Clinical Impact of Digitalis Therapy in a Large Multicenter Cohort of CRT-Recipients.

(1) Introduction: Digitalis use in patients with severe heart failure is controversial. We assessed the effects of digitalis therapy on mortality in a large, observational study in recipients of cardiac resynchronization therapy (CRT). (2) Methods: Consecutive patients receiving a CRT-defibrillator in three European tertiary referral centers were enrolled and followed-up for a mean 37 months ± 28 months. Digitalis use was assessed at the time of CRT implantation. A multivariate Cox-regression model and propensity score matching were used to determine all-cause mortality as the primary endpoint. CRT-response (defined as improvement of ≥1 NYHA class), echocardiographic improvement (defined as improvement of LVEF of ≥ 5%) and incidence of ICD shocks and rehospitalization were assessed as secondary endpoints in a subgroup of patients. (3) Results: The study comprised 552 CRT-recipients with standard indications, including 219 patients (40%) treated with digitalis. Compared to patients without digitalis, they had more often atrial fibrillation, poorer LVEF and a higher NYHA class (all p ≤ 0.002). Crude analysis of all-cause mortality demonstrated a similar relative risk of death for patients with and without digitalis (HR = 1.14; 95% CI 0.88-1.5; p = 0.40). After adjustment for independent predictors of mortality, digitalis therapy did not alter the risk for death (adjusted HR = 1.04; 95% CI 0.75-1.45; p = 0.82). Furthermore, in comparison to 286 propensity-score-matched patients, mortality was not affected by digitalis intake (propensity-adjusted HR = 1.11; 95% CI 0.72-1.70; p = 0.64). A CRT-response was predominant in digitalis non-users, concerning both improvement of HF symptoms and LVEF (NYHA p < 0.01; LVEF p < 0.01), while patients on digitalis had more often ventricular tachyarrhythmias requiring ICD shock (p = 0.01); although, rehospitalization for cardiac reasons was significantly lower among digitalis users compared to digitalis non-users (HR = 0.58; 95% C. I. 0.40-0.85; p = 0.01). (4) Conclusions: Digitalis therapy had no effect on mortality, but was associated with a reduced response to CRT and increased susceptibility to ventricular arrhythmias requiring ICD shock treatment. Although, digitalis administration positively altered the likelihood for cardiac rehospitalization during follow-up.

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

Background: Despite known clinical benefits, guideline-recommended heart rate (HR) control is not achieved for a significant proportion of patients with HF with reduced ejection fraction. The wearable cardioverter-defibrillator (WCD) provides continuous HR monitoring and alerts that could aid medication titration. Objective: This study sought to evaluate sex differences in achieving guideline-recommended HR control during a period of WCD use. Methods: Data from patients fitted with a WCD from 2015 to 2018 were obtained from the manufacturer's database (ZOLL). The proportion of patients with adequate nighttime resting HR control at the beginning of use (BOU) and at the end of use (EOU) were compared by sex. Adequate HR control was defined as having a nighttime median HR <70 beats/min. Results: A total of 21,440 women and a comparative sample of 17,328 men (median 90 [IQR 59-116] days of WCD wear) 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 beats/min improved by EOU, 43% of women and 36% of men did not achieve guideline-recommended HR control. Conclusion: A significant proportion of women and men did not achieve adequate HR control during a period of medical therapy optimization. Compared with men, a greater proportion of women receiving WCD shocks had insufficiently controlled HR in the week preceding ventricular tachyarrhythmia/ventricular fibrillation and 43% of nonshocked women, compared with 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 uptitration of beta-blockers, with particular focus on reducing the treatment gap in women.

Risk of Cardiac Implantable Electronic Device Infection after Early versus Delayed Lead Repositioning.

(1) Background: Early reintervention increases the risk of infection of cardiac implantable electronic devices (CIEDs). Some operators therefore delay lead repositioning in the case of dislocation by weeks; however, there is no evidence to support this practice. The aim of our study was to evaluate the impact of the timing of reoperation on infection risk. (2) Methods: The data from consecutive patients undergoing lead repositioning in two European referral centers were retrospectively analyzed. The odds ratio (OR) of CIED infection in the first year was compared among patients undergoing early (≤1 week) vs. delayed (>1 week to 1 year) reoperation. (3) Results: Out of 249 patients requiring CIED reintervention, 85 patients (34%) underwent an early (median 2 days) and 164 (66%) underwent a delayed lead revision (median 53 days). A total of nine (3.6%) wound/device infections were identified. The risk of infection was numerically lower in the early (1.2%) vs. delayed (4.9%) intervention group yielding no statistically significant difference, even after adjustment for typical risk factors for CIED infection (adjusted OR = 0.264, 95% CI 0.032-2.179, p = 0.216). System explantation/extraction was necessary in seven cases, all being revised in the delayed group. (4) Conclusions: In this bicentric, international study, delayed lead repositioning did not reduce the risk of CIED infection.

Apixaban for Stroke Prevention in Subclinical Atrial Fibrillation.

BACKGROUND: Subclinical atrial fibrillation is short-lasting and asymptomatic and can usually be detected only by long-term continuous monitoring with pacemakers or defibrillators. Subclinical atrial fibrillation is associated with an increased risk of stroke by a factor of 2.5; however, treatment with oral anticoagulation is of uncertain benefit. METHODS: We conducted a trial involving patients with subclinical atrial fibrillation lasting 6 minutes to 24 hours. Patients were randomly assigned in a double-blind, double-dummy design to receive apixaban at a dose of 5 mg twice daily (2.5 mg twice daily when indicated) or aspirin at a dose of 81 mg daily. The trial medication was discontinued and anticoagulation started if subclinical atrial fibrillation lasting more than 24 hours or clinical atrial fibrillation developed. The primary efficacy outcome, stroke or systemic embolism, was assessed in the intention-to-treat population (all the patients who had undergone randomization); the primary safety outcome, major bleeding, was assessed in the on-treatment population (all the patients who had undergone randomization and received at least one dose of the assigned trial drug, with follow-up censored 5 days after permanent discontinuation of trial medication for any reason). RESULTS: We included 4012 patients with a mean (±SD) age of 76.8±7.6 years and a mean CHA2DS2-VASc score of 3.9±1.1 (scores range from 0 to 9, with higher scores indicating a higher risk of stroke); 36.1% of the patients were women. After a mean follow-up of 3.5±1.8 years, stroke or systemic embolism occurred in 55 patients in the apixaban group (0.78% per patient-year) and in 86 patients in the aspirin group (1.24% per patient-year) (hazard ratio, 0.63; 95% confidence interval [CI], 0.45 to 0.88; P = 0.007). In the on-treatment population, the rate of major bleeding was 1.71% per patient-year in the apixaban group and 0.94% per patient-year in the aspirin group (hazard ratio, 1.80; 95% CI, 1.26 to 2.57; P = 0.001). Fatal bleeding occurred in 5 patients in the apixaban group and 8 patients in the aspirin group. CONCLUSIONS: Among patients with subclinical atrial fibrillation, apixaban resulted in a lower risk of stroke or systemic embolism than aspirin but a higher risk of major bleeding. (Funded by the Canadian Institutes of Health Research and others; ARTESIA ClinicalTrials.gov number, NCT01938248.).

Use of the Wearable Cardioverter-Defibrillator Among Patients With Myocarditis and Reduced Ejection Fraction or Ventricular Tachyarrhythmia: Data From a Multicenter Registry.

Background Data on the use of the wearable cardioverter-defibrillator (WCD) among patients with myocarditis remain sparse. Consequently, evidence for guideline recommendations in this patient population is lacking. Methods and Results In total, 1596 consecutive patients were included in a multicenter registry from 8 European centers, with 124 patients (8%) having received the WCD due to myocarditis and reduced left ventricular ejection fraction or prior ventricular tachyarrhythmia. The mean age was 51.6±16.3 years, with 74% being male. Patients were discharged after index hospitalization on heart failure medication: Angiotensin-converting enzyme inhibitors (62.5%), angiotensin-receptor-neprilysin inhibitor (22.9%), aldosterone-antagonists (51%), or beta blockers (91.4%). The initial median left ventricular ejection fraction was 30% (22%-45%) and increased to 48% (39%-55%) over long-term follow-up (P<0.001). The median BNP (brain natriuretic peptide) level at baseline was 1702 pg/mL (565-3748) and decreased to 188 pg/mL (26-348) over long-term follow-up (P=0.022). The mean wear time was 79.7±52.1 days and 21.0±4.9 hours per day. Arrhythmic event rates documented by the WCD were 9.7% for nonsustained ventricular tachycardia, 6.5% for sustained ventricular tachycardia, and 0% for ventricular fibrillation. Subsequently, 2.4% of patients experienced an appropriate WCD shock. The rate of inappropriate WCD shocks was 0.8%. All 3 patients with appropriate WCD shock had experienced ventricular tachycardia/ventricular fibrillation before WCD prescription, with only 1 patient showing a left ventricular ejection fraction <35%. Conclusions Patients with myocarditis and risk for occurrence of ventricular tachyarrhythmia may benefit from WCD use. Prior ventricular arrhythmia might appear as a better risk predictor than a reduced left ventricular ejection fraction <35% in this population.

Editorial: Developments in cardiac implantable electronic device therapy: how can we improve clinical implementation?

CIED, cardiac implantable electronic devices; CRT, cardiac resynchronization therapy; CRT-D, cardiac resynchronization therapy defibrillator; EA, electroanatomical; ICD, implantable cardioverter defibrillator; LBB, left bundle branch; LBBAP, left bundle branch area pacing; LV, left ventricular; LVEF, left ventricular ejection fraction; NT-proBNP, N-terminal pro-B-type natriuretic peptide; MRI, cardiac magnetic resonance imaging; S-ICD, subcutaneous defibrillator.

Age differences of patients treated with wearable cardioverter defibrillator: Data from a multicentre registry.

BACKGROUND: Wearable cardioverter defibrillators (WCD) are used as a 'bridging' technology in patients, who are temporarily at high risk for sudden cardiac death (SCD). Several factors should be taken into consideration, for example patient selection, compliance and optimal drug treatment, when WCD is prescribed. We aimed to present real-world data from seven centres from Germany and Switzerland according to age differences regarding the outcome, prognosis, WCD data and compliance. MATERIALS AND METHODS: Between 04/2012 and 03/2021, 1105 patients were included in this registry. Outcome data according to age differences (old ≥45 years compared to young <45 years) were analysed. At young age, WCDs were more often prescribed due to congenital heart disease and myocarditis. On the other hand, ischaemic cardiomyopathy (ICM) was more present in older patients. Wear days of WCD were similar between both groups (p = .115). In addition, during the WCD use, documented arrhythmic life-threatening events were comparable [sustained ventricular tachycardia: 5.8% vs. 7.7%, ventricular fibrillation (VF) .5% vs. .6%] and consequently the rate of appropriate shocks was similar between both groups. Left ventricular ejection fraction improvement was documented over follow-up with a better improvement in younger patients as compared to older patients (77% vs. 63%, p = .002). In addition, at baseline, the rate of atrial fibrillation was significantly higher in the older age group (23% vs. 8%; p = .001). The rate of permanent cardiac implantable electronic device implantation (CiED) was lower in the younger group (25% vs. 36%, p = .05). The compliance rate defined as wearing WCD at least 20 h per day was significantly lower in young patients compared to old patients (68.9% vs. 80.9%, p < .001). During the follow-up, no significant difference regarding all-cause mortality or arrhythmic death was documented in both groups. A low compliance rate of wearing WCD is predicted by young patients and patients suffering from non-ischaemic cardiomyopathies. CONCLUSION: Although the compliance rate in different age groups is high, the average wear hours tended to be lower in young patients compared to older patients. The clinical events were similar in younger patients compared to older patients.

Clinical outcomes of subcutaneous vs. transvenous implantable defibrillator therapy in a polymorbid patient cohort.

Background: The subcutaneous implantable cardioverter-defibrillator (S-ICD) has been designed to overcome lead-related complications and device endocarditis. Lacking the ability for pacing or resynchronization therapy its usage is limited to selected patients at risk for sudden cardiac death (SCD). Objective: The aim of this single-center study was to assess clinical outcomes of S-ICD and single-chamber transvenous (TV)-ICD in an all-comers population. Methods: The study cohort comprised a total of 119 ICD patients who underwent either S-ICD (n = 35) or TV-ICD (n = 84) implantation at the University Hospital Frankfurt from 2009 to 2017. By applying an inverse probability-weighting (IPW) analysis based on the propensity score including the Charlson Comorbidity Index (CCI) to adjust for potential extracardiac comorbidities, we aimed for head-to-head comparison on the study composite endpoint: overall survival, hospitalization, and device-associated events (including appropriate and inappropriate shocks or system-related complications). Results: The median age of the study population was 66.0 years, 22.7% of the patients were female. The underlying heart disease was ischemic cardiomyopathy (61.4%) with a median LVEF of 30%. Only 52.9% had received an ICD for primary prevention, most of the patients (67.3%) had advanced heart failure (NYHA class II-III) and 16.8% were in atrial fibrillation. CCI was 5 points in TV-ICD patients vs. 4 points for patients with S-ICD (p = 0.209) indicating increased morbidity. The composite endpoint occurred in 38 patients (31.9 %), revealing no significant difference between patients implanted with an S-ICD or TV-ICD (unweighted HR 1.50, 95 % confidence interval (CI) 0.78-2.90; p = 0.229, weighted HR 0.94, 95% CI, 0.61-1.50, p = 0.777). Furthermore, we observed no difference in any single clinical endpoint or device-associated outcome, neither in the unweighted cohort nor following inverse probability-weighting. Conclusion: Clinical outcomes of the S-ICD and TV-ICD revealed no differences in the composite endpoint including survival, freedom of hospitalization and device-associated events, even after careful adjustment for potential confounders. Moreover, the CCI was evaluated in a S-ICD cohort demonstrating higher survival rates than predicted by the CCI in young, polymorbid (S-)ICD patients.

Sex differences and adherence of patients treated with wearable cardioverter-defibrillator: Insights from an international multicenter register.

AIMS: Treatment with the wearable cardioverter defibrillator (WCD) may protect against sudden cardiac death (SCD) as a bridging therapy until a cardioverter-defibrillator may be implanted. We analyzed in a multicenter setting a consecutive patient cohort wearing WCD to explore sex differences. METHODS AND RESULTS: We analyzed 708 consecutive patients, 579 (81.8%) from whom were males and 129 (18.2%) females (age, 60.5 ± 14 vs. 61.6 ± 17 years old; p = .44). While the rate of ischemic cardiomyopathy (ICM) as a cause of prescription of WCD was significantly higher in males as compared to females (42.7% vs. 26.4%; p = .001), females received it more frequently due to nonischemic cardiomyopathy (NICM) (55.8% vs. 42.7%); p = .009). The wear time of WCD was equivalent in both groups (21.1 ± 4.3 h/days in males vs. 21.5 ± 4.4 h/days in females; p = .27; and 62.6 ± 44.3 days in males vs. 56.5 ± 39 days in females; p = .15). Mortality was comparable in both groups at 2-year-follow-up (6.8% in males vs. 9.7% in females; p = .55). Appropriate WCD shocks and the incidence of ICD implantations were similar in both groups (2.4% in males vs. 3.9% in females; p = .07) (35.1% in males vs. 31.8% in females; p = .37), respectively. In age tertile analysis, compliance was observed more in 73-91 years old group as compared with 14-51 years old group (87.8% vs. 68.3%; p < .001). CONCLUSION: Compliance for wearing WCD was excellent regardless of sex. Furthermore, mortality and the incidence of ICD implantations were comparable in both sexes. Appropriate WCD shocks were similar in both sexes.

A Case Series of Concomitant Cardiac Electrical Disease among Takotsubo Syndrome Patients and Literature Review.

The pathophysiology of Takotsubo Syndrome (TTS) is not completely understood and the trigger of sudden cardiac death (SCD) in TTS is not clear either. We therefore sought to find an association between TTS and primary electrical diseases. A total of 148 TTS patients were analyzed between 2003 and 2017 in a bi-centric manner. Additionally, a literature review was performed. The patients were included in an ongoing retrospective cohort database. The coexistence of TTS and primary electrical diseases was confirmed in five cases as the following: catecholaminergic polymorphic ventricular tachycardia (CPVT, 18-year-old female) (n = 1), LQTS 1 (72-year-old female and 65-year-old female) (n = 2), LQTS 2 (17-year-old female) (n = 1), and LQTS in the absence of mutations (22-year-old female). Four patients suffered from malignant tachyarrhythmia and recurrent syncope after TTS. Except for the CPVT patient and one LQTS 1 patient, all other cases underwent subcutaneous ICD implantation. An event recorder of the CPVT patient after starting beta-blocker did not detect arrhythmias. The diagnosis of primary electrical disease was in 80% of cases unmasked on a TTS event. This diagnosis triggered a family clinical and genetic screening confirming the diagnosis of primary electrical disease. A subsequent literature review identified five cases as the following: a congenital atrioventricular block (n = 1), a Jervell and Lange-Nielsen Syndrome (n = 1), and a family LQTS in the absence of a mutation (n = 2), LQTS 2 (n = 1). A primary electrical disease should be suspected in young and old TTS patients with a family history of sudden cardiac death. In suspected cases, e.g., ongoing QT interval prolongation, despite recovery of left ventricular ejection fraction a family screening is recommended.

Real life experience with the wearable cardioverter-defibrillator in an international multicenter Registry.

Patients at high risk for sudden cardiac death (SCD) may benefit from wearable cardioverter defibrillators (WCD) by avoiding immediate implantable cardioverter defibrillator (ICD) implantation. Different factors play an important role including patient selection, compliance and optimal drug treatment. We aimed to present real world data from 4 centers from Germany and Switzerland. Between 04/2012 and 03/2019, 708 patients were included in this registry. Patients were followed up over a mean time of 28 ± 35.5 months. Outcome data including gender differences and different etiologies of cardiomyopathy were analyzed. Out of 708 patients (81.8% males, mean age 61.0 ± 14.6), 44.6% of patients had non-ischemic cardiomyopathy, 39.8% ischemic cardiomyopathy, 7.9% myocarditis, 5.4% prior need for ICD explantation and 2.1% channelopathy. The mean wear time of WCD was 21.2 ± 4.3 h per day. In 46% of patients, left ventricular ejection fraction (LVEF) was > 35% during follow-up. The younger the patient was, the higher the LVEF and the lower the wear hours per day were. The total shock rate during follow-up was 2.7%. Whereas an appropriate WCD shock was documented in 16 patients (2.2%), 3 patients received an inappropriate ICD shock (0.5%). During follow-up, implantation of a cardiac implantable electronic device was carried out in 34.5% of patients. When comparing German patients (n = 516) to Swiss patients (n = 192), Swiss patients presented with longer wear days (70.72 ± 49.47 days versus 58.06 ± 40.45 days; p = 0.001) and a higher ICD implantation rate compared to German patients (48.4% versus 29.3%; p = 0.001), although LVEF at follow-up was similar between both groups. Young age is a negative independent predictor for the compliance in this large registry. The most common indication for WCD was non-ischemic cardiomyopathy followed by ischemic cardiomyopathy. The compliance rate was generally high with a decrease of wear hours per day at younger age. Slight differences were found between Swiss and German patients, which might be related to differences in mentality for ICD implantation.

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

BACKGROUND: The 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 RESULTS: 781 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. CONCLUSIONS: Mortality 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.

Sex differences in arrhythmic burden with the wearable cardioverter-defibrillator.

BACKGROUND: Data on the arrhythmic burden of women at risk for sudden cardiac death are limited, especially in patients using the wearable cardioverter-defibrillator (WCD). OBJECTIVE: We aimed to characterize WCD compliance, atrial and ventricular arrhythmic burden, and WCD outcomes by sex in patients enrolled in the Prospective Registry of Patients Using the Wearable Cardioverter Defibrillator (WEARIT-II U.S. Registry). METHODS: In the WEARIT-II Registry, we stratified 2000 patients by sex into women (n = 598) and men (n = 1402). WCD wear time, ventricular and atrial arrhythmic events during WCD use, and implantable cardioverter-defibrillator (ICD) implantation rates at the end of WCD use were evaluated. RESULTS: The mean WCD wear time was similar in women and men (94 days vs 90 days; P = .145), with longer daily use in women (21.4 h/d vs 20.7 h/d; P = .001). Burden of ventricular tachycardia or ventricular fibrillation was higher in women, with 30 events per 100 patient-years compared with 18 events per 100 patient-years in men (P = .017), with similar findings for treated and non-treated ventricular tachycardia/ventricular fibrillation. Recurrent atrial arrhythmias/sustained ventricular tachycardia was also more frequent in women than in men (167 events per 100 patient-years vs 73 events per 100 patient-years; P = .042). However, ICD implantation rate at the end of WCD use was similar in both women and men (41% vs 39%; P = .448). CONCLUSION: In the WEARIT-II Registry, we have shown a higher burden of ventricular and atrial arrhythmic events in women than in men. ICD implantation rates at the end of WCD use were similar. Our findings warrant monitoring women at risk for sudden cardiac death who have a high burden of atrial and ventricular arrhythmias while using the WCD.

Influence of decompensated heart failure on cardiac acoustic biomarkers: impact on early readmissions.

AIMS: Preventing hospitalization by detecting early evidence of heart failure (HF) decompensation in an outpatient setting can improve patient's quality of life and reduce costs of care. The purpose of this study was to assess the value of cardiac acoustic biomarkers (CABs), a combination of cardiohaemic vibrations synchronized with ECG signals, and heart rate (HR) for detecting HF decompensation during first 3 months after hospital discharge for HF. METHODS AND RESULTS: Patients with an ejection fraction ≤35% (HFrEF) and hospitalized for decompensated HF were enrolled in a prospective observational study. All subjects wore a wearable cardioverter-defibrillator (ZOLL LifeVest® , Pittsburgh, PA, USA) that is capable of recording CABs and HR. The primary endpoint of the study was the first HF event, defined as HF readmission or HF emergency room visit. From June 2017 through August 2019, 671 patients with HFrEF were enrolled. Eighty-one patients (12.1%) had a total of 112 HF events. The algorithm detected HF events with a median of 32 days (interquartile range = 11-45) in advance of the first HF event. The algorithm had a sensitivity of 69%, specificity of 60%, positive predictive value of 19%, and a negative predictive value of 94%. Of note, the baseline (first 7 days post-enrolment) algorithm using CABs and HR was superior to New York Heart Association classification in detecting patients more likely to have HF decompensation (sensitivity and specificity of 61% and 68% vs. 46% and 55%, respectively). CONCLUSIONS: This prospective international registry showed that an algorithm incorporating CABs and HR data detected HF events 30 days in advance of the event in patients with HFrEF during first 3 months after hospital discharge. Therefore, integrating CAB technology into clinical practice may prevent HF rehospitalizations.

Physical Activity in Adults With Wearable Cardioverter Defibrillators in the Post-Myocardial Infarction Period.

PURPOSE: Wearable cardioverter defibrillators (WCDs) provide lifesaving defibrillation and are equipped with accelerometers, capable of providing information on patient wear time and physical activity (PA). The purpose of this study was to report on patient PA while wearing a WCD. METHODS: This study derived data from the WCD vendor in patients prescribed WCD post-myocardial infarction (MI) with left ventricular ejection fraction ≤35% in 2016. Using the device accelerometer, the relationship between wear time and PA was examined in a sample of consistent wearers of the WCD. Demographic variables, including sex and age, were examined for impact on wear time and PA. Changes in PA over time were also examined. RESULTS: A total of 1952 patients (71% male) with a median age of 63 yr were included. Descriptive analyses indicated that overall median wear time was 23.8 hr/d; PA was 5568 steps/d. Significant differences in PA over time were identified, with median steps increasing by 67% from the first week of wear to the last week of wear. Patient age and wear time significantly predicted PA; patient age also significantly predicted patient wear time. There were significant differences in median hours of wear time, as well as median steps, based on sex. CONCLUSIONS: PA in adults early after hospital discharge is modest and improves over the course of the 90-d WCD prescription in regular wearers. Improved health status may account for this change. The WCD accelerometer may have value in future clinical care and research by providing a window into daily patient PA levels via remote monitoring.

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

BACKGROUND: Heightened 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. OBJECTIVE: To determine the relationship between physical activity, recorded by accelerometer in a wearable cardioverter-defibrillator (WCD), and sustained ventricular arrhythmia among female patients. METHODS: A 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). RESULTS: Among 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. CONCLUSION: For 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.