Quantitative Doppler echocardiography

Quantitative echocardiography refers to using spectral Doppler measurements of blood velocity, in combination with 2D imaging, to obtain calculated values for flow (e.g. stroke volume, regurgitant volume), area (stenotic valve area, regurgitant orifice area), and pressure (e.g. pulmonary artery pressure, transvalvular gradient). Relevant formulae used by the echocardiography machine software for calculating these parameters are provided. Physical phenomena, such jets, the Venturi effect, and the Coanda effect, are explained, along with applications of the continuity principle, the Bernoulli equation, and pressure half-time measurements. The emphasis throughout the chapter is on practical calculations that can be performed rapidly with TOE in the operating room. The concept of pressure recovery is touched on but discussed in more detail in Chapter 13: Prosthetic valves.