Diastolic function assessment from mitral flow Doppler echocardiography
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. The mitral flow Doppler patterns in left ventricular (LV) diastolic dysfunction has been divided into four stages.
Stage I LV diastolic dysfunction: In mild diastolic dysfunction, E/A ratio is reversed and less than 0.75. 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 deceleration time of the early diastolic filling (DT) is normally less than 220 msec. The DT is prolonged in diastolic dysfunction. These patients are generally asymptomatic .
Stage II LV 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 demonstrated during Valsalva maneuver.
Stage III LV diastolic dysfunction: 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.
Stage IV LV diastolic dysfunction: In stage IV, this restrictive filling pattern pattern remains fixed even during Valsalva maneuver.
Initial stages are considered reversible with treatment (I to III). Stage IV is considered as advanced. Use of drugs producing bradycardia like beta blockers in stages III and IV may precipitate low output state .