Fig. 4.30 Pulsed-wave Doppler mapping.
Pulsed-wave Doppler echocardiography can be used to 'map-out' the extent of a jet of dregurgitation such as mitral regurgitation. As a rough approximation, the more widespread the area over which the jet can be detected in the left atrium, the more severe the MR. In fact, the area of origin of the jet at the valve is a more accurate approximation to severity, but it is more difficult to measure. Some jets run in a direction which makes it difficult to align the beam parallel with flow; others can be difficult to map because they cannot be detected in standard planes of view. However, if the limitations are recognised, mapping is a guide to severity. It can be useful to record diagrams of the jet for future reference. Mapping of tricuspid regurgitation is also helpful; however, some regurgitation is detected close to most valves, especially the tricuspid valve, even in normal horses.