Ch 14 Normal Doppler Patterns Flashcards
How do we take a Vmax measurement?
Place a caliper at the highest velocity (peak) of a spectral waveform to measure the max velocity
What other measurement may also be generated after a Vmax is done?
A maximum instantaneous pressure gradient
What does VTI stand for?
Velocity time integral
How can we take measurements of changing velocities over a period of flow?
By tracing the outline of the specific spectral doppler waveform of interest (called a VTI)
What do VTI measurements represent?
-Velocity (cm/s or m/s) vs time
-Meaning the tracing represents the distance measured flow has traveled (cm)
(think of VTI as stroke distance)
A VTI can be thought of as “stroke distance”, what does this mean?
Is the distance a column of blood travels with each heartbeat
The result of a VTI is the appearance of what 3 things?
-Vmax velocity
-Max instantaneous pressure gradient
-Mean instantaneous pressure gradient (obtained at regular intervals throughout the period of flow)
How do we obtain a PW of the LV inflow (MV)?
-Done in AP4 (b/c of parallel alignment)
-PW sample volume box placed centrally at tips of MV leaflets, on the LV side of valve
How will flow appear on the PW tracing of MV inflow?
Flow is antegrade, appearing above the baseline in diastole
What are we able to visualize + quantify from doing a PW of the MV inflow?
Allows visualization + quantification of the movement of blood from LA to LV in diastole
What does the Vmax caliper of the E wave velocity represent? What part of the ECG does it correlate with?
-Early diastolic filling (80%)
-After T wave on ECG
What does the Vmax caliper of the A wave velocity represent? What part of the ECG does it correlate with?
-Late diastolic filling after atrial contraction (20%)
-After P wave on ECG
What is the E/A slope (aka deceleration time)?
Time b/w peak E velocity + point of deceleration to the baseline in ms
What is the E/A ratio?
Generated after completion of measurements + allows evaluation of diastolic dysfunction
What is the normal range for Peak E (m/s)?
0.46-1.12
What is the normal range for Peak A (m/s)?
0.35-0.98
What is the normal range for deceleration time (m/s)?
112.8-296.4
What is the normal range for E/A ratio?
0.64-2.74
What are the E/A ratio + E wave basic expectations for normal young healthy adults?
-E/A ratio >1
-E wave of approx 1 m/s or greater
(E wave normally bigger than A wave)
MV inflow changes with aging due to what?
The LV becoming less compliant + more stiff
What happens to the E/A ratio as people age?
The A wave increases in size compared to the E wave - b/c LV is harder to fill, a stronger atrial kick is required
List 4 changes to MV inflow due to aging?
-Reduction in E velocity
-Prolongation of early diastolic deceleration
-Increase in A velocity
-E/A ratio of <1
What is grade 1 impaired relaxation of MV inflow?
Normal age related change causing A wave to be bigger than E wave
List 4 pitfalls when using PW over the LV infow (MV)?
-Not being truly parallel to flow (watch where flow is going)
-Sample volume size (3mm is ideal, larger will lead to spectral broadening)
-Sample volume placement (placing SVB too high/low leads to different appearances of waveforms)
-High HRs can lead to E/A wave fusion (increase sweep speed to see waveforms)