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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.

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.

The number of cardioverter/defibrillator (ICD) implantations has been steadily increasing; thus, ICD lead-associated complications are an important issue. No clear recommendations for the diagnosis and management are available. This article gives an overview of how to diagnose and manage an ICD lead defect. Possible therapeutic options are discussed by reviewing the literature.

Patients with an implantable cardioverter defibrillator (ICD) may experience loss of consciousness. Electromagnetic interference (EMI) may trigger undesired or inhibit necessary therapy in patients with an ICD. Therefore, questions about personal or professional activities for ICD patients arise. Restricting driving or other personal activities has adverse effects on the patient's quality of life. The national Societies of Cardiology provide recommendations for ICD patients concerning driving of motor vehicles. Patients with an ICD that is implanted prophylactically do not have to refrain from driving after recovery from the implantation procedure. Patients with arrhythmias are classified into different groups depending on the risk of recurrence of tachycardias and symptoms. Commercial driving is not allowed for patients with an ICD in Germany except for those with a prophylactic indication without a history of arrhythmias. Those patients may drive small cars but no trucks or busses. Guidelines for medical fitness in commercial or military flying are regulated by the Joint Aviation Authorities (JAA) and ventricular tachycardias are a contraindication for both. Fortunately, loss of consciousness is not dangerous in most jobs. Strong sources of EMI can occur at special workplaces. Patients have to be advised and tested individually concerning their risk for EMI at their employment site before returning safely. Modern life exposes to an increasing amount of EMI. Intact household devices usually do not interfere with ICDs. Mobile phones may interfere with implanted devices. Interaction can be minimized by special precautions like maintaining a distance of minimum 10 cm between mobile phone and ICD. Electronic surveillance systems work differently and have the potential to interact with devices. Patients should be advised to pass those systems with avoiding longer exposure. The presence of an ICD is presently a contraindication for undergoing magnetic resonance imaging (MRI) because of a high risk of destruction of the system with even potential harm to the patient. High-frequency application for electrocautery devices or ablation is possible under certain precautions that have to be planned before. There is a high sensitivity of ICD systems to ionizing radiation with defect of the devices after a cumulative dose > 5 Gy.

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.

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 at > or = 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 with < 100 ms and the stability criterion with < 50 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.

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.

Patients with implantable cardioverter defibrillators (ICD) often suffer inappropriate ICD-therapies. The incidence, causes and risk factors of ICD-therapies for a rhythm other than ventricular tachyarrhythmias (VT) were determined retrospectively in 462 consecutive patients (pts). Inappropriate ICD-therapies were identified based on stored R-R intervals and/or electrograms. Eighty-two pts (18%) had inappropriate ICD-therapies. Actuarial rates for inappropriate ICD-therapies were 13%, 20%, 24% and 29% at 1, 2, 3 and 4 years after ICD-implantation, respectively. Atrial fibrillation with rapid ventricular response was the most common cause (34 pts, 39%). In 26 pts (30%), sinus tachycardia triggered inappropriate ICD-therapies, in 21 pts (24%) overseeing, mostly due to fractures and insulation failures of the leads, in three pts atrial flutter, in two pts non-sustained VT, in one pt supra-ventricular tachycardia and in another pt T-wave double sensing caused inappropriate ICD-therapies. In order to prevent recurrences of inappropriate ICD-therapies due to atrial fibrillation or sinus tachycardia, a rate stability (n = 19) or onset (n = 15) criterion was programmed, 41 pts additionally received beta-blocking agents and/or digoxin. In pts with overseeing an operative revision of lead system was performed. During further follow-up (15 +/- 13 months), 15 pts had recurrences of inappropriate ICD-therapies (eight pts due to atrial fibrillation, three due to sinus tachycardia and four due to overseeing). On multivariate analysis (Cox regression), history of atrial fibrillation, maximum heart rate during exercise and low cut-off rate for VT-detection were predictors of inappropriate ICD-therapies. Thus, inappropriate ICD-therapies are frequent, especially in the first year after implantation. Additional detection criteria, beta-blocking agents and/or digoxin prevent recurrences in most patients. In patients with a history of atrial fibrillation, high heart rate during exercise or a low cut-off rate for VT-detection, activation of additional detection criteria should be considered directly after ICD-implantation.

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.

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.

Unlabelled: 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., Conclusions: 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.

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.