Theo báo cáo trên, tâm nhĩ trái đến rối loạn chức năng tâm trương thất bằng cách điều chỉnh đóng góp co. Với thời gian, điều này gây ra một "không phù hợp làm việc" theo sau bởi một gia tăng trong tâm nhĩ | 62 S. Maccio and P. Marino Figure . Normal left atrial strain curve obtained by placing the sample volume in the basal segment of the interatrial septum. Left ventricular end-diastole is the starting point of the cycle. Cellular Pathophysiology of Atrial Remodeling As reported above the left atrium responds to ventricular diastolic dysfunction by up-regulating its contractile contribution. With time this causes a work mismatch followed by an increase in atrial operative According to several experimental findings the increased wall stress induces73 an overexpression of P-myosin heavy chain at the atrial level such isoform would be responsible for a slowing down of the contraction speed. Along with alterations existing at the tissue level it is possible to identify and explain diastolic alterations of the left atrium at a cellular level. There are many proteins that contribute to the active and passive tensions of the atrial walls. Atrial cardiomyocytes have a cytoskeleton made of microtubules intermediate filaments desmin microfilaments actin and endosarcomeric proteins titin nebulin a-actin myomesin and M protein alterations that have direct repercussions on diastolic 75 Among these molecules titin appears to be the most important its role at the sarcomeric level is crucial through the presence of several isoforms in determining the modulation of passive tension as demonstrated by the experimental work of Wu et The atrium that is chronically exposed to a pressure or volume overload reacts initially with an increased contractile status partly mediated by the Frank-Starling mechanism. However such status impacts on the homeostasis of intracellular calcium and its reuptake. In this condition in fact there is an overload of cytosolic calcium calcium overload that the proteins assigned to the reuptake of the sarcoplasmatic grid among which the 4. Role of the Left Atrium 63 phospholambans are particularly significant cannot .
