Doppler tracing of mitral flow in left ventricular diastolic dysfunction
Doppler interrogation of mitral valve is usually done from the apex through the apical four chamber view. The transducer is placed directly over the apex beat and the echo beam is directed upwards. A good four chamber view of the heart is obtained, showing all four chambers and both atrioventricular valves. The Doppler cursor is then aligned along the long axis of the left ventricle, passing through the mitral valve. The Doppler sample volume is placed just distal to the mitral valve so that it picks up the flow in the left ventricular inflow. The initial portion of the mitral diastolic flow is called the E wave (early diastolic) and the final portion which occurs during atrial systole is called the A wave. Normally most of the left ventricular filling occurs during early diastole and the E wave is taller than the A wave. When the ventricular relaxation is impaired in diastolic dysfunction, the atrial contribution to ventricular filling progressively increases and the A wave height increases so that there is equalization of the E and A waves. As the severity of diastolic dysfunction increases, A wave becomes taller than E wave. This phase is known as E/A reversal. Still further, the E wave becomes taller due to elevated left atrial pressure, mimicking the restrictive filling pattern. This is a type of pseudonormalization of the mitral flow pattern.
The upper half of the image shows the apical four chamber view of the heart. LV: left ventricle; RV: right ventricle; RA: right atrium; LA: left atrium. The Doppler cursor and the sample volume are seen along midline of the left ventricle. The lower half of the image shows the Doppler flow pattern across the mitral valve. The x-axis is time and y-axis represents the velocity in centimeters/second.