Electroanatomical voltage mapping with contact force sensing for diagnosis of arrhythmogenic right ventricular cardiomyopathy

Background Three-dimensional electroanatomical mapping (EAM) can be helpful to diagnose arrhythmogenic right ventricular cardiomyopathy (ARVC). Yet, previous studies utilizing EAM have not systematically used contact-force sensing catheters (CFSC) to characterize the substrate in ARVC, which is the current gold standard to assure adequate tissue contact. Objective To investigate reference values for endocardial right ventricular (RV) EAM as well as substrate characterization in patients with ARVC by using CFSC. Methods Endocardial RV EAM during sinus rhythm was performed with CFSC in 12 patients with definite ARVC and 5 matched controls without structural heart disease. A subanalysis for the RV outflow tract (RVOT), septum, free-wall, subtricuspid region, and apex was performed. Endocardial bipolar and unipolar voltage amplitudes (BVA, UVA), signal characteristics and duration as well as the impact of catheter orientation on endocardial signals were also investigated. Results ARVC patients showed lower BVA vs. controls (p = 0.018), particularly in the subtricuspid region (1.4, IQR:0.5–3.1 vs. 3.8, IQR:2.5-5 mV, p = 0.037) and RV apex (2.5, IQR:1.5–4 vs. 4.3,IQR:2.9–6.1 mV, p = 0.019). BVA in all RV regions yielded a high sensitivity and specificity for ARVC diagnosis (AUC 59–78%, p < 0.05 for all), with the highest performance for the subtricuspid region (AUC 78%, 95% CI:0.75–0.81, p < 0.001, negative predictive value 100%). A positive correlation between BVA and an orthogonal catheter orientation (46°-90°:r = 0.106, p < 0.001), and a negative correlation between BVA and EGM duration (r = −0.370, p < 0.001) was found. Conclusions EAM using CFSC validates previous bipolar cut-off values for normal endocardial RV voltage amplitudes. RV voltages are generally lower in ARVC as compared to controls, with the subtricuspid area being commonly affected and having the highest discriminatory power to differentiate between ARVC and healthy controls. Therefore, EAM using CFSC constitutes a promising tool for diagnosis of ARVC

Analysis and modeling of gas-phase processes in a CHF3/Ar discharge

The present work deals with the diagnostics of fluorocarbon plasmas by different experimental methods and complementary numerical analysis of the plasma. The plasma diagnostics were performed with non-invasive methods. In this paper, we present results obtained by laser-induced fluorescence and UV absorption measurements. The complementary numerical simulations accounted for the electron-neutral interactions, discharge dynamics, and chemical reactions. Several insights were obtained from the combined experimental and numerical approaches, especially concerning the conclusiveness of the results and previous observations from the literature. As important initial neutral species, CF 3 and H originate from electron collisions with CHF3. The atomic hydrogen is responsible for fluorine abstraction reactions which result in the formation of hydrofluoric acid as well as in unsaturated carbon bonds. It was found from the simulations that in the examined discharges, this reaction is the most important channel for the high-rate production of the CF molecule in the gas phase via CF2 + H ? CF + HF. For this molecule, no anisotropy in the density was found and the production solely occurs in the gas phase. Contrary to that, the production of CF2 via the abstraction of fluorine from CF3 in the gas phase was found to be of less importance for the overall concentration of this molecule. Instead, chemical reactions at the chamber walls which release CF2 were identified experimentally as major sources. According to the simulations, the unsaturated fluorocarbon molecules react to oligomers, such that the net reaction can be roughly described by nCHF3 ? (CF2)n + nHF. A good agreement between the simulated and the experimentally observed densities and rates was obtained, which confirms the interpretation of the ongoing plasma-chemical processes as well as the underlying physical discharge parameters consistently. Fluorocarbon plasmas are applied in several industrial branches. They can be either used for etching in the semiconductor industry or for coating of surfaces with low-k dielectric, hydrophobic and oleophobic polymer films. The net-result -etching or deposition- depends on the fluorine to carbon ratio and thus, on the plasma chemistry. Despite of the successful application of fluorocarbon plasmas in the industry, several details about the chemical kinetics are still a matter of discussion. In particular, this accounts for the kinetics of CF2

Discovery of N-(4-Aminobutyl)-N'-(2-methoxyethyl)guanidine as the First Selective, Nonamino Acid, Catalytic Site Inhibitor of Human Dimethylarginine Dimethylaminohydrolase-1 (hDDAH-1)

N-(4-Aminobutyl)-N′-(2-methoxyethyl)guanidine ( 8a ) is a potent inhibitor targeting the hDDAH-1 active site (Ki = 18 μM) and derived from a series of guanidine- and amidine-based inhibitors. Its nonamino acid nature leads to high selectivities toward other enzymes of the nitric oxide-modulating system. Crystallographic data of 8a -bound hDDAH-1 illuminated a unique binding mode. Together with its developed N-hydroxyguanidine prodrug 11 , 8a will serve as a most widely applicable, pharmacological tool to target DDAH-1-associated diseases

Convergence of the generalized-alpha scheme for constrained mechanical systems

peer reviewedA variant of the generalized-alpha scheme is proposed for constrained mechanical systems represented by index-3 DAEs. Based on the analogy with linear multistep methods, an elegant convergence analysis is developed for this algorithm. Second-order convergence is demonstrated both for the generalized coordinates and the Lagrange multipliers, and those theoretical results are illustrated by numerical tests