Echo and diastolic dysfunction

Echocardiography in Diastolic Dysfunction:
Diastolic dysfunction is defined clinically as symptoms of heart failure in the presence of a normal ejection fraction.

Echocardiography can be used to describe diastolic dysfunction. There are 4 echocardiographic indicators of diastolic function:


 * transmitral Doppler inflow velocity patterns


 * pulmonary venous Doppler flow patterns


 * tissue Doppler patterns


 * color flow propagation patterns

Doppler mitral inflow velocity

Measurement of transmitral flow velocities can be used to characterize left ventricular filling. Transmitral doppler flows are generally

obtained within a sample volume at the tips of the mitral leaflets from the apical four-chamber view using transthoracic echocardiography,

or using a four-chamber, horizontal plane, or esophageal view using transesophageal echocardiography.

There are 3 phases of left ventricular filling:


 * early “active” relaxation - E wave


 * passive filling


 * late active filling during atrial contraction - A wave

Three diagnostic parameters can be estimated using the Doppler velocity profile.


 * E/A ratio (normal value >= 1.0)


 * deceleration time of the early filling curve (normal value >150 to <=220 msec)


 * isovolumic relaxation time - measured using simultaneous interrogation of LV outflow and mitral inflow.

An E/A ratio < 1 or deceleration time >220 msec is suggestive of diastolic dysfunction. However, the E/A ratio can be falsely

normal during early diastolic dysfunction, a process known as pseudonormalization. Pseudonormalization can sometimes be unmasked

by having the patient perform a Valsalva maneuver.

image

Color Flow Mapping

By simultaneously imaging flow in the pulmonary veins, left atrium, and left ventricular, it is possible to estimate the the "quantity of inflowing blood", and using M-mode, it is further possible to estimate the rate of inflow, termed the flow propagation velocity Vp. Low flow states are suggestive of impaired relaxation or restrictive physiology.

Pulmonary venous flow

Tissue Doppler echocardiography

References:

Chethan 22:21, 1 October 2007 (MST)