Prä- oder intrahospitaler Herz-Kreislauf-Stillstand

Analysis of the effect of cortisone on the QT interval

BACKGROUND

Cardiac death caused by malignant arrhythmias is very prevalent. Prolongation of the QT interval is a relevant aspect in arrhythmia mechanisms. Prior studies have revealed that the QTc interval could be shortened by cortisone. Moreover, in an animal model of long QT syndrome, cortisone treatment shortens the ventricular action potential duration. The present study investigated the effect of methylprednisolone (MPS) on the QTc interval in cardiovascularly healthy humans.

METHODS

Patients who had just been diagnosed with multiple sclerosis receiving MPS therapy were analysed prospectively. Demographic data, laboratory values, anti-arrhythmic medication and baseline and follow-up ECGs were extracted from the patients' medical records.

RESULTS

Seventy-eight patients were included. The mean ± standard deviation age was 47 ± 15 years. The values of the electrolytes were normal. All patients were treated with MPS for 3 or 5 days. The heart rate increased at the beginning of MPS therapy and decreased during the subsequent period. ECG measurements showed that the QTc interval was prolonged at the beginning of MPS therapy and shortened over the course of treatment. The longest QTc intervals were obtained by calculation with Bazett's formula.

CONCLUSIONS

In humans, cortisone shortens the QTc interval over time. The analysis indicates a cumulative effect of cortisone that lasts longer. The results of our pilot study reveal that cortisone might be added to therapeutic strategies in patients with long QT syndromes. Further clinical studies have to be carried out to analyze potential clinical options.

[ECG results: tips and tricks for the correct diagnosis : Bradycardia and tachycardia rhythm disorders]

The 12-lead surface electrocardiogram (ECG) is of great importance for the diagnostics of cardiac arrhythmias. For the correct and systematic analysis it has a sensitivity and specificity for the correct diagnosis of supraventricular tachycardia or ventricular tachycardia of more than 95%. Nevertheless, the assessment of cardiac rhythm disorders is difficult for many physicians. In this way errors can occur, frequently due to a non-systematic analysis of the ECG; therefore, the aim of this article is to present the techniques and the necessary knowledge for assessment of the most frequent bradycardiac and tachycardiac heart rhythm disorders. Additionally, special features in the analysis of the ECG results in children are discussed.

[Identification of common locations of out-of-hospital cardiac arrests in a German metropolis]

BACKGROUND

Most patients who suffer a sudden cardiac arrest initially have a shockable rhythm. Fast defibrillation and correctly performed cardiopulmonary resuscitation (CPR) are key factors for patient survival. These can be carried out by bystanders if an automated external defibrillator (AED) is available even in the absence of emergency services.

AIM

The place and time of CPRs in a German city were investigated and the strategic placement of emergency medical services and AEDs necessary were evaluated.

METHODS

All prehospital resuscitation attempts by Bochum's emergency services in 2011 were retrospectively analyzed. The city was divided into a grid, according to the city map to describe the location of every resuscitation. The distribution of cases was correlated to the city grid and time of day.

RESULTS

There were 299 cardiac arrests (mean age 74.2 ± 12.47 years; 59% of patients were male). Most resuscitations happened in a home environment between 8 am and 8 pm. There was a higher proportion of resuscitation attempts in grid squares with a high population density. Of the resuscitations in public places 16 of 47 (34%) happened in city district centers. In 72% of all cases, only a nonshockable rhythm could be documented as primary arrhythmia on the arrival of the emergency services. Of the 299 attempted resuscitations, a return of spontaneous circulation was achieved in 41%.

CONCLUSIONS

The knowledge about increased frequency of resuscitations in city centers provides insight for strategic placement of emergency devices and services in those areas. This can possibly minimize the time until first response and enables early defibrillation with AED in a first-responder program. In addition, bystanders should obtain clear instructions for resuscitation by the dispatcher of the emergency services.

[Worldwide experience with automated external defibrillators: What have we achieved? What else can we expect?]

INTRODUCTION

In Germany approximately 70,000-100,000 SCD patients die from sudden cardiac death (SCD). SCD is not caused by a single factor but is a multifactorial problem. In 50 % of SCD victims, sudden cardiac death is the first manifestation of heart disease. SCD is caused by ventricular tachyarrhythmias in approximately 90 % of patients, whereas SCD is caused by bradyarrhythmias in 5-10 % of the patients.

METHODS

Risk stratification is not possible in the majority of them prior to the fatal event. Early defibrillation is the method of choice to terminate ventricular fibrillation. Therefore, it is mandatory to install automatic external defibrillators (AED) in places with many people. There is general agreement that early defibrillation with automated external defibrillators (AED) is an effective tool to treat patients with ventricular fibrillation and will improve survival.

CONCLUSION

It seems necessary to teach cardiocompression and AED use, also to children and adolescents. AED therapy "at home" did not improve survival in patients with cardiac arrest and can not be recommended.

[Fundamentals of 12-lead electrocardiography in intensive care medicine]

The surface electrocardiogram (ECG) is an important diagnostic tool for the diagnosis of arrhythmias and acute coronary syndrome. Arrhythmias are divided into bradycardias (heart rate < 50/min) and tachycardias (heart rate > 100/min). Among tachycardias, differentiation between small QRS complexes (QRS width < 0.12 s) and broad QRS compexes (≥ 0.12 s) during tachycardia is necessary. It is important to analyze the relationship between P wave and QRS complex, to look for an electric alternans as a leading finding for an accessory pathway. Wide QRS complex tachycardias (QRS width ≥ 0.12 s) occur in supraventricular tachycardias (SVT) with aberrant conduction, SVT with bundle branch block or ventricular tachycardia (VT). In broad complex tachycardias, atrioventricular (AV) dissociation, negative or positive concordant pattern in V1-V6, a notch in V1, and qR complexes in V6 in tachycardias with left bundle branch block morphologies are findings indicating VT. In addition, an R/S relationship < 1 in V6 favors VT when right bundle branch block tachycardia morphologies are present. By correctly analyzing the surface ECG with a systematic approach, the specificity and sensitivity of correctly identifying a SVT or VT can be increased to greater than 95 %. The12-lead surface ECG is an important diagnostic tool for intensive care medicine. However, good ECG knowledge and systematic analysis are necessary to make the right diagnosis.

[Ten years of early defibrillation: "Bochum against sudden cardiac death". Acceptance and critical analysis of using automated external defibrillators]

BACKGROUND

There is a comprehensive early defibrillation program in Bochum (Germany); since 2003 a total of 175 automated external defibrillators (AEDs) have been installed in urban areas by the city of Bochum and private companies. These were preferably installed in places with high foot traffic, e.g., public buildings, companies, and event/shopping centers. Approximately 15,000 laypeople who work in the vicinity of the AED locations were trained in the use of defibrillators and in basic resuscitation. In addition, rescue workers on fire trucks and medically trained personnel in physicians' medical practices were equipped as "first responders" with AEDs.

RESULTS

After an initiation phase, all available information after each AED use since August 2004 has been collected by the project coordinator. During the period of data collection (August 2004 to August 2013), an AED was used in a total of 17 patients who had suffered sudden cardiac death (SCD) under the project in Bochum. Eleven patients had primary ventricular fibrillation (VF). Six of these survived without neurological deficit. In another 6 patients, a nondefibrillatable rhythm disorder was diagnosed. The AEDs are reliable and showed impeccable rhythm analysis before the instructions to provide any necessary shock.

DISCUSSION

Compared to the number of existing units and an estimated number of 37-100 SCD/100,000, the use of the AEDs only 17 times appears relatively small. To improve the effectiveness of the AED program in Bochum, an analysis of the emergency service responses, which were necessary because of sudden circulatory collapse, is currently being performed. This will allow areas with an increased incidence of SCD to be identified and a plan for the strategic placement of AED and emergency services can be made.

[Sudden cardiac death and automated external defibrillators. Where we are in 2012?]

Sudden cardiac death (SCD) is one of the major problems in the western world with approximately 70.000-100.000 SCD patients (pts) in Germany and 450.000 SCD victims in the US. SCD is not caused by a single factor but is a multifactorial problem. SCD is caused by ventricular tachyarrhythmias in approximately 90% of pts, whereas SCD is caused by bradyarrhythmias in 5-10%. In 50% of SCD victims, sudden cardiac death is the first manifestation of a heart disease. There is general agreement that early defibrillation with automated external defibrillators (AED) is an effective tool to treat pts with ventricular fibrillation. Nevertheless, further stragies on cardiopulmonary resuscitation and AED therapy are necessary to improve survival of patients with cardiac arrest.

[Life-threatening brady- and tachyarrhythmias]

Bradycardic (heart rate<50/min) and tachycardic heart rhythm disturbances (100/min) require rapid therapeutic strategies. Supraventricular tachycardias (SVT) are sinus tachycardia, atrial tachycardia, AV-nodal reentrant tachycardia and tachycardia due to accessory pathways. Mostly SVT are characterized by small QRS complexes (QRS width<0.12 ms). It is essential to evaluate the arrhythmia history, to perform a good physical examination and to exactly analyze the 12-lead electrocardiogram. An exact diagnosis is then possible in >90% of SVT patients. Ventricular tachycardias have a broad QRS complex (>or=0.12 s), ventricular flutter and ventricular fibrillation are associated with chaotic electrophysiologic findings. For acute therapy, we will present the new concept of the "5A" that includes adenosine, adrenaline, ajmaline, amiodarone and atropine. Additional "B, C and D strategies" include betablocking agents, cardioversion as well as defibrillation. The "5A" concept allows a safe and effective antiarrhythmic treatment of all bradycardic and tachycardic arrhythmias as well as asystolia.