Diastolic function assessment from mitral flow Doppler echocardiography

Mitral flow by Doppler has an early diastolic E wave and a late diastolic A wave during atrial contraction. The normal ratio between the amplitudes of E and A waves (E/A ratio) is 0.75 to 1.5. In mild diastolic dysfunction, E/A ratio is reversed and less than 0.75 (Stage I diastolic dysfunction). The reversal is due to the increase in A wave due to the more forceful atrial contraction to overcome the left ventricular diastolic dysfunction. The decelaration time of the early diastolic filling (DT) is normally less than 220 msec. The DT is prolonged in diastolic dysfunction. In stage II diastolic dysfunction, the E wave becomes taller due to elevated left atrial pressure. This is called pseudonormalization of the filling pattern. In this stage E/A reversal can still be domonstrated during Valsalva maneuver. In stage III diastolic dysfunction, the E wave becomes very high so that E/A ratio is more than 1.5 and the DT is below 150 msec. This is also called restrictive filling pattern. In stage IV, this restrictive filling pattern pattern remains fixed even during Valsalva maneuver.