Iatrogénie des diurétiques dans l insuffisance cardiaque (étude de 50 cas)

Cette thèse consiste dans un premier temps, en une description des différentes formes d insuffisance cardiaque et quelques données épidémiologiques, des manières de diagnostiquer la pathologie ainsi que les différents traitements adaptés à chaque type de formes décrites. Dans un second temps, elle consiste plus particulièrement en un exposé de la iatrogénie des diurétiques, des mécanismes mis en place par l organisme lors de l installation d une insuffisance rénale aiguë. Dans un dernier temps, les résultats d une étude incluant 50 patients insuffisants cardiaques sont publiés. La recherche des facteurs prédictifs d insuffisance rénale chez ces patients et donc de prolongation de l hospitalisation ou l augmentation de la mortalité ont été déterminés. Une discussion sur cette étude a ensuite été entreprise.ROUEN-BU Médecine-Pharmacie (765402102) / SudocSudocFranceF

Valeur diagnostique et pronostique de la mesure du rehaussement tardif par IRM dans une cohorte de patients porteurs d insuffisance cardiaque à fraction d éjection préservée (cohorte collag4)

L insuffisance cardiaque à fraction d éjection préservée (ICFEP) est une pathologie fréquente dont le pronostic est sévère. La caractérisation de sa population est imprécise et son mécanisme physiopathologique est discuté. La fibrose myocardique pourrait jouer un rôle dans cette maladie. Nous avons supposé que le rehaussement tardif en IRM, marqueur de fibrose, pourrait être corrélé au pronostic des patients porteurs d ICFEP. Méthodes : Nous avons inclus prospectivement 68 patients entre février 2009 et juillet 2012, admis dans notre service de cardiologie pour une insuffisance cardiaque. Les critères d inclusion étaient la présence des critères cliniques d insuffisance cardiaque de Framingham, associés à un dosage de NT-ProBNP > 300 ng/ml et une fraction d éjection du ventricule gauche échographique > 50%. Une exploration complète comprenant un examen clinique, une échographie cardiaque standard, une IRM cardiaque avec séquences de rehaussement tardif (Gadolinium), a été réalisée à l état stable, 2 mois après l inclusion. Le rehaussement tardif était décrit de manière qualitative (localisation), semi-quantitative (score), et quantitative (masse de rehaussement). Le critère de jugement était le décès ou l hospitalisation pour insuffisance cardiaque. Le suivi a été de 12 mois. Résultats : L échantillon était principalement composé de femmes, âgées de 73 ans en moyenne, symptomatiques d insuffisance cardiaque, hypertendus, diabétiques et en surpoids. La moitié de l échantillon présentait une fibrillation auriculaire et 25% des patients ont une cardiopathie ischémique. Au total 63 IRM de rehaussement tardif ont pu être interprétées. Un patient sur deux présente du rehaussement tardif. Le rehaussement se concentre principalement dans les segments médio-basaux de la paroi inférieure, avec une localisation intra-murale ou sous-endocardique. Il existe une corrélation significative entre la masse de rehaussement et la dysfonction diastolique. Le taux d évènements est de 25%. Il existe une tendance entre la masse de rehaussement et la survenue d évènement mais sans lien significatif. Conclusion : Le rehaussement tardif est localisé aux parois inférieures du coeur. Sa masse est corrélée à la dysfonction diastolique et tend à être liée à la survenue de décès ou d insuffisance cardiaque.ROUEN-BU Médecine-Pharmacie (765402102) / SudocSudocFranceF

Experimental study of smectite interaction with metal iron at low temperature: 1. Smectite destabilization.

Interaction between metal Fe and a variety of natural and synthetic smectite samples with contrasting crystal chemistry was studied by scanning electron microscopy and X-ray diffraction from experiments conducted at 80°C. These experiments demonstrate an important reactivity contrast as a function of smectite crystal chemistry. An XRD method involving the use of an internal standard allowed quantification of the relative proportion of smectite destabilized as a function of initial pH conditions as well as of smectite structural parameters. In mildly acidic to neutral pH conditions, a significant proportion of metal Fe is corroded to form magnetite without smectite destabilization. Under basic pH conditions, smectite and metal Fe are partly destabilized to form magnetite and newly-formed 1:1 phyllosilicate phases (odinite and crondstedtite). More specifically, systematic destabilization of both metal Fe and smectite is observed for dioctahedral smectites while trioctahedral smectites are essentially unaffected under similar experimental conditions. In addition, smectite reactivity is enhanced with increasing Fe3+ content and with the presence of Na+ cations in smectite interlayers. A conceptual model for smectite destabilization is proposed. This model involves first the release of protons from smectite structure, MeFe3+OH groups being deprotonated preferentially and metal Fe acting as proton acceptor. Corrosion of metal Fe results from its interaction with these protons. The Fe2+ cations resulting from this corrosion process sorb on the edges of smectite particles to induce the reduction of structural Fe3+ and migrate into smectite interlayers to compensate for the increased layer-charge deficit. Interlayer Fe2+ cations subsequently migrate to the octahedral sheet of smectite because of the extremely large layer-charge deficit. At low temperature, this migration is favored by the reaction time and by the absence of protons within the ditrigonal cavity. Smectite destabilization results from the inability of the tetrahedral sheets to accommodate the larger dimensions of the newly formed trioctahedral domains resulting from the migration of Fe2+ cations

124 Peak systolic 2D strain may help to characterize arrhytmogenic right ventricular cardiomyopathy

BackgroundArrythmogenic right ventricular cardiomyopathy (ARVC) is an inherited disease characterized by progressive fibrofatty replacement of the right ventricle (RV). The diagnosis of ARVC remains a challenge for clinicians. We hypothesized that 2D strain imaging helps to differentiate ARVC from normals.Material and Methods20 patients meeting both the Task Force and cardiac MRI criteria for ARVC were compared to 10 age-matched controls. From the apical-4 chamber view, we measured the end-diastolic RV area, the peak systolic S tissue velocity at the tricuspid level. A 2D strain region of interest including the RV free wall and the septum (occasionally diseased in ARVC) was manually traced, from which the averaged peak systolic 2D strain along 6 segments was calculated. Pulmonary systolic pressure as well as the systolic right atrial area were measured as surrogate for RV loading conditions. Overall, patients with ARVC had both larger right atrial and ventricular area (p<0.03 and p<0.02, respectively), compared to controls while pulmonary systolic pressure were similar in both groups (p=0.40). Peak systolic 2D strain was statistically deteriorated in ARCV patients (13±6 vs. 23±4% in normals, p<0.001) so as peak systolic S tissue velocity (8±3 vs. 12±4 in normals, p<0.005). From the ROC analysis, a peak systolic 2D strain of 19.7% had a sensitivity and specificity of 82% and 86% (AUC=90) while the peak systolic tissue velocity of 12 cm/s gave a sensitivity of 83% and a specificity of 71% (AUC=79).ConclusionPeak systolic 2D strain is deteriorated in ARVC patients and may help to characterize arrythmogenic right ventricular cardiomyopathy

Performance comparison of multi-user detectors for the downlink of a broadband MC-CDMA system

In this paper multi-user detection techniques, such as Parallel and Serial Interference Cancellations (PIC & SIC), General Minimum Mean Square Error (GMMSE) and polynomial MMSE, for the downlink of a broadband Multi-Carrier Code Division Multiple Access (MCCDMA) system are investigated. The Bit Error Rate (BER) and Frame Error Rate (FER) results are evaluated, and compared with single-user detection (MMSEC, EGC) approaches, as well. The performance evaluation takes into account the system load, channel coding and modulation schemes

The subelliptic heat kernel on SU(2): Representations, Asymptotics and Gradient bounds

The Lie group SU(2) endowed with its canonical subriemannian structure appears as a three-dimensional model of a positively curved subelliptic space. The goal of this work is to study the subelliptic heat kernel on it and some related functional inequalities.Comment: Update: Added section + Correction of typo

Digital phenotyping: Towards replicable findings with comprehensive assessments and integrative models in bipolar disorders

Background: Digital phenotyping promises to unobtrusively obtaining a continuous and objective input of symptomatology from patients\u27 daily lives. The prime example are bipolar disorders, as smartphone parameters directly reflect bipolar symptomatology. Empirical studies, however, have yielded inconsistent findings. We believe that three main shortcomings have to be addressed to fully leverage the potential of digital phenotyping: short assessment periods, rare outcome assessments, and an extreme fragmentation of parameters without an integrative analytical strategy. Methods: To demonstrate how to overcome these shortcomings, we conducted frequent (biweekly) dimensional and categorical expert ratings and daily self-ratings over an extensive assessment period (12 months) in 29 patients with bipolar disorder. Digital phenotypes were monitored continuously. As an integrative analytical strategy, we used structural equation modelling to build latent psychopathological outcomes (mania, depression) and latent digital phenotype predictors (sleep, activity, communicativeness). Outcomes: Combining gold-standard categorical expert ratings with dimensional self and expert ratings resulted in two latent outcomes (mania and depression) with statistically meaningful factor loadings that dynamically varied over 299 days. Latent digital phenotypes of sleep and activity were associated with same-day latent manic psychopathology, suggesting that psychopathological alterations in bipolar disorders relate to domains (latent variables of sleep and activity) and not only to specific behaviors (such as the number of declined incoming calls). The identification of latent psychopathological outcomes that dimensionally vary on a daily basis will enable to empirically determine which combination of digital phenotypes at which days prior to an upcoming episode are viable as digital prodromal predictors. (DIPF/Orig.

Digital phenotyping: towards replicable findings with comprehensive assessments and integrative models in bipolar disorders

Background: Digital phenotyping promises to unobtrusively obtaining a continuous and objective input of symptomatology from patients’ daily lives. The prime example are bipolar disorders, as smartphone parameters directly reflect bipolar symptomatology. Empirical studies, however, have yielded inconsistent findings. We believe that three main shortcomings have to be addressed to fully leverage the potential of digital phenotyping: short assessment periods, rare outcome assessments, and an extreme fragmentation of parameters without an integrative analytical strategy. Methods: To demonstrate how to overcome these shortcomings, we conducted frequent (biweekly) dimensional and categorical expert ratings and daily self-ratings over an extensive assessment period (12 months) in 29 patients with bipolar disorder. Digital phenotypes were monitored continuously. As an integrative analytical strategy, we used structural equation modelling to build latent psychopathological outcomes (mania, depression) and latent digital phenotype predictors (sleep, activity, communicativeness). Outcomes: Combining gold-standard categorical expert ratings with dimensional self and expert ratings resulted in two latent outcomes (mania and depression) with statistically meaningful factor loadings that dynamically varied over 299 days. Latent digital phenotypes of sleep and activity were associated with same-day latent manic psychopathology, suggesting that psychopathological alterations in bipolar disorders relate to domains (latent variables of sleep and activity) and not only to specific behaviors (such as the number of declined incoming calls). The identification of latent psychopathological outcomes that dimensionally vary on a daily basis will enable to empirically determine which combination of digital phenotypes at which days prior to an upcoming episode are viable as digital prodromal predictors