Herzrhythmusstörungen in der Intensivmedizin

Ohne Zusammenfassung     

Akuttherapie bei bradykarden Rhythmusstörungen oder Schrittmachernotfällen

Bradyarrhythmia (BA) is caused by sinus node dysfunction (SND), high degree atrioventricular (AV) block or bundle branch blocks. SNDs can be sinus bradycardia or sinus arrest. First degree AV-blocks are caused by rhythm disturbances in the atrium, AV nodes, bundle of His or the Tawara system. First or second degree AV blocks are seen very frequently within 24 h after an infarct and these arrhythmias are frequently transient and no longer present after 72 h. Third degree AV blocks are also frequently transient in patients with inferoposterior myocardial infarction (MI) and permanent in patients with anterior MI. In patients with BA iv atropine (1–3 mg) is helpful in 70–80% and will lead to an increased heart rate. The need for pacemaker stimulation (PM) is different in patients with inferior (IMI) or anterior MI (AMI). Whereas BA is frequently transient in patients with IMI without the need of permanent PM, there is usually a need of permanent PM in patients with AMI. In these patients BA is mainly caused by septal necrosis. PM emergencies are relatively rare, however, they can lead to life-threatening clinical situations. Bradycardia without PM-SA is mainly caused by pacing or sensing problems and myopotentials, whereas bradycardia with PM-SA is frequently observed in patients with exit-block, oversensing and pacemaker syndrome. In bradycardia-related pacemaker emergencies application of atropine (0.5 mg iv) or orciprenalin (0.25–0.5 mg iv) is necessary. If these strategies fail transvenous or transcutaneous external stimulation is necessary and cardiopulmonary resuscitation is mandatory when asystole is present.     

Contrast medium induced nephropathy in patients undergoing percutaneous coronary intervention for acute coronary syndrome: differences in STEMI and NSTEMI

Abstract  

The aim of this study was to assess the incidence, clinical predictors, and outcome of patients developing contrast medium induced nephropathy (CIN) after percutaneous coronary intervention (PCI) for acute coronary syndrome (ACS).     

Prevalence of ventricular discordance and its relation to functional capacity in idiopathic dilated cardiomyopathy

Introduction  Although left ventricular (LV) dilatation is the most distinguishing morphologic feature of idiopathic dilated cardiomyopathy (IDC), right ventricular (RV) dilatation may variably contribute to total cardiac enlargement. The prevalence and functional importance of the relative degree of left and right ventricular dilatation has not been comprehensively studied using cardiac magnetic resonance imaging (MRI). Methods  Our prospective study included 58 consecutive IDC patients with a LV ejection fraction <40% and NYHA functional class ≥2. MRI was performed with a 1.5 Tesla scanner for RV and LV dimensional and functional analysis. Cardiopulmonary exercise testing was used for evaluation of exercise capacity. Patients were grouped into tertiles based on the distribution of LV end-diastolic volume. Results  Compared to control subjects a considerable heterogeneity in the relative degree of left and right ventricular dilatation was noted in IDC patients. Within the entire patient group, a strong correlation between the degree of ventricular volume discordance and the extent of LV enlargement was observed (r = 0.8; P < 0.001). Tertile analysis revealed that the LV/RV volume ratio significantly differed in the three subgroups of patients (1.0 ± 0.3 vs. 1.5 ± 0.4 vs. 2.1 ± 0.9; P < 0.001). Only weak correlations between MRI data and patients’ functional capacity were found. LV ejection fraction was identified as the only independent predictor of maximum oxygen consumption in our setting. Conclusion  In IDC patients the degree of ventricular volume discordance is strongly related to the extent of left ventricular enlargement. However, comprehensive biventricular assessment of cardiac function by MRI adds little to our understanding of the cardiac mechanisms limiting exercise tolerance when compared to exclusive left ventricular measurements.     

Examining impulsivity as an endophenotype using a behavioral approach: a DRD2 TaqI A and DRD4 48-bp VNTR association study

Background  

Research on the genetic basis for impulsivity has revealed an array of ambiguous findings. This may be a result of limitations to self-report assessments of impulsivity. Behavioral measures that assess more narrowly defined aspects of impulsivity may clarify genetic influences. This study examined the relationship between possession of the DRD2 TaqI A and DRD4 48 bp VNTR genetic polymorphisms and performance on a behavioral measure of impulsivity, the delay discounting task (DDT), and three traditional self-report measures.     

Notfälle bei Herzschrittmacherpatienten

Pacemaker emergencies are relatively rare; however, they can lead to life-threatening clinical situations. In emergencies, evaluation of clinical characteristics and exact analysis of a surface ECG is mandatory. There are “early” complications (within 6 months after pacemaker [PM] implant) and “late” complications observed during long-term follow-up. Among “early” complications, infection, perforation, hematothorax, pneumothorax and dislocation of electrodes are well known. Among “late” complications it seems helpful to identify bradycardias with or without PMstimulus artifacts (SA). Bradycardia without PM-SA are mainly caused by pacing or sensing problems and myopotentials, whereas bradycardia with PM-SA were frequently observed in patients with exit block, oversensing and pacemaker syndrome. In bradycardia- related pacemaker emergencies application of atropine (0.5 mg i.v.) or orciprenalin (0.25–0.5 mg i.v.) is necessary. If these strategies fail transvenous or transcutaneous external stimulation is necessary; cardiopulmonary resuscitation is mandatory when asystole is present. Tachycardias can be caused by implanted PM (“PMT”) or caused by other reasons. Diagnosis of PMT is relatively easy in patients with sequential PM using surface ECG. In these patients vagal maneuvers are the first therapeutic options. Interference in implanted cardiac devices are possible by direct electric energy and electromagnetic interference. Driving should only be limited for the first week after PM implantation.     

The RIONI study rationale and design: validation of the first stored electrograms transmitted via home monitoring in patients with implantable defibrillators.

Appropriate and inappropriate therapies of implantable cardioverter defibrillators (ICDs) have a major impact on morbidity and quality of life in ICD recipients. The recently introduced home monitoring of ICD devices is a promising new technique which remotely offers information about the status of the system. Stored intracardiac electrograms (IEGMs), which are essential for correct classification of appropriate and inappropriate ICD discharges, have until now not been available with ICD home monitoring on a day-by-day basis because of limitations of transferable data. We demonstrate the first compressed IEGMs daily transferable via home monitoring (IEGM-online). Validation of these electrograms will be performed in the Reliability of IEGM-Online Interpretation (RIONI) study. A total of 210 episodes of stored IEGMs will be collected by at least 12 European centres. The primary endpoint of this study is to investigate whether the IEGM-online based evaluation of the appropriateness of the ICDs therapeutic decision following episode detection is equivalent to the evaluation based on the complete ICD episode Holter extracted from the IEGM stored. The evaluation is independently done by an expert board of three experienced ICD investigators. The equivalence of the two methods is accepted if the evaluations yield a different conclusion for <10% of all evaluated IEGMs. The conclusion of the study is expected at the beginning of 2007. If RIONI successfully validates IEGMs transmitted via home monitoring, a strong basis for the use of this promising technique will be established.