abstract Figure. Wereable Cardioverter Defibrillator

Heart failure monitoring using the wearable cardioverter defibrillator in patients with newly diagnosed heart failure

Abstract Funding Acknowledgements Type of funding sources: None. Background The wearable cardioverter-defibrillator (WCD) can be prescribed in patients with newly diagnosed heart failure. The WCD provides additional heart failure parameters, like heart rate, step count and body position, accessible via remote monitoring. The purpose of this study was to evaluate clinical relevance of additionally recorded data in patients using the WCD. Methods Patients with newly diagnosed heart failure and WCD, an average wear time with at least 20 hours per day and available heart failure parameters were included. The heart failure parameters were provided in 5-minute data intervals. An approximate for the heart rate variability was calculated via the standard deviation of the cycle length of the given heart rate per 5-minute data interval (HRV5). Results 276 patients (68% male) were included between 04/2013 and 12/2017. Mean age was 57.4 ± 15.3 years. 174 patients (63%) suffered from non-ischemic and 102 patients (37%) from ischemic cardiomyopathy. Mean NYHA functional class at prescription was 2.6 ± 0.8. Mean left ventricular ejection fraction (LVEF) was 25.3 ± 8.5%. Mean wear time of the WCD was 111.8 ± 74.5 days. Recorded median heart rate using the WCD was 70.8 (IQR 63.1 - 78.7) beats per minute on the first wear day and 64.5 (IQR 59.7 - 71.3) on the last wear day. Median step count amounted to 4294 (IQR 2283 - 7092) steps on the first wear day compared to 5688 (IQR 3153 - 8263) steps on the last wear day. Median HRV5 was 85.4 (IQR 60.1 - 109.8) ms on the first wear day and 110.4 (IQR 78.6 - 134.9) ms on the last wear day. Between the first and last seven days of usage, median heart rate was significantly reduced (69.5 (IQR 62.0 - 76.8) to 65.9 (IQR 60.4 - 72.2) beats per minute; p &amp;lt; 0.001), while median step counts per day (4657 (IQR 2778 – 6918) to 5562 (IQR 3890 – 8446) steps; p &amp;lt; 0.001) and HRV5 (89.0 (IQR 64.8 - 110.7) to 111.0 (IQR 83.7 - 134.7) ms; p &amp;lt; 0.001) were significantly elevated. A higher delta of heart rate correlated with a higher delta of HRV5A (p &amp;lt; 0,001; rs = 0.488) between the first and last seven days of usage. A higher delta of step counts per day in the first and last seven days correlated with a higher HRV5 (p &amp;lt; 0.001; rs = 0.320). Patients with a higher delta of step count per day (p = 0,005; rs = 0,189) and patients with a higher delta of HRV5 (p = &amp;lt; 0.001; rs = 0.255) showed a higher delta of LVEF measured at prescription and three months follow-up. Conclusion The WCD provides heart failure monitoring using additional heart failure parameters. Patients with newly diagnosed heart failure show a significant difference in heart rate, step count per day and heart rate variability approximate between beginning and end of prescription time. Step count and heart rate variability correlate with LVEF reverse remodeling. Remote monitoring for parameters regarding heart failure might be helpful for close monitoring and further heart failure therapy optimization during WCD wearing.