الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
The left atrial appendage (LAA) is a long, hook-like true diverticulum of the left atrium (LA) . The LAA lies within the pericardium, next to the superior lateral aspect of the main pulmonary artery, and superior to the left ventricular free wall (1) . The LAA has unique developmental, anatomical, and physiological properties. These properties render it ideal to act as a reservoir in conditions of volume overload, and to effect the adaptive responses necessary for the reduction of circulating blood volume. The LAA is the major site of thrombus formation in atrial fibrillation and to a lesser extent in mitral valve disease(1). Although that AF is the most common cause of thrombus formation inside left atrial appendage but many patients with sinus rhythm also can develop thrombi inside the LAA(135,136). In patients with mitral stenosis, active left atrial appendage blood flow and contractile function may be disturbed . This might be due to the significant increase in left atrial pressure caused by afterload elevation . Left atrial appendage contractile dysfunction may cause blood stasis in the left atrial appendage cavity and this might be one of the mechanisms for formation of spontaneous echo contrast and thrombus in left atrial appendage (1) . Echocardiography, particularly transesophageal echocardiography (TEE), is currently the modality of choice for evaluation of the LAA. It allows complete delineation of the LAA anatomy in almost all patients and, at the same time, also permits a detailed assessment of its function (112) . Speckle-tracking echocardiography (STE) is a recently developed technique for the characterization and quantification of myocardial deformation (133) . It permits measurement of LA & LAA strain and strain rate which can be used to assess the function of LAA adequately (133) .
This study is to assess the function of left atrial appendage in patients with mitral stenosis whose are in sinus rhythm by 2 –D speckle tracking strain and strain rate.