Kommentar zu den ESC-Leitlinien 2015 „Ventrikuläre Arrhythmien und Prävention des plötzlichen Herztodes“

Sudden cardiac death while waiting: do we need the wearable cardioverter-defibrillator?

Sudden cardiac death (SCD) is the most frequent cause of cardiovascular death in industrialized nations. Patients with cardiomyopathy are at increased risk for SCD and may benefit from an implantable cardioverter-defibrillator (ICD). The risk of SCD is highest in the first months after myocardial infarction or first diagnosis of severe non-ischemic cardiomyopathy. On the other hand, left ventricular function may improve in a subset of patients to such an extent that an ICD might no longer be needed. To offer protection from a transient risk of SCD, the wearable cardioverter-defibrillator (WCD) is available. Results of the first randomized clinical trial investigating the role of the WCD after myocardial infarction were recently published. This review is intended to provide insight into data from the VEST trial, and to put these into perspective with studies and clinical experience. As a non-invasive, temporary therapy, the WCD may offer advantages over early ICD implantation. However, recent data demonstrate that patient compliance and education play a crucial role in this new concept of preventing SCD.

Validation of Algorithms to Identify Acute Myocardial Infarction, Stroke, and Cardiovascular Death in German Health Insurance Data

Purpose

Validation of outcomes allows measurement of and correction for potential misclassification and targeted adjustment of algorithms for case definition. The purpose of our study was to validate algorithms for identifying cases of acute myocardial infarction (AMI), stroke, and cardiovascular (CV) death using patient profiles, ie, chronological tabular summaries of relevant available information on a patient, extracted from pseudonymized German claims data.

Patients and Methods

Based on the German Pharmacoepidemiological Research Database (GePaRD), 250 cases were randomly selected (50% males) for each outcome between 2016 and 2017 based on the inclusion criteria age ≥50 years and continuous insurance ≥1 year and applying the following algorithms: hospitalization with a main diagnosis of AMI (ICD-10-GM codes I21.- and I22.-) or stroke (I63, I61, I64) or death with a hospitalization in the 60 days before with a main diagnosis of CV disease. Patient profiles were built including (i) age and sex, (ii) hospitalizations incl. diagnoses, procedures, discharge reasons, (iii) outpatient diagnoses incl. diagnostic certainty, physician specialty, (iv) outpatient encounters, and (v) outpatient dispensings. Using adjudication criteria based on clinical guidelines and risk factors, two trained physicians independently classified cases as “certain”, “probable”, “unlikely” or “not assessable”. Positive predictive values (PPVs) were calculated as percentage of confirmed cases among all assessable cases.

Results

For AMI, the overall PPV was 97.6% [95% confidence interval 94.8–99.1]. The PPV for any stroke was 94.8% [91.3–97.2] and higher for ischemic (98.3% [95.0–99.6]) than for hemorrhagic stroke (86.5% [76.5–93.3]). The PPV for CV death was 79.9% [74.4–84.4]. It increased to 91.7% [87.2–95.0] after excluding 32 cases with data insufficient for a decision.

Conclusion

Algorithms based on hospital diagnoses can identify AMI, stroke, and CV death from German claims data with high PPV. This was the first study to show that German claims data contain information suitable for outcome validation.

Automated mechanical cardiopulmonary resuscitation devices versus manual chest compressions in the treatment of cardiac arrest: protocol of a systematic review and meta-analysis comparing machine to human

INTRODUCTION

Cardiac arrest is a leading cause of death in industrialised countries. Cardiopulmonary resuscitation (CPR) guidelines follow the principles of closed chest compression as described for the first time in 1960. Mechanical CPR devices are designed to improve chest compression quality, thus considering the improvement of resuscitation outcomes. This protocol outlines a systematic review and meta-analysis methodology to assess trials investigating the therapeutic effect of automated mechanical CPR devices at the rate of return of spontaneous circulation, neurological state and secondary endpoints (including short-term and long-term survival, injuries and surrogate parameters for CPR quality) in comparison with manual chest compressions in adults with cardiac arrest.

METHODS AND ANALYSIS

A sensitive search strategy will be employed in established bibliographic databases from inception until the date of search, followed by forward and backward reference searching. We will include randomised and quasi-randomised trials in qualitative analysis thus comparing mechanical to manual CPR. Studies reporting survival outcomes will be included in quantitative analysis. Two reviewers will assess independently publications using a predefined data collection form. Standardised tools will be used for data extraction, risks of bias and quality of evidence. If enough studies are identified for meta-analysis, the measures of association will be calculated by dint of bivariate random-effects models. Statistical heterogeneity will be evaluated by I²-statistics and explored through sensitivity analysis. By comprehensive subgroup analysis we intend to identify subpopulations who may benefit from mechanical or manual CPR techniques. The reporting follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement.

ETHICS AND DISSEMINATION

No ethical approval will be needed because data from previous studies will be retrieved and analysed. Most resuscitation studies are conducted under an emergency exception for informed consent. This publication contains data deriving from a dissertation project. We will disseminate the results through publication in a peer-reviewed journal and at scientific conferences.

PROSPERO REGISTRATION NUMBER

CRD42017051633.

Acute management of ventricular tachycardia

Acute management of patients with ventricular arrhythmia (VA) is aimed at immediate VA termination if the patient is hemodynamically instable and early termination after initial diagnostic work-up if tolerated. Prolonged episodes of VA may lead to hemodynamic and metabolic decompensation and early resumption of normal ventricular activation is warranted. Termination is best performed by electrical cardioversion, anti-tachycardia pacing (if available, in cases with an implanted defibrillator [ICD]) or defibrillation. Antiarrhythmic drug treatment may lead to rhythm stabilization in cases of VA recurrence. Scrutinizing the electrocardiogram (ECG) of VA is extremely helpful to differentiate potential mechanisms, underlying cardiac pathologies and identify treatment options, as well as a differential diagnosis if a ventricular origin is unclear. In general, structural VA should be differentiated from idiopathic and non-structural (idiopathic) VA. On the other hand, based on ECG morphology VA should be classified into monomorphic versus polymorphic ventricular tacyhcardia (VT)/ventricular fibrillation (VF). Polymorphic VT/VF may be related to reversible causes as well as genetically determined arrhythmia syndromes and a specialized treatment pathway may be chosen: (1) VA termination, (2) evaluation and treatment of potential VA causes, (3) acute (medical treatment) and chronic (interventional treatment using catheter ablation) prevention of recurrence and (4) treatment of underlying heart disease, if identified, are crucial pillars of VA management. These patients can be managed in dedicated VT units and by multispecialty teams integrating all potential aspects of rhythm stabilization and treating underlying cardiac abnormalities. Heart failure management in patients with reduced left ventricular function may be crucial for the long-term prognosis.

Arrhythmia-Induced Cardiomyopathy

BACKGROUND

Heart failure affects 1–2% of the population and is associated with elevated morbidity and mortality. Cardiac arrhythmias are often a result of heart failure, but they can cause left-ventricular systolic dysfunction (LVSD) as an arrhythmia-induced cardiomyopathy (AIC). This causal relationship should be borne in mind by the physician treating a patient with systolic heart failure in association with cardiac arrhythmia.

METHODS

This review is based on pertinent publications retrieved by a selective search in PubMed (1987–2017) and on the recommendations in current guidelines.

RESULTS

The key criterion for the diagnosis of an AIC is the demonstration of a persistent arrhythmia (including pathological tachycardia) together with an LVSD whose origin cannot be explained on any other basis. Nearly any type of tachyarrhythmia or frequent ventricular extrasystoles can lead, if persistent, to a progressively severe LVSD. The underlying pathophysiologic mechanisms are incompletely understood; the increased ventricular rate, asynchronous cardiac contractions, and neurohumoral activation all seem to play a role. The most common precipitating factors are supraventricular tachycardias in children and atrial fibrillation in adults. Recent studies have shown that the causal significance of atrial fibrillation in otherwise unexplained LVSD is underappreciated. The treatment of AIC consists primarily of the treatment of the underlying arrhythmia, generally with drugs such as beta-blockers and amiodarone. Depending on the type of arrhythmia, catheter ablation for long-term treatment should also be considered where appropriate. The diagnosis of AIC is considered to be well established when the LVSD normalizes or improves within a few weeks or months of the start of targeted treatment of the arrhythmia.

CONCLUSION

An AIC is potentially reversible. The timely recognition of this condition and the appropriate treatment of the underlying arrhythmia can substantially improve patient outcomes.

[Diagnosis of ischemia and revascularization in patients with ventricular tachyarrhythmia]

Sustained ventricular tachyarrhythmia usually occurs on the basis of structural heart disease, particularly coronary heart disease (CAD). Although monomorphic ventricular tachycardia (VT) appears mainly in patients with CAD, it is typically not triggered by acute ischemia, in contrast to polymorphic VT or ventricular fibrillation (VF). To judge if VT is caused by acute ischemia is even more difficult in context with an elevated highly sensitive troponin T which is generally elevated in sustained VT because tachycardia in chronic stable coronary artery sclerosis causes a mismatch between increased oxygen demand and limited oxygen supply. Therefore, acute coronary angiography and revascularization may frequently not be necessary in monomorphic VT, will usually not improve rhythm stabilization, and may lead to misinterpretation of monomorphic VT being caused by a coronary stenosis. This can lead to withholding antiarrhythmic therapy after revascularization since it is assumed that the cause of VT has been treated. On the other hand, acute coronary angiography and revascularization are useful in polymorphic VT/VF, ECG signs of ischemia, or typical chest pain before occurrence of VT/VF. Coronary angiography should also be performed in patients with VT with newly diagnosed reduced left ventricular function and before catheter ablation.