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Choc Septique : Défaillance Myocardique et Altérations des Relations Force-Fréquence et Relaxation-Fréquence

Abstract : Septic shock is a major cause of mortality in hospital. It is characterized by vasoplegia, tachycardia and by myocardial dysfunction for many patients. Physiologically, tachycardia raises cardiac output by multiplying cardiac cycles but it also has its own effects that raise ventricle contractility and relaxation. These phenomenons are named force-frequency relationship (FFR) and frequency dependant acceleration of relaxation (FDAR). Septic myocardial dysfunction is characterized by alterations of myocardial contractility and also by modifications of ventricular relaxation. In the first part of this study, we showed that cardiac dysfunction is present in our septic shock model induced by injected endotoxin. It also reveals that caspase (proteases involved in the apoptosis pathway) activation takes part in the development of this dysfunction. Next, we investigated the role of circulating mediators in the onset of this dysfunction. Identity of these mediators is probably cytokinic. TNF-α and IL-1β have already shown their ability to induce such a dysfunction but in our model they were not necessary to induce it, and other cytokines might be involved. At last we showed that septic myocardial dysfunction present alteration of FFR and FDAR and that this phenomenon may be linked to the increase of myocardial phosphatases. Thus, these new knowledge of septic shock mechanisms doesn't allow direct modification of treatment for septic patients, but they point new investigation fields that could tend to improve therapeutic strategies of septic shock.
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https://tel.archives-ouvertes.fr/tel-00459520
Contributor : Olivier Joulin <>
Submitted on : Wednesday, February 24, 2010 - 11:21:49 AM
Last modification on : Thursday, February 21, 2019 - 9:56:04 AM
Long-term archiving on: : Friday, June 18, 2010 - 7:33:59 PM

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  • HAL Id : tel-00459520, version 1

Citation

Olivier Joulin. Choc Septique : Défaillance Myocardique et Altérations des Relations Force-Fréquence et Relaxation-Fréquence. Physiologie [q-bio.TO]. Université du Droit et de la Santé - Lille II, 2009. Français. ⟨tel-00459520⟩

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