AMA Category 1 Credit for Physicians Only.
ASRT CME is not available.
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The LVI E velocity represents the velocity of the flow of blood into the LV from the LA during the rapid filling phase of diastole. If the LAP is low the velocity will be lower. If the LAP is high, then the velocity of the blood will be higher. In severe MR, an E velocity > 120 cm/sec indicates severe MR.
The TDI E` velocity measures the velocity of the mitral valve annulus during ventricular relaxation and early passive filling. As the ventricle relaxes and fills, the mitral valve annulus moves away from the LV apex. During atrial systole, the mitral valve annulus is pulled away from the LV apex by atrial contraction resulting in the TDI A` velocity measurement. If a ventricle relaxes poorly, then the mitral valve annulus velocity is decreased. If the LAP is low, the speed of filling is slower but the velocity of the mitral valve annulus is near normal. If the LAP is higher, the speed of filling is increased but the mitral valve annular velocity is near normal. Therefore, the E` velocity indicates the speed of LV lengthing during rapid filling of the LV.
Isaaz et al (Am J Cardiol 1989;64:66-75) first reported DTI of the posterior wall, however, in the 1990s the E/E` ratio was used to compare the passive LV inflow velocities to the velocity of LV lengthening. If the LAP is high, the LVI E velocity is high and, in the case of normal relaxation, the LV lengthening will be near normal yielding a high ratio. If the LAP is low the LVI E velocity is low, however, LV lengthing is near normal yielding a low ratio. In diastolic dysfunction, the LVI E velocity can appear while the LAP is high, however, the LV lengthening is decreased yielding a high ratio. Therefore, the mitral valve annlus E` velocity corrects the LVI E wave velocity for LV lengthing. The E/E` ratio has been shown to be predictive of LAP or PCWP .
A low E/E` ratio is < 8 which indicates a LAP < 10 mmHg. A high E/E` ratio is > 15 and indicates a LAP > 15 mmHg. As with other echocardiographic measurements, other methods should be performed to confirm the LAP (Valsalva maneuver, pulmonary S/D ratio, pulmonary vein A wave velocity, mitral A wave duration/pulmonary A wave duration).
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