Bonjour à tous,
Voilà, j'ai un petit peu de mal à traduire certains mots d'un texte sur wikipedia sur le LQTS :
Alors déjà : refractoriness veut-il bien dire résistant dans le sens résistance électrique ?All forms of the long QT syndrome involve an abnormal repolarization of the heart. The abnormal repolarization causes differences in the "refractoriness" of the myocytes. After-depolarizations (which occur more commonly in LQTS) can be propagated to neighboring cells due to the differences in the refractory periods, leading to re-entrant ventricular arrhythmias.
It is believed that the so-called early after-depolarizations (EADs) that are seen in LQTS are due to re-opening of L-type calcium channels during the plateau phase of the cardiac action potential. Since adrenergic stimulation can increase the activity of these channels, this is an explanation for why the risk of sudden death in individuals with LQTS is increased during increased adrenergic states (ie exercise, excitement) -- especially since repolarization is impaired. Normally during adrenergic states, repolarizing currents will also be enhanced to shorten the action potential. In the absence of this shortening and the presence of increased L-type calcium current, EADs may arise.
The so-called delayed after-depolarizations (DADs) are thought to be due to an increased Ca2+ filling of the sarcoplasmic reticulum. This overload may cause spontaneous Ca2+ release during repolarization, causing the released Ca2+ to exit the cell through the 3Na+/Ca2+-exchanger which results in a net depolarizing current.
L'after-repolarization en gras, c'est bien de la EAD qu'ils parlent ? D'ailleurs en passant c'est quoi la différence entre EAD et DAD ?
Et enfin le plus gros mystère... Adrenergic states ?? Un état adrénergique ? J'ai fait une recherche sur google et je n'ai pas vu de site internet qui parlait d'état adrénergique... Ce serait récepteur ?
Merci de vos futures réponses !
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