[From loss of consciousness to syncope]. / Vom Bewusstseinsverlust zur Synkope.

Syncope is the most frequent cause for transient loss of consciousness. Recent ESC guidelines pinpoint the position of syncope within the context of loss of consciousness. The individual risk of syncope is determined by various factors. Odds are that almost one in two women and one in four men suffers from syncope at least once in their lives. Age-dependent risk is highest at both the age of 15 and after the 60(th) birthday. Only a fraction of cases are witnessed by a doctor, which makes it difficult to analyze. Prognosis after syncope is strictly related to the existence of structural heart disease. Therefore, its diagnosis and therapy should be given priority. In case of high risk of recurrence, syncope should be adequately treated to prevent further relapse, regardless of the primary disease. Syncopes are classified on the basis of their pathophysiological cause: reflex syncope, orthostatic syncope, arrhythmic cardiac syncope, mechanically caused syncope due to structural cardiovascular disease, and syncope due to cerebrovascular disease. The cause of up to one third of syncopes remains unknown; however, the majority of which are probably reflex syncopes.

[Antithrombotic therapy in atrial fibrillation: when vitamin K antagonists? When aspirin? When heparin? When combinations of anticoagulant and antiplatelet drugs?]. / Thromboembolieprophylaxe bei Vorhofflimmern : Wann orale Antikoagulanzien? Wann Aspirin? Wann Heparine? Wann Kombinationen?

Morbidity and mortality associated with atrial fibrillation are mainly related to thromboembolic complications, particularly ischemic strokes. The prevention of thromboembolism is an important component in the management of patients with atrial fibrillation. The choice of optimum antithrombotic therapy for a given patient depends on the risk of thromboembolism, on the one hand, and the risk of intracerebral hemorrhage, on the other hand. Concerning the benefit-to-risk stratification the problem lies in the similar and sometimes even identical risk factors for both thromboembolism and haemorrhage.At present, oral vitamin K antagonists are recommended for patients with atrial fibrillation at moderate or high risk of ischemic stroke. The thromboembolic risk should be assessed using validated stratification schemes, such as the CHADS(2) score. Aspirin alone is recommended for patients at low risk of thromboembolic complications. A combination of anticoagulant and antiplatelet drugs is necessary in patients with atrial fibrillation undergoing percutaneous coronary intervention and stent implantation, but the optimal therapeutic management of these patients has not yet been defined. Hopefully, the development of new antithrombotic agents being easier to use and having a superior benefit-to-risk ratio will extend effective prevention of thromboembolic events to a greater part of the atrial fibrillation population at risk.

Antibiotic resistant pathogenic bacteria and their resistance genes in bacterial biofilms.

Biofilm-forming bacteria are ubiquitous in the environment and also include biofilm-forming pathogens. Environmental biofilms may form a reservoir for risk genes and may act as a challenge for human health. Examples of the health relevance of biofilms are the increase in antibiotic resistant bacteria hosted in biofilms in hospital and environment and consequently the interaction of these bacteria with human cells, e.g. in the immune system. Although data concerning the occurrence and spread of resistant bacteria within hospital care units are available, the fate of these bacteria in the environment and especially in the aquatic environment has barely been investigated. Once antibiotic resistant bacteria have entered the environment, a back coupling by ingestion or other possible entry into the host has to be prevented. Therefore a strategy to investigate paths of entry, accumulation and spread of resistant bacteria in environmental compartments has been developed using quantitative determination of genetic resistance determinants. Additionally a bacterial bioassay assessed bioeffectivity thresholds of low antibiotic concentrations. This approach enables an evaluation of the potential of contaminated waters to exert a selection pressure on bacterial communities and thus promote the persistence of resistant organisms. Completed with an indicator system for the identification of sources of multiresistant bacteria a concept for monitoring and evaluation of environmental compartments with respect to their potential of antibiotic resistance dissemination is suggested.

[Cardiac resynchronization therapy: who is suitable? Who requires an additional ICD as a backup?]. / Kardiale Resynchronisation: Wer ist geeignet?--Wer benötigt einen zusätzlichen ICD als Backup?

Cardiac resynchronization therapy (CRT) has significant positive effects on the quality of life, enables patients to cope more efficiently with cardiopulmonary stress and leads to a reduction of total mortality in patients suffering from congestive heart failure NYHA classes III and IV, reduced ventricular function and left bundle branch block with a QRS complex wider than 150 ms. In a large number of patients suited for CRT, an additional defibrillator function seems to work out well concerning an additional prognostic improvement by means of reducing sudden cardiac death. Due to partially contradictory study outcomes, it still remains to be discussed whether all patients suited for CRT really need an ICD.

[Atrial fibrillation--frequency control or cardioversion?]. / Vorhofflimmern--Frequenzkontrolle oder Rhythmisierung?

Atrial fibrillation is the most common arrhythmia in need of treatment in clinic and practice. Nevertheless, many principles of therapy for the treatment of atrial fibrillation are based still at present on empirical principles but not on knowledge obtained in proved clinical trials. So far scientific data are not sufficient for therapy recommendation "cardioversion or rate control". At present this question is examined in randomized clinical trials; however, the results will not be available until at least the year 2000. Currently, the therapy strategy (cardioversion versus rate control) is decided individually. Doing this the complaints of the patients and the principle "nihil nocere" mainly determine the decision.

Double-blind, placebo-controlled cross-over study of intravenous S-adenosyl-L-methionine in patients with fibromyalgia.

The objective of this study was to test the efficacy of intravenously administered S-adenosyl-L-methionine (SAMe) in patients with fibromyalgia (FM). Thirty-four out-patients with fibromyalgia symptoms received SAMe 600 mg i.v. or placebo daily for 10 days in a cross-over trial. There was no significant difference in improvement in the primary outcome: tender point change between the two treatment groups. There was a tendency towards statistical significance in favour of SAMe on subjective perception of pain at rest (p = 0.08), pain on movement (p = 0.11), and overall well-being (p = 0.17) and slight improvement only on fatigue, quality of sleep, morning stiffness, and on the Fibromyalgia Impact Questionnaire for pain. No effect could be observed on isokinetic muscle strength, Zerrsen self-assessment questionnaire, and the face scale. No effect of SAMe in patients with FM was found in this short term study.

Esophageal balloon electrode catheter for transthoracic recording of His-bundle potential with transesophageal atrial pacing.

To evaluate the influence of transesophageal atrial pacing of the transthoracic His potential identification, we combined signal-averaged ECG with transesophageal atrial pacing with low threshold for pacing averaging ECG recording. A tripolar 10 French esophageal balloon electrode catheter, with one cylindrical electrode on the tip of the catheter and two balloon electrodes on the cardiac side of the catheter, used in 53 patients, allowed a painless transesophageal atrial pacing and a high signal to noise distance in the signal-averaged ECG. Transesophageal atrial pacing allowed in 37 of 53 patients an identification of His potential by increasing the distance between the end of the atrial potential and the onset of the His potential in the pacing averaging ECG. The esophageal balloon electrode catheter allowed a painless transesophageal atrial pacing with low threshold for atrial capture during a long pacing time and a high signal to noise distance in the pacing averaging ECG. The increasing of the heart rate with transesophageal atrial pacing allowed the transthoracic identification of the His potential in the pacing averaging ECG.

[The pharmacokinetics of a new anti-arrhythmic substance, Z-2-amino-5-chlorobenzophenoneamidinohydrazone (AWD-G256)]. / Untersuchungen zur Pharmakokinetik der neuen antiarrhythmischen Substanz Z-2-Amino-5-chlorbenzophenonamidinohydrazonacetat (AWD-G256).

In 4 studies blood levels and metabolites of Z-2-amino-5-chlorobenzophenoneamidinohydrazoneacetate (AWD-G256) after different dosages and forms of application on patients and healthy volunteers were investigated. In addition the pharmacokinetic parameters were calculated. The determination of pharmacokinetic parameters was possible only after i.v. application of dosages higher than 0.30 mg.kg-1 b.m. as well as p.o. administration of dosages higher than 100 mg. The blood level curve after i.v. application demonstrated a 2-compartment model and after p.o. application a 1-compartment model. Exact pharmacokinetic data can't be clear estimated with this studies.

[Hemodynamic effects and adverse effects of the anti-arrhythmic substance AWD-G256 in man]. / Hämodynamische Effekte und Verträglichkeit der antiarrhythmischen Substanz AWD-G256 beim Menschen.

In 19 patients with different supraventricular tachycardias the antiarrhythmic drug AWD-G256 was studied to investigate the effects on hemodynamic parameters. Over all, stroke volume, pulmonary pressure and systemic blood pressure were not significantly altered. The only main adverse effect was a transient rise of serum transaminases in two patients. We conclude that AWD-G256 is usually hemodynamically tolerated, but the antiarrhythmically effective dosage is not reached yet.

[Clinical-electrophysiologic studies on the actions of the anti-arrhythmic substance AWD-G256 in man]. / Klinisch-elektrophysiologische Untersuchungzen zur Wirkung der antiarrhythmischen Substanz AWD-G256 beim Menschen.

The effects of the new antiarrhythmic drug AWD-G256 (1) were investigated by clinical electrophysiology (His bundle electrography, programmed electrical stimulation) in 19 patients with supraventricular tachycardias but without structural heart disease. In a maximal dosage of 0.45 mg/kg body mass 1 only minimally affects electrophysiological parameters of the impulse formation and conduction. At this time the therapeutic value of 1 is not clear.

Right ventricular conductance to establish closed-loop pacing.

Innovations in pacing technology, which include the addition of rate-responsive features to programmable pacemakers, can improve the quality of life of patients suffering from sick sinus syndrome. Among the strategies providing rate-adaptive cardiac pacing, the most attractive is the physiological restoration of closed-loop chronotropic control. This paper describes how autonomic nervous system (ANS) control information is extracted from dynamic measures of myocardial contractile performance obtained from unipolar conductance measurements using the stimulation electrode in the right ventricular cavity. The pacemaker uses the ANS information to modulate pacing rate and restore normal physiological control of heart rate. A new algorithm, regional effective slope quantity (RQ), for isolating the ANS signal was developed. The resulting signal, ventricular inotropic parameter (VIP), is a normalized parameter proportional to the strength of the ANS inotropic signals to the myocardium. The efficacy of the ANS control concept was evaluated in multi-centre studies. Patients with AV block and VIP-controlled pulse generators performed defined exercise protocols. The ANS-controlled pacing rate and the spontaneous sinus rate were closely correlated. Blood pressure and subjective patient reports further indicated that good control of the cardiovascular circulation was achieved.

Autonomic nervous system controlled closed loop cardiac pacing.

A multicenter clinical study is presented, which focuses on the reestablishment of closed loop cardiac control in patients with chronotropic insufficiency. Using the information about sympathetic tone contained in the myocardial contractility, it is possible to reconnect the heart rate to the physiological control mechanisms. Intracardiac impedance is measured with the ventricular electrode and the ventricular inotropic parameter (VIP) is derived from that. The VIP serves directly as input to the control of heart rate by the pacemaker. Over 200 patients have received autonomic nervous system (ANS) controlled pacemakers. The patient-pacemaker system was investigated in different ways. This included standard exercise tests, long-term studies of every day activities over 24 hours, psychological, and pharmacological challenges. To prove the validity of the approach we specifically looked at (1) the appropriateness of changes in paced heart rate with sympathetic tone during exercise, (2) the correlation between heart rate and sinus rate, if detectable, and (3) the correlation between the echocardiographically determined preejection period (PEP) and the VIP controlled heart rate.

Balloon electrode catheter for transesophageal atrial pacing and transesophageal ECG recording.

A new balloon electrode catheter (10 French) with five or six balloon electrodes placed on the cardiac side was developed for transesophageal atrial pacing and bipolar ECG recording. The diameter of the hemispheric electrodes is 6 mm and the length of the esophageal balloon is 10 cm. The transesophageal atrial pacing threshold was measured with the balloon electrode catheter by transesophageal programmed atrial stimulation (TPS) (n = 54). At the onset of TPS, the feeling, capture (n = 54), and pain voltage threshold (n = 6) were measured by increasing the amplitude of the pacing voltage during high rate bipolar atrial pacing and bipolar atrial ECG recording. In 38 TPS, the capture threshold was lower than the feeling threshold (n = 28). In 16 TPS, the capture threshold was higher than the feeling threshold. In conclusion, painless atrial pacing and excellent ECG recording can be achieved with a multipolar esophageal balloon electrode catheter with a low pacing voltage amplitude and a high P wave amplitude.

Termination of tachycardias by transesophageal electrical pacing.

To evaluate the therapeutic significance of noninvasive transesophageal pacing for termination of tachycardias the method of rapid atrial or ventricular transesophageal pacing was used in 233 patients with different tachycardiac arrhythmias. We were able to terminate atrial flutter in 136 of 162 patients by transesophageal rapid atrial stimulation (conversion to sinus rhythm in 75 cases, induction of atrial fibrillation in 61 cases). Atrial tachycardias were interrupted in 17 of 23 patients (sinus rhythm in 11 cases, atrial fibrillation in six cases). AV reciprocating/AV nodal supraventricular reentry tachycardias were terminated in 62 of 63 patients (sinus rhythm in 58 cases, atrial fibrillation in four cases). By transesophageal rapid ventricular pacing ventricular tachycardias could be terminated in ten of 15 patients. The success rate of transesophageal pacing was influenced by the pacing rate, by the type of tachycardiac arrhythmia inclusive by the type of atrial flutter and by the tachycardia's cycle length. Because the success rates are comparable with invasive technique and the procedure is simpler, the noninvasive transesophageal antitachycardiac pacing should be respected as the method of the first choice in patients with supraventricular tachycardias.