الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
The basic feature of left ventricular volume overload is that the end diastolic volume of the ventricle is increased showing a greater than normal cavity dimensions at end diastole. Good myocardial function stimulates a powerful contraction. Through the Frank-Starling law, the additional volume is ejected rapidly, and the end diastolic dimensions and volume remain normal. Most patients tolerate even quite severe Left Ventricular (LV) volume overload very well for years, but eventually myocardial function becomes impaired. If this trend is unchecked, myocardial performance deteriorates rapidly to the point where the risk associated with surgical correction of original lesion becomes high
Pulsed wave Doppler of both mitral inflow pattern and pulmonary venous flow allow the differentiation of various diastolic filling patterns, and correlating them with the severity of diastolic dysfunction. However, in clinical routine, the echocardiographer is faced with several drawbacks in mitral and pulmonary inflow interpretation when several haemodynamic alteration (like changes in preload, HR and relaxation) occurs simultaneously or when pulmonary venous signals cannot be registered sufficiently. These conditions mainly affect global LV diastolic performance rather than regional diastolc myocardial performance which is more independent, quantitative method
Tissue Doppler Imaging (TDI) is a relatively recent method that can be used to assess both global and regional LV diastolic function, it employs the Doppler principle to provide direct local measurements of myocardial velocities throughout the cardiac cycle. Large Doppler signals obtained from the left ventricular wall can be displayed selectively as color or pulsed Doppler images by eliminating small Doppler signals produced by blood flow. It has a great potential in the diagnosis of diastolic left ventricular dysfunction overcoming load dependence of conventional Doppler techniques
Radial and longitudinal ventricular function can be assessed by analysis of myocardial wall velocity and displacement indices, or by the analysis of wall deformation using the rate of deformation of a myocardial segment (strain rate) and its deformation overtime (strain). A quick and easy assessment of left ventricular ejection fraction is obtained by mitral annular velocity measurement during a routine, especially in patients with poor endocardial definition or abnormal septal motion. Strain rate and strain are less affected by passive myocardial motion and to be uniform throughout the left ventricle in normal subjects.