heart author" faq

Doppler Echocardiogram


Doppler echocardiography (see figures 109, 110, 111, 112, 113) depends on the detection of changes of frequency between intracardiac sound waves and their reflections. The initial sound wave's frequency is the same as that of its reflection only if the target is stationary. If the target is moving toward or away from the source, then the reflected wave or echo will have either a higher or lower frequency respectively. This frequency shift (or Doppler effect) allows calculation of the velocity of detected moving objects. In echocardiography, a column of blood can be detected with the Doppler technique. The column is graphically shown to be orange in color if it is moving toward the probe or blue if moving away from the probe. This technique detects aberrant blood flow through the damaged heart valves. For example, regurgitation of blood can be detected in a damaged aortic or other cardiac valve during the filling phase of the ventricles or atria. Abnormal flow can also be detected in a site of an abnormal shunt of blood from our heart chamber to the other (like an atrial septal defect or a ventricular septal defect ( see fig 20, 21), also see definitions of atrial septal defect and ventricular septal defect).