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Der Einsatz aktiver Implantate ist in Deutschland vom Gesetzgeber im Medizinproduktegesetz sowie den zugehorigen Verordnungen geregelt. Uber die Medizinprodukte-Betreiberverordnung durfen Medizinprodukte nur von Personen betrieben oder angewendet werden, die eine dafur erforderliche Ausbildung und Erfahrung besitzen. Dies bedeutet, dass Arzte, die eine Therapie mit implantierbaren Defibrillatoren (ICD) anwenden, neben fundierten Kenntnissen in der Rhythmologie auch grundlegende technische Kenntnisse erwerben mussen. Die vorliegende „Sachkunde der ICD-Therapie“ fasst die Inhalte fur den Erwerb der erforderlichen Sachkunde und die vermittelten theoretischen Kenntnisse zusammen. Die Sachkunde behandelt neue Techniken wie den vollstandig subkutanen ICD und Veranderungen der Sonden Anschlusse sowie die aktuellen europaischen Leitlinien, neue Studien zur Indikation und Studien uber intraoperative Testungen und Programmierungsempfehlungen. In der Nachsorge wird insbesondere auf telemedizinische Abfragen und rechtliche Grundlagen sowie die aktuelle Studienlage hingewiesen. Gemeinsam mit den praktischen Erfahrungen, die in der klinischen Aus- und Weiterbildung erlangt werden, stellen die dargestellten Inhalte die Voraussetzung fur eine qualitativ hochwertige ICD-Therapie dar.

Als wissenschaftliche Fachgesellschaft vertritt die Deutsche Gesellschaft fur Kardiologie den Standpunkt, dass die Standards zur Durchfuhrung einer Katheterablation bei Patienten mit Vorhofflimmern (VHF) stetig kritisch betrachtet und angepasst werden mussen, um dauerhaft eine gute Behandlungsqualitat mit hoher Erfolgs- und geringer Komplikationsrate zu gewahrleisten. Das ist insbesondere auch deshalb notwendig, weil die Anzahl von Zentren und Kardiologen, die diese Intervention durchfuhren, rasant ansteigt. Im vorliegenden Positionspapier werden daher zunachst die aktuelle Datenlage zur Katheterablation von VHF sowie die Indikationsstellung zur Ablation, Komplikationen des Verfahrens und neueste Entwicklungen detailliert ausgefuhrt, bevor abschliesend eine Darstellung der personellen, technischen und raumlichen, strukturellen sowie organisatorischen Anforderungen an klinische Zentren erfolgt, an denen Katheterablationen von VHF durchgefuhrt werden.

Die ICD-Therapie hat sich durch eine Vielzahl randomisierter Studien in den vergangenen Jahren zu einem etablierten Bestandteil in der Behandlung von Herzerkrankungen und der Prophylaxe des plotzlichen Herztods entwickelt. Im internationalen Vergleich werden in Deutschland uberproportional viele ICD implantiert, ohne hierfur schlussige Grunde zu kennen. Moglicherweise liegt fur spezielle Patientengruppen eine Uberversorgung mit ICD vor. Eine individuelle Beurteilung in Anlehnung an Leitlinien und entsprechende Beratung von Patienten konnen hier wertvoll sein.

Implantable cardioverter defibrillators (ICD) have undoubtedly developed into one of the most successful therapies in the field of cardiology over the last decades; however, a significant number of ICD operations are carried out in patients who do not benefit from ICD therapy despite significant left ventricular dysfunction. These patients can easily be identified. An ICD therapy does not prolong life in the setting of significant chronic kidney disease. In elderly patients the benefit of prophylactic ICD therapy is very small. Simple risk scores can identify other patients who do not benefit from this treatment. The number of ICD operations can also be significantly reduced by the use of devices with an extended longevity.

The HAWAI registry evaluated the role of heart rate variability in predicting the occurrence of ventricular tachycardia and fibrillation (VT/VF) and sinus tachycardia in patients with an implantable cardioverter-defibrillator (45 patients with 155 RR recordings). A significant decrease of the mean value of all RR intervals (MeanNN) was observed in the period starting 20 and 40 min prior to VT/VF and sinus tachycardia, respectively. The standard deviation of RR intervals (SDNN) and the power at low frequency (LF) were the only parameters with significant changes prior to VT/VF. For sinus tachycardia, the root mean square of successive differences of all successive RR intervals (r-MSSD) and the power at low and high frequency (HF) decreased, whereas SDNN and the power at very low frequency increased. Comparison of RR recordings preceding VT/VF and sinus tachycardia revealed significant differences of the MeanNN, SDNN, r-MSSD, LF and HF. Based on a classification and regression tree analysis, MeanNN, SDNN and r-MSSD showed a sensitivity of 94.4% and a specificity of 50.6% as predictors of VT/VF. Our results suggest that the temporal changes in heart rate before an arrhythmic event can be used to predict the occurrence of VT/VF. These parameters may be used to optimize pacing therapies designed to prevent VT/VF recurrences as well as for improving device-based discriminators for VT/VF and sinus tachycardia.

In diesem Artikel soll eine Ubersicht uber wichtige, publizierte Arbeiten auf dem Gebiete der Therapie mit dem implantierbaren Kardioverter/Defibrillator (ICD) im Jahre 2012 gegeben werden. Wesentliche Arbeiten betrafen Analysen zur Therapieeffektivitat und -sicherheit des subkutan implantierbaren ICD, zu geschlechtsspezifischen Unterschieden in der Komplikationsrate und Prognose nach ICD-Implantation, zur Notwendigkeit der intraoperativen Testung der Defibrillationsschwelle und zur Beeinflussung der Prognose nach ICD-Implantation durch Verhinderung von ICD-Schockentladungen. Die Relevanz der Studienergebnisse fur den klinischen Alltag wird jeweils kurz diskutiert.

Implantable cardioverter defibrillators (ICD) have undoubtedly developed into one of the most successful therapies in the field of cardiology over the last decades; however, a significant number of ICD operations are carried out in patients who do not benefit from ICD therapy despite significant left ventricular dysfunction. These patients can easily be identified. An ICD therapy does not prolong life in the setting of significant chronic kidney disease. In elderly patients the benefit of prophylactic ICD therapy is very small. Simple risk scores can identify other patients who do not benefit from this treatment. The number of ICD operations can also be significantly reduced by the use of devices with an extended longevity.

Die kardiale Resynchronisationstherapie hat sich in den letzten 10 Jahren zu einem etablierten Verfahren zur Therapie der fortgeschrittenen Herzinsuffizienz bei Patienten mit Linksschenkelblock entwickelt. Wenngleich in Einzelfallen eine Proarrhythmie beschrieben wurde, so konnte doch in groseren Serien keine Haufung ventrikularer Tachyarrhythmie-Episoden gefunden werden. Persistierendes Vorhofflimmern konvertiert zumindest bei einem Teil der durch biventrikulare Stimulation behandelten Patienten wieder in Sinusrhythmus, moglicherweise abhangig von der Dauer des Vorhofflimmerns.

Bei Postinfarkt-Patienten konnte durch die prophylaktische Defibrillator-Implantation eine bedeutsame Senkung der Sterblichkeit erreicht werden. Dagegen bleibt die prophylaktische ICDImplantation bei Patienten mit idiopathischer dilatativer Kardiomyopathie umstritten. Die Ergebnisse von 2 Studien, die keinen Vorteil durch die ICD-Implantation zeigten (CAT, AMIOVIRT), werden im Kontext der noch nicht publizierten Daten der COMPANION-Studie diskutiert, in der die Kombination aus Resynchronisation und Defibrillation den gunstigsten Effekt zeigte.

This article aims to give an overview over important articles in the field of implantable cardioverter defibrillator (ICD) therapy in 2012. Important publications concern analyses on therapy efficacy and safety of the subcutaneous ICD, gender-specific differences in the complication rate and prognosis after ICD implantation, the necessity of intraoperative testing of the defibrillation threshold and the impact of preventive measures to reduce ICD therapies on prognosis after device implantation. The relevance of the study findings for daily clinical practice is briefly discussed.

Riata® and Riata ST® implantable cardioverter defibrillator (ICD) leads (St. Jude Medical, Sylmar, CA) show an increased incidence of insulation defects, particularly "inside-out" lead fracture where inner, separately insulated cables penetrate through the surrounding silicone of the lead body. The exact incidence of Riata® lead problems is not clear and seems to range between 2-4% per year in the first 5 years after implantation according to new registry data. We recommend beyond a detailed information the following care of patients with Riata® and Riata ST® leads: 1) Activation of automatic ICD alerts, 2) remote monitoring with automatic daily alerts whenever possible, 3) monthly ICD controls in patients at high risk (pacemaker dependency, history of ventricular tachyarrhythmias) and high or moderate lead-related risk (8F, 7F single coil), 3-monthly controls in moderate patient and lead-related risk, 3 to 6-monthly controls in low patient and lead-related risk (no bradycardia, no history of ventricular tachyarrhythmia). Every ICD control should include meticulous analysis of oversensing artifacts in stored electrograms (EGMs) of sustained and non-sustained ventricular tachyarrhythmias and registration of EGMs during provocation testing (pectoral muscle activity, arm movements). If electrical abnormalities are observed, reoperation with addition of a new ICD lead is recommended; lead extraction only if indicated according to current guidelines. Fluoroscopy should only be performed if electrical abnormalities are found by an experienced electrophysiologist and a high frame rate and resolution. Management of fluoroscopic abnormalities in the absence of electrical abnormalities is not clear. Therefore, routine fluoroscopy of patients with Riata® leads without electrical abnormalities is not recommended.

Aims To collect information on the use of the Reveal implantable loop recorder (ILR) in the patient care pathway and to investigate its effectiveness in the diagnosis of unexplained recurrent syncope in everyday clinical practice. Methods and results Prospective, multicentre, observational study conducted in 2006–2009 in 10 European countries and Israel. Eligible patients had recurrent unexplained syncope or pre-syncope. Subjects received a Reveal Plus, DX or XT. Follow up was until the first recurrence of a syncopal event leading to a diagnosis or for ≥1 year. In the course of the study, patients were evaluated by an average of three different specialists for management of their syncope and underwent a median of 13 tests (range 9–20). Significant physical trauma had been experienced in association with a syncopal episode by 36% of patients. Average follow-up time after ILR implant was 10 ± 6 months. Follow-up visit data were available for 570 subjects. The percentages of patients with recurrence of syncope were 19, 26, and 36% after 3, 6, and 12 months, respectively. Of 218 events within the study, ILR-guided diagnosis was obtained in 170 cases (78%), of which 128 (75%) were cardiac. Conclusion A large number of diagnostic tests were undertaken in patients with unexplained syncope without providing conclusive data. In contrast, the ILR revealed or contributed to establishing the mechanism of syncope in the vast majority of patients. The findings support the recommendation in current guidelines that an ILR should be implanted early rather than late in the evaluation of unexplained syncope.

Aims To assess procedural characteristics and adjudicated procedure-related (≤30 days) major adverse events among patients who underwent cardiac resynchronization therapy (CRT) implantation in the CARE-HF study. The CARE-HF study shows that CRT improves symptoms and reduces morbidity and mortality in New York Heart Association (NYHA) class III/IV chronic heart failure (CHF) patients. However, safe and proper implantation of pacing systems remains key to effective CRT delivery. Methods and results Generalized linear modeling was used to examine the relationships between first implant success/failure and: NYHA class; beta-adrenergic blocker use; underlying ischemic vs. non-ischemic heart disease; history of coronary artery bypass graft or valve surgery; left ventricular (LV) end-diastolic volume ≤ vs. >300 cm3; and, influence of the participating study-centres. Implantation was attempted in 404/409 patients assigned to CRT, and in 65/404 patients assigned to medical therapy. Among these 469 patients, 450 (95.9%) received a successfully implanted and activated device. Complications occurred within 24 h in 47 patients (10.0%), mainly lead dislodgments ( n = 10, 2.1%) and coronary sinus dissection/perforation ( n = 10, 2.1%), and between 24 h and 30 days in 26 patients (5.5%), mainly lead dislodgment ( n = 13, 2.8%). Mean LV lead stimulation threshold was significantly higher than at the right atrium or right ventricle, though remained stable, delivering effective, and reliable CRT. Implanting experience was the only predictor of procedural outcome. Conclusion Transvenous CRT system implantation, using a CS lead designed for long-term LV pacing, was safe and reliable. As implanting centres become more experienced, this success rate is expected to increase further.

Diabetics would benefit from a device capable of providing continuous non-invasive monitoring of their blood glucose levels. A feasibility study was performed to determine whether a technique applying spatially resolved diffuse reflectance measurements could be used to detect changes in the blood glucose levels of diabetic volunteers by monitoring the tissue reduced scattering coefficient. A correlation was observed between step changes in blood glucose concentration and tissue reduced scattering coefficient in 17 out of 22 subjects. A study on non-diabetic volunteers was used to estimate the physiological baseline noise level.

Cardiac resynchronization therapy (CRT) is now considered an established therapy for patients with chronic heart failure in the presence of a wide QRS complex. Though proarrhythmic effects have been described in a few cases, CRT did not increase the frequency of ventricular tachyarrhythmias in prospective studies. In patients on CRT therapy, persistent atrial fibrillation sometimes converts back to sinus rhythm, possibly dependent on the duration of atrial fibrillation.

This study was carried out to compare cardiac output measurements determined by thermodilution and by Portapres, a non-invasive system.Eighty-seven non-invasive blood pressure measurements were performed in 46 patients in our critical care unit utilising the new, non-invasive Portapres system. Cardiac output values were obtained from these blood pressure values using an aortic impedance model and compared to cardiac output values estimated by the thermodilution technique.Statistically significant (p0.01) differences (2.3 l/min; limits of agreement +/-5 l/min) were noted between invasive and non-invasive cardiac output measurements. Differences in measured cardiac outputs increased for patients receiving catecholamine therapy, in patients with hemodynamic instability (e.g., sepsis and cardiac insufficiency), in patients with artificial ventilation, in patients with long duration of intensive care, in younger (60 yr) patients and in women. We found no influence of the body mass index (BMI) on the accuracy of Portapres results. In only one single subgroup, 10 patients with pulmonary diseases, Portapres measurements were not statistically significant different from reference results.To date, Portapres measurements cannot replace thermodilution cardiac output estimations. Fluctuations of finger arterial perfusion due to hemodynamic instability, hypothermia and catecholamines may be responsible for problems of Portapres use in critically ill patients.

About three years ago, the German Government initiated a complete change in the reimbursement system for costs of the in-hospital treatment of patients. A commission of representatives from every component of the German health system decided to adapt the Australian refined Diagnosis Related Groups (AR-DRG system). The AR-DRG system was selected as it would fit best to the German system and because of its high flexibility and preciseness reflecting severity of diseases and treatments. In October 2002, the first German Diagnosis Related Groups (G-DRGs) were calculated from the data of about 116 hospitals. These data now allow first analyses in how far a correct and precise grouping of patients in specific hospital settings is indeed performed and corresponds to the actual costs. Thus, we thoroughly calculated all costs for material and personnel during the in-hospital stay for each patient discharged during the first 4 months of 2002 from our cardiological department. After performing the grouping procedure for each patient, we analyzed in how far inhomogeneous patient distribution in the DRGs occurred and which impact this had on costs and potential reimbursements. Several different problems were identified which should be outlined in this work regarding three G-DRGs: costs of patients who received an implantable cardioverter defibrillator (F01Z) were markedly influenced by multimorbidity and additional expensive interventions which were not reflected by this G-DRG. Use of numerous catheters and expensive drugs represented a major factor for costs in patients with coronary angioplasty in acute myocardial infarction (F10Z) but seemed to be not sufficiently included in the cost weight. A specific area of patient management in our department is high frequency ablation of tachyarrhythmias which is included in other percutaneous interventions (F19Z). Complex procedures such as ablation of ventricular tachycardia or new innovative procedures as ablation of atrial fibrillation were associated with high costs leading to inadequate reimbursement. Furthermore, problems in the associated codes for diseases and procedures became apparent. Opportunities for future optimization such as specific new DRGs, splitting of DRGs, or the impact of changes in reimbursement for high-outliers were discussed.

In patients with congestive heart failure, unexplained syncope is often due to ventricular arrhythmias and associated with a poor prognosis. Electrophysiological studies should be considered early in the work-up of syncope. Implantation of a defibrillator might become necessary in many patients with syncope and heart failure.

The high incidence of inappropriate therapies due to supraventricular tachycardia remains a major unsolved problem of the implantable cardioverter defibrillator. A new morphology discrimination (MD) algorithm has been introduced to improve specificity of ICD therapy without loss of sensitivity. It was the aim of this study to systematically analyze sensitivity and specificity of the MD criterion in combination with the enhanced detection criteria sudden onset and rate stability in the detection of ventricular and supraventricular tachycardia. After ICD implantation in 259 patients, 787 detected episodes in 74 patients with available stored electrograms were documented during a follow-up period of 359 +/- 214 days. With a nominal programming of the MD algorithm ator = 60%, sensitivity and specificity for all episodes were 82.6%/77.2%. For sinus tachycardia, atrial fibrillation and atrial flutter the specificities were 80.6%, 69.6% and 75%, respectively. In patients with primarily appropriate MD detection, sensitivity and specificity significantly improved to 95.8%/91.7%. Programming the sudden onset criterion with100 ms and the stability criterion with50 ms, sensitivity and stability of the combined application of the MD algorithm and sudden onset and MD algorithm and stability were 96.2%/52.2% and 94.4%/63.8%, respectively. The MD criterion in combination with other enhanced detection criteria might significantly improve specificity of tachyarrythmia detection of ICD therapy.

This retrospective study was performed to provide data on ventricular tachycardias (VT) with a cycle length longer than the initially programmed tachycardia detection interval (TDI) in patients with implantable cardioverter defibrillators (ICDs).It has been clinical practice to program a safety margin of 30 to 60 ms between the slowest spontaneous or inducible VT and the TDI.Baseline characteristics of 659 consecutive patients with ICDs were prospectively; follow-up information was retrospectively collected.During a mean follow-up of 31+/-23 months, 377 patients (57.2%) had at least one recurrent VT or ventricular fibrillation; 47 patients (7.1%) suffered 61 VTs above the TDI. The risk of a VT above the TDI ranged between 2.7% and 3.5% per year during the first four years after ICD implantation. The difference between the cycle length of the slowest VT before ICD implantation, spontaneous or induced, and the first VT above TDI was 108+/-58 ms. Fifty-four VTs (88.5%) above the TDI were associated with significant clinical symptoms (angina or palpitation 63.9%, heart failure 6.6% and syncope 8.2%). Six patients (9.8%) had to be resuscitated. Kaplan-Meyer analysis identified New York Heart Association class II or III (p = 0.021), ejection fraction0.40 (p = 0.027), spontaneous (p0.001) or inducible (p0.001) monomorphic VTs and the use of class III antiarrhythmic drugs (amiodarone, p0.001; sotalol, p = 0.004) as risk predictors of VTs above the TDI. The risk of recurrent VTs above TDI was 11.8%, 12.5% and 26.6% during the first, second and third year after first VT above TDI, respectively.The risk of VTs above the TDI is significantly increased in some patients, and many VTs above TDI cause significant clinical symptoms. A larger safety margin between spontaneous or inducible VTs and the TDI seems to be necessary in selected patients. This is in conflict with an increased risk of inadequate episodes and demands highly specific and sensitive detection algorithms in these patients.

The scientific basis and the reasoning underlying the changes in antiarrhythmic approaches to ventricular arrhythmias during recent decades are discussed. The early enthusiasm in the use of antiarrhythmic drugs in patients after myocardial infarction to prevent sudden cardiac death was severely affected by the results of the Cardiac Arrhythmia Suppression Trial (CAST) which show an increased mortality of patients on sodium-channel antagonist antiarrhythmic drugs. A transient euphoria for drugs that prolong repolarization received criticism after premature termination of the Survival With Oral D-sotalol-trial (SWORD). Recently, attention has focused on the use of the implantable cardioverter defibrillator in both secondary and primary prevention of sudden death. In contrast, catheter ablation, although very useful in supraventricular tachycardia, still plays a limited role in the management of ventricular tachyarrhythmias in the presence of organic heart disease.

Bildgebende Verfahren in der Dermatologie sind wichtige Hilfsmittel in der klinischen Diagnostik. Das Ziel dieser Techniken ist die Darstellung intraepidermaler, dermaler und subkutaner Prozesse, ohne das ein operativer Eingriff an der Haut vorgenommen werden mus. Der bisherige „Goldstandard“ in Bezug auf die bildliche Darstellung eines Hautschnittes ist die Histologie, was sich auch in absehbarerer Zeit nicht andern wird. Fur die dermatologische in vivo Routinediagnostik stehen uns bislang nur wenige technische Verfahren hilfreich zur Seite. Die hochfrequente Sonographie konnte sich in den letzten Jahren in der Krankenhausroutine, vor allen Dingen zur praoperativen Tumordickenbestimmung, etablieren. Herkommliche Sonographiegerate mit einer Frequenz von 3,5–7,5 MHz erlauben keine ausreichende Auflosung der Hautkompartimente, erst ab einer Frequenz von 20 MHz ist es moglich, Bilder zu erzeugen, die mit einem histologischen Schnittbild korreliert werden konnen.

Postoperative tests of implantable cardioverter defibrillators (ICDs) are routinely performed to ensure appropriate defibrillation by the device. However, efficacy and complications of this procedure are unknown. To scrutinize the currently accepted indications to test the defibrillation function of the ICD we retrospectively analyzed 844 ICD-tests in 439 ICD-systems and 409 patients. 755 ICD-tests (89.4%) were routinely performed (57% before discharge and 43% during follow-up); 58 tests (6.9%) were performed after a change of the antiarrhythmic drug regimen, 24 tests (2.9%) after a revision of a part of the ICD-system, and seven tests (0.8%) because of a suspected dysfunction of the ICD. During routine-tests six ICD-systems (0.8%) failed to defibrillate the patient. However, in all but one test abnormalities of the ICD-system had been observed before the test. After addition of antiarrhythmic drugs, three of 58 ICD-systems (5.2%) failed to defibrillate the patient during the test (amiodarone: n = 2, flecainide: n = 1). Four of seven ICD-systems (57%) tested due to a suspected dysfunction failed to defibrillate the patient. After revisions of parts of the ICD-systems, ICD-tests never revealed a failure of defibrillation. During 16 ICD-tests (1.9%) complications occurred. The most frequent complications was inappropriate shocks (n = 10; 1.2%), the most severe one (transient) neurologic symptoms (n = 4; 0.48%). Our experience demonstrates that postoperative tests of the defibrillation function of ICDs rarely reveal ICD-dysfunction. As testing is unpleasant for the patient and not free of complications, tests might be restricted to those patients in whom an ICD-dysfunction is suspected (based on clinical presentation, results of chest-x-ray, testing of sensing signal and stimulation threshold) or class I or class III antiarrhythmic drugs have been added to the antiarrhythmic drug regimen.

Analysis of the uncertainties in the optical properties obtained from reflectance data was used to compare the performance of the continuous wave and frequency domain approaches. The surface corresponding to the uncertainty as a function of the noise levels in steady state reflectance and phase difference reveals three distinct domains: a domain in which frequency domain data does not improve sensitivity, a domain in which continuous wave data does not improve sensitivity and a domain in which combining continuous wave and steady state data is an advantageous strategy. The noise levels which define these domains depend upon the optical properties of the tissue and the distances at which measurements are made. Presently, for typical optical properties and homogeneous tissues, optical systems which measure reflectance at short distances operate in the domain for which frequency domain information does not improve sensitivity and continuous wave systems will provide the best sensitivity to changes in optical properties.

Treatment strategies in patients with life-threatening ventricular tachyarrhythmias (i.e. sustained ventricular tachycardia, ventricular fibrillation, aborted sudden cardiac death) are changing. Amiodarone and d,l-sotalol, chosen by electrophysiologic study guidance, can be considered as drugs of choice for the pharmacological treatment. Compared to these agents, which both have additional electrophysiologic effects, the new pure class III agents seem to be less effective. With regard to antiarrhythmic efficacy, clinical trials comparing the long-term efficacy of antiarrhythmic agents and the implantable cardioverter/defibrillator are under way. Preliminary results indicate that the implantable cardioverter/defibrillator may provide superior outcome with regard to sudden cardiac death compared to the use of class III agents.

Ultimately, implantable cardioverter-defibrillators (ICD) will one day be implantable like present pacemakers. However, due to the size of the pulse generator and the low defibrillation efficacy of monophasic shocks, only a few selected patients have been implanted transvenously-pectorally. Therefore, we have prospectively investigated whether a transvenous-pectoral approach is in general feasible with a new downsized ICD capable of delivering biphasic shocks. Out of 33 patients, 76% received a bipolar transvenous defibrillation lead system. In the first 13 consecutive patients, a randomized crossover study showed that this high efficacy was above all achieved by a superior defibrillation efficacy of the biphasic waveform in comparison to the monophasic waveform (69% vs. 23%; p = 0.03). Not a single patient could be defibrillated exclusively with the monophasic waveform. In a further 15 consecutive patients, a crossover study showed that a position of the transvenous anode within the Vena anonyma instead of the Vena cava superior is, in general, not superior (87% vs. 80%; p = 0.67). Only one patient could be exclusively defibrillated with the V. anonyma position. Intraoperatively, no complications occurred and all but one patient received a pectoral implantation of the pulse generator. Postoperatively, in five patients local complications related to the ICD system were seen; two needed a surgical revision. In two patients movements of the left shoulder joint were temporarily restricted. Thus, in the majority of patients a new downsized ICD capable of biphasic shocks can be implanted transvenously-pectorally like a pacemaker.

The goal of this panel is to discuss some significant examples of current R&D projects related to visual interfaces, which are part of the different R&D programmes partially funded by the European Commission, and in particular of the Esprit programme. Even if the panel will concentrate on user interface issues, the scope of the presented projects is fairly broad: from user interface development technologies (as in HYPERFACE and INTERACTORS), to banking and financial environments and applications (as in FAST), to hypermedia platforms and applications (as in MINERS), to navigational user interfaces to traditional information systems (as in HIFI), to multimedia educational environments (as in MULTED), to multimedia medical information (as in MILORD), to 3D interaction with data bases (as in FADIVA). All the presented projects make large use of multimedia concepts and technologies.

Technical improvements of third generation implantable cardioverter defibrillators (ICD) like antitachycardia pacing modalities lead to an extended use of ICDs, not only in patients with aborted sudden cardiac death, but also in patients with hemodynamically tolerable ventricular tachycardia. In addition, anticipated results of current prospective studies might indicate the prophylactic use of ICDs in patients with high risk for sudden cardiac death, but without documented ventricular tachyarrhythmias. This report reviews mortality and complications associated with the ICDs with epicardial defibrillation leads. Mortality is separated in cardiac death, sudden cardiac, arrhythmogenic "not so sudden" cardiac death, and overall mortality. Pulmonary complications and infections are related to the underlying disease and the surgical procedure. Device- and lead-related complications, high defibrillation thresholds, pacemaker interactions, inappropriate shocks, arrhythmic effects, syncope, and psychosocial problems are reported, respectively.

To determine the effects and the underlying mechanisms of sudden rise of impedance during radiofrequency (RF) catheter ablation, 60 RF applications were delivered to isolated preparations of ventricular myocardium at three different power levels (mean: 3.7, 11.3, 19.3 watts). Pulse duration was 30 s, current voltage and catheter tip temperature were continuously monitored. Impedance rise occurred during 34 of 60 applications; the incidence of impedance rise increased at higher power levels. Impedance rise was significantly more often observed when the preparations were superfused with heparinized blood compared to saline solution (p less than 0.05). Catheter-tip temperature during radiofrequency application without impedance rise was significantly lower compared to applications with impedance rise (mean = 108 degrees C vs. 121 degrees C, p less than 0.01). The increase of catheter-tip temperature and maximal-tip temperature following impedance rise was significantly higher in blood when compared to saline solution (mean = +48 degrees C vs. +13 degrees C (p less than 0.001), Tmax: 121 degrees C vs. 245 degrees C). Following impedance rise, insulation defects of the electrode catheter and vaporized crater formation of the myocardium was often observed.During radiofrequency catheter ablation impedance rise occurs following overheating of the catheter electrode (greater than 110 degrees C). After impedance rise, catheter-tip temperature markedly increases. Insulation defects of the catheter and vaporized craters in the myocardium frequently occur after impedance rise. The results have important implications for the clinical use of RF-currents for catheter ablation; energy application should be immediately stopped after the occurrence of impedance rise.

We report two cases of licorice-induced arrhythmias. In both cases the ingestion of large amounts of licorice caused a marked hypokalemia. The importance of licorice-induced hypokalemia for the development of arrhythmias is underestimated from the small number of published cases. We conclude that patients with a predisposition for arrhythmias should avoid licorice candies.

The contrast between samples simulating musculoskeletal neoplasms and muscle or bone marrow achieved with FLASH sequences, was analysed in phantom studies and was compared with theoretically calculated contrast with and without correction for flip angle distribution over the slice profile. The contrast was correlated closer with the flip angle than with TR or TE. For delineation of the tumour from muscle, only a FLASH sequence with a large flip angle following intravenous administration of Gd-DTPA can be recommended, if a tumour shows a clear Gd-DTPA uptake. With all FLASH sequences analysed, no sufficient contrast between "tumour" without Gd-DTPA uptake and muscle was obtained. Maximal contrast between "tumour" and bone marrow was achieved with small flip angles; and an additional peak was noted with large flip angles and short TR. Experimentally measured T2*-dependent contrasts were nearly identical with theoretically calculated contrasts without correction of flip angle distribution. For calculation of T1-dependent contrasts, correction of the flip angle distribution over the slice profile was of high value.

Nuclear long-distance energy, i.e. the transportation of chemically bound energy, represents a potential application for process heat plants in which the endothermic reaction takes place at the heat source (high temperature reactor) whereas the exothermic back reaction occurs at the region of heat utilization (consumer). Due to the following criteria, i.e. reversibility of the chemical reaction, sufficiently large reaction enthalpy, favourable temperature region for the forward and back reactions, and the available technology, a combination of the methods of endothermic steam reforming of methane and exothermic methanation is chosen. As well as supplying household and industrial consumers with heating, process steam and electrical energy, an interconnected system with synthesis gas consumers (e.g. methanol production and iron ore reduction plants) is possible. It is shown that the amount of reactor heat which is convertible into long-distance energy depends considerably on the helium temperatures in the high temperature reactor and lies between 60 and 73% of the reactor power. Conceivable circuit schemes for the nuclear steam-reforming plants and the methanation plants are described. Finally, it is demonstrated, with the help of a simple model for cost estimations, that the nuclear long-distance energy system can make heating for households available in competition with oil heating and that due to the lower specific transport costs, for distances larger than 50 km it is also more economical than the hot water supply from the thermal power coupling of steam turbine plants using light water reactors (LWRs) or high temperature reactors (HTRs).

1. Rapid inward sodium current (INa) was studied on intact rat papillary muscles and trabeculae excised from right or left ventricle using the loose-patch-clamp technique. All experiments were carried out at 25 degrees C. 2. Currents were recorded from patches with a large current density of mean 5.9 +/- 0.5 mA/cm2. 3. The current was reduced by tetrodotoxin (TTX) in a dose-dependent manner. The concentration of TTX producing half-maximal blockade of INa was 6.3 +/- 0.8 mumol/l. 4. Na+ current appeared upon depolarization at a threshold potential of about -55 mV and reached its maximum at about -20 mV. 5. Kinetic data were evaluated using the Hodgkin-Huxley model. 6. Time constants of activation (tau m) were estimated using single-pulse and tail-current measurements. They had a maximum of about 0.4 ms near the threshold potential and declined at more positive and at more negative potentials to values near 0.1 ms. 7. Two time constants were necessary to describe inactivation. Both time constants had their maximal values of 135 +/- 8.1 and 29.1 +/- 5.9 ms at about -80 mV and decreased towards 4 and 0.5 ms at potentials positive to -20 mV.

A case of choledocho-gastric fistula resulting from a cholangio-carcinoma is reported. The final diagnosis was obtained by ERCP, whereas CT, barium examination, and gastroscopy initially did not allow a conclusive diagnosis. The only clinical finding was epigastric pain. Choledocho-gastric fistula is extremely rare.