Stellungnahme zum Einsatz des tragbaren Kardioverter/Defibrillators

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.

[Patients with a wearable cardioverter-defibrillator (WCD) : Prescription, function and rehabilitation support]

Assessment of a permanent risk of life-threatening ventricular arrhythmia in patients with severely reduced left ventricular ejection fraction (LVEF <35%), e. g. after myocarditis, dilated cardiomyopathy, acute myocardial infarction, in patients with postpartum cardiomyopathy or implantable cardioverter-defibrillator (ICD) and cardiac resynchronization treatment plus defibrillator (CRT-D) infection with temporary explantation of the system is a medical challenge. This is time-consuming and unsafe because life-threatening ventricular arrhythmias may occur during the time of risk assessment. During this phase of risk stratification, a wearable cardioverter-defibrillator (WCD) is indicated. The WCD, which is usually worn by the patient for several months, combines continuous retrievable electrocardiogram (ECG) recordings with a reliable defibrillation capability. The prescription of a WCD guarantees safe rehabilitation procedures for patients following acute inpatient treatment. Rehabilitation measures in patients with a WCD are indicated because of the underlying systolic cardiac insufficiency due to severe myocardial disease. In almost half of the patients, who are potentially threatened by ventricular tachyarrhythmias or sudden cardiac death (SCD), the LVEF and heart failure symptoms improve under controlled medication within a few months. Thus, the risk of SCD is lowered so that in many cases a first line ICD implantation is no longer necessary. The purpose of this article is to provide recommendations for rehabilitation procedures of patients with a WCD. A review of the currently available data on WCD publications was carried out with special emphasis on the current national and international guidelines.

[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.

The wearable cardioverter-defibrillator: current technology and evolving indications

The wearable cardioverter-defibrillator has been available for over a decade and now is frequently prescribed for patients deemed at high arrhythmic risk in whom the underlying pathology is potentially reversible or who are awaiting an implantable cardioverter-defibrillator. The use of the wearable cardioverter-defibrillator is included in the new 2015 ESC guidelines for the management of ventricular arrhythmias and prevention of sudden cardiac death. The present review provides insight into the current technology and an overview of this approach.

Avoiding Untimely Implantable Cardioverter/Defibrillator Implantation by Intensified Heart Failure Therapy Optimization Supported by the Wearable Cardioverter/Defibrillator-The PROLONG Study

BACKGROUND

Optimal timing of implantation of an implantable cardioverter/defibrillator (ICD) after newly diagnosed heart failure is unclear given that late reverse remodelling may occur. We aimed to analyze left ventricular ejection fraction (LVEF) after diagnosis of an LVEF ≤35% during optimization of heart failure drug therapy.

METHODS AND RESULTS

One hundred fifty-six patients with newly diagnosed LVEF ≤35% receiving a wearable cardioverter/defibrillator (WCD) were analyzed. WCD was prescribed for 3 months until first re-evaluation. Indications for prolongation of WCD wearing period instead of ICD implantation were: (1) LVEF at 3-month visit 30% to 35%; (2) increase in LVEF of ≥5% compared to the last visit; and (3) nonoptimized heart failure medication. Mean LVEF was 24±7% at diagnosis and 39±11% at last follow-up (mean, 12±10 months). Whereas 88 patients presented a primary preventive ICD indication (LVEF ≤35%) at 3-month follow-up, only 58 showed a persistent primary preventive ICD indication at last follow-up. This delayed improvement in LVEF was related to nonischemic origin of cardiomyopathy, New York Heart Association functional class at baseline, heart rate, better LVEF after 3 months, and higher dosages of mineralocorticoid receptor antagonist. Twelve appropriate WCD shocks for ventricular tachycardia/ventricular fibrillation occurred in 11 patients. Two patients suffered from ventricular tachycardia/ventricular fibrillation beyond 3 months after diagnosis.

CONCLUSIONS

A relevant proportion of patients with newly diagnosed heart failure shows recovery of LVEF >35% beyond 3 months after initiation of heart failure therapy. To avoid untimely ICD implantation, prolongation of WCD period should be considered in these patients to prevent sudden cardiac death while allowing left ventricular reverse remodeling during intensified drug therapy.

[Updated ESC guideline: innovations for the treatment of ventricular arrhythmias and recommendations for prevention of sudden cardiac death]

The 2015 European Society of Cardiology Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death is an update of the former 2006 European/American guidelines. This new consensus document gives a detailed overview on prevention and therapy of ventricular arrhythmias and sudden cardiac death. This includes detailed discussion of channelopathies and various cardiomyopathies. Gaps in evidence are identified and also discussed. DNA analysis and postmortem assessment in sudden cardiac death victims is for the first time part of these new recommendations. In addition, for the first time recommendations on subcutaneous implantable cardioverter-defibrillator (ICD) and the wearable defibrillator are given. The guidelines strengthen the role of ICD therapy in primary and secondary prevention of sudden cardiac death although data used as the basis for these recommendations are 10-15 years old and patients' characteristics including therapeutic options have changed during that time. Systematic reassessment of left ventricular function 6-12 weeks after infarction is also included as a new recommendation. The role of catheter ablation in electrical storm and for those presenting with a first episode of sustained ventricular tachycardia has also been upgraded in the new guidelines. Hopefully, the new guidelines will reach not only cardiologists and help to improve patient care, but also contribute to reducing the high number sudden cardiac deaths in Europe.

[The wearable cardioverter/defibrillator : Temporary protection from sudden cardiac death]

In the majority of cases sudden cardiac death (SCD) is caused by ventricular tachyarrhythmia. Implantable cardioverter-defibrillators (ICD) represent an evidence-based and established method for prevention of SCD. For patients who do not fulfill the criteria for guideline-conform implantation of an ICD but still have an increased, e.g. transient risk for SCD, a wearable cardioverter-defibrillator (WCD) vest was developed to temporarily prevent SCD. Numerous studies have shown the safety and efficacy of the WCD, although there is still a gap in evidence concerning a reduction in overall mortality and improvement in prognosis. This article gives an overview on the currently available literature on WCD, the indications, potential risks and complications.

Experience With the Wearable Cardioverter-Defibrillator in Patients at High Risk for Sudden Cardiac Death

Supplemental Digital Content is available in the text.

Background:

This study evaluated the wearable cardioverter-defibrillator (WCD) for use and effectiveness in preventing sudden death caused by ventricular tachyarrhythmia or fibrillation.

Methods:

From April 2010 through October 2013, 6043 German WCD patients (median age, 57 years; male, 78.5%) were recruited from 404 German centers. Deidentified German patient data were used for a retrospective, nonrandomized analysis.

Results:

Ninety-four patients (1.6%) were treated by the WCD in response to ventricular tachyarrhythmia/fibrillation. The incidence rate was 8.4 (95% confidence interval, 6.8–10.2) per 100 patient-years. Patients with implantable cardioverter-defibrillator explantation had an incidence rate of 19.3 (95% confidence interval, 12.2–29.0) per 100 patient-years. In contrast, an incidence rate of 8.2 (95% confidence interval, 6.4–10.3) was observed in the remaining cardiac diagnosis groups, including dilated cardiomyopathy, myocarditis, and ischemic and nonischemic cardiomyopathies. Among 120 shocked patients, 112 (93%) survived 24 hours after treatment, whereas asystole was observed in 2 patients (0.03%) with 1 resulting death.

ConclusionS:

This large cohort represents the first nationwide evaluation of WCD use in patients outside the US healthcare system and confirms the overall value of the WCD in German treatment pathways.

[Mismanagement in the arrhythmia recognition algorithm of the LifeVest® with consecutive fatal outcome]

We describe for the first time the misinterpretation of a wearable cardioverter defibrillator in the arrhythmia recognition algorithm with subsequent fatal outcome of a multi-morbid patient with an ischemic cardiomyopathy and a highly reduced left ventricular pump function (30 %). The patient's death was preceded by a life-threatening shockable rhythm which was repeatedly documented, but ultimately not correctly recognized by the system and therefore not treated.

[The Wearable Cardioverter-Defibrillator (WCD)]

While the implantable cardioverter-defibrillator (ICD) has been proven to be the best choice for patients with long-term risk for sudden cardiac arrest/sudden cardiac death (SCA/SCD), the question is how to manage patients with only temporary risk, e.g., during the guidelines-recommended waiting period until the decision for an ICD can be made. These patient groups should be monitored around the clock to guarantee a lifesaving shock within a few minutes, if necessary.These conditions can be accomplished by the wearable cardioverter-defibrillator (WCD) in the outpatient sector. The WCD is worn on the skin and consists of four nonadhesive ECG electrodes as well as three defibrillation electrodes-two at the back and one at the front-embedded in a garment. The defibrillation unit is connected via a cord and can be worn over the shoulder or on a belt. Cardiac events can be recorded and retrospectively analyzed by the treating physician.The WCD is a safe and effective measure to terminate potentially lethal ventricular tachycardia and ventricular fibrillation. It may be used early after myocardial infarction with reduced left ventricular ejection fraction (LVEF), as well as for patients with acute heart failure in nonischemic cardiomyopathy with uncertain cause and prognosis. In addition, it may be used for patients waiting for heart transplantation, for patients who cannot be implanted an ICD due to comorbidities, and for patients after explantation of their ICD, e.g., because of infection until reimplantation.One may expect that risk stratification of patients with the WCD will lead to even better selection for ICD use.