Ventricular arrhythmias in patients with newly diagnosed nonischemic cardiomyopathy: Insights from the PROLONG study

Predictors of ventricular tachyarrhythmia in patients with a wearable cardioverter defibrillator: an international multicenter registry

BACKGROUND AND AIMS

Wearable cardioverter defibrillator (WCD) can protect patients from sudden cardiac death due to ventricular tachyarrhythmias and serve as a bridge to decision of definite defibrillator implantation. The aim of this analysis from an international, multicenter WCD registry was to identify predictors of sustained ventricular tachycardia (VT) and/or ventricular fibrillation (VF) in this population.

METHODS

One thousand six hundred seventy-five patients with WCD were included in a multicenter registry from 9 European centers, with a median follow-up of 440 days (IQR 120-893). The primary study end point was the occurrence of sustained VT/VF.

RESULTS

Sustained VT was detected by WCD in 5.4% and VF in 0.9% of all patients. Of the 30.3% of patients receiving ICD implantation during follow-up, sustained VT was recorded in 9.3% and VF in 2.6%. Non-ischemic cardiomyopathy (HR 0.5, p < 0.001), and medication with angiotensin-converting enzyme inhibitors (HR 0.7, p = 0.027) and aldosterone antagonists (HR 0.7, p = 0.005) were associated with a significantly lower risk of VT/VF.

CONCLUSIONS

Patients who received WCD due to a transient increased risk of sudden cardiac death have a comparatively lower risk of VT/VF in the presence of non-ischemic cardiomyopathy. Of note, optimal medical treatment for heart failure not only results in an improvement in left ventricular ejection fraction but also in a reduction in the risk for VT/VF.

Peripartum cardiomyopathy: risk factors and predictors of outcome

PURPOSE OF REVIEW

Peripartum cardiomyopathy (PPCM) contributes significantly to maternal morbidity and mortality worldwide. In this review, we describe the present-day epidemiology and current understanding of the pathogenesis of PPCM. We provide an updated approach to diagnosis and management of PPCM, and discuss risk factors and predictors of outcome.

RECENT FINDINGS

The highest incidences of PPCM have been reported in African, Asian, and Caribbean populations. Contemporary literature supports a 'two-hit' hypothesis, whereby the 'first hit' implies a predisposition, and the 'second hit' refers to an imbalanced peripartal hormonal milieu that results in cardiomyopathy. Whereas a half of patients will have left ventricular (LV) recovery, a tenth do not survive. Clinical findings and special investigations (ECG, echocardiography, cardiac MRI, biomarkers) can be used for risk stratification. Frequent prescription of guideline-directed medical therapy is associated with improved outcomes.

SUMMARY

Despite advances in elucidating the pathogenesis of PPCM, it remains unclear why only certain women develop the disease. Moreover, even with better diagnostic work-up and management, it remains unknown why some patients with PPCM have persistent LV dysfunction or die. Future research should be aimed at better understanding of the mechanisms of disease and finding new therapies that could improve survival and LV recovery.

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.

Usage of the wearable cardioverter-defibrillator during pregnancy

Background

Pregnancy 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 results

This 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).

Conclusion

Uneventful 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.

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 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.

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.

Viral Myocarditis-From Pathophysiology to Treatment

The diagnosis of acute and chronic myocarditis remains a challenge for clinicians. Characterization of this disease has been hampered by its diverse etiologies and heterogeneous clinical presentations. Most cases of myocarditis are caused by infectious agents. Despite successful research in the last few years, the pathophysiology of viral myocarditis and its sequelae leading to severe heart failure with a poor prognosis is not fully understood and represents a significant public health issue globally. Most likely, at a certain point, besides viral persistence, several etiological types merge into a common pathogenic autoimmune process leading to chronic inflammation and tissue remodeling, ultimately resulting in the clinical phenotype of dilated cardiomyopathy. Understanding the underlying molecular mechanisms is necessary to assess the prognosis of patients and is fundamental to appropriate specific and personalized therapeutic strategies. To reach this clinical prerequisite, there is the need for advanced diagnostic tools, including an endomyocardial biopsy and guidelines to optimize the management of this disease. The severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) has currently led to the worst pandemic in a century and has awakened a special sensitivity throughout the world to viral infections. This work aims to summarize the pathophysiology of viral myocarditis, advanced diagnostic methods and the current state of treatment options.

Incidence and predictors of early and late sudden cardiac death in hospitalized Japanese patients with new-onset systolic heart failure

BACKGROUND

Patients with heart failure (HF) and low left ventricular ejection fraction (LVEF) are at high risk of sudden cardiac death (SCD). Optimal HF treatment can improve LVEF and reduce the risk of SCD. The aim of this study was to evaluate the incidence and predictors of SCD in Japanese patients with new-onset systolic HF and to investigate factors that affect LVEF improvement.

METHODS

We retrospectively studied 174 consecutive hospitalized patients with new-onset HF and LVEF ≤35% (median age, 66 years; men, 71%). The primary outcome was a composite of SCD, sustained ventricular arrhythmias, and appropriate implantable cardioverter-defibrillator therapy.

RESULTS

The cumulative rates of meeting of the primary outcome at 3, 12, and 36 months after discharge were 3.9%, 8.1%, and 10.5%, respectively. Atrial fibrillation was a significant predictor of the primary outcome within 12 months after discharge (odds ratio, 5.87; 95% confidence interval [CI], 1.60-21.57). Among 104 patients who completed follow-up echocardiography within 12 months after discharge, changes in LVEF were inversely associated with SCD (odds ratio/1% increase, 0.78; 95% CI, 0.65-0.93). A QRS duration <130 ms and a B-type natriuretic peptide level <170 pg/mL were predictors of LVEF improvement to >35% (odds ratio, 3.69; 95% CI, 1.15-11.77; odds ratio, 3.19; 95% CI, 1.33-7.69, respectively).

CONCLUSIONS

Our results showed a high incidence of meeting of the primary outcome within 12 months after discharge in hospitalized patients with new-onset systolic HF. An improved LVEF may reduce the risk of late SCD.

Benefit of a wearable cardioverter defibrillator for detection and therapy of arrhythmias in patients with myocarditis

Aims

Myocarditis may lead to malignant arrhythmias and sudden cardiac death. As of today, there are no reliable predictors to identify individuals at risk for these catastrophic events. The aim of this study was to evaluate if a wearable cardioverter defibrillator (WCD) may detect and treat such arrhythmias adequately in the peracute setting of myocarditis.

Methods and results

In this observational, retrospective, single centre study, we reviewed patients presenting to the Charité Hospital from 2009 to 2017, who were provided with a WCD for the diagnosis of myocarditis with reduced ejection fraction (<50%) and/or arrhythmias. Amongst 259 patients receiving a WCD, 59 patients (23%) were diagnosed with myocarditis by histology. The mean age was 46 ± 14 years, and 11 patients were women (19%). The mean WCD wearing time was 86 ± 63 days, and the mean daily use was 20 ± 5 h. During that time, two patients (3%) had episodes of sustained ventricular tachycardia (VT; four total) corresponding to a rate of 28 sustained VT episodes per 100 patient‐years. Consequently, one of these patients underwent rhythm stabilization through intravenous amiodarone, while the other patient received an implantable cardioverter defibrillator. Two patients (3.4%) were found to have non‐sustained VT.

Conclusions

Using a WCD after acute myocarditis led to the detection of sustained VT in 2/59 patients (3%). While a WCD may prevent sudden cardiac death after myocarditis, our data suggest that WCD may have impact on clinical management through monitoring and arrhythmia detection.

The impact of wearable cardioverter-defibrillator use on long-term decision for implantation of a cardioverter-defibrillator in a semirural acute care hospital

Purpose

Large-scale multi-center studies have reported on efficacy of the wearable cardioverter-defibrillator (WCD). However, outcomes focused on WCD patients treated at community-based acute care centers are lacking.

Methods

Patients with cardiomyopathy were included when left ventricular ejection fraction (LVEF) at baseline was ≤ 35%. There were 120 patients meeting the criteria who also had LVEF measured at baseline and after 90 days of WCD use.

Results

After 90 days of WCD use, there were 44 (37%) patients in whom LVEF improved to > 35%. Comparison of patients, by whether LVEF improved or not, indicated that median days of WCD wear and hours of daily use were similar as well as characteristics, such as gender, age, and starting LVEF; and diagnoses leading to WCD prescription were similar between groups as were symptom-based prescription of medications. At the end of WCD use, improved LVEF > 35% correlated with fewer implantable cardioverter-defibrillator (ICD) implants. There were 4 (3%) episodes of new atrial fibrillation detected during WCD use. The WCD appropriately delivered a shock to 3 (2.5%) patients with VT/VF being terminated by the first shock. All shocked patients survived for at least 24 h post-shock.

Conclusions

During WCD use, ischemic and non-ischemic cardiomyopathy patients manifest improved LVEF by 90 days. Long-term care decisions, such as implantation of an ICD, were influenced by LVEF improvement and occurrence of spontaneous VT/VF. The WCD protected patients from sudden cardiac death (SCD) until patient response to guideline-directed medical therapy could be determined.

Effectiveness, efficacy, and safety of wearable cardioverter-defibrillators in the treatment of sudden cardiac arrest - Results from a health technology assessment

OBJECTIVES

To assess the effectiveness, efficacy, and safety of a wearable cardioverter-defibrillator (WCD) in adult persons with high risk for sudden cardiac arrest and for which an implantable cardioverter is currently not applicable.

METHODS

We performed a systematic literature search in Medline, Embase, Cochrane Library, and CRD-databases. Study selection was performed by two reviewers independently. Data were presented quantitatively; due to heterogeneity of studies no meta-analysis was performed.

RESULTS

One randomized-controlled trial (RCT), one non-randomized comparative trial, and forty-four non-comparative trials were included. The RCT reported an overall mortality of 3.1 percent in the WCD group versus 4.9 percent in controls (relative risk [RR]: .64; 95 percent confidence interval [CI], .43-.98, p = .04), but no significant effect on arrhythmia-related mortality. The RR for arrhythmia-related mortality amounted to .67 (95 percent CI, .37-1.21, p = .18) as assessed in the RCT. Appropriate shocks were observed in 1.3 percent of patients in both comparative studies, and inappropriate shocks in .6 percent of patients in the RCT. Termination of ventricular tachycardia (VT) or ventricular fibrillation (VF) was successful in 75 to 100 percent of appropriate shocks in all studies. Adverse events assessed in the RCT showed a lower incidence of shortness of breath (38.8 percent vs. 45.3 percent; p = .004), higher incidence of rash at any location (15.3 percent vs. 7.1 percent; p < .001), and higher incidence of itching at any location (17.2 percent vs. 6.4 percent; p < .001) for WCD.

CONCLUSIONS

Available evidence demonstrates that the WCD detects and terminates VT/VF events reliably and shows a high rate of appropriate shocks in mixed patient populations. Data of large registries confirm that the WCD is a safe intervention.

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.

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.

Extended use of the wearable cardioverter-defibrillator in patients at risk for sudden cardiac death

Aims

Data on outcomes in patients using the wearable cardioverter-defibrillator (WCD) > 90 days are limited. We aimed to analyse the clinical course of patients with WCD use ≤90 days vs. WCD use >90 days.

Methods and results

We assessed arrhythmia events during WCD use, and ejection fraction (EF) improvement/implantable cardioverter-defibrillator (ICD) implantation at the end of WCD use in patients with WCD use ≤90 days vs. WCD use >90 days enrolled in the WEARIT-II registry, further assessed by disease aetiology (ischaemic vs. non-ischaemic vs. congenital/inherited heart disease). There were 981 (49%) patients with WCD use >90 days, and 1019 patients with WCD use ≤90 days (median 120 vs. 55 days). There was a lower incidence of sustained ventricular tachycardia/ventricular fibrillation (VT/VF) events (11 vs. 50 events per 100 patient-years, P < 0.001), WCD treated VT/VF events (1 vs. 8 events per 100 patient-years, P < 0.001), and non-sustained VT events (21 vs. 51 events per 100 patient-years, P = 0.008) with WCD use >90 vs. WCD use ≤90 days. Non-ischaemic cardiomyopathy patients presented with similar rates of sustained VT/VF events during WCD use >90 vs. ≤90 days (13.4 vs. 13.7 events per 100 patient-years, P = 0.314), while most of these events terminated spontaneously. One-third of the patients with extended WCD use further improved their EF and they were not implanted with an ICD, with similar rates among ischaemic and non-ischaemic patients.

Conclusions

In WEARIT-II, patients with extended WCD use >90 days remain at risk for ventricular arrhythmia events. One-third of the patients with WCD use >90 days further improved their EF, avoiding the need to consider ICD implantation.

Sudden cardiac death in nonischemic cardiomyopathy

Sudden cardiac death (SCD) is a major cause of mortality in patients with nonischemic cardiomyopathy (NICM). Identifying patients who are at highest risk for SCD is an ongoing challenge. At present, guidelines recommend the use of an implantable cardioverter-defibrillator (ICD) in patients with NICM with a reduced left ventricular ejection fraction (LVEF) and heart failure (HF) symptoms. Some recent data, however, suggest that ICDs may not increase longevity in this population. Conversely, community-based studies have demonstrated that many at-risk individuals who may benefit from ICD therapy remain unprotected. Current recommendations for ICD implantation are continually debated, justifying comprehensive individualized risk assessment. Various promising techniques for further risk stratification are under evaluation, including cardiac magnetic resonance imaging, electrocardiographic assessment of electrical instability, and genetic testing. However, none of these strategies has been fully adapted into guidelines. Hence, clinical risk stratification practice today depends on LVEF and HF symptoms, which have poor sensitivity and specificity for predicting SCD risk.

Wearable Cardioverter-Defibrillator Therapy for the Prevention of Sudden Cardiac Death: A Systematic Review and Meta-Analysis

OBJECTIVES

This study sought to synthesize the available evidence on the use of the wearable cardioverter-defibrillator (WCD).

BACKGROUND

Observational WCD studies for the prevention of sudden cardiac death have provided conflicting data. The VEST (Vest Prevention of Early Sudden Death) trial was the first randomized controlled trial (RCT) showing no reduction in sudden cardiac death as compared to medical therapy only.

METHODS

We searched PubMed, EMBASE, and Google Scholar for studies reporting on the outcomes of patients wearing WCDs from January 1, 2001, through March 20, 2018. Rates of appropriate and inappropriate WCD therapies were pooled. Estimates were derived using DerSimonian and Laird's method.

RESULTS

Twenty-eight studies were included (N = 33,242; 27 observational, 1 RCT-WCD arm). The incidence of appropriate WCD therapy was 5 per 100 persons over 3 months (95% confidence interval [CI]: 3.0 to 6.0, I2 = 93%). In studies on ischemic cardiomyopathy, the appropriate WCD therapy incidence was lower in the VEST trial (1 per 100 persons over 3 months; 95% CI: 1.0 to 2.0) as compared with observational studies (11 per 100 persons over 3 months; 95% CI: 11.0 to 20.0; I2 = 93%). The incidence of inappropriate therapy was 2 per 100 persons over 3 months (95% CI: 1.0 to 3.0; I2 = 93%). Mortality while wearing WCD was rare at 0.7 per 100 persons over 3 months (95% CI: 0.3 to 1.7; I2 = 94%).

CONCLUSIONS

The rate of appropriately treated WCD patients over 3 months of follow-up was substantial; higher in-observational studies as compared with the VEST trial. There was significant heterogeneity. More RCTs are needed to justify continued use of WCD in primary prevention.

Role of the Wearable Defibrillator in Newly Diagnosed Heart Failure

PURPOSE OF REVIEW

The wearable defibrillator (WCD) was shown to be safe and effective in detecting and terminating ventricular tachyarrhythmias and therefore allows temporary protection from sudden cardiac death. This review gives an overview of the current data on WCD in newly diagnosed cardiomyopathy.

RECENT FINDINGS

Patients with newly diagnosed heart failure and reduced LVEF appear to have an increased risk of ventricular tachyarrhythmias, which may decrease over time when heart failure medication is optimized and left ventricular function improves. This was shown to apply for patients with ischemic and non-ischemic cardiomyopathy, including peripartum cardiomyopathy. Prolongation of the WCD period may support to further optimization of heart failure medication, by protecting the patient from sudden cardiac death during this time and to avoid untimely ICD implantation. The WCD should be considered in structured patient management for newly diagnosed heart failure during the early phase of the disease. Careful patient selection, structured patient management, and patient's compliance is crucial for a successful WCD strategy.

Misunderstood or Mistrusted? The Under-Utilization of the Wearable Cardioverter Defibrillator in Clinical Practice

Annually in the United States, sudden cardiac death (including out-of-hospital cardiac arrests) is responsible for over 300,000 deaths, comprising 40%-50% of total mortality rates from cardiovascular disease. Among the highest-risk patients are those with ischemic and nonischemic cardiomyopathy who have a reduced left ventricular ejection fraction (≤ 35%-40%). However, not everyone is a candidate for an implantable cardioverter defibrillator. In 2002, the wearable cardioverter defibrillator (WCD) gained Food and Drug Administration approval for its efficacy in the prevention of sudden cardiac arrest or death in certain at-risk populations and has been making its way into national guidelines with Class IIa to IIb strength of evidence. Despite the prevalence of sudden cardiac death and the demonstrated efficacy of the WCD, this technology remains under-prescribed. This study seeks to explicate the potential causes for under-utilization of WCDs and offer means of overcoming barriers to its use. Among these reasons include confusion about the guidelines and when to prescribe, who can prescribe the device, and debate about whether the WCD is efficacious based on recent studies. Other social barriers to prescription include cost and adherence to therapy by the patient. This study sets the stage for further research on the improvement of education about the device and opens discourse about its prescription in clinical practice.

Therapy optimization in patients with heart failure: the role of the wearable cardioverter-defibrillator in a real-world setting

Background

The wearable cardioverter-defibrillator (WCD) has emerged as a valuable tool to temporarily protect patients at risk for sudden cardiac death (SCD). The aim of this study was to determine the value of the WCD for therapy optimization of heart failure patients.

Methods

One hundred five consecutive patients that received WCD between 4/2012 and 9/2016 were included in the study. All patients were followed for clinical outcome and echocardiographic parameters during WCD therapy and had continued follow-up after WCD therapy, irrespective of subsequent implantable cardioverter-defibrillator (ICD) implantation.

Results

The most common indication for WCD were newly diagnosed ischemic (ICM) or non-ischemic cardiomyopathy (NICM) with left ventricular ejection fraction (LVEF) ≤35%. Mean WCD wear time was 68.8 ± 50.4 days with a mean daily use of 21.5 ± 3.5 h. Five patients (4.8%) received a total of five appropriate WCD shocks.

During WCD wear, patients with ICM and NICM showed significant improvement in LVEF, reducing the proportion of patients with a need for primary preventive ICD implantation to 54.8% (ICM) and 48.8% (NICM). An ICD was finally implanted in 51.4% of the study patients (24 trans-venous ICDs, 30 subcutaneous ICDs).

After discontinuation of WCD therapy, all patients were followed for a mean of 18.6 ± 12.3 months. 5.6% of patients with implanted ICDs received appropriate therapies. No patient with subcutaneous ICD needed change to a trans-venous device. None of the patients without an implanted ICD suffered from ventricular tachyarrhythmias and no patient died suddenly.

In patients with NICM a significant LVEF improvement was observed during long-term follow-up (from 34.8 ± 11.1% to 41.0 ± 10.2%).

Conclusions

WCD therapy successfully bridged all patients to either LVEF recovery or ICD implantation. Following WCD, ICD implantation could be avoided in almost half of the patients. In selected patients, prolongation of WCD therapy beyond 3 months might further prevent unnecessary ICD implantation. The WCD as an external monitoring system contributed important information to optimize device selection in patients that needed ICD implantation.

[Ventricular arrhythmias : What has been confirmed in therapy?]

Ventricular arrhythmias include a wide range of potentially benign single ventricular premature contractions to ventricular tachycardia and ventricular fibrillation with a risk for sudden cardiac death. The diagnosis of ventricular arrhythmia is made by 12-lead electrocardiogram, 24 h Holter monitoring, an external or implantable loop recorder, or during in-hospital monitoring. Especially the diagnosis of wide complex tachycardias is challenging in terms of differentiating between ventricular tachycardia and supraventricular tachycardia with aberrant atrioventricular conduction. After documentation of ventricular arrhythmias, diagnostic work-up with respect to structural or electrical cardiomyopathy is mandatory followed by risk stratification for sudden cardiac death. Therapeutic options for treatment of ventricular arrhythmias range from pharmacological therapy and interventional procedures such as catheter ablation and implantable devices. The current article provides an overview of the diagnosis of ventricular tachycardia and underlying cardiomyopathies. Furthermore, medical and interventional therapies are described. In addition, the indications for implantable and wearable defibrillators are presented.

Ventricular arrhythmias in patients with newly diagnosed nonischemic cardiomyopathy: Insights from the PROLONG study

BACKGROUND

Patients with nonischemic cardiomyopathy (NICM) reportedly have low incidence of appropriate shocks from wearable cardioverter-defibrillators (WCDs). A recent study questions the benefit from primary preventive implantation of implantable cardioverter-defibrillators in NICM. We therefore analyzed a subgroup of patients with NICM from the PROLONG study.

HYPOTHESIS

Patients with newly diagnosed NICM show a risk for ventricular tachyarrhythmia.

METHODS

The PROLONG study included 167 patients with newly diagnosed heart failure and left ventricular ejection fraction (LVEF) ≤35% with a WCD. Patients with NICM were identified and included in this analysis.

RESULTS

117 patients presented with NICM. Sixty-five (55%) were male; mean age was 51 ± 15 years. Mean LVEF at diagnosis was 23% ± 7%. Mean follow-up was 11 ± 10 months. Mean WCD wear time was 101 ± 82 days; mean wear time per day was 21.4 ± 4.5 hours. Overall, 12 ventricular arrhythmias occurred in 10 (9%) patients (6 DCM, 4 PPCM). Nine appropriate WCD shocks for hemodynamically unstable ventricular tachycardia/fibrillation in 8 (7%) patients were observed. Two patients presented sustained hemodynamically stable ventricular tachycardia for >30 minutes detected by the WCD, but withheld WCD therapy.

CONCLUSIONS

Patients with newly diagnosed NICM and LVEF ≤35% show an elevated risk of ventricular tachycardia/fibrillation during initiation and optimization of heart failure therapy. To prevent sudden cardiac death, WCD should be considered in patients with newly diagnosed NICM with severely reduced LVEF.