Images in cardiovascular medicine. Phenotype of infiltrating T lymphocytes in cardiac sarcoidosis.
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Biomedical subjects
Publications and source records attributed to Bernhard Maisch.
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OBJECTIVES: This study investigated the incidence of appropriate implantable cardioverter defibrillator (ICD) interventions for ventricular tachycardia (VT) or ventricular fibrillation (VF) in patients with idiopathic dilated cardiomyopathy (IDC) and nonsustained VT in the presence of a left ventricular ejection fraction below 30%, versus in patients with syncope and patients with a history of VT or VF. BACKGROUND: To date, only limited information is available about the prophylactic use of ICDs in patients with IDC. METHODS: From January 1993 to July 2000, 101 patients with IDC underwent implantation of ICDs with electrogram storage capability at our institution. Patients were placed into one of three groups according to their clinical presentation: asymptomatic or mildly symptomatic nonsustained VT in the presence of a left ventricular ejection fraction < or = 30% (49 patients, prophylactic group), unexplained syncope or near syncope (26 patients, syncope group) and a history of sustained VT or VF (26 patients, VT/VF group). RESULTS: During 36 +/- 22 months follow-up, 18 of 49 patients (37%) in the prophylactic group received appropriate shocks for VT or VF, compared with 8 of 26 patients (31%) in the syncope group and with 9 of 26 patients (35%) of the VT/VF group. Multivariate Cox analysis of baseline clinical variables identified left ventricular ejection fraction, atrial fibrillation and a history of sustained VT or VF as predictors for appropriate ICD interventions during follow-up. CONCLUSIONS: Patients with IDC and prophylactic ICD implantation for nonsustained VT in the presence of a left ventricular ejection fraction < or = 30% had an incidence of appropriate ICD interventions similar to that of patients with a history of syncope or sustained VT or VF. These findings indicate that ICDs may have a role in not only secondary but also primary prevention of sudden death in IDC.
PATHOGENESIS: All forms of chronic heart failure (high-output and low-output failure) are accompanied by an "arterial underfilling" inducing the activation of various neurohumoral systems (renin-angiotensin-aldosterone system, sympathic nervous system, non-osmotic stimulation of vasopressin). Elevated levels of those neurohormones detrimentally modulate renal function. Subsequently, renal salt and volume retention occurs leading to the main symptoms of heart failure, edema formation and dyspnea. DIURETIC THERAPY: Diuretics, which have been discovered more than 40 years ago, beneficially influence renal salt- and volume retention by their effects on tubular sodium reabsorption. While thiazides are recommended in mild forms, loop diuretics are used in severe stages of congestive heart failure. The clinician has to consider the changed pharmacokinetic and -dynamic properties during the application of diuretics in patients with chronic heart failure. In addition, increased sodium reabsorption occurs immediately after cessation of diuretic action often nullifying the preceding diuresis. Thus, salt- and volume restriction should be guaranteed, and a regular application of loop diuretics during the day should be preferred due to the short-acting nature of currently available loop diuretics. Sometimes, diuresis does not longer occur during the treatment with one substance (diuretic resistance), although the therapeutic goals of water excretion have not been achieved. After ruling out factors reducing the actions of diuretics (non-compliance, hyponatremia, etc.), a sequential nephron blockade should be initiated (combination of loop diuretics and a thiazide or an aldosterone-receptor antagonist) to increase diuresis and to elevate symptoms of volume overload. SIDE EFFECTS: Loop diuretics and thiazides often induce mild hypokalemia, which has been demonstrated to be not as benign as thought before. Chronic treatment with oral potassium supplements has several drawbacks, as urine excretion of potassium is subsequently increased and supplementation is not as effective as believed. Diuretic-induced hypokalemia seems to be aldosterone dependent. As aldosterone levels increase during diuretic therapy even during chronic treatment with an angiotensin-converting enzyme (aldosterone-escape) a combined treatment including an aldosterone-receptor antagonist has been suggested. Beneficial effects of aldosterone-receptor blockade on mortality (RALES trial) appear to be mediated be extrarenal and renal mechanisms. The suggested beneficial renal mechanisms of aldosterone receptor blockade are discussed in detail in the review. CONCLUSION: In conclusion, diuretic therapy of patients with congestive heart failure is effective to relieve symptoms and, presumably, to prolong life. As renal function and pharmacokinetics and -dynamics of diuretics are changed in heart failure, diuretic treatment has to be adapted to provide optimal treatment. Increased levels of aldosterone appear to play an important role in diuretic-induced hypokalemia, and in the progression of heart and renal failure. Thus, aldosterone receptor antagonists should be used in the treatment of heart failure more frequently.
BACKGROUND: Once contraindicated, beta-blockers have become an established, evidence-based, recommended treatment concept in chronic heart failure during the last years. PATHOPHYSIOLOGY: The increased activation of the adrenergic system in heart failure syndrome, which leads to transmission of several adverse biological signals to myocytes through adrenergic receptors, provides the rationale for the use of beta-blockers in patients with chronic heart failure. Long-term treatment with different types of beta-blockers addictive to an ACE-inhibitor and diuretics results in normalization of left ventricular shape, an improvement of left ventricular function, and a reduction of hospitalization rate for heart failure. Hemodynamic and clinical improvement is independent of etiology and severity of left ventricular dysfunction. THERAPEUTICAL RECOMMENDATIONS ACCORDINGS TO STUDIES: Adequately powered clinical trials (CIBIS II, MERIT-HF, COPERNICUS) testing different types of beta-blockers (bisoprolol, metoprolol, carvedilol) clearly demonstrated that total mortality and the incidence of sudden cardiac death were significantly reduced in heart failure patients by each of these agents. On the basis of all available evidence, all patients with chronic, stable heart failure (NYHA class II-IV) and with impaired left ventricular function (LVEF < 45%) should receive one of the three above mentioned beta-blockers. Protective effects of beta-blockers in heart failure comprise decrease in heart rate, a decrease of energy consumption, antifibrillatory effects, protection against adrenergic overactivation, and hence, inhibition of myocardial cell necrosis. Moreover, several beta-blockers induce an up-regulation of beta-receptors leading to an improvement of contractility during long-term treatment. It should be mentioned that even a low dosage of beta-blockers exert negative inotropic effects and may lead to a deterioration of hemodynamics and heart failure symptoms in patients with heart failure. The patients treated should be informed that the success of the "paradoxical intervention" will be obvious until 2-3 months after initiation of additional beta-blocker therapy. Beta-blocker treatment for heart failure should be started in stable patients with a very low initial dosage and then up-titrated to the maximal tolerated dosage and should be continued indefinitely. Mortality reduction by beta-blockade in heart failure is no class effect. So far, beneficial effects could only be demonstrated for lipophilic agents. Whether the non-selective beta-blocker carvedilol with additional properties has advantages over the beta-1-selective metoprolol is currently investigated in the COMET (Carvedilol or Metoprolol European Trial) study. Despite the impressive effects in terms of morbidity and mortality reduction, the transfer of these benefits to the clinical practice setting is difficult, with international data showing only 10% of patients with heart failure being treated.
BACKGROUND: Drugs for counteracting the neuroendocrine activation in heart failure can reduce the adverse remodelling of the extracellular matrix of the heart. Progression of heart failure can, however, often not be prevented and the question arises whether important pharmacological targets remain unidentified. Promising are drugs targeted at ventricular diastolic dysfunction which is a marker of early progression of heart failure. PATHOPHYSIOLOGY: Left ventricular dysfunction is characteristic of overloaded hypertrophied hearts with molecular structures that are not adapted to the increased Ca2+ diffusion distances. Thus, the Ca(2+)-pump (SERCA2) of sarcoplasmic reticulum is inadequately expressed leading to a reduced force development and relaxation of hypertrophied cardiomyocytes. ETOMOXIR: Drugs in development (CPT-1 inhibitor/PPARalpha activator) that increase glucose oxidation can enhance SERCA2 expression. The lead compound etomoxir had a selective influence on the contraction and relaxation rate of pressure-overloaded hearts. The functional parameters were correlated with the proportion of alpha-myosin heavy chains. Since viral or inflammatory injury of the heart can also induce a fetal phenotype, metabolic modulators such as etomoxir represent a promising therapeutic approach also for cardiomyopathies with inadequate SERCA2 expression.
DEFINITION AND CLASSIFICATION: Cardiomyopathies are disorders affecting the heart muscle that frequently result in congestive heart failure. Five major forms are recognized: dilated, hypertrophic, restrictive, right ventricular, and nonclassifiable cardiomyopathies with distinct hemodynamic properties. Furthermore, the new WHO/WHF definition also comprises inflammatory cardiomyopathy, defined as myocarditis in association with cardiac dysfunction. Idiopathic, autoimmune, and infectious forms of inflammatory cardiomyopathy were recognized. Viral cardiomyopathy is defined as viral persistence in a dilated heart. It may be accompanied by myocardial inflammation and then termed inflammatory viral cardiomyopathy (or viral myocarditis with cardiomegaly). If no inflammation is observed in the biopsy of a dilated heart (< 14 lymphocytes and macrophages/mm2), the term viral cardiomyopathy or viral persistence in dilated cardiomyopathy should be applied. DIAGNOSIS AND TREATMENT: In recent years, there have been breakthroughs in understanding the molecular and genetic mechanisms involved in this group of conditions, enabling improvement of diagnostic strategies and introduction of new therapies. Ongoing evaluation of antiviral, immunoglobulin, and immunosuppressive therapies including the European Study of Epidemiology and Treatment of Cardiac Inflammatory Diseases (ESETCID), removal of antibodies by immunoadsorption, anticytokine and gene therapy, as well as the mechanical support devices may provide new treatment options.
BACKGROUND: Inflammatory processes induced by rival infection are believed to be one of the major pathogenetic mechanisms in inflammatory dilated cardiomyopathy. Although the reason for progression to myocardial failure is not fully understood, postulated mechanisms include persistent viral infection alone or in combination with autoimmune processes. PATHOPHYSIOLOGY: Murine models of myocarditis have provided insight into the mechanisms by which autoimmune responses to cardiac antigens, probably in response to viral infection of the myocardium, arise and cause tissue pathology. Organ-specificity, cross-reactivity between microbial agents and cardiac tissue, and induction of tolerance to self-antigen are issues still at stake. In addition, cytokines mediate activation and effector phase of innate and specific immunity, which are both important in controlling viral infection. The innate immune response not only has an important protective function but also serves to initiate and regulate subsequent specific immune responses. In man, on the one hand specific T cells and antibodies against different cardiac tissue components have been demonstrated in myocardium and sera of patients with inflammatory cardiomyopathy, and on the other hand viral genome has been identified in endomyocardial biopsies due to the rapid development of new molecular biological techniques such as polymerase chain reaction (PCR), southern blot analysis and in-situ hybridization. But it is still a mater of debate whether virus infection itself, the ensuing immune response, or both, contribute to the deterioration of left ventricular function. CONCLUSION: Taking these mechanisms into account, screening for viral genome by PCR and detection of inflammatory infiltrates by immunohistochemistry are considered crucial for the establishment of a definite diagnosis thereby allowing for the initiation of specific therapeutic strategies.
BACKGROUND: Despite routine use of angiotensin-converting enzyme (ACE) inhibitors, beta-blockers and spironolactone in patients with heart failure due to dilated cardiomyopathy (DCM), these patients still have a considerable annual mortality rate of 5-10%. Sudden unexpected death accounts for up to 50% of all deaths and is most often due to rapid ventricular tachycardia or ventricular fibrillation and less often due to bradyarrhythmias or asystole. THERAPEUTIC OPTIONS: The use of beta-blockers in patients with heart failure has been shown to improve overall mortality considerably. This survival benefit has been demonstrated for bisoprolol, metoprolol and carvedilol. Therefore, one of these three beta-blocking agents should be administered routinely starting with low doses in all patients with New York Heart Association (NYHA) class II or III heart failure in addition to ACE inhibitors, unless there is a contraindication to beta-blocker use. In addition, NYHA class IV heart failure patients have been shown to benefit from carvedilol therapy, if tolerated. The conflicting results of GESICA and CHF-STAT studies do not support a strategy of "prophylactic" amiodarone therapy in patients with DCM in order to prevent sudden cardiac death. Despite growing evidence that implantable cardioverter defibrillator (ICD) therapy results in improved overall survival py preventing sudden cardiac death in patients at high risk for serious arrhythmic events, arrhythmia risk stratification with regard to prophylactic ICD implantation remains highly controversial in patients with DCM. CONCLUSION: This review describes potential arrhythmia mechanisms in DCM and summarizes the results of antiarrhythmic drug trials and of prophylactic ICD trials in patients with heart failure as well as our knowledge concerning arrhythmia risk stratification in patients with DCM.
BACKGROUND: Partial fatty acid oxidation inhibitors have raised great interest since they are expected to counteract a dysregulated gene expression of hypertrophied cardiocytes. Some of these compounds have been developed for treating non-insulin-dependent diabetes mellitus and stable angina pectoris. A shift from fatty acid oxidation to glucose oxidation leads to a reduced gluconeogenesis and improved economy of cardiac work. An increased glucose oxidation can be achieved with the following enzyme inhibitors: etomoxir, oxfenicine, methyl palmoxirate, S-15176, metoprolol, amiodarone, perhexiline (carnitine palmitoyltransferase-1); aminocarnitine, perhexiline (carnitine palmitoyltransferase-2); hydrazonopropionic acid (carnitine-acylcarnitine translocase); MET-88 (gamma-butyrobetaine hydroxylase); 4-bromocrotonic acid, trimetazidine, possibly ranolazine (thiolases); hypoglycin (butyryl-CoA dehydrogenase); dichloroacetate (pyruvate dehydrogenase kinase). CLINICAL TRIALS with trimetazidine and ranolazine showed that this shift in substrate oxidation has an antianginal action. Etomoxir and MET-88 improved the function of overloaded hearts by increasing the density of the Ca(2+) pump of sarcoplasmic reticulum (SERCA2). The promoters of SERCA2 and alpha-myosin heavy-chain exhibit sequences which are expected to respond to transcription factors responsive to glucose metabolites and/or peroxisome proliferator-responsive element (PPAR) agonists. Further progress in elucidating novel compounds which upregulate SERCA2 expression is closely linked to the characterization of regulatory sequences of the SERCA2 promoter.
BACKGROUND: Research in atherosclerosis is a good example how helpful different disciplines such as clinicians, epidemiologists and basic science can collaborate. In recent years our knowledge on cellular and subcellular mechanisms involved in initiation and progress of atherosclerosis has expanded due to the shared knowledge of different disciplines and thanks to new technologies in molecular biology. PATHOPHYSIOLOGY OF LDL AND HDL METABOLISM: The understanding of the molecular basis of inborn errors of LDL metabolism - such as familial hypercholesterolemia due to a defect of the LDL receptor - provided us new insights in physiology and pathophysiology of LDL metabolism. Most recently we have learned much about the vasoprotective HDL cholesterol. HDL is the major player in reverse cholesterol transport and some of its receptors such as ABCA1 and SR-BI were identified. This knowledge gives us a deeper understanding of the complex system which performs reverse cholesterol transport from peripheral tissue and the vessel wall back to the liver. PLAQUE FORMATION: Furthermore the process of formation and progression of the atherosclerotic plaque has been the focus of recent research. The stability or instability of plaques is depending on the complex interaction of adhesion molecules, monocytes, macrophages, endothelial cells, cytokines, transmitters and proteinases. Since we are unable to prevent plaque formation completely, the stabilization of plaques is a major goal for the coming years. Despite some success (such as the use of statines and ACE inhibitors) there is still a long way to go.
The spectrum of pericardial diseases comprises pericarditis, pericardial neoplasms, cysts, and congenital defects. Due to the insufficient diagnostic value of standard, noninvasive diagnostic techniques, many cases remained etiologically unclear, and were therefore classified as idiopathic. A major improvement in the classification of pericardial disease is its clear distinction between the two most frequent forms of idiopathic pericarditis: viral infection and autoreactive pericarditis. This classification has major therapeutic consequences. In autoreactive forms, systemic and intrapericardial corticosteroid treatment has a favorable effect; its application in viral forms is contraindicated. The new classification of pericardial diseases synthesizes the achievements of modern imaging with molecular biology and immunology. Systematic implementation of new techniques of pericardial fluid analyses, pericardioscopy and pericardial biopsy, and the application of molecular biology and immunology techniques have opened new windows to the pericardial diseases, permitting early specific diagnosis, and creating foundations for etiologic treatment in many cases.
BACKGROUND: Periodontopathogens may play a role in the etiology of cardiovascular disease. The aim of the present study was to investigate biopsies of aortic tissue for the presence of periodontopathogens. METHODS: Samples taken from the aortas of 26 patients connected to a heart-lung machine during open-heart surgery were analyzed in a gene-diagnostics laboratory by polymerase chain reaction. Immediately after biopsy, the samples were transferred into liquid nitrogen and stored at -80 degrees C. 16S rRNA gene-directed primers were used for general detection of bacterial cells, and specific primers for detection of Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans. Questionable amplificons were verified by Southern hybridization using DNA probes. RESULTS: Bacterial DNA was found in 23 of 26 (88.5%) samples, in most cases only in concentrations around the detection limit. Four samples were clearly positive for P. gingivalis; A. actinomycetemcomitans was not detected. CONCLUSION: These results might indicate a link between periodontopathogens entering the cardiovascular system and cardiovascular disease.
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This paper reports a case of acute severe thrombocytopenia (platelet count: 1 x 10(9)/liter) occurring within minutes of an initial abciximab bolus during coronary angioplasty and stenting in a patient with unstable angina. After six days with platelets again in the normal range the patient developed stent thrombosis. The stent was reopened and the glycoprotein receptor inhibitor tirofiban (Aggrastat) was administered without any adverse effects on platelet count. Antibodies against heparin-platelet factor 4 complexes could be excluded. Allo- and autoantibodies (IgG, IgA, IgM) directed against platelets with and without binding of abciximab could not be detected by indirect and direct platelet fluorescence antiglobulintest. A possible activation or lysis of the platelets by abciximab could also be excluded by an in vitro bleeding test investigating the effect of abciximab on heparin and citrate blood of the patient and two healthy donors. The mechanisms of abciximab-induced thrombocytopenia in this case remain unclear. The possible mechanisms are discussed.
The pathophysiology of viral myocarditis is still a matter of debate. Humoral autoimmunity in postviral heart disease remains an attractive but complex hypothesis. Antigenic mimicry with or without cytolytic antibody properties has been shown to play a role in the immunopathogenesis of myocarditis with respect to sarcolemmal/myolemmal epitopes (including the beta-receptor), myosin and some mitochondrial proteins including the antinucleotide translocator (ANT)-carrier and dihydrolipoamid dehydrogenase. Today, refined two-dimensional Western blots are able to identify receptors and enzymes that are target of a humoral immune response or the consequence of an "immunization process." A humoral immune response to an invading agent will most likely lead to immunodestruction first. After conversion to IgG, the continuing antibody response may indicate the healing or healed process and last for many years or life-long. This paper reviews our present knowledge on the humoral immune response in myocarditis and its interplay with the viral agents and the other components of the immune system.