Electro-mechanical dysfunction in long QT syndrome: Role for arrhythmogenic risk prediction and modulation by sex and sex hormones.

Long QT syndrome (LQTS) is a congenital arrhythmogenic channelopathy characterized by impaired cardiac repolarization. Increasing evidence supports the notion that LQTS is not purely an "electrical" disease but rather an "electro-mechanical" disease with regionally heterogeneously impaired electrical and mechanical cardiac function. In the first part, this article reviews current knowledge on electro-mechanical (dys)function in LQTS, clinical consequences of the observed electro-mechanical dysfunction, and potential underlying mechanisms. Since several novel imaging techniques - Strain Echocardiography (SE) and Magnetic Resonance Tissue Phase Mapping (TPM) - are applied in clinical and experimental settings to assess the (regional) mechanical function, advantages of these non-invasive techniques and their feasibility in the clinical routine are particularly highlighted. The second part provides novel insights into sex differences and sex hormone effects on electro-mechanical cardiac function in a transgenic LQT2 rabbit model. Here we demonstrate that female LQT2 rabbits exhibit a prolonged time to diastolic peak - as marker for contraction duration and early relaxation - compared to males. Chronic estradiol-treatment enhances these differences in time to diastolic peak even more and additionally increases the risk for ventricular arrhythmia. Importantly, time to diastolic peak is particularly prolonged in rabbits exhibiting ventricular arrhythmia - regardless of hormone treatment - contrasting with a lack of differences in QT duration between symptomatic and asymptomatic LQT2 rabbits. This indicates the potential added value of the assessment of mechanical dysfunction in future risk stratification of LQTS patients.

Intra-individual head-to-head comparison of Sirolimus®- and Paclitaxel®-eluting stents for coronary revascularization. A randomized, multi-center trial.

BACKGROUND: Despite the known effects of drug-eluting stents (DES), other cofactors attributed to patient characteristics affect their success. Interest focused on designing a study minimizing these factors to answer continuing concerns on the heterogeneity of response to different DESs. The study's aim was to investigate the feasibility and impact of an intra-individual comparison design in patients (pts) with two coronary artery stenosis treated with a Sirolimus- (SES) and a Paclitaxel- (PES) eluting stent. METHODS AND RESULTS: The study was conducted as a prospective, randomized, multi-center trial in 112 pts who consented to treatment with a SES and a PES. Pts were eligible if they suffered from the presence of two single primary target lesions in two different native coronary arteries. Lesions were randomized to either SES or PES treatment. The primary endpoint was in-stent luminal late loss (LLL), as determined by quantitative angiography at 8 months; clinical follow up was obtained at 1, 8, and 12 months additionally. The LLL (0.13 ± 0.28 mm SES vs. 0.26 ± 0.35 mm PES, p=0.011) showed less neointima in SES. With a predefined cut-off criterion of 0.2mm difference in LLL, 53/87 pts SES and PES were similar effective. 34/87 pts had a divergent result, 26 pts had greater benefit from SES while 8 pts had greater benefit from PES. Overall, MACE (MI, TLR, and death) occurred in 19 (17%) pts. Based on lesion analysis of 108 lesions treated with SES and 110 lesions treated with PES, 5 (4.6%) lesions with SES and 3 (2.7%) lesions with PES required repeated TLR. CONCLUSION: An intra-individual comparison design to assess differences in efficacy of different DESs is feasible, safe and achieves similar results to inter-individual studies. This study is among the first to show that failure of one DES does not necessarily implicate failure of another DES and vice versa.

Prognostic value of the ECG on admission in patients with acute major pulmonary embolism.

A number of ECG abnormalities can be observed in the acute phase of pulmonary embolism (PE). Their prognostic value has not yet been systematically studied in large patient populations. In 508 patients with acute major PE derived from a large prospective registry, the current authors assessed, on admission, the impact of specific pathological ECG findings on early (30-day) mortality. Atrial arrhythmias, complete right bundle branch block, peripheral low voltage, pseudoinfarction pattern (Q waves) in leads III and aVF, and ST segment changes (elevation or depression) over the left precordial leads, were all significantly more frequent in patients with a fatal outcome. Overall, 29% of the patients who exhibited at least one of these abnormalities on admission did not survive to hospital discharge, as opposed to only 11% of the patients without a pathological 12-lead ECG. Multivariate analysis revealed that the presence of at least one of the above ECG findings was, besides haemodynamic instability, syncope and pre-existing chronic pulmonary disease, a significant independent predictor of outcome. In conclusion, ECG may be a useful, simple, non-costly tool for initial risk stratification of patients with acute major pulmonary embolism.

[Cardiac arrhythmias and sudden cardiac death in women]. / Herzrhythmusstörungen und plötzlicher Herztod bei Frauen.

BACKGROUND: Gender specific cardiac arrhythmias have been recognized for more than 80 years. The impact of gonadal steroids on the autonomic system and on the cellular electrophysiology of the cardiac autonomic system are discussed as is a direct genetic disposition on a cellular, functional or metabolic level. We nevertheless have to be aware of age- and gender-specific differences of heart diseases, which have an impact on the incidence, form and severity of cardiac arrhythmias. CARDIAC ARRHYTHMIAS IN WOMEN: Gender-specific electrophysiologic differences like a higher basic heart rate and a longer QT-interval, beginning after puberty, are the main changes in ECGs in women and have a strong relationship to constitutional and hormonal influences. Supraventricular arrhythmias, i. e. in women sinus and AV-nodal-reentry tachycardias, less frequently Wolff-Parkinson-White tachycardias, may show clearly cyclical differences. Atrial fibrillation is more frequent in women, is more symptomatic, and there are more problems in therapy. Ventricular arrhythmias, occurring equally in healthy persons, show a strong relationship to coronary artery disease in men, which is less significant in women (in women more arrhythmogenic co-factors). Women suffer from acquired and congenital long-QT syndrome, and consequently more often from torsade-de-pointes tachycardias (stronger drug-induced QT-lengthening, more short-long sequences, differences in Ikr sensitivity). Sudden cardiac death is three times more often in men. Women suffer from it about ten years later; it is a more heterogenous phenomenon than in men, and the prognosis is worse. Women are underrepresented in controlled studies for primary and secondary prevention compared to men. CONCLUSIONS: As the underlying reasons of gender-specific differences in cardiac arrhythmias are not known in detail, the findings discussed imply the necessity of more basic studies to evaluate gender-specific solutions for risk stratification and therapy.

[New aspects of ICD therapy: from rhythm therapy to complex cardiac monitoring. Development of an implantable, ICD-assisted, intrathoracic 6-channel ECG for continuous monitoring of high infarct risk patients]. / Neue Aspekte der ICD-Therapie: Von der Rhythmustherapie zur komplexen kardialen Uberwachung. Entwicklung eines implantierbaren, ICD-gestützten, intrathorakalen 6-Kanal-EKG zur kontinuierlichen Uberwachung von infarktgefährdeten Risikopatienten.

Implantable defibrillator systems (ICD) are therapy of choice for the treatment of life-threatening ventricular arrhythmias and in prevention of sudden cardiac death. In more than 80% of patients who receive an ICD, the underlying cardiac disease is a coronary heart disease. Since arrhythmogenic sudden cardiac death can be reliably prevented in these patients by the use of ICD technology, the cardiac prognosis for these patients is determined by the occurrence of myocardial ischemia and myocardial infarction, as well as from the heart failure which develops in consequence. An intrathoracic 6-channel ECG comparable to the standard surface ECG can be reconstructed by further technical development of the electrode configurations currently present in ICD systems. The importance of this development in early diagnosis of myocardial ischemias and myocardial infarction can hardly be adequately estimated at the moment. The chronic consequences of myocardial infarction can be completely prevented or at least greatly reduced by means of such diagnostics and inclusion of immediate initiation of effective, appropriate early therapeutic measures before more serious symptoms even occur. In the development and pilot studies thus far, it has been found that the intrathoracic 6-channel ECG which can be generated in the ICD is capable of reliably recognizing acute myocardial ischemia, irrespective of localization or extent earlier and better than the standard surface ECG. Continuous preventive ischemia monitoring using the implanted ICD thus appears possible in patients at risk of infarction.

[Bronchoscopy and rhythmic disorders. Premedication with atropine-sulfate, as a rule?]. / Bronchoskopie und Herzrhythmusveränderungen. Ist eine Prämedikation mit Atropin stets erforderlich?

Ikeda has introduced flexible bronchoscopy in the seventies of the last century. Since then the over one hundred year old procedure of direct airways inspection has widely spread and enhanced the diagnostic and therapeutic means. Thus the flexible bronchoscopy has become an important part of modern medicine. The close combination of atropine as premedication with bronchoscopy is justified with the terms "cardioprotection" and reduction of mucus secretion. As there is to this date no controlled study to prove this assumption, with the start of bronchoscopy we controlled every patient with a holter-ecg for 24-hours and estimated semiquantitatively the mucus secretion during procedure by a four point scale. Consecutively 55 patients could be randomised, 25 (7 females, 18 males) in the group with and 30 (7 females, 18 males) without atropine. In the records there were no detectable significant differences between the groups with atropine (A) and without atropine (P), as well as for registered bradycardias (A: 0 vs. P: 0, minimum of heart beats A: 63.8 vs. P: 74.1 min -1) as well as for alterations of heart rhythms, e. g. SVES (A: 7.3 % vs. P: 5.5 %), VES (A: 9.0 % vs. P: 9.0 %) or a combination of SVES with VES (A: 12.7 % vs. P: 10.9 %). The same results could be seen for each single of the first twenty minutes, additionally the first and the second recorded hour and the whole registered 24 hours. Moreover the times needed to complete the bronchoscopy showed no significant difference (mean of t A: 16.8 vs. P: 15.6 min, t-minimum 10 vs. 10 min, t-maximum A: 30 vs. P: 35 min). The same absence of differences was seen in estimated endobronchial mucus secretion (mean A: 1.88 vs. P: 2.0). According to these results of our studied group, there are no reasons, why a premedication with atropine in flexible bronchoscopy in local anaesthesia should be used. Even without the administration of atropine, flexible bronchoscopy could be performed as a safe and sophisticated method in direction of not inducing relevant arrhythmia, with low impact on patients.

Extragonadal retroperitoneal germ cell tumor: evidence of origin in the testis.

BACKGROUND: The origin of extragonadal retroperitoneal germ cell tumors remains controversial. Whether they develop primarily in the retroperitoneum or whether they are metastases of a primary testicular tumor has long been debated. PATIENTS AND METHODS: We retrospectively analyzed 26 patients treated as having primary extragonadal retroperitoneal germ cell tumors based upon the findings of testicular palpation by the referring physician. Testicular evaluation was then extended with ultrasonographical and histological examinations. RESULTS: Biopsy of the extragonadal tumor was performed in 25 patients, confirming diagnosis of extragonadal retroperitoneal germ cell tumor. Prior to treatment patients were clinically evaluated by several physicians and the testes were not considered suspicious for testicular cancer. At urological workup, testes were found to be atrophic and/or indurated in 14 (54%) patients, enlarged in one (4%) and unremarkable in 11 (42%). Ultrasound examination of the testes in 20 patients showed pathological findings in all of them. Histology of the testis was available in 25 of 26 patients and revealed active tumor in three, intratubular germ cell neoplasia in four, scar tissue in 12, sclerosis in three, sclerosis and fibrosis in one, and fibrosis alone in two. CONCLUSIONS: So-called primary extragonadal germ cell tumors in the retroperitoneum are very likely a rare or non-existing entity and should be considered as metastases of a viable or burned-out testicular cancer until proven otherwise. All of our patients with histologically examined testes had pathological finding, 76% of which were either viable tumor or scars.

Clusters of life-threatening ventricular arrhythmias in patients with implanted cardioverter-defibrillators: prevalence, characteristics, and risk stratification.

BACKGROUND: Series of discharges from an implanted defibrillator (ICD) to terminate life-threatening ventricular tachyarrhythmias are one particular aspect of energy use and success of ICD therapy. Little is known about prevalence. characteristics, and risk stratification of so-called "cluster arrhythmias." HYPOTHESIS: The objective of this study was to examine the frequency of cluster arrhythmias, to characterize the temporal relationship precisely, and to assess the accompanying circumstances of their occurrence, whereby risk stratification was to be made if appropriate. METHODS: In all, 63 consecutive patients were followed prospectively over 727 +/- 684 days to determine the presence and characteristics of cluster arrhythmias (45,801 patient days). In 30 patients, 374 ICD episodes of ventricular tachyarrhythmias were analyzed for their temporal relationship. After a first successfully terminated ventricular tachyarrhythmia, further ICD discharges within 3 h were observed during 145 of 374 (39%) episodes; mean time interval between these arrhythmias was 25 +/- 32 min. RESULTS: Arrhythmia clusters occurred in 19 of 30 (63%) patients. In multivariate analysis, only underlying heart disease was predictive for accumulation of ventricular tachyarrhythmias. Cluster arrhythmias were more frequent among patients with ischemic heart disease than among those with nonischemic heart disease (40.0 vs. 29.2%, p < 0.05). Ejection fraction, age, gender, and other parameters were not predictive for occurrence of arrhythmia clusters. In 4 of 19 patients, accumulation of ICD discharges was predictive for new onset of myocardial ischemia elicited by exercise test. CONCLUSIONS: Cluster arrhythmias are most common in patients with ICDs with coronary heart disease and may indicate disease progression and increasing instability, for example, due to new onset of myocardial ischemia.

Impact of electrocardiogram recording format on QT interval measurement and QT dispersion assessment.

The aim of this study was to determine the effect of recording conditions on the operator dependent measures of QT dispersion in patients with known and/or suspected repolarization abnormalities. Among several methods for risk stratification, QT dispersion has been suggested as a simple estimate of repolarization abnormalities. In a cohort of high and low risk patients, different components of the repolarization process were assessed in the 12-lead ECG using three different paper speeds and amplifier gains. To assess measurement error and reproducibility, a straight line was repeatedly measured. The operator error was 0.675 +/- 0.02 mm and the repeatability of the measurement error was 31 +/- 6%. The QT interval was most frequently measurable in V2-V5. Depending on the lead selected for analysis, the incidence of visible U waves was greatest in the precordial leads with high amplifier gain and low paper speed, strongly affecting QT interval measurement. The timing of the onset of the QRS complex (QRS onset dispersion) or offset of the T wave was strongly dependent on the paper speed. Paper speed, but not amplifier gain, had a significant shortening effect on the measurement of the maximum QT interval. As QT interval measurement in each ECG lead incorporates QRS onset and T wave offset (depending on the number of visible U waves), the dispersion of each of these parameters significantly affected QT dispersion. Thus, QT dispersion appears to reflect merely the presence of more complex repolarization patterns in patients at risk of arrhythmias.

3D assessment of myocardial perfusion parameter combined with 3D reconstructed coronary artery tree from digital coronary angiograms.

In patients with coronary artery disease coronary angiography plays an important role in the clinical decision-making process. However, it has been recognized that no simple relation exists between the visually or quantitatively evaluated severity of coronary artery stenoses and its effects on regional myocardial perfusion. This paper describes for the first time the development and application of a 3D technique that visualizes and quantifies regional myocardial perfusion parameters from biplane coronary angiograms by using the impulse response analysis technique. The 3D reconstructed coronary tree is automatically superimposed on the 3D perfusion image to generate and visualize an 'integrated' 3D image. The preliminary results in patients with critical coronary artery stenoses indicate that our combined 3D fusion image provides flow information from the major coronary arteries. This 3D fusion image may provide useful information in the management of patients with coronary artery disease.

[Antiarrhythmic therapy in patients with heart failure]. / Therapie kardialer Arrhythmien bei Herzinsuffizienz.

In patients with severe chronic heart failure, many deaths are sudden due to life-threatening ventricular arrhythmias. Supraventricular arrhythmias such as paroxysmal or chronic atrial fibrillation may also cause serious complications in those patients due to acute loss of atrial contraction, pump failure during rapid ventricular response and embolic events. Two therapeutic strategies are currently available for therapy and prevention of malignant ventricular arrhythmias and subsequent sudden arrhythmic death: antiarrhythmic drug therapy and implantable defibrillators. However, selection of the most beneficial strategy for the individual patient to reduce the risk of sudden death remains a major challenge in cardiology. Betablockers exert a favorable antiarrhythmic action without increasing proarrhythmia, thus betablockers may serve as a basic medication in patients at risk for sudden death. However, the general use of antiarrhythmic drug therapy for symptomatic ventricular arrhythmias is not recommended, as these drugs have been shown to increase mortality in patients with severe congestive heart failure due to proarrhythmic or negative inotropic effects (e.g. class Ia antiarrhythmics). Even class III antiarrhythmic drugs such as amiodarone, which has been studied sufficiently in patients with left ventricular dysfunction, is not effective enough for significant reduction of cardiac mortality in patients with symptomatic ventricular arrhythmias and depressed ventricular function (e.g. EMIAT, CAMIAT). But as a positive result of available studies, amiodarone does not increase mortality in those patients. Dofetilide has also not been shown to prolong life significantly by suppressing malignant ventricular arrhythmias (DIAMOND-Study). In patients with symptomatic ventricular arrhythmias or aborted sudden death, ICD therapy has been proven to be superior to antiarrhythmic drug therapy in cardiac mortality reduction as a secondary prevention strategy (e.g. AVID, CASH, CIDS). For primary prevention of sudden arrhythmic death in high risk patients, 2 studies (MADIT, MUSST) have already demonstrated favorable results, decreasing mortality by ICD therapy in selected patient populations with partly-reduced ventricular function and unsustained but inducible ventricular tachycardias. This topic is, however, undergoing further evaluation by ongoing trials (e.g. MADIT II, SCD-HeFT). From available data, antiarrhythmic drug therapy in high risk patients is not justified on a routine basis, whereas ICD therapy as a secondary and perhaps primary prevention strategy will significantly reduce cardiac mortality in patients with severe heart failure. Sotalol, a class III antiarrhythmic agent, has recently been shown to reduce ICD-shock delivery which indicates that concomitant drug therapy in patients with an ICD device already implanted may be beneficial in terms of reducing ICD discharges due to ventricular and supraventricular tachycardias. In patients with paroxysmal atrial fibrillation and congestive heart failure, restitution of sinus rhythm is the primary therapeutic goal which can be safely achieved by amiodarone and dofetilide (DIAMOND). In the latter, continuous monitoring of the patient is mandatory because of increased risk of torsade de pointes arrhythmias during the first days of drug administration. In patients with chronic atrial fibrillation rate control and anticoagulation with warfarin is the primary therapeutic option, which can be achieved with either drug treatment (Digoxin, betablockers, amiodarone) or by His bundle ablation with subsequent pacemaker insertion.

[Acute myocardial ischemia and ventricular arrhythmias in the pathogenesis of sudden cardiac death in coronary disease]. / Akute Myokardischämie und ventrikuläre Arrhythmien in der Pathogenese des plötzlichen Herztodes bei koronarer Herzkrankheit.

There is increasing evidence for a fatal interaction of myocardial ischemia, ventricular arrhythmias and sudden cardiac death in some patients with coronary artery disease. Evidence comes from autopsy studies, from the evaluation of patients who survived an episode of sudden cardiac death, from follow-up data of these patients either treated or not by revascularization therapy and/or an implantable cardioverter-defibrillator and indicate that reducing the individual ischemic burden will be beneficial to reduce the incidence of sudden cardiac death. Studies in patients with stable and especially with unstable angina using Holter monitoring could demonstrate that there is a close and causal relationship between myocardial ischemia inducing or aggravating life-threatening ventricular arrhythmias and sudden cardiac death particularly in patients with unstable and postinfarction status. This review summarizes some of our clinical knowledge on this topic and indicates that preventive strategies for myocardial ischemia are the antiarrhythmic treatment of choice in patients with severe coronary artery disease and patients with evidence or at risk for ischemic proarrhythmia.

Usefulness of carvedilol in unstable angina pectoris.

The safety and efficacy of adding oral carvedilol (25 mg twice daily) to standardized treatment of unstable angina was assessed in a multicenter, randomized, double-blind, placebo- controlled trial on 116 patients with acute unstable angina. Patients were monitored in an intensive care unit and underwent 48-hour Holter monitoring to assess transient ischemia. Carvedilol as adjunctive therapy resulted in a significant reduction of median heart rate (65 vs 75 beats/min, p <0.05), mean systolic blood pressure (133 vs 130 mm Hg, p <0.05), and mean rate-pressure product (8,337 vs 10,042, p <0.05). Carvedilol reduced the ischemic burden during 48 hours of treatment by 75% (49 vs 204 minutes), including a 36% reduction of patients with ischemic episodes (p <0.05), a 66% reduction of the mean number of ischemic episodes (8 vs 24, p <0.05), and a 76% reduction in the mean duration of ischemic episodes (50 vs 205 minutes, p <0.05). Side effects occurred in 8 of 59 patients (13.6%) in the carvedilol group and in 5 of 54 patients (8.8%) given placebo. Although not significant, the early onset of maximal blood pressure reduction and the delayed effect on heart rate were closely correlated to drug-induced hypotension and bradycardia in the carvedilol group. Thus, carvedilol as an adjunctive to standardized treatment effectively reduces heart rate and blood pressure, and thus the ischemic burden in patients with unstable angina pectoris, but requires close monitoring of patients at risk for bradycardia or hypotension.

Fusion imaging: combined visualization of 3D reconstructed coronary artery tree and 3D myocardial scintigraphic image in coronary artery disease.

BACKGROUND: In patients with coronary artery disease, coronary angiography is performed for assessment of epicardial coronary artery stenoses. In addition, myocardial scintigraphy is commonly used to evaluate regional myocardial perfusion. These two-dimensional (2D) imaging modalities are typically reviewed through a subjective, visual observation by a physician. Even though on the analysis of 2D display scintigraphic myocardial perfusion segments are arbitrarily assigned to three major coronary artery systems, the standard myocardial distribution territories of the coronary tree correspond only in 50-60% of patients. On the other hand, the mental integration of both 2D images of coronary angiography and myocardial scintigraphy does not allow an accurate assignment of particular myocardial perfusion regions to the corresponding vessels. To achieve an objective assignment of each vessel segment of the coronary artery tree to the corresponding myocardial regions, we have developed a 3D 'fusion image' technique and applied it to patients with coronary artery disease. The morphological data (coronary angiography) and perfusion data (myocardial scintigraphy) are displayed in a 3D format, and these two 3D data sets are merged into one 3D image. RESULTS: Seventy-eight patients with coronary artery disease were studied with this new 3D fusion technique. Of 162 significant coronary lesions, 120 (74%) showed good coincidence with regional myocardial perfusion abnormality on 3D fusion image. No regional myocardial perfusion abnormality was found in 44 (26%) lesions. Furthermore, the 3D fusion image revealed 24 ischemic myocardial regions that could not be related to angiographically significant coronary artery lesions. CONCLUSION: The results of this study demonstrate that our newly developed 3D fusion technique is useful for an accurate assignment of coronary vessel segments to the corresponding myocardial perfusion regions, and suggest that it may be helpful to improve the interpretative and decision-making process in the treatment of patients with coronary artery disease.

[Arterial occlusion of the eye in infectious endocarditis]. / Arterienverschluss des Auges bei infektiöser Endokarditis.

BACKGROUND: Infectious endocarditis can lead to embolic arterial retinal occlusions. Which therapy is indicated? RESULTS: A 33-year-old man suddenly became blind in his left eye as the result of a central retinal artery occlusion (CRAO). This occurred during high-dosage treatment for infectious endocarditis that had been diagnosed 3 weeks earlier. The echocardiogram showed distinct vegetation and an abscess on the aortic valve. The CRAO together with the ultrasound findings was considered an absolute indication for surgery of the aortic valve. During this emergency operation, a 2 cm deep abscess cavity was found between the mitral and aortic valves. After removal of the abscess, together with the infected valve, a prosthetic valve was inserted. Following the operation, the patient made an uneventful recovery. The antibiotic treatment was continued for several months. The left eye remained sightless. No recurrence of infectious endocarditis occurred during the follow-up of 2 1/4 years. A branch retinal arterial occlusion occurred in the right eye of a 35-year-old man who had suffered from chronic infectious endocarditis for several months. Insufficiency of more than one valve had been diagnosed on several occasions. The patient, a drug-addict, had refused surgical treatment on each occasion. After 3 months, the right eye became completely blind owing to CRAO. Following high-dosage treatment with antibiotics, the infectious endocarditis was healed. The right eye remained blind. One year later the patient died. CONCLUSION: Retinal arterial occlusion of embolic origin in a patient with infectious endocarditis is an indication for immediate medical and/or surgical treatment. This is of particular importance if there is ultrasound evidence of an abscess in the valve area.

[Risk assessment in coronary heart disease: ventricular arrhythmias, myocardial ischemia and sudden cardiac death]. / Risikostratifikation bei koronarer Herzkrankheit: Ventrikuläre Arrhythmien, myokardiale Ischämie und plötzlicher Herztod.

There is increasing evidence for a fatal interaction of myocardial ischemia, ventricular arrhythmias, and sudden cardiac death in some patients with coronary artery disease. Evidence comes from autoptic studies, from the evaluation of patients who survived an episode of sudden cardiac death, from follow-up data of these patients either treated or not by revascularization therapy and/or an implantable cardioverter-defibrillator and indicate that reducing the individual ischemic burden will be beneficial to reduce the incidence of sudden cardiac death. Studies in patients with stable and especially with unstable angina using Holter monitoring could demonstrate that there is a close and causal relationship between myocardial ischemia inducing or aggravating life-threatening ventricular arrhythmias and sudden cardiac death particularly in patients with unstable and postinfarction status. This review summarizes some of our clinical knowledge on this topic and indicates that preventive strategies for myocardial ischemia are the antiarrhythmic treatment of choice in patients with severe coronary artery disease and evidence or at risk for ischemic proarrhythmia.

[Magnesium deficiency and magnesium substitution. Effect on ventricular cardiac arrhythmias of various etiology]. / Magnesiummangel und Magnesiumsubstitution. Einfluss auf ventrikuläre Herzrhythmusstörungen unterschiedlicher Atiologie.

During recent years there has been an increasing but still controversial discussion on the antiarrhythmic effects and overall benefit of magnesium when directed to patients with various types of ventricular tachyarrhythmias. While magnesium is considered to be a simple, safe and cost-effective approach and many casuistic and empiric reports have indicated antiarrhythmic properties of magnesium in patients with suspected or manifest ventricular arrhythmias, controlled studies proving the antiarrhythmic and overall benefit and justifying a broader use of magnesium in treating various types of ventricular arrhythmias are missing or rare. At present, antiarrhythmic properties and clinical benefit of magnesium application has only been established in patients with torsade de pointes and digitalis-induced ventricular tachyarrhythmias. In perioperative patients at risk for ventricular tachyarrhythmias and in patients suffering from manifest heart failure, data may also indicate some antiarrhythmic properties of magnesium, however, in this case with a wide consensus that the prevention of magnesium deficit is more effective and preferred in most patients over the therapeutic application of magnesium. Another group of patients who may profit from such a therapeutic approach are patients with frequent ventricular arrhythmias and stable underlying heart disease, in whom a recently published double-blind, randomized study documented an antiarrhythmic effect of a 3 week treatment with potassium and magnesium. For all other types of ventricular tachyarrhythmias, the therapeutic use of magnesium can be considered as not harmful, but also as not proven to be effective.