R-wave detection by subcutaneous ECG. Possible use for analyzing R-R variability

BACKGROUND

Atrial arrhythmia (AA) discrimination remains a technological challenge for implanted cardiac devices. We examined the feasibility of R-wave detection by a subcutaneous far field ECG (SFFECG) and analysis of these signals for R to R variability as an indicator of atrial arrhythmia (AA).

METHODS

Surface ECG and SFFECG (from the pacemaker pocket) were recorded in sixteen patients (61.5 +/- 11.4 years) with AA. The SFFECG was recorded with a pacemaker sized four electrode array acutely placed in the pacemaker pocket during implantation. The signals were analyzed to obtain peak-to-peak R wave amplitude and R to R interval variability (indicative of AAs).

RESULTS

In sixteen patients R waves were visually discernible in all recordings. The percentage over and under detection for automatic R wave recognition SFFECG was 3 and 9%, respectively. R to R variability analysis using the SFFECG produced results concordant to those using the surface ECG.

CONCLUSION

SFFECG might be a helpful adjunct in implantable device systems for detection of R waves and may be used for measurement of R to R variability.

Erythroid progenitor renewal versus differentiation: genetic evidence for cell autonomous, essential functions of EpoR, Stat5 and the GR

The balance between hematopoietic progenitor commitment and self-renewal versus differentiation is controlled by various transcriptional regulators cooperating with cytokine receptors. Disruption of this balance is increasingly recognized as important in the development of leukemia, by causing enhanced renewal and differentiation arrest. We studied regulation of renewal versus differentiation in primary murine erythroid progenitors that require cooperation of erythropoietin receptor (EpoR), the receptor tyrosine kinase c-Kit and a transcriptional regulator (glucocorticoid receptor; GR) for sustained renewal. However, mice defective for GR- (GR(dim/dim)), EpoR- (EpoR(H)) or STAT5ab function (Stat5ab(-/-)) show no severe erythropoiesis defects in vivo. Using primary erythroblast cultures from these mutants, we present genetic evidence that functional GR, EpoR, and Stat5 are essential for erythroblast renewal in vitro. Cells from GR(dim/dim), EpoR(H), and Stat5ab(-/-) mice showed enhanced differentiation instead of renewal, causing accumulation of mature cells and gradual proliferation arrest. Stat5ab was additionally required for Epo-induced terminal differentiation: differentiating Stat5ab(-/-) erythroblasts underwent apoptosis instead of erythrocyte maturation, due to absent induction of the antiapoptotic protein Bcl-X(L). This defect could be fully rescued by exogenous Bcl-X(L). These data suggest that signaling molecules driving leukemic proliferation may also be essential for prolonged self-renewal of normal erythroid progenitors.

Predictors of chronotropic incompetence in the pacemaker patient population

AIMS

We prospectively evaluated results from cardiopulmonary exercise testing for chronotropic incompetence (CI) in a cohort of 292 pacemaker patients. In addition, we evaluated comorbidity and antiarrhythmic patient data as indicators of CI.

METHODS AND RESULTS

On the basis of exercise stress testing and application of the definition of CI by Wilkoff, 51% of our cohort was categorized as having CI. Indications for pacemaker implant for this patient group were 42% atrioventricular block, 56% sinus node disease, and 59% atrial fibrillation. Maximum oxygen uptake (VO(2) max) and exercise duration were significantly reduced among CI pacemaker patients, whereas oxygen uptake at the anaerobic threshold remained unchanged. The following clinical characteristics were significant predictors of CI: existence of coronary artery disease (P = 0.038), presence of an acquired valvular heart disease (P = 0.037), and former cardiac surgery (P = 0.041). Age, gender, arterial hypertension, cardiomyopathy, congenital heart disease, left ventricular ejection fraction, and time period between stress-exercise examination and pacemaker implantation were not significant predictors of CI. Chronic antiarrhythmic therapy with digitalis (P = 0.013), beta blockers (P = 0.036), and amiodarone (P = 0.045) were significant predictors of CI. In contrast, medication with class I and IV antiarrhythmics had no significant correlation with CI.

CONCLUSION

We found the following characteristics predictive of CI in this pacemaker patient population: VO(2) max, existence of coronary artery disease or acquired valvular heart disease, previous cardiac surgery, as well as medication with digitalis, beta blockers, and amiodarone.

Effects of different steroid treatment on reperfusion-associated production of reactive oxygen species and arrhythmias during coronary surgery

BACKGROUND

During conventional cardiac surgery ischemia and reperfusion may cause excessive production of reactive oxygen species leading to tissue damage including early arrhythmias. We therefore assessed the kinetics of markers of radical stress including oxidized and reduced glutathione (GSSG/GSH), oxidized proteins (PCG) and malondialdehyde (MDA), and tested the hypothesis that different steroid treatments inhibit these markers and early reperfusion-associated supraventricular and ventricular extrasystolic beats.

METHODS

In a randomized, controlled, blinded, prospective trial 36 patients received a preoperative infusion of methylprednisolone (MP, 15 mg kg-1, n = 12), tirilazad mesylate (TM, 10 mg kg-1, n = 12) or placebo (PL, NaCl, n = 12). Coronary sinus and arterial blood was drawn at baseline and 2, 5, 15, 30, 60 and 240 min after aortic declamping. Holter-ECG analysis was used to identify arrhythmias.

RESULTS

Cardiac GSSG release occurred very early (< 15 min) and was not significantly attenuated by either drug treatment. Cardiac PCG production showed biphasic increases, lasted > 4 h and was significantly reduced only by TM. Cardiac MDA release was short (< 30 min) and significantly reduced by MP and TM. Neither treatment had a significant influence on the early occurrence of ventricular or supraventricular arrhythmias. The number of patients needing cardioversions or defibrillations also were not different.

CONCLUSIONS

The results indicate that cardiac production of reactive oxygen species occurs after reperfusion in humans and is not inhibited by steroid treatment. Steroid treatment effectively reduces lipid peroxidation during cardiac surgery but has no influence on arrhythmias.

Relaxin: a pregnancy hormone as central player of body fluid and circulation homeostasis

The peptide relaxin has long been regarded as an important hormone of pregnancy, contributing to changes in connective tissue composition as well as to regulation of implantation, myometrial activity and labor. On the other hand, the astonishing pleiotropy of this hormone escaped scientific awareness. This review focuses on new facets of relaxin, including its antifibrotic effects, its role in the control of pituitary hormone release, its vasodilator and pro-angiogenic properties and its versatile myocardial actions. Recent progress in understanding relaxin's receptor and signaling mechanisms is also highlighted. The peptide will be characterized as potential regulator of body fluid and circulation homeostasis.

Cessation of pulmonary and coronary secretion of adrenomedullin peptides in the progression of human heart failure

In human heart failure (CHF), adrenomedullin (AM) counteracts vasoconstriction and sodium retention. We investigated circulating levels of proadrenomedullin N-20 peptide (PAMP) and AM, and left ventricular expression of preproAM and calcitonin receptor-like receptor (CRLR) mRNA. Peptide levels were determined from the left ventricle, pulmonary artery, coronary sinus, and antecubital vein in patients demonstrating severe CHF (n = 12; mean +/- SEM cardiac index, 1.9 +/- 0.2 l/min/m(2); pulmonary wedge pressure, 32 +/- 1 mmHg), moderate CHF (n = 11; cardiac index, 2.9 +/- 0.2; pulmonary wedge pressure, 14 +/- 2), and in controls (n = 11). Left ventricular mRNA was quantified using RT-PCR and Southern blot hybridization. Depending on sites of measurement, PAMP and AM in severe CHF were 1.3 - 2.0 and 1.2 - 1.9 times as high as in moderate CHF, and 3.8 - 4.6 and 2.3 - 2.8 times as high as in controls. Only patients with moderate CHF demonstrated pulmonary and coronary net release of both peptides, that is, significant step-ups in concentrations between the pulmonary artery, left ventricle, and coronary sinus. In failing ventricles, preproAM mRNA increased 2.9 times above control, but CRLR mRNA was unchanged. Altogether, the heart and the lungs release AM peptides in moderate CHF. This secretion breaks down in severe CHF: a process that may contribute to and indicate decompensation. Unlike AM, the CRLR is not transcriptionally upregulated in severe CHF.

Flow-induced pressure differentially regulates endothelin-1, urotensin II, adrenomedullin, and relaxin in pulmonary vascular endothelium

We hypothesized that increased pulmonary vascular pressure--one of the characteristics of congestive heart failure--directly regulates pulmonary endothelial vasoconstrictors (endothelin-1, urotensin II) and vasodilators (adrenomedullin, relaxin). To this end, we subjected pulmonary artery endothelial cells in a novel flow-chamber model to different shear stresses (17, 29, and 46 dyn/cm(2)) at low and elevated levels of downstream pressure (10 and 30 mm Hg). Application of elevated pressure over 16 h increased gene expression and peptide secretion of endothelin-1 at all shear levels, whereas secretion of adrenomedullin rose via decreased expression of its clearance receptor. In contrast, preprourotensin II mRNA and urotensin II peptide decreased in response to elevated pressure, and relaxin remained unaffected. This is the first study to identify pressure as key regulator of mediator synthesis by pulmonary vascular endothelium. Pressure-induced mediator regulation may represent an early event in the development of secondary pulmonary hypertension.

Acute hemodynamic effects of beta-blockers in patients with severe congestive heart failure: comparison of celiprolol and esmolol

The present study was designed to investigate, in patients with severe heart failure, the dose-dependent acute hemodynamic effects of celiprolol versus those of esmolol. Celiprolol is a beta 1 -receptor blocker with vasodilating properties, whereas esmolol is an ultra-short-acting beta 1 -blocker. Included were 14 patients with decompensated chronic heart failure (NYHA class IV) due to coronary heart disease (n = 8) or to dilated cardiomyopathy (n = 6). Each patient received both celiprolol and esmolol in random fashion. The beta-blockers were administered in four dose tiers, with an increase in dosage every 15 min. Hemodynamic measurements were obtained with a Swan-Ganz thermodilution catheter. Administration of celiprolol (5, 10, 20, and 50 microg/kg) took place intravenously. After intravenous administration of a loading dose of 500 microg/kg, we continuously infused esmolol at increasing doses, which were individually titrated for each patient. Mean infusion rates of esmolol were as follows: 40, 75, 140, and 230 micromol/kg per minute. Celiprolol and esmolol induced a comparable dose-dependent decrease in heart rate to a minimum of -10% below baseline. Esmolol caused a significant dose-dependent decrease (-25% below baseline at the highest dose level) in cardiac index (CI). After administration of celiprolol, CI decreased only transiently (-10% below baseline at the second and third dose level) and did not differ from the baseline at the highest dose level. For treatment of severe heart failure, initiation of intravenous beta-blocker therapy with low doses of a beta 1 -blocker with vasodilating effects may have hemodynamic advantages over conventional beta-blockade.

Effects of alcohol on the heart

Some evidence suggests that light to moderate alcohol consumption protects against cardiovascular diseases. However, this cardioprotective effect of alcohol consumption in adults is absent at the population level. Approximately 20 to 30% of patients admitted to a hospital are alcohol abusers. In medical practice, it is essential that patients' levels of consumption are known because of the many adverse effects that might result in the course of routine care. Ethanol damage to the heart is evident if alcohol consumption exceeds 90 to 100 g/d. Heavy ethanol consumption leads to increased risk for sudden cardiac death and cardiac arrhythmias. In patients with coronary heart disease, alcohol use was associated with increased mortality. An early response to drinking was an increased ventricular wall thickness to diameter ratio, possibly proceeding with continuous drinking to alcoholic cardiomyopathy, which had a worse outcome compared with idiopathic dilative cardiomyopathy if drinking was not stopped or at least reduced (< 60 g/d). In the ICU, patients with chronic alcoholism have more cardiac complications postoperatively. These complications probably are caused by biventricular dysfunction, particularly with the occurrence of severe infections or septic shock, events that are three to four times more frequent among chronic alcoholics than occasional drinkers or nondrinkers. To prevent further complications from drinking and for long-term management of drinking, patients with alcohol abuse and heart failure should be treated in brief intervention and follow-up programs. Prognosis is good even in patients with New York Heart Association class IV heart failure caused by cardiomyopathy if complete abstinence is accomplished. Noncompliance to smoking and alcohol restrictions, which are amenable to change, dramatically increases the risk for hospital readmissions among patients with heart failure.

Role of Kozak sequence polymorphism of platelet glycoprotein Ibalpha as a risk factor for coronary artery disease and catheter interventions

OBJECTIVES

We sought to determine the role of the -5T/C polymorphism of the platelet glycoprotein (GP) Ibalpha as a potential risk factor for coronary artery disease (CAD) and adverse events complicating a coronary catheter intervention.

BACKGROUND

The platelet GP Ib-IX-V receptor complex plays a crucial role in arterial thrombus formation. The -5T/C polymorphism of GP Ibalpha is associated with increased receptor density.

METHODS

We genotyped 1,000 patients with angiographically confirmed CAD, as well as 1,000 age- and gender-matched control subjects, for this polymorphism by polymerase chain reaction/restriction fragment length polymorphism. Among the patients with CAD, 269 underwent percutaneous transluminal coronary angioplasty (PTCA), 103 underwent directional coronary atherectomy and 278 underwent stenting. This intervention group was followed for a 30-day composite end point of target vessel revascularization, myocardial infarction or death.

RESULTS

Carriers of the -5C allele were significantly over-represented in the group of patients developing acute coronary syndromes (relative risk [RR] 1.43, 95% confidence interval [CI] 1.05 to 1.95, p = 0.02). The -5C allele furthermore predicted an increased risk for developing complications after PTCA (RR 3.75, 95% CI 1.15 to 12.27, p = 0.029).

CONCLUSIONS

The -5C allele of the GP Ibalpha Kozak polymorphism may represent a risk factor in clinical conditions in which thrombosis plays an important role, such as in acute coronary syndromes and in complications after PTCA.

The pregnancy hormone relaxin is a player in human heart failure

Human congestive heart failure is characterized by complex neurohumoral activation associated with the up-regulation of vasoconstricting and salt-retaining mediators and the compensatory rise of counter-regulatory hormones. In the present study, we provide the first evidence that relaxin (RLX), known as a pregnancy hormone, represents a potential compensatory mediator in human heart failure: plasma concentrations of RLX and myocardial expression of the two RLX genes (H1 and H2) correlate with the severity of disease and RLX responds to therapy. The failing human heart is a relevant source of circulating RLX peptides, and myocytes as well as interstitial cells produce RLX. Elevation of ventricular filling pressure up-regulates RLX expression and the hormone acts as a potent inhibitor of endothelin 1, the most powerful vasoconstrictor in heart failure. Furthermore, RLX modulates effects of angiotensin II, another crucial mediator. Our data identify RLX as a new player in human heart failure with potential diagnostic and therapeutic relevance.

Computer-aided measurement of cell shortening and calcium transients in adult cardiac myocytes

The contractile cycle of the cardiac myocyte is essentially controlled by the concentration of intracellular calcium ([Ca2+]i). Measurement of [Ca2+]i using Ca2+-dependent fluorescence and simultaneous monitoring of cell dynamics enable characterization of a variety of substances interacting with ion channels and contractile proteins. In this report we describe a novel method featuring up to 480 frames/s for monitoring rapid changes in cellular calcium and cell length, in which every individual cycle allows effective evaluation of major cell parameters. Computers aid in determination of time to peak (in ms), time to 50% decrease (ms), diastolic Ca2+ (relative fluorescence units, rfu), systolic Ca2+ (rfu), Ca2+ transients (rfu), DeltaCa2+/Delta(t) rise (rfu/s), and DeltaCa2+/Delta(t) fall (rfu/s). Contractile parameters are as follows: maximum cell length (microm), minimum cell length (microm), absolute cell shortening (microm), peak DeltaL/Delta(t) shortening (microm/s), and peak DeltaL/Delta(t) relaxation (microm/s). In summary, we succeeded in demonstrating that this system is a unique and valuable tool that allows simultaneous and accurate assessment of contractile parameters and of calcium movements of isolated adult cardiac myocytes.

beta(1)-Adrenoceptor antibodies induce positive inotropic response in isolated cardiomyocytes

beta(1)-Adrenoceptor autoantibodies are present in approximately 30% of patients suffering from dilated cardiomyopathy. The inotropic effects mediated by these antibodies remain to be studied. Monoclonal antibodies were raised against a peptide corresponding to the second extracellular loop of the human beta(1)-adrenoceptor in balb/C mouse (n=6), and were characterized by enzyme immunoassay after purification by protein A. Purified immunoglobulin G from non-immunized animals (controls) did not influence Ca(2+) transient and cell shortening of rat cardiomyocytes measured by confocal-laser-scanning-microscopy. beta(1)-adrenoceptor antibodies caused a dose-related increase in Ca(2+) transient (dilution 1:2: +35.3+/-5.1%), and in cell shortening (dilution 1:2: +40.5+/-6.3%) (P<0.01 vs. controls). The effect of the beta(1)-adrenoceptor antibodies was blocked by the antigenic peptide and by the antagonist metoprolol. In addition, beta(1)-adrenoceptor antibodies induced a dose-dependent increase of the cyclic adenosine monophosphate. The inotropic response induced by isoproterenol was attenuated by the beta(1)-adrenoceptor antibody. beta(1)-adrenoceptor antibodies as partial agonists induce a specific positive inotropic effect via the protein-kinase-A-cascade.

Immunohistological changes in dilated cardiomyopathy induced by immunoadsorption therapy and subsequent immunoglobulin substitution

BACKGROUND

Immunoadsorption (IA) and subsequent immunoglobulin (Ig) G substitution represent an additional therapeutic approach in dilated cardiomyopathy (DCM). It remains to be elucidated whether this treatment modulates myocardial inflammation, which is possibly a causal factor of ventricular dysfunction.

METHODS AND RESULTS

From 25 DCM patients (EF <30%), 12 patients were randomized for IA therapy and subsequent IgG substitution at 1-month intervals until month 3. Before (<7 days) and after IA therapy, right ventricular biopsies were obtained from all patients. Biopsies were also obtained at intervals of 3 months from 13 patients without IA/IgG treatment (controls). IA/IgG treatment induced improvement in left ventricular ejection fraction from 21.3+/-1.7% (+/-SEM) to 27.0+/-1.3% (P<0.01 versus baseline/controls) and reduction of the beta-receptor autoantibody serum levels (P<0.01 versus baseline/controls). The number of CD3 cells decreased from 5.7+/-0.8 to 2.9+/-0.5 cells/mm(2) (P<0.01 versus baseline/controls). This decline was paralleled by a decrease in CD4 (P<0.01 versus baseline/controls) and CD8 (P<0.05 versus baseline/controls) lymphocytes. The number of leukocyte common antigen-positive cells (leukocytes) was reduced from 20.0+/-3.2 to 9.9+/-2.8 cells/mm(2) (P<0.01 versus baseline/P<0.05 versus controls). HLA class II expression decreased from 2.1+/-0.7% to 1.1+/-0.4% (P<0.05 versus controls/baseline). The number of immunopositive cells and the expression of HLA class II in controls remained stable. In both groups, the degree of fibrosis remained unchanged.

CONCLUSIONS

IA and subsequent IgG substitution mitigate myocardial inflammation in DCM.

Pulmonary adrenomedullin counteracts deterioration of coronary flow and myocardial performance evoked by pulmonary endothelins in experimental acute respiratory distress syndrome

OBJECTIVES

We recently showed that pulmonary endothelins may affect coronary circulation under various experimental and clinical conditions. Here, we investigated the effect of pulmonary mediators on coronary tone in experimental acute respiratory distress syndrome. We focused particularly on pulmonary endothelin-1, a major vasoconstrictor in acute respiratory distress syndrome, and on adrenomedullin, a potent vasodilator that is up-regulated by inflammatory stimuli.

DESIGN

Controlled experiment that used isolated organs.

SETTING

Experimental laboratory.

SUBJECTS

Wistar rats.

INTERVENTIONS

The saline effluent from an isolated lung was used to serially perfuse the coronary vessels of an isolated heart. We compared serial perfusion after 2-hr pretreatment of lungs with vehicle or endotoxin (50 microg/mL), and we used the following drugs to elucidate the coronary response observed: the endothelin type A receptor antagonist BQ-123 (2 microM), the endothelin type B antagonist A-192621 (500 nM), the endothelin-converting enzyme inhibitor phosphoramidon (50 microM), the calcitonin gene-related peptide type-1 receptor antagonist hCGRP(8-37) (2 microM), and the adrenomedullin receptor antagonist hAM(22-52) (200 nM) (n = 6 each).

MEASUREMENTS AND MAIN RESULTS

In controls, serial perfusion decreased coronary flow to 87 +/- 3% of baseline (p < .05). BQ-123 and phosphoramidon prevented this effect, whereas blockade of endothelin type B and adrenomedullin-binding receptors had no effect. After endotoxin challenge, coronary flow significantly increased to 110 +/- 2%. This response was augmented by BQ-123 (124 +/- 2%) and phosphoramidon (123 +/- 3%); A-192621 had no effect. Application of hCGRP(8-37) and hAM(22-52) significantly decreased coronary flow to 81 +/- 3% and 88 +/- 2%, respectively. Flow decrease after blockade of both adrenomedullin-binding receptors (73 +/- 2%) significantly deteriorated peak left ventricular pressure, to 82 +/- 6% of baseline; rate of pressure increase, to 81 +/- 5%; and rate of pressure decline, to 77 +/- 6%. Endotoxin pretreatment elevated pulmonary venous big endothelin-1 (three-fold), endothelin-1 (two-fold), and adrenomedullin (five-fold).

CONCLUSION

In experimental acute respiratory distress syndrome, pulmonary adrenomedullin--via calcitonin gene-related peptide type-1 receptor and adrenomedullin receptor--outweighs the coronary vasoconstrictor impact of pulmonary big endothelin-1 exerted via endothelin type A receptors after conversion to mature endothelin-1. The consequence is prevention of flow-related deterioration of myocardial performance.

Dexamethasone inhibits stimulation of pulmonary endothelins by proinflammatory cytokines: possible involvement of a nuclear factor kappa B dependent mechanism

OBJECTIVES

Recent studies have indicated effectiveness of glucocorticoid (GC) treatment in late, fibroproliferative adult respiratory distress syndrome. There is furthermore growing evidence for a role of endothelin-1 (ET-1) in lung fibroproliferation, but the impact of GC on stimulated pulmonary ET-1 is not well defined.

DESIGN AND SETTING

Prospective study in an experimental laboratory.

SUBJECTS

Male Wistar rats.

INTERVENTIONS

Isolated lungs were perfused over 120 min in recirculatory mode in presence of vehicle, interleukin-1 beta (IL-1 beta; 5 ng/ml) plus tumor necrosis factor-alpha (TNF-alpha; 5 ng/ml), dexamethasone (Dx; 1 nmol/l), Dx (10 nmol/l), IL-1 beta plus TNF alpha plus Dx 1, or IL-1 beta plus TNF alpha plus Dx 10 (n = 6 each). Pulmonary artery endothelial cells were stimulated over 30 min using a similar protocol.

MEASUREMENTS AND RESULTS

Control lungs released 15.2 +/- 0.6 pg/ml big ET-1 and 0.46 +/- 0.06 pg/ml ET-1, and contained 0.73 +/- 0.05 ng/g wet weight (ww) big ET-1 and 3.06 +/- 0.22 ng/g ww ET-1. IL-1 beta plus TNF-alpha increased release of big ET-1 and ET-1, to 220% and 217%, and lung content of peptides, to 236% and 230%. Dx dose-dependently inhibited the cytokine-induced rise in peptide release and lung content and completely suppressed these effects at 10 nmol/l. Electrophoretic mobility shift assays with nuclear extracts of pulmonary artery endothelial cells demonstrated nuclear binding of the transcription factor nuclear factor kappa B in response to IL-1 beta plus TNF-alpha, which was decreased in presence of Dx 1 and Dx 10.

CONCLUSIONS

GC inhibit the cytokine-induced upregulation of pulmonary vascular and tissue endothelins, possibly via nuclear factor kappa B dependent mechanisms. This finding may reinforce the therapeutic employment of GC in late ARDS.

Identification of six methylenetetrahydrofolate reductase (MTHFR) genotypes resulting from common polymorphisms: impact on plasma homocysteine levels and development of coronary artery disease

Although three common MTHFR polymorphisms (C677T, A1298C, T1317C) have been reported, only polymorphism C677T has been investigated intensively as a risk factor for coronary artery disease (CAD). We investigated polymorphism frequencies, allelic associations and the effect of the resulting MTHFR genotypes on total plasma homocysteine (tHcy) levels and on coronary risk in a case-control study with 1000 angiographically confirmed Middle-European CAD patients and 1000 matched controls. Three out of four theoretically possible MTHFR haplotypes were detected: *1 (677C, 1298A), *2 (677T, 1298A), and *3 (677C, 1298C). The frequencies were *1: 36.4 and 34.4%; *2: 30.8 and 32.3%; and *3: 32.8 and 33.3%, in cases and controls, respectively. Only one patient was heterozygous for 1317C. None of the six resulting genotypes showed significant influence on tHcy levels. Moreover, there was no significant association with CAD risk or with disease severity or early disease manifestation. In the subgroup presenting with acute coronary syndromes, MTHFR genotypes *2/*3 and *3/*3 were surprisingly underrepresented (relative risk of *3/*3, 0.40; 95% confidence interval 0.20-0.79, P=0.009). We conclude from our genotype-based analysis that, in this well-fed Middle-European population, the observed common allelic variants of the MTHFR gene have no significant influence on tHcy levels or on the chronic process of CAD development.

Homocysteine inhibits TNF-alpha-induced endothelial adhesion molecule expression and monocyte adhesion via nuclear factor-kappaB dependent pathway

Cellular adhesion molecules play a pivotal role in the pathogenesis of atherosclerosis by mediating the adherence of blood leukocytes. Since hyperhomocysteinemia appears to be an independent risk factor for the development of atherosclerosis, in this study we investigated the effect of homocysteine on basal and TNF-alpha-induced expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell-adhesion molecule-1 (VCAM-1), and endothelial leukocyte adhesion molecule-1 (E-selectin) on human umbilical-vein endothelial cells. Incubation of endothelial cells with homocysteine resulted in dose-dependent reduction in TNF-alpha-induced (5 ng/ml) expression of VCAM-1, E-selectin, and ICAM-1 (the latter less pronounced). This effect was found to be specific since other thiol compounds-cysteine and glutathione-did not mimic homocysteine activity. Homocysteine attenuated TNF-alpha-stimulated U-937 adhesion to the endothelial monolayer and reduced TNF-alpha-induced activation of the transcription factor NF-kappaB, indicating that NF-kappaB inhibition may play a role in inhibiting expression of adhesion molecules in endothelial cells.

The beta3-adrenergic receptor Trp64Arg mutation is not associated with coronary artery disease

There is some evidence that the Trp64Arg polymorphism of the beta3-adrenergic receptor (beta3-AR) is associated with atherogenic risk factors that include weight gain, insulin resistance, and diabetes. The objective of this cross-sectional study was to investigate the relationship between the Trp64Arg polymorphism and coronary artery disease (CAD). A total of 1,000 consecutive patients with angiographically confirmed CAD and 1,000 controls, carefully matched for age and sex, were genotyped for the Trp64Arg polymorphism by polymerase chain restriction and subsequent restriction fragment length polymorphism analysis. Among cases with CAD, 83.3% were wild-type Trp/Trp, 15.8% were heterozygotes, and 0.9% were homozygous Arg/Arg compared with 82.3%, 17.3%, and 0.4%, respectively, among controls (P = .27). The odds ratios for the presence of Trp/Arg and Arg/Arg in cases and controls were 0.90 (95% confidence interval [CI] 0.7 to 1.2; P = .40) and 2.2 (95% CI 0.7 to 7.2; P = .17), respectively. There was no effect modification by gender and atherogenic risk factors, including diabetes, hypercholesterolemia, hypertension, and smoking. Furthermore, there was no evidence of an association with premature disease onset (< 40 years) or extent of disease. In conclusion, the results of this study in a large sample of clinically well-characterized patients indicate that neither the Trp/Arg nor the Arg/Arg genotype represents a major risk factor for angiographically confirmed coronary artery disease.

[Pregnancy risks in acquired heart diseases]

Optimal management of pregnancies for patients with acquired heart disease requires exact knowledge of the hemodynamic influence of pregnancy-related cardiovascular adaptation processes on the heart disease. Maternal and fetal risks must be carefully considered and mutually weighed. Critical time periods, during which closely networked, interdisciplinary support for the patient is essential, are primarily during the 30th to 32nd week of pregnancy. This is the period in which maximum increases in heart rate, cardiac output, and plasma volume are observed. The peripartal phase represents another critical period. Owing to the mechanically related fixation of cardiac output, stenotic valvular diseases are generally tolerated much poorer than are valvular insufficiency defects. Therapeutic objectives are reduction in heart rate and--in cases of pulmonary-venous congestion--decrease in preload. Vaginal deliveries are possible with slight to moderate valvular stenosis; cesarean section is to be preferred in more severe cases. In patients with valvular insufficiency and normal left ventricular function pregnancy is usually well tolerated. Reduction in regurgitation is even often observed owing to pregnancy-induced decrease in peripheral vascular resistance. Since ACE inhibitors and AT1 antagonists are contraindicated during pregnancy, afterload reduction can be achieved by a combination of hydralazin and nitrates, or calcium antagonists. Peripartal cardiomyopathy is rare and is associated with a high degree of maternal mortality (25-50%). Apart from the necessary consideration of pregnancy-related contraindications, therapeutic principles do not differ from those for other forms of heart failure. Most patients exhibiting hypertrophic obstructive cardiomyopathy satisfactorily pass through their pregnancies. Individual cases have been described, however, of both pregnancy-related cardiac decompensation as well as sudden death. Aortal and coronary-arterial dissections represent rare, life-endangering complications for mother and fetus: these developments can occur among predisposed patients as a result of the hormonal and hemodynamic adaptation processes during pregnancy. Close interdisciplinary collaboration and tightly networked support for patients are the prerequisite for successful management of high-risk pregnancies involving maternal heart disease.