L'ERETHISME CARDIAQUE

editorial reviewe

Two biomarkers for the screening of cardiac risk among runners ?

Background Heart-type fatty acid-binding protein (H-FABP) is a low molecular weight protein involved in the intracellular uptake and buffering of long chain fatty in the myocardium. Troponin T is a component of the contractile apparatus of the striated musculature. Both are early markers for acute coronary syndrome. Objective The aim of our study was to compare the results obtained with the H-FABP and the highly sensitive cardiac troponins (hsTnT) and to test their cardiospecificity in healthy runners. Design Prospective, cohort study. Setting Amateur marathon runners. Patients 23 runners (marathon) were enrolled. Interventions We drowned blood samples at three times: just before (T0), just after (T1), and three hours after the end of the race (T3). Main outcome measurements H-FABP and hs-TnT were performed according to the manufacturer's instructions. A linear regression was calculated to observe if there is any correlation between the two biomarkers. Values above the 95th percentile for H-FABP (2.5 ng/mL) and the 99th percentile for hsTnT (14 ng/L) were considered as positive. Results At T0, none of the subjects were positive for hsTnT but 35% were positive for H-FABP; at T1, 83% for hsTnT and 100% for H-FABP; at T3, 83% for hsTnT and 96% for H-FABP. At T0, the regression equation was H-FABP T0=3.9454–0.1001×hsTnT T0; at T1: H-FABP T1=51.838–1.7026×hsTnT T1; at T3: H-FABP T3=47.977–1.6193×hsTnT T3. No correlation was observed between the 2 biomarkers. Conclusion We observed a significant increase of H-FABP and hsTnT in runners. These markers are independent to each other. These values could biologically correspond to a heart ischemia. These biomarkers could be helpful for the screening of cardiac risk among runners

Impact of different endurance races on the heart: the point of view of the biologist

peer reviewedObjective The aim of this study was to investigate the impact of intense exercise, represented by different endurance races, in relationship with oxidative stress and cardiac markers. In a second time, we tried to demonstrate if oxidative stress induced by physical activity is a physiological or pathological process, and to establish some issues to diagnose the risk of sudden death in athletes. Methods Four populations were compared, a control group of 16 participants “sedentary” (37 ± 4,39 years old), a group of 24 semi-marathon runners (41 years ± 8,76 years old), a group of 28 marathon runners (44,1 ± 8,37 years old) and a group of 33 ultra-trail runners (45,8 ± 8,7 years old). Three blood tests were drowned, one just before, one just after, and the last three hours after the end of the race.Different oxidative and stress and cardiac biomarkers were measured. The ultra-trail runners will be subject to an echocardiography and an ECG pre- and post-race. For statistical analysis, STATISTICA 10 software was used. We performed a non-parametric test of Kruskal-Wallis for independent sample and a Friedman ANOVA for paired samples. Results Myeloperoxydase increased during exercise, but the release is less important according to the level of training of the runners. GSH/GSSG ratio seems to remain stable during the race but it could increase during the 24 hours post-race. There is a decrease in lipidic peroxidation during exercise. But, we note an increase of creatine kinase, isoform MB, myoglobin and C-reactive protein during the race. We observe an increase of troponin T and natriuretic peptide but with a different kinetic than the kinetic obtained for a myocardial infarction. Medical imaging in ultra-trail runners present cardiac adaptations to endurance training, as left ventricular hypertrophy (LVH) and incomplete right bundle branch block (IRBBB). A decrease of systolic and diastolic volumes of the left ventricle and a decrease of longitudinal strain were observed by echocardiography at the end of the race. Conclusion Endurance races induce the income of oxidative stress objectified by different biomarkers increase, but a cell necrosis is not specially observed. In fact, the increase of the cardiac markers during endurance races but may be explained by a transient modification of myocyte permeability, with a release of pool cytosolic. These races may induce micro-muscle damages causing the appearance of an inflammatory process explaining our observations of markers of inflammation. For the medical imaging, it was observed a myocardial adaptation to training and a transient impairment of ventricular function due to dehydration

Imaging of cardiac neuronal function after cocaine exposure using Carbon-11 hydroxyephedrine and positron emission tomography

AbstractObjectives. The aim of the study was to define the effect of cocaine on the myocardial uptake and retention of C-11 hydroxyephedrine in the anesthetized dog model.Background. Cardiac toxcity of cocaine has been linked to its inhibitory effect on norepinephrine reuptake by the sympathetic nerve terminals of the heart. Carbon-11 hydroxyephedrine is a C-11-labled norepinephrine analog that has high specific affinity for uptake-1 and thus makes possible the assessment of the effect of cocaine on norepinephrine reuptake by cardiac sympathetic nerve terminals.Methods. The cardiac kinetics of C-11 hydroxyephedrine as assessed by dynamic positron emission tomographic imaging were used to characterize norepinephrine reuptake by the sympathetic nerve terminals. Carbon-11 hydroxyephedrine was injected intravenously before, as well as at 5 min and 2.5 h after, intravenous administration of 2 mg/kg body weight of cocaine in anesthetized dogs. Hemodynamic variables and microsphere-determined cardiac blood flow were also measured before and after cocaine exposure.Results. Intravenous injection of cocaine did not significantly affect hemodynamic variables and myocardial blood flow in the anesthetized animals. Compared with baseline, myocardial retention of C-11 hydroxyephedrine was significantly reduced by 78 ± 3% (mean ± SD) at 5 min and remained significantly reduced (28 ± 17%) at 2.5 h after cocaine injection. Cocaine administration after C-11 hydroxyephedrine injection (39 min) resulted in rapid biexponential clearance of C-11 hydroxyephedrine from myocardium.Conclusions. These results suggest prolonged effects of cocaine on the sympathetic nerve terminals of the heart. Positron emission tomography provides a noninvasive and sensitive means to objectively assess the cardiac pharmacokinetics of drugs such as cocaine

Impact of contractile reserve on acute response to cardiac resynchronization therapy

Background: Cardiac resynchronization therapy (CRT) provides benefit for congestive heart failure, but still 30% of patients failed to respond to such therapy. This lack of response may be due to the presence of significant amount of scar or fibrotic tissue at myocardial level. This study sought to investigate the potential impact of myocardial contractile reserve as assessed during exercise echocardiography on acute response following CRT implantation. Methods: Fifty-one consecutive patients with heart failure (LV ejection fraction 27% ± 5%, 67% ischemic cardiomyopathy) underwent exercise Doppler echocardiography before CRT implantation to assess global contractile reserve (improvement in LV ejection fraction) and local contractile reserve in the region of the LV pacing lead (assessed by radial strain using speckle tracking analysis). Responders were defined by an increase in stroke volume ≥15% after CRT. Results: Compared with nonresponders, responders (25 patients) showed a greater exercise-induced increase in LV ejection fraction, a higher degree of mitral regurgitation and a significant extent of LV dyssynchrony. The presence of contractile reserve was directly related to the acute increase in stroke volume (r = 0.48, p<0.001). Baseline myocardial deformation as well as contractile reserve in the LV pacing lead region was greater in responders during exercise than in nonresponders (p<0.0001). Conclusions: Heart failure patients referred to CRT have less chance of improving under therapy if they have no significant mitral regurgitation, no LV dyssynchrony and no contractile myocardial recruitment at exercise

The Brugada Syndrome

peer reviewedThe Brugada syndrome, a genetically transmitted disease according to an autosomal mode with a variable penetrance, is responsible for sudden death secondary to polymorphic ventricular tachycardia. The diagnosis is based on a typical electrocardiographical paturn that combines a right bundle branch block with ST elevation in the right precordial leads. In high risk patients, the automatic implantable defibrillator has the unique capability to protect against the occurrence of ventricular arrhythmias

syncope

peer reviewedSyncope remains a clinical challenge. Accurate history taking, physical examination and EKG are mainstays of the diagnosis work up. The most important parameter for prognosis and requiring aggressive management is a structural heart disease. Patient without cardiopathy presenting multiple episodes may be candidate for tilt testing and loop EKG recorder

Formation pour le personnel dirigeant des centres d’hébergements wallons pour personnes handicapées :Certification obligatoire ou réelle acquisition de compétences ?

Malgré l’hétérogénéité du secteur non-marchand, celui-ci est confronté depuis plusieurs années à une tendance à la managérialisation. Ce changement structurel renvoie à une politique de réduction des coûts ainsi qu’à la transformation du mode organisationnel (pression au niveau du temps, standardisation, multiplication des moyens de contrôle, etc) (RAVON, 2008 ;SANCHEZ-MAZAS M. et TSCHOPP F. 2010). Le développement de cette logique gestionnaire entraine un souci constant d’efficacité et de performance qui deviennent les maitres-mots (DE GAULEJAC V. 2005).Par exemple, en analysant les règles d’agrément des institutions du sous-secteur du handicap en Belgique francophone, on remarque que le pouvoir subsidiant (AWIPH ) introduit un cadre de plus en plus contraignant qui s’inscrit dans cette perspective. En effet, des injonctions économiques, institutionnelles, comptables et financières sont formulées, la charge administrative s’intensifie, la prise en charge des bénéficiaires est soumise au respect d’un canevas imposé, etc. Afin de s’assurer d’une connaissance suffisante du personnel d’encadrement des centres agréés et subsidiés, l’AWIPH impose à ces catégories de travailleurs de suivre une formation professionnalisante dont le nombre d’heures varient selon le niveau hiérarchique du travailleur .Par cadre, il faut comprendre les directeurs, sous-directeurs et éducateurs-chefs de groupe. Cette formation reprend différents aspects théoriques et techniques de la gestion tant humaine qu’administrative ou financière d’une institution d’accueil ou de résidence pour personnes handicapées. Elle concerne les matières suivantes :fonctionnement institutionnel, législation, gestion et comptabilité, ressources humaines. A cet égard, nous avons mené une enquête auprès de certains instructeurs et responsables de ce type de formation afin d’améliorer notre compréhension des finalités de la formation proposée ainsi que de la pertinence du programme de cours par rapport aux connaissances requises pour occuper ces postes. Dans un deuxième temps, nous avons interrogé des personnes inscrites à ces formations c’est-à-dire des (futurs) directeurs ou cadres de centres d’hébergement wallons afin de savoir quelles étaient pour eux les motivations de leur inscription, la plus-value de la formation notamment en termes de compétences transférables et valorisables dans leur fonction. Par conséquent, cette analyse permettra également de nous questionner sur la spécificité des compétences à mobiliser actuellement pour occuper de telles fonctions.BibliographieDE GAULEJAC V. la société malade de la gestion, Paris :Seuil, 2005.RAVON B. (dir.), « Le malaise des travailleurs sociaux :usure professionnelle ou déni de reconnaissance ?» La lettre, Observatoire national de la pauvreté et de l’exclusion sociale, n°6 octobre 2008.SANCHEZ-MAZAS M. TSCHOPP F. « La rationalisation des métiers du social L’installation de la logique marchande dans les professions sociales », Les politiques sociales, 1 & 2 / 2010.info:eu-repo/semantics/nonPublishe

les cadres intermédiaires du secteur social belge

Cette contribution rend compte d’une étude de cas menée auprès de deux organismes habilités à dispenser des formations certificatives auprès du personnel d’encadrement et de direction des services d’accueil et d’hébergement des personnes handicapées en Belgique francophone. Le but est de questionner les processus d’appropriation de la formation et de l’acquisition des compétences dans le cadre d’une formation contraignante.Nous commencerons par contextualiser le cas belge en interrogeant l’introduction de logiques gestionnaires au sein du secteur à partir d’une analyse socio-historique de l’encastrement politique des activités associatives. Ce constat nous permettra de comprendre le contexte dans lequel s’inscrivent les nouvelles figures du personnel d’encadrement. Nous nous intéresserons plus particulièrement aux rôles et statuts des cadres intermédiaires ainsi qu’aux répercussions de l’émergence de cette catégorie sur l’organisation du travail. Ensuite, nous nous demanderons quelles sont les conséquences d’une contrainte formative sur le processus de professionnalisation lui-même. Enfin, nous présenterons les résultats de notre enquête.info:eu-repo/semantics/publishe