[Adults with congenital heart disease presenting to the emergency department : Potential pitfalls]. / Erwachsene mit angeborenen Herzfehlern im Notaufnahmedienst : Was ist zu beachten?

The number of adults with congenital heart disease (ACHD) already exceeds the number of children with congenital heart disease in the industrialized world. ACHD patients often show complex pathophysiology and anatomy even after reparative cardiac surgery. In case of complications patients may rapidly deteriorate and become unstable, even when they were asymptomatic or had only mild symptoms before the onset of the complication. Compared to all patients seen by emergency physicians, emergencies in ACHD patients are still rare. This review is aimed to guide management in ACHD emergency situations. Approximately two-thirds of all emergency admissions are caused by arrhythmias or acute heart failure. Sustained arrhythmias may rapidly lead to acute cardiac decompensation in ACHD patients. If medical treatment fails or patients present in hemodynamically unstable conditions, prompt electrical cardioversion is mandatory. Symptomatic bradycardia may require urgent pacemaker implantation. Depending on the underlying heart defect, placement of temporary transvenous pacemaker leads may be impossible. Acute heart failure in ACHD patients is often caused by acute right heart failure. Other more frequent emergencies are infections, syncope, thromboembolic events, and aortic dissection. It is highly recommended to contact the tertiary care center that follows the patient regularly early in case of patient presentation to the emergency room.

Platypnea-orthodeoxia syndrome: an unusual cause of breathlessness in late pregnancy.

A pregnant patient with shortness of breath and arterial oxygen desaturation is presented. The primary and tentative initial diagnosis was pulmonary embolism. Her desaturation and dyspnea were aggravated in the upright compared with the supine position. The minimal response to supplemental oxygen suggested right-to-left shunting, which was confirmed by echocardiography. Shunting was minimal in the supine and maximal in the upright position, leading to the diagnosis of platypnea-orthodeoxia syndrome. By two weeks postpartum the patient's symptoms had resolved and shunting was undetectable.

Non-vitamin K antagonist oral anticoagulants (NOACs) for thromboembolic prevention, are they safe in congenital heart disease? Results of a worldwide study.

BACKGROUND: Current guidelines consider vitamin K antagonists (VKA) the oral anticoagulant agents of choice in adults with atrial arrhythmias (AA) and moderate or complex forms of congenital heart disease, significant valvular lesions, or bioprosthetic valves, pending safety data on non-VKA oral anticoagulants (NOACs). Therefore, the international NOTE registry was initiated to assess safety, change in adherence and quality of life (QoL) associated with NOACs in adults with congenital heart disease (ACHD). METHODS: An international multicenter prospective study of NOACs in ACHD was established. Follow-up occurred at 6 months and yearly thereafter. Primary endpoints were thromboembolism and major bleeding. Secondary endpoints included minor bleeding, change in therapy adherence (≥80% medication refill rate, ≥6 out of 8 on Morisky-8 questionnaire) and QoL (SF-36 questionnaire). RESULTS: In total, 530 ACHD patients (mean age 47 SD 15 years; 55% male) with predominantly moderate or complex defects (85%), significant valvular lesions (46%) and/or bioprosthetic valves (11%) using NOACs (rivaroxaban 43%; apixaban 39%; dabigatran 12%; edoxaban 7%) were enrolled. The most common indication was AA (91%). Over a median follow-up of 1.0 [IQR 0.0-2.0] year, thromboembolic event rate was 1.0% [95%CI 0.4-2.0] (n = 6) per year, with 1.1% [95%CI 0.5-2.2] (n = 7) annualized rate of major bleeding and 6.3% [95%CI 4.5-8.5] (n = 37) annualized rate of minor bleeding. Adherence was sufficient during 2 years follow-up in 80-93% of patients. At 1-year follow-up, among the subset of previous VKA-users who completed the survey (n = 33), QoL improved in 6 out of 8 domains (p ≪ 0.05). CONCLUSIONS: Initial results from our worldwide prospective study suggest that NOACs are safe and may be effective for thromboembolic prevention in adults with heterogeneous forms of congenital heart disease.

Prebiotic RNA polymerisation: energetics of nucleotide adsorption and polymerisation on clay mineral surfaces.

We measured the binding energy and bonding parameters between model nucleotide functional groups and model clay mineral surfaces in solutions of acidic pH. We demonstrate that basal surfaces of clay minerals interact most strongly with nucleobases and show that the adsorption of the phosphate group to clay edges could facilitate polymerisation. Our results suggest that Al- and Fe-rich edge sites behave similarly in nucleotide polymerisation through change of the phosphodiester bond strength. We present an internally consistent set of thermodynamic parameters that represent the nucleotide-clay mineral system.

A Microkinetic Model of Calcite Step Growth.

In spite of decades of research, mineral growth models based on ion attachment and detachment rates fail to predict behavior beyond a narrow range of conditions. Here we present a microkinetic model that accurately reproduces calcite growth over a very wide range of published experimental data for solution composition, saturation index, pH and impurities. We demonstrate that polynuclear complexes play a central role in mineral growth at high supersaturation and that a classical complexation model is sufficient to reproduce measured rates. Dehydration of the attaching species, not the mineral surface, is rate limiting. Density functional theory supports our conclusions. The model provides new insights into the molecular mechanisms of mineral growth that control biomineralization, mineral scaling and industrial material synthesis.

Heparin-induced thrombocytopenia in pregnancy: an interdisciplinary challenge-a case report and literature review.

Heparin-induced thrombocytopenia is a serious adverse event of anticoagulation with a high risk of thromboembolic complications. As a consequence, anticoagulants other than heparins must be administered. These may be unavailable, contraindicated during pregnancy, off-label, impractical due to short half-lives and, most importantly, may be unfamiliar to many anesthesiologists. Impaired coagulation bears the risk of adverse events following neuraxial procedures and of peripartum hemorrhage. We describe the case of heparin-induced thrombocytopenia in a 29-year-old pregnant woman at 27weeks of gestation with severe valvular heart disease.

Monitoring bacterially induced calcite precipitation in porous media using magnetic resonance imaging and flow measurements.

A range of nuclear magnetic resonance (NMR) techniques are employed to provide novel, non-invasive measurements of both the structure and transport properties of porous media following a biologically mediated calcite precipitation reaction. Both a model glass bead pack and a sandstone rock core were considered. Structure was probed using magnetic resonance imaging (MRI) via a combination of quantitative one-dimensional profiles and three-dimensional images, applied before and after the formation of calcite in order to characterise the spatial distribution of the precipitate. It was shown through modification and variations of the calcite precipitation treatment that differences in the calcite fill would occur but all methods were successful in partially blocking the different porous media. Precipitation was seen to occur predominantly at the inlet of the bead pack, whereas precipitation occurred almost uniformly along the sandstone core. Transport properties are quantified using pulse field gradient (PFG) NMR measurements which provide probability distributions of molecular displacement over a set observation time (propagators), supplementing conventional permeability measurements. Propagators quantify the local effect of calcite formation on system hydrodynamics and the extent of stagnant region formation. Collectively, the combination of NMR measurements utilised here provides a toolkit for determining the efficacy of a biological-precipitation reaction for partially blocking porous materials.

Community structure of subsurface biofilms in the thermal sulfidic caves ofAcquasanta Terme, Italy.

We performed a microbial community analysis of biofilms inhabiting thermal (35 to 50 degrees C) waters more than 60 m below the ground surface near Acquasanta Terme, Italy. The groundwater hosting the biofilms has 400 to 830 microM sulfide, <10 microM O(2), pH of 6.3 to 6.7, and specific conductivity of 8,500 to 10,500 microS/cm. Based on the results of 16S rRNA gene cloning and fluorescent in situ hybridization (FISH), the biofilms have low species richness, and lithoautotrophic (or possibly mixotrophic) Gamma- and Epsilonproteobacteria are the principle biofilm architects. Deltaproteobacteria sequences retrieved from the biofilms have <90% 16S rRNA similarity to their closest relatives in public databases and may represent novel sulfate-reducing bacteria. The Acquasanta biofilms share few species in common with Frasassi cave biofilms (13 degrees C, 80 km distant) but have a similar community structure, with representatives in the same major clades. The ecological success of Sulfurovumales-group Epsilonproteobacteria in the Acquasanta biofilms is consistent with previous observations of their dominance in sulfidic cave waters with turbulent water flow and high dissolved sulfide/oxygen ratios.

Pulse oximetry: analysis of theory, technology, and practice.

Interest in two-wavelength classic, that is, nonpulse, oximetry began early in the 20th century. Noninvasive in vivo measurements of oxygen saturation showed promise, but the methods were beset by several problems. The pulse oximetry technique, by focusing on the pulsatile arterial component, neatly circumvented many of the problems of the classic nonpulse arterial approach. Today's pulse oximeter owes a good measure of its success to the technologic advances in light emission and detection and the ready availability of microcomputers and their software. Many clinicians have recognized how valuable the assessment of the patient's oxygenation in real time can be. This appreciation has propelled the use of pulse oximeters into many clinical fields, as well as nonclinical fields such as sports training and aviation. Understanding how and what pulse oximetry measures, how pulse oximetry data compare with data derived from laboratory analysis, and how the pulse oximeter responds to dyshemoglobins, dyes, and other interfering conditions must be understood for the correct application and interpretation of this revolutionary monitor.