Wearable Cardioverter Defibrillator Shock Research Articles

Sex differences in achieving guideline-recommended heart rate control among a large sample of patients at risk for sudden cardiac arrest

BackgroundDespite known clinical benefits, guideline-recommended HR control is not achieved for a significant proportion of patients with HF and reduced ejection fraction. The Wearable Cardioverter Defibrillator (WCD) provides continuous heart rate (HR) monitoring and alerts that could aid medication titration. ObjectiveThis study sought to evaluate sex differences in achieving guideline-recommended HR control during a period of WCD use. MethodsData from patients fitted with a WCD from 2015 to 2018 were obtained from the manufacturer´s database (ZOLL, Pittsburgh, PA). The proportion of patients with adequate nighttime resting HR control at the beginning of WCD use (BOU) and at the end of WCD use (EOU) were compared by sex. Adequate HR control was defined as having a nighttime median HR <70 bpm. ResultsA total of 21,440 women and a comparative sample of 17,328 men (median 90 days of WCD wear, IQR 59-116) were included in the final dataset. Among patients who did not receive a shock, over half had insufficient HR control at BOU (59% of women, 53% of men). Although the proportion of patients with resting HR ≥70 improved by EOU, 43% of women and 36% of men did not achieve guideline-recommended HR control. ConclusionsA significant proportion of women and men did not achieve adequate HR control during a period of medical therapy optimization. Compared to men, a greater proportion of women receiving WCD shocks had insufficiently controlled HR in the week preceding VT/VF and 43% of non-shocked women, compared to 36% of men, did not reach adequate HR control during the study period. The WCD can be utilized as a remote monitoring tool to record HR and inform adequate up-titration of BB, with particular focus on reducing the treatment gap in women.

The use of wearable cardioverter defibrillator among patients suffering from myocarditis: data from a multicenter registry

Abstract Background Data on the use of the wearable cardioverter defibrillator (WCD) among patients suffering from myocarditis in a large cohort remains sparse. Subsequently several guidelines give a different recommendation regarding WCD indication in this cohort. Methods 1596 patients were included in a multicenter registry from ten European centers. Among this cohort 132 (8%) patients received a WCD due to myocarditis. The mean follow-up time of the whole cohort was 620.2±607.8 days. The presence of ventricular tachyarrhythmias and/or WCD shocks during WCD use were evaluated. Results The mean age of patients was 52.5±16.3 years (75% males). 20% of patients suffered from atrial fibrillation, 17% diabetes mellitus, 40% were smoker and 38.9% suffered from arterial hypertension. The body-mass-index (BMI) of the cohort was 27.8±5.7 kg/m². The initial left ventricular ejection fraction (LVEF) was 33.4±14.6% and increased to 45.9±13.2% (p&amp;lt;0.05) over long-term follow-up. Patient were discharged on ACE-inhibitors (62.5%), ARNI (21.2%), aldosterone-antagonist (50%), beta-blockers (89.5%) and amiodarone (13.6%). An improvement of LVEF (LVEF&amp;gt;35%) was documented in 81.2% of patients. The BNP level was at baseline 7401±30584 pg/ml and decreased to 530±803 pg/ml (p&amp;lt;0.05) over long-term follow-up. The wear duration was 78.5±51.5 days and 34% of patients wore the WCD for longer than 90 days. The wear-hours per day were 21.1±4.8 hours. In 3.1% sustained ventricular tachycardia, 0.8% ventricular fibrillation and 9.1% non-sustained ventricular tachycardia were documented. Subsequently 3% of patients suffered from an appropriate WCD shock. The rate of inappropriate WCD shock was 0.8%. Patients suffering from WCD shock were at age 31, 31, 61, 24 and 51 years and suffered a former non-sustained ventricular tachycardia before receiving a WCD. Among these patients suffering from appropriate WCD shock only two patients showed an LVEF&amp;lt;35%. Among the myocarditis patients 48% suffered from a former ventricular tachycardia and/or ventricular fibrillation and therefore received a WCD. Conclusions Myocarditis patients can be effectively protected by WCD and may benefit from its’ use. WCD shock occurred also in patients with an LVEF &amp;gt;35%.

Wearable cardioverter defibrillator after ICD-system explantation: data from a multicenter registry

Abstract Background Data on the use of wearable cardioverter defibrillator (WCD) among patients after cardiac implantable electronic device explantation of 1- to 3-chamber Implantable Cardioverter-defibrillator system (ICD) are sparse. Subsequently several guidelines give a different recommendation regarding WCD indication in this cohort. Objectives We aimed to study the baseline characteristics and outcome of patients treated with WCD after ICD explantation. The primary outcome is appropriate WCD shock. Methods 1104 patients were included in a multicenter registry from seven European centers. Among this cohort 109 patients received a WCD to bridge the time after ICD-system explantation until reimplantation due to a persistent ICD-indication. The mean follow-up time of the whole cohort was 824±773 days. Cardiovascular history and non-cardiovascular morbidities were evaluated. In addition, the presence of ventricular tachyarrhythmias and/or WCD shocks was evaluated in the explantation group. Furthermore, after ICD-reimplantation the rate of rehospitalization for ventricular tachyarrhythmias, atrial fibrillation, stroke and congestive heart failure was followed. Results In the explantation group patients were older (65±14 versus 59±15; p&amp;lt;0.001) and were hospitalized longer (21±15 days versus 14±12 days; p&amp;lt;0.001). The index LVEF differed significantly (35.7±14.1% versus 29.3±11.5%; p&amp;lt;0.001). The LVEF value did not differ significantly over short-term follow-up (35.7±14.2% versus 37.9±11.9%; p=0.204). Wear days among patients after ICD-system explantation were 61±46 days. An appropriate WCD shock was documented in 7.3% after ICD-system explantation during WCD use. Up to 80.6% of patients after ICD-system explantation received a reimplantation. The rate of rehospitalization due to ventricular tachyarrhythmias was 7.3%, due to heart failure 6.8% and due to atrial fibrillation 4.1%. After ICD-implantation the rate of appropriate shocks was 12/89 (13.4%). In the multivariable regression analysis myocarditis and ICD-system explantation were positive predictors for the risk of ventricular tachyarrhythmias, but nevertheless an improved left ventricular ejection fraction (LVEF) and use of aldosterone antagonists were negative predictors for the risk of ventricular tachyarrhythmias. Conclusions Cccurrence of malignant arrythmia after ICD-system explantation is high and the use of WCD among these patients could be beneficial in preventing sudden cardiac death.

Incidence of sustained ventricular tachyarrhythmias in patients with non-ischemic cardiomyopathy in a multicenter multinational WCD cohort

Abstract Background Defibrillator use in patients with non-ischemic cardiomyopathy (NICM) and HFrEF remains controversial after the DANISH study. The new ESC guidelines recommend individualized risk stratification in these patients. The wearable cardioverter-defibrillator (WCD) seems to be appropriate to both protect and screen patients with HFrEF at risk for sudden cardiac death (SCD). Puropose: To evaluate the rate of ventricular tachyarrhythmias (VT/VF) in NICM vs. ICM patients receiving a WCD for temporary SCD protection. Methods 1157 patients were included in a multicenter registry from eight European centers. Among these patients, 602 patients received a WCD due to ischemic cardiomyopathy (ICM) and 555 patients for non-ischemic cardiomyopathy (NICM). Incidence of VT/VF and/or appropriate WCD shock discharge during WCD use were evaluated. The mean follow-up (FU) time of the whole cohort was 620.2±607.8 days. Results NICM patients were younger (mean 56.5±14.8a vs 63.9±11.6a; p&amp;lt;0.001) and less often male (75% vs. 87.2%; p&amp;lt;0.001) compared to ICM patients. Heart failure medication at hospital discharge did not differ between the two groups except for a higher prescription rate of aldosterone-antagonists in NICM compared to ICM patients (73.8% vs. 66.7%; p=0.02). The index left ventricular ejection fraction (LVEF) was significantly lower in NICM compared to ICM patients (mean 26.1±9.1% versus 29.5±9.2%; p&amp;lt;0.001). A larger extent of LVEF recovery was detected in NICM patients compared to ICM patients up to the end of WCD use (mean LVEF post WCD: 45.7±35.4% vs. 40.2±11.8%; p=0.02). Average daily WCD wear-time was significantly lower in NICM patients compared to ICM patients (mean 20.7±4.9h vs. 21.6±3.7h; p=0.01). NICM patients had a significantly lower incidence of sustained ventricular tachyarrhythmia (VT/VF) compared to ICM patients (3.4% vs. 6.6%; p=0.02). Consistently, rate of appropriate WCD shock was significantly lower in NICM vs. ICM patients (0.7% vs. 3.7%; p&amp;lt; 0.001), as was rate of re-hospitalization (30.2% vs. 46.1%; p&amp;lt;0.001). Both groups showed a similar mortality rate during FU. Conclusions Patients at risk for SCD with NICM showed a more pronounced LVEF recovery, significantly lower incidence of VT/VF with concomitant shocks and hospitalization, while overall mortality was unchanged compared to ICM patients. These results indicate that WCD use might facilitate individual SCD risk stratification in NICM patients.

Cardiovascular rehabilitation with a WCD

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): ZOLL Background The wearable cardioverter-defibrillator (WCD) is a temporary treatment option for patients at high risk for sudden cardiac death (SCD) in whom implantation of a cardioverter defibrillator (ICD) is temporarily not possible. Exercise training and rehabilitation has an IA recommendation in these patients. There are no data on safety and outcomes of patients with a WCD undergoing cardiac rehabilitation. Purpose The aim of this study is to evaluate the safety and feasibility of wearing a WCD while undergoing a cardiac rehabilitation program. Methods We performed a retrospective analysis of all patients with a successfully completed stationary rehabilitation program. Results 55/896 patients (6.1%) registered in the Austrian WCD registry completed a stationary rehab program (60±11 years, 1% female). Underlying cardiac disease was ischaemic cardiomyopathy (CMP) in 27/55 (49%), dilatative CMP in 15/55 (27%), inflammatory CMP in 10/55 (18%) patients. One patient had valvular CMP, one patient had tako tsubo CMP, one patient had a primary electrical disease (each 1,8%). The baseline LVEF at rehab start was 36% [12;80%], duration of rehab was 28 days [18;42] compared to a total prescription duration of 94 days [26;294]. 75.6% (41/55) patients completed a regular rehab duration with a WCD, 3.6% (2/55) got their WCD stopped during rehab due to recovery of the LV function, 21,8% (12/55) got a WCD prescribed during rehab. The daily wearing duration was 23.4h [12.6;23.9]. 2848 (mean 52±117/patient) automatic alarms and 340 (mean 6±9/patient) manual alarms were generated. Within this cohort 3,6% (2/55) patients had shocks for VT/VF during prescription: one patient for a VF event that was terminated with the first shock, another patient had three VT events that were also terminate with the first WCD shock. All events happened before rehabilitation, so no patient had a WCD treatment during rehab, neither appropriate, nor inappropriate. Two patient had recurrent stable VTs that were controlled with antiarrhythmic drugs during prescription, only one of them during rehab. 3 patients had a reported syncope during rehab, all of them associated with hypotension, one patient had an ambulatory check-up at the CIED clinic because of false automatic alarms due to artefacts. Following a relevant weight loss through rehab measurements, the fabric garment of the WCD had a poor fit and was adapted. The LVEF after rehab was 42% [23;73%]. At the end of WCD prescription 33/55 (60%) had a restitution of their cardiac function with no need for an ICD, 19/55 (35%) patients were implanted with an ICD. One patient (1,8%) had a heart transplantation, one patient (1,8%) had the desire to stop WCD prescription and one patient (1,8%) had a terminal non-cardiac disease. Conclusion Completing a cardiovascular rehabilitation program is feasible and safe for patients prescribed with a WCD and may contribute positively to the restitution of the cardiac function.

Post-Shock Asystole in Patients Dying Out of Hospital While Wearing a Cardioverter Defibrillator

BackgroundThe wearable cardioverter-defibrillator (WCD) prevents sudden cardiac death due to ventricular tachycardia (VT) or ventricular fibrillation (VF) but does not pace for post-shock asystole (PS-A) or bradycardia (PS-B;<50 beats/ min). ObjectivesThe purpose of this study was to assess PS-A and PS-B in patients dying out of hospital (OOH) while wearing a WCD. MethodsThe database of the U.S. Food and Drug Administration Manufacturers and User Facility Device Experience (MAUDE) was queried for manufacturers’ reports of OOH deaths while patients were wearing a WCD. Excluded were patients who did not receive a shock or were initially shocked for asystole or during resuscitation. ResultsFrom January 2017 to March 2022, 313 patients received an initial WCD shock for VF (n = 150), VT (n = 90), and non-VF/VT rhythms (n = 73). PS-A occurred in 204 patients (65.2%), and PS-B occurred in 111 (35.5%); 85 (41.7%) PS-A patients also had PS-B. Most PS-A patients (n = 185; 90.7%) had an initial shocked rhythm of VF or VT, but 19 patients (9.3%) were initially inappropriately shocked for atrial fibrillation/supraventricular tachycardia (n = 7) and idioventricular (n = 8) or sinus (n = 4) rhythm. PS-A occurred after the first WCD shock in 118 (63.8%) and after the first, second, or third shocks in 159 patients (85.9%). Seven patients had post-shock heart block. Eight patients had permanent pacemakers; 1 became nonfunctional after 1 shock, and 7 showed noncapture and/or asystole after 1 to 4 shocks. ConclusionsPost-shock asystole appears to be common in patients who die OOH after being shocked by a WCD for VF or VT. PS-A also occurs after inappropriate WCD shocks for non-VF/VT rhythms. Implanted pacemakers may not prevent PS-A after a WCD shock. WCD backup pacing should be explored.

Usage of the wearable cardioverter-defibrillator during pregnancy.

BackgroundPregnancy can trigger or aggravate the risk for life-threating arrhythmias in cardiac diseases. Pregnancy is associated with reluctance for implantable cardioverter-defibrillators (ICD) due to concerns about radiation. Thus, the wearable cardioverter-defibrillator (WCD) might be an option during pregnancy. Aim of the study was to collect experiences about the use of WCD in pregnancy.Methods and resultsThis study retrospectively included eight women who received a WCD during pregnancy. They suffered from ventricular tachycardia (VT) without known cardiac disease (n = 3), Brugada syndrome (n = 1), hypertrophic cardiomyopathy (n = 1), dilated cardiomyopathy (n = 1), non-compaction (n = 1), and survived sudden cardiac arrest during a preceding pregnancy (n = 1). WCD usage was started between 13 and 28 weeks of gestation. WCD wearing period ranged from 3 days to 30.9 weeks, WCD wearing time ranged from 13.0 to 23.7 h per day. Two women (25%) abandoned WCD already during pregnancy. Neither appropriate nor inappropriate WCD shocks were recorded. Antiarrhythmic management included beta-blockers (n = 5) and flecainide (n = 2). After delivery, ICD were implanted (n = 4), refused (n = 2) and estimated not necessary after successful catheter ablation (n = 2).ConclusionUneventful pregnancy is possible in women at risk for sudden cardiac death by interdisciplinary monitoring and diligent pharmacotherapy protected by the WCD. Since no WCD shocks were recorded, the effectiveness of WCD during pregnancy is still unclear. However, arrhythmia detection by WCD was very good despite the changed anatomy in pregnancy. Nevertheless, further studies are necessary to assess effectiveness of WCD in pregnant women. Furthermore, efforts should be made to increase the wearing adherence of WCD during pregnancy.

Ventricular arrhythmias and prognosis of patients after explantation of an infected ICD compared to patients with newly diagnosed heart failure using the wearable cardioverter-defibrillator

Abstract Funding Acknowledgements Type of funding sources: None. Introduction The wearable cardioverter-defibrillator (WCD) is a tool for temporary protection from sudden cardiac death (SCD). It is used in patients with newly diagnosed heart failure with reduced ejection fraction (HFrEF) as well as in patients with a preexisting ICD indication who need explantation of the device. There is no data on long-term prognosis after the WCD in this latter group of patients. Methods All patients receiving the WCD at a Medical School between 2012 and 2017 were analyzed. Patients with newly diagnosed HFrEF from the PROLONG-II study were compared to patients receiving the WCD after an ICD explantation. Follow-up (FU) data were analyzed after 3 months and at last available FU including WCD data, clinical status, medication, echocardiography and ECG. Results 353 patients (69% male) with newly diagnosed HFrEF from the PROLONG-II study were compared to 29 patients (86% male) having received a WCD after explantation of an ICD (45% with secondary preventive indication). Mean baseline LVEF was 25±8% and 34±13% respectively (p&amp;lt;0.001). Follow-up was 2.8±1.5 and 3.2±1.8 years. WCD shocks occurred in 14 (4%) of the patients with newly diagnosed HFrEF and in 3 (10%) patients after ICD explantation (2 with a secondary preventive indication). During long-term FU, patients with an explanted ICD had a poorer prognosis compared to patients with newly diagnosed HFrEF (p=0.02), and appropriate WCD shocks were associated with even higher mortality in patients after ICD explantation (p=0.045). Conclusion Patients after ICD explantation have an increased risk of ventricular arrhythmias and WCD shocks, but also show an increased risk of all-cause mortality despite wearing the WCD compared to patients with newly diagnosed HFrEF.

Delayed Improvement of Left Ventricular Function in Newly Diagnosed Heart Failure Depends on Etiology-A PROLONG-II Substudy.

In patients with newly diagnosed heart failure with reduced ejection fraction (HFrEF), three months of optimal therapy are recommended before considering a primary preventive implantable cardioverter-defibrillator (ICD). It is unclear which patients benefit from a prolonged waiting period under protection of the wearable cardioverter-defibrillator (WCD) to avoid unnecessary ICD implantations. This study included all patients receiving a WCD for newly diagnosed HFrEF (n = 353) at our center between 2012 and 2017. Median follow-up was 2.7 years. From baseline until three months, LVEF improved in patients with all peripartum cardiomyopathy (PPCM), myocarditis, dilated cardiomyopathy (DCM), or ischemic cardiomyopathy (ICM). Beyond this time, LVEF improved in PPCM and DCM only (10 ± 8% and 10 ± 12%, respectively), whereas patients with ICM showed no further improvement. The patients with newly diagnosed HFrEF were compared to 29 patients with a distinct WCD indication, which is an explantation of an infected ICD. This latter group had a higher incidence of WCD shocks and poorer overall survival. All-cause mortality should be considered when deciding on WCD prescription. In patients with newly diagnosed HFrEF, the potential for delayed LVEF recovery should be considered when timing ICD implantation, especially in patients with PPCM and DCM.

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.

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.

Decline in physical activity in the weeks preceding sustained ventricular arrhythmia in women.

BackgroundHeightened risk of cardiac arrest following physical exertion has been reported. Among patients with an implantable defibrillator, an appropriate shock for sustained ventricular arrhythmia was preceded by a retrospective self-report of engaging in mild-to-moderate physical activity. Previous studies evaluating the relationship between activity and sudden cardiac arrest lacked an objective measure of physical activity and women were often underrepresented.ObjectiveTo determine the relationship between physical activity, recorded by accelerometer in a wearable cardioverter-defibrillator (WCD), and sustained ventricular arrhythmia among female patients.MethodsA dataset of female adult patients prescribed a WCD for a diagnosis of myocardial infarction or dilated cardiomyopathy was compiled from a commercial database. Curve estimation, to include linear and nonlinear interpolation, was applied to physical activity as a function of time (days before arrhythmia).ResultsAmong women who received an appropriate WCD shock for sustained ventricular arrhythmia (N = 120), a quadratic relationship between time and activity was present prior to shock. Physical activity increased starting at the beginning of the 30-day period up until day -16 (16 days before the ventricular arrhythmia) when activity begins to decline.ConclusionFor patients who received treatment for sustained ventricular arrhythmia, a decline in physical activity was found during the 2 weeks preceding the arrhythmic event. Device monitoring for a sustained decline in physical activity may be useful to identify patients at near-term risk of a cardiac arrest.

917Appropriate shocks in WCD patients - Results from the Austrian WCD registry

Abstract Background The wearable cardioverter-defibrillator (WCD) is a temporary treatment option for patients at high risk for sudden cardiac death (SCD) and/or for patients in whom implantation of a cardioverter defibrillator (ICD) is temporarily not possible. Purpose To investigate incidence and predictors of appropriate WCD shocks. Methods We performed a retrospective analysis of all patients with appropriate shocks delivered by a WCD in the cohort of the Austrian WCD registry between 2010 and 2018. Within this dataset, we identified predictors within the baseline characteristics, the indication for the WCD and preceding alarms automatically recorded by the WCD. Results: Baseline Within 879 registered in the Austrian WCD registry, 31 patients (3,5%) received appropriate WCD shocks due to ventricular tachycardia (VT) or ventricular fibrillation (VF). Compared to the total cohort, shocked patients were elder (mean age 67 ± 14 vs. 60 ± 14 years, p = 0,001) and the percentage of female patients was lower (11% vs. 21%, p = 0,262). The mean baseline LVEF at prescription was 33 ± 15% in the population with appropriate shocks compared to 32 ± 14% in the all-over cohort (p = ns). In the Austrian WCD population, 378/879 patients had a WCD due to secondary prevention. Within this cohort 5,6% (21/378) had shocks for VT/VF again, compared to 10/501 (2%) shocked patients in the primary prevention cohort. 31/879 (3.5%) patients received 57 appropriate shocks, the per patient shock rate was 2 [1;5]. These shocks were induced by 25 ventricular tachycardia and 26 times ventricular fibrillation. The octagenarians with 11% (7/34) shocked patients, showed a significant higher likelihood to receive shocks (p = 0,008) as well as the cohort of secondary preventive prescribed WCD-patients (p = 0,007). There were more shocks in patients, when prescribed with a WCD due to ICD associated infections (p = 0,001), when used as a bridge to ICD (p = 0,042) and in patients with ongoing risk stratification (p = 0,009). Looking through the automatically recorded alarms preceding a WCD shock, shocked patients experienced significantly more often non sustained VTs (p &amp;lt; 0,0005) and sustained VTs that were haemodynamically tolerated and did not require a treatment (p &amp;lt; 0,0005). Conclusion The WCD is effective in preventing SCD and an important risk stratification tool. We identified advanced age, patients with either already confirmed indication for ICD implantation (either temporary contraindication for implantation or temporary explantation) or risk stratification of an unclear cardiomyopathy, the cohort of secondary prevention and preceding nsVTs and stable VTs as predictors for appropriate WCD therapies.

Protected risk stratification with the wearable cardioverter-defibrillator: results from the WEARIT-II-EUROPE registry

BackgroundThe prospective WEARIT-II-EUROPE registry aimed to assess the value of the wearable cardioverter-defibrillator (WCD) prior to potential ICD implantation in patients with heart failure and reduced ejection fraction considered at risk of sudden arrhythmic death.Methods and results781 patients (77% men; mean age 59.3 ± 13.4 years) with heart failure and reduced left ventricular ejection fraction (LVEF) were consecutively enrolled. All patients received a WCD. Follow-up time for all patients was 12 months. Mean baseline LVEF was 26.9%. Mean WCD wearing time was 75 ± 47.7 days, mean daily WCD use 20.3 ± 4.6 h. WCD shocks terminated 13 VT/VF events in ten patients (1.3%). Two patients died during WCD prescription of non-arrhythmic cause. Mean LVEF increased from 26.9 to 36.3% at the end of WCD prescription (p < 0.01). After WCD use, ICDs were implanted in only 289 patients (37%). Forty patients (5.1%) died during follow-up. Five patients (1.7%) died with ICDs implanted, 33 patients (7%) had no ICD (no information on ICD in two patients). The majority of patients (75%) with the follow-up of 12 months after WCD prescription died from heart failure (15 patients) and non-cardiac death (15 patients). Only three patients (7%) died suddenly. In seven patients, the cause of death remained unknown.ConclusionsMortality after WCD prescription was mainly driven by heart failure and non-cardiovascular death. In patients with HFrEF and a potential risk of sudden arrhythmic death, WCD protected observation of LVEF progression and appraisal of competing risks of potential non-arrhythmic death may enable improved selection for beneficial ICD implantation.Graphic abstract

The Wearable Cardioverter-Defibrillator: Experience in 153 Patients and a Long-Term Follow-Up.

Background: The wearable cardioverter-defibrillator (WCD) is available for patients at high risk for sudden cardiac death (SCD) when immediate implantable cardioverter-defibrillator (ICD) implantation is not possible or indicated. Patient selection remains challenging especially in primary prevention. Long-term data on these patients is still lacking. Methods: 153 patients were included in this study. They were prescribed the WCD between April 2012 and March 2019 at the University Medical Center, Mannheim, Germany. The mean follow-up period was 36.2 ± 15.6 months. Outcome data, including all-cause mortality, were analyzed by disease etiology and ICD implantation following WCD use. Results: We analyzed 56 patients with ischemic cardiomyopathy, 70 patients with non-ischemic cardiomyopathy, 16 patients with prior need for ICD/CRT-D (device for cardiac resynchronization therapy with defibrillator) explanation, 8 patients with acute myocarditis and 3 patients with congenital diseases. 58% of the patients did not need ICD/CRT-D implantation after WCD use. 4% of all patients suffered from appropriate WCD shocks. 2 of these patients (33%) experienced appropriate ICD shocks after implantation due to ventricular tachyarrhythmias. Long-term follow-up shows a good overall survival. All-cause mortality was 10%. There was no significant difference between patients with or without subsequent ICD implantation (p = 0.48). Patients with ischemic cardiomyopathy numerically showed a higher long-term mortality than patients with non-ischemic cardiomyopathy (14% vs. 6%, p = 0.13) and received significantly more ICD shocks after implantation (10% of ischemic cardiomyopathy (ICM) patients versus 3% of non-ischemic cardiomyopathy (NICM) patients, p = 0.04). All patients with ventricular tachyarrhythmias during WCD use or after ICD implantation survived the follow-up period. Conclusion: Following WCD use, ICD implantation could be avoided in 58% of patients. Long-term follow-up shows good overall survival. The majority of all patients did not suffer from WCD shocks nor did receive ICD shocks after subsequent implantation. Patient selection regarding predictive conditions on long-term risk of ventricular tachyarrhythmias needs further risk stratification.

Impact of wearable cardioverter-defibrillator compliance on outcomes in the VEST trial: As-treated and per-protocol analyses.

Vest Prevention of Early Sudden Death Trial did not demonstrate a significant reduction in arrhythmic death with the wearable cardioverter-defibrillator (WCD), but compliance with the device may have substantially affected the results. ThePletcher influence of WCD compliance on outcomes has not yet been fully evaluated. Using linear and pooled logistic models, we performed as-treated analyses omitting person-time in the hospital and adjusted for correlates of WCD compliance. To assess the impact of early stopping of WCD, we performed a per-protocol Kaplan-Meier analysis, censoring after the last day the WCD was worn. Interactions of potential effect modifiers with treatment assignment and WCD compliance on outcomes were investigated. Finally, we used linear models to identify predictors of WCD compliance. A per-protocol analysis demonstrated a significant reduction in total (P < .001) and arrhythmic (P = .001) mortality. Better WCD compliance was independently predicted by cardiac arrest during index myocardial infarction (MI), higher Cr, diabetes, prior heart failure, EF ≤ 25%, Polish enrolling center and number of WCD alarms, while worse compliance was predicted by being divorced, Asian race, higher body mass index, prior percutaneous coronary intervention, or any WCD shock. Neither excluding time in hospital from the as-treated analysis nor adjustment for factors affecting WCD compliance materially changed the results. No variable demonstrated a significant interaction in either the intention-to-treat or as-treated analysis. Robust sensitivity analyses of as-treated and per-protocol analyses suggest that the WCD is protective in compliant patients with ejection fraction less than or equal to 35% during the first 3 months post-MI.

Comparison of the Outcome of Patients Protected by the Wearable Cardioverter Defibrillator (WCD) for

The wearable cardioverter/defibrillator (WCD) is recommended to prevent sudden cardiac death (SCD). Guidelines suggest a 90 days' period, but prolongation of WCD wear time until increasing the ejection fraction (≥35%) might be suggested. A cohort of 153 patients with prescribed WCD were divided into two groups: A <90 wear days' group (n=112) vs. ≥90 wear days' group (n=41) and followed. In the first group, WCD shock occurred in 3.6% of patients, 47.3% improved in left ventricular ejection fraction (LVEF) after 3 months, and 37.5% had a cardiac implantable electronic device (CIED) implantation with appropriate implantable cardioverter defibrillator (ICD) shock events occurring in 6 patients. Two of these patients already received WCD shock therapy due to ventricular fibrillation. A 20.5% improved in LVEF after 6-12 months, but 73% were already implanted with ICD. In the second group, 4.9% received WCD shock, 34.1% improved in LVEF after 3 months, 48.8% were implanted with ICD, and 2 had ICD shocks during follow up time. LVEF improvement after 6-12 months occurred in 26.8%. ICD implantation was prevented in 7.3% of patients due to LVEF recovery. Prolonging wearing days of WCD may reduce the number of inappropriate ICD implantation.

P2281Inadequate heart rate control begets sustained ventricular arrhythmias in a large cohort of women

Abstract Background The Wearable Cardioverter Defibrillator (WCD) is an effective therapy for treating ventricular arrhythmias (VT/VF) in at-risk patients, while providing continuous heart rate (HR) monitoring. Because women are under-represented in defibrillator trials, we chose to specifically focus on HR control in women prior to VT/VF events. Purpose To evaluate HR profiles preceding sustained VT/VF in women fitted with a WCD. Methods Data from women fitted with WCD (≥30 days use) from 2015 to 2018 were obtained from the manufacturer's database. HR is expressed as a weekly resting nighttime median (midnight to 7 am). Men (random sample) with the same inclusion criteria served as a control. Results A total of 21,440 women, age 67±15 years, were included for analysis. Over a median WCD use of 90 days (59–116 days), 118 women (0.6%) and 133 men (0.8%) received shocks for VT/VF (p=0.01). Resting HR one-week preceding VT/VF was above the target of 70bpm in 55% of shocked women (65 of 118) versus 44% of non-shocked women (9,272 of 21,322, p=0.01) (figure). HR one week before WCD shock was similar in women and men (71 bpm vs. 72 bpm; p=0.60). Younger women (≤50 years) had higher HR prior to shock than older women (HR 80 bpm vs. 70 bpm p=0.003). Among shocked patients, 24-hour-survival was 89% in women and 88% in men. During three-month follow-up, the same percentage of men and women died after receiving adequate WCD shock therapy (18%). Heart rate profiles Conclusions Women with adequate heart rate control experienced significantly less spontaneous VT/VF than those with higher heart rates. The WCD can be utilized as a diagnostic tool to monitor HR in at-risk women in addition to treating sustained VT/VF.

2404The use of wearable cardioverter defibrillator in France

Abstract Background The wearable cardioverter defibrillator (WCD) has been shown to be useful during transient periods of high sudden cardiac death risk, and the issue of compliance recently pointed out. This Registry was designed to provide real-world data on WCD use in France, in terms of compliance, potential adverse events, as well as efficacy. Methods and results Multicenter evaluation (WEARIT FRANCE Registry) was conducted in France between January 2017 and March 2018. Overall, 1,157 patients were analyzed: 950 with ischemic heart disease (82%, including 647 patients after myocardial infarction), 119 after ICD explant (10%), and 88 pre-transplant (8%). The median age was 61 years; the median ejection fraction was 25%. Median WCD wear time was 62 days, with median daily use of 23.4 hours. Less than 1% of patients did not wear WCD at least 4 hours per day. During follow-up, a total of 42 sustained ventricular tachyarrhythmias (VT/VF) occurred in 36 patients, of whom 50% (n=18) received appropriate WCD shocks, giving an incidence of appropriate therapy of 1.56%. The rate of all VT/VF episodes were 3.1% among patients with ischemic cardiomyopathy (n=29/950) versus 3.4% for the others (n=7/207). Of the ischemic patients wearing beyond 30 days (N=784), 5 received appropriate therapy of VT/VF episodes. Overall shock survival was 100%. At the end of the WCD period, 586 patients (51%) were implanted with an implantable cardioverter defibrillator. Eight patients (0.69%) received inappropriate WCD shocks. Regarding the apparent very low proportion of women considered for WCD therapy, we aimed to appreciate in which extent Conclusions In this multicenter nationwide WCD evaluation, 3.1% of patients presented with sustained VT/VF with 47% of those patients developing VT/VF after 30 days. The incidence of inappropriate therapy was low. The compliance to WCD in this real life evaluation was very high. These data suggest that the WCD, when worn appropriately, may be helpful in the arsenal to protect high-risk patients against SCD, especially in case of transient risk situations. Acknowledgement/Funding Zoll

P2280Incidence and predictors of alarms in patients with wearable cardioverter defibrillator (WCD) - results of the Austrian WCD Registry

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.