Angol
For almost 40 years, a small but intense group of cardiovascular investigators have evaluated cardiac performance by measuring the mass, velocity, and acceleration of blood ejected from the left ventricle. These studies reveal that energy is transferred from ventricle to blood very early in systole, and that the left ventricle is charac terized as an impulse generator. Recent explosive developments in Doppler echocar diography have allowed study of the energetics of ventricular contraction through noninvasive acceleration, velocity, and volumetric flow measurements. Compared against reference standards of ejection fraction, dP/dt, and instantaneous pressure gradient across the aortic valve, Doppler acceleration and velocity measurements are highly sensitive to changes in ventricular performance. Most patients seeking cardiovascular care present with coronary artery disease as a chief concern. This book focuses upon identification of coronary disease presence and severity through the evaluation of left ventricular Doppler ejection responses to stress loading. Chapters I through 4 detail basic research on the dynamics of left ventricular ejection in ischemic and nonischemic animal models. Chapters 5 through 13 present clinical correlates of changes in the Doppler systolic ejection pulse during exercise and under pharmacologic stress loading. Angiographic anatomy, thallium perfusion defects, and radionuclear ejection fraction responses serve as reference standards. Chapters 14, 15 and 16 address applications of Doppler echocardiography during the stresses of brief coronary occlusion, myocar dial infarction and post infarction recovery, while chapters 17 and 20 illustrate applications of stress Doppler techniques in valvular heart disease.
