tailieunhanh - Ebook A practical approach to clinical echocardiography: Part 2

Part 2 book "A practical approach to clinical echocardiography" presentation of content: Diastolic function, tissue doppler echocardiography current status an, deformation imaging theory and practice, pericardial diseases, ischemic heart disease, congenital heart disease in adults,. And other content. | Chapter 12 Introduction Both ventricles of the heart are bidirectional hemodynamic pumps and engage in functions of suction (relaxation) and ejection (contraction). Relaxation aids in filling during diastole, and therefore, filling parameters denote diastolic function. The phenomena of relaxation and contraction are interlinked and energy-dependent. Diastole precedes systole, because no ejection is possible unless there is filling first. The processes of relaxation and filling constitute diastolic function. Increased resistance to filling is the simplest way of defining diastolic dysfunction. Diastolic dysfunction is the first manifestation of a disease process and explains the symptoms better. Abnormalities of diastolic function are common to virtually all forms of cardiac disease. Noninvasive evaluation of diastolic ventricular function is based on Doppler echocardiographic visualization of inflow and/or ventricular tissue re-extension, although many more parameters are described. The study of pressure–volume loop during diastole is the ideal way to understand and assess diastolic function. However, there are several surrogate methods and parameters in echo-Doppler techniques, which provide reasonable, reliable and actionable information about diastolic function. In general, diastolic dysfunction may be characterized by enlargement of upstream chamber (atrium), alteration in various phases of diastole and raised filling pressures. However, diastolic dysfunction is dynamic and in early phases, filling pressures are Diastolic Function not increased. Assessment of diastolic function in simulated physiological situation, like exercise, may provide enhanced information. Diastolic compensatory mechanisms that maintain filling volume are the earliest evidence of dysfunction. There is also evidence of regional diastolic wall motion nonuniformity. Noninvasive surrogates often reported in clinical studies reflect integrative properties that lack specificity. .