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Abstract:
With Doppler echocardiography, in addition to delineation of cardiac structures and their motion, intracardiac pressure and blood flow characteristics can also be assessed. The theoretical basis for this diagnostic method had been formulated by Christian Doppler approximately 100 years prior to its initial use for measuring blood flow in the heart with the aid of ultrasonic waves. The development of continuous-wave Doppler which subsequently yielded the capability for determination of the direction of blood flow, was followed by the development of pulsed Doppler for measurement of blood flow velocity in localized regions of the heart. Inter-currently, combinations of pulsed Doppler together with echocardiography as well as that of pulsed and continuous-wave Doppler were successfully incorporated into a single unit. The most recent development is represented by the realization of color Doppler systems. The possible applications of Doppler echocardiography in cardiology are manifold. Stroke volume and cardiac output determinations are based on measurement of the velocity profile in a specified region of the heart or neighboring great vessels and calculation of the respective area of flow. Intracardiac pressures can be determined in the presence of valvular stenosis, regurgitation or shunt using the pressure differences between contiguous cardiac or vascular structures as calculated by the modified Bernoulli equation and the clinically-measurable or estimable pressure in one of the respective areas. Further methods encompass parameters which can be obtained with the aid of the velocity profile of the pulmonary flow. While two-dimensional echocardiography remains the standard for assessment of systolic left ventricular function, evaluation of diastolic function can be achieved with Doppler echocardiography based on parameters of mitral inflow.(ABSTRACT TRUNCATED AT 250 WORDS)