Apical Echo and Doppler Flashcards
Standard echo views:
Parasternal
Apical
Subcostal
Suprasternal
The apical views:
apical 4-chamber
apical 5-chamber
apical 2-chamber
apical long-axis(a.k.a. apical 3-chamber)
Views from the apical long axis window are used for
assessment of wall motion
Doppler assessment of valve function
What are you looking at in the Apical window:
Looking at the heart from the lower-left corner of the ribcage: PMI(point of maximal impulse)The apex of the heart is closer to the surface than the base is.
What is your Transducer placement as your home based view:
PMI, with beam-edge indicator toward patient’sLEFT shoulderfor the 4-chamber view(use this as your home-base view)
The heart is upside down?Apex is at the top?
Yes, because the probe is closest to the apex.The convention is to leave the view this way.
How do you get a Apical 5-chamber view:
From the 4-chamber view,lay the probe down toward the patient’s chest a bit, so that the plane includes theaortic root.
The four probe movements:
RockAngleRotateSlideUse them to fix the image.
Slide to
bring the apex to the right or left of the screen (put it in the middle)
Rock to
make the heart vertical(i.e., to move the base of the heart)
Angle to
get the atria backor to get 5-chamber view
Rotate to
open up all four chambersor to move from 4-chamber to 2-chamber, etc.
Looking for two things with Doppler in cardiac work.
- Direction of flow (i.e., regurgitation)
- Velocity (i.e., stenosis)
Smaller opening (stenosis) leads to faster flow: = V x CSA
Doppler angle relative to flow:
90° is the worst
(cosine is 0, and 0 times anything is 0, so no frequency shift)
0° gives the maximum frequency shift possible.
Apical view has valve flow almost directly toward the beam or away from the beam: 0°
(flow is parallel to the Doppler beam)
Which valves have flow toward the beam?
Tricuspid and Mitral valve
Which have flow away from the beam?
Aortic
What if you’re a bit off from 0°?
Not a big problem, since even 30° off = only 5% error in velocity estimate.
Still, try for as close to 0° as possible.
PW has a sample volume (gate):
scanner pays attention only to that one portion of the Doppler beam, ignoring the rest.
CW has a continuous
CW gives you everything along the beam
Can you change the size of the gate?
You can change the size of the gate, though it’s usually best to leave it fairly small for precise evaluation.
In the real world, why what doppler do techs use for the Aortic valve? Why?
techs will often use CW Doppler for the aortic valve, because of the “aliasing” phenomenon that occurs with PW Doppler: PW processing can’t keep up with higher frequencies, so the waveform wraps around the spectral display. This gets worse with more depth and with higher velocities/higher frequency-shifts.
What is flow direction on the spectral display below the baseline?
is away from the beam
for cardiac work-it is different in the vascular lab
What is flow direction on the spectral display above the baseline?
is toward the beam
for cardiac work-it is different in the vascular lab
Remember the flow directions in the heart relative to the Doppler beam! Think which sites are proximal/distal—where flow comes from, where it goes to.
a
In this apical 4-chamber illustration, what disorder are you looking for with this placement of the gate?
The gate is in the LA, behind the valve when it’s closed, so you’re looking for regurgitation (insufficiency) of MV.
Where would you place the sample volume to look for aortic valve stenosis?(Where is the flow going?)And again, what part of the cardiac cycle?
a
Where do you put the gate for evaluating stenosis?
put the gate at the tips of the open leaflets.
Where do you put the gate for regurgitation?
get the gate behind the leaflets. and check for flow when valve is closed.
What Characteristic shape do AV valves have?
M shape, sort of like the M-mode, and for the same reason: passive then active filling moving the valve leaflets.This is above baseline, since flow should betoward the beam in apical view.Flow should cease when the valve closes.
What kind of wave form do Semilunar valves have?
which way is flow from the beam?
a single-phase waveform below the baseline. (Flow away from beam)
What units do they use for echo?
m/sec for units, though some use cm/sec.
You just move the decimal two places to the right: 1.33 m/sec = 133 cm/sec
In the right heart, are there higher or lower velocities and pressures?
There are lower velocities in the right heart, since there are lower pressures
(and lower pressure-gradients) there.
Why are the velocities in the right heart lower?
because the pressures are lower
There are lower pressure gradients
WNL values for valve velocities: Ao MV PV TV Where are velocities lower? Why?
Ao 1.7 m/sec
MV 1.2 m/sec
PV 0.9 m/sec
TV 0.7 m/sec
Velocities are lower in the tricuspid valve because the right heart
What happens if the velocity in the valves gets appreciably higher than the normal limits?
than the opening to the valves must be smaller than normal (stenosis).
For example, an aortic-valve velocity of 3 m/sec is abnormal, and 5 m/sec suggests severe stenosis.
How can the pressure gradient across the valve be calculated?
Pressure gradient across valve can be calculated with the velocity information—remember Bernoulli?
How can area be calculated in a stenotic valve?
area of a stenotic valve can be calculated with velocity and area—remember continuity equation?
Waveforms should include EKG because:
EKG for timing of cardiac events.
What do you have with cardiac Doppler waveforms?
you have big chambers,
churning flow patterns,
which means waveforms aren’t always tidy.(Reynolds…)
Timing with EKG:
Semilunar valve opens at_______________, closes at ____________.
AV valve opens at___________,closes at _________.
Again: When is end-diastole?
Semilunar valve opens at peak of R wave, closes at end of T wave.
AV valve opens at end of T wave, closes at peak of R wave.
(Remember ~50 msec delay between electrical and physical events…)
Again: When is end-diastole? beginning of R wave
What does MV regurge look like?
Flow away from the beam is evident during systole(when there should be no flow).
Controls:
Doppler beam, gate Gain Baseline Scale Freeze & measure
What is a common mistake when doing apical view?
Don’t get the probe out too far lateral
Beware of rounded apex—
What does the apex evaluate?
no good, oblique section of heart. Must see the apex to evaluate for wall motion, aneurysm, thrombus.
What do you want to avoid in a 4 chamber view? What position should the heart be in?
Avoid a tilted heart in the 4-chamber view
Find the window that places it vertical
When do you expect the heart to be tilted to the right?
in the 2-chamber and long-axis views.
What motion can cause you to lose the view?
Rocking
