Echocardiography Flashcards
Minimal equipment for Echo
- Multiple probes of different frequencies
- Electrocardiogram
- Cardiac packages for flow and measures ($$$$$)
- Printing/reporting ability
What are the three modes of echocardiography? (See images in the powerpoint for examples)
- ) 2 dimensional
- ) M mode or motion mode
- ) Doppler echocardiography
2 dimensional mode
- most simplistic
- Used to assess the structure of the heart, valve structure, and any abnormalities
- Used for anatomic evaluation of the heart
- Long (sagittal plane) and short axis (transverse plane) with standard views
M-mode (motion)
- Used to provide assessment of function
- Nothing about blood flow
Doppler echocardiography (spectral and color)
- Evaluates direction and speed (velocity) of blood flow
- Alignment is crucial - the Doppler waves need to be parallel to blood flow for accuracy
Spectral doppler
- Measure speed of blood flow in a direction
- More quantitative
Color doppler
- Assessment of blood flow
- Relatively qualitative
- Laminar or turbulent
Short axis view (see image)
- Transverse section of the heart
- Making slides across the heart from apex to base
Long axis view (see image)
- 4- chamber and LV outflow view
What information can you get from 2D views?
- Anatomic evaluation of the heart
- Provides information on anomalies, chamber enlargements, pericardial effusion, etc.
Long axis four chamber view what can you see?
- Right ventricle and right atrium
- Tricuspid valve
- Left ventricle and left atrium
- Mitral valve
How thick should right ventricular wall thickness be?
- About 1/3 the thickness of the left ventricle
What can you see on the long-axis LV outflow view?
- Left ventricle
- Aortic arch
- Right pulmonary artery
- Left atrium
What can you see on the mushroom view? (See images)
- Left ventricle in short-axis view
- Interventricular septum
- Papillary muscles are visible too
Fish lips what can you see?
- More right ventricle
- Mitral valve
- Left ventricle
- Interventricular septum
- SEE IMAGE
What can you see in the Mercedes benz view?
- Aorta with semilunar valves
- Heart base
- Left atrium and auricle (The whale)
- Right atrium and tricuspid valve
- Right ventricle and pulmonic artery
- Pulmonic valve
- Tricuspid valve
- SEE IMAGE
What can you see with the right parasternal long-axis 5 chamber view?
- Right ventricle and tricuspid valve
- Right atrium
- Left atrium
- Left ventricle
- Mitral valve
- Aortic semilunar valves
- Aorta
Which valve is most likely to have endocarditis in a horse?
- Tricuspid valve
Where do you obtain M-mode images from?
- Mushroom view (LV view)
- Fish lips (MV view)
- Mercedes Benz (LA:Ao view)
What does M-mode evaluate?
- Cardiac motion over time
Why is M-mode more useful than 2-D view for measurements?
- Resolution of chamber surfaces more readily defined for accurate measurements
Make sure you know what each section is for M mode for MV view
- Just do it - look at the images
MV view on M-mode purpose
- Evaluate mitral valve motion
- Evaluates left ventricular diastolic function
- Done with the Fish lips view
M-mode: LA:Ao view
- Mercedes benz
- Evaluates aortic valve motion
- Evaluates left atrial size
Make sure you know what each section is for M mode for MV view for LA:Ao view
- Just do it
- Make sure you know diastole and systole
M-mode: LA:Ao view purpose
- Might be useful for subaortic stenosis or evaluating animals with low cardiac output
What should aortic root diameter to left atrial diameter be?
- 1:1 normally
M mode LV size and function
- consistency is key
- Measure the walls to determine hypertrophy or thinning
- Measure the internal dimension to determine contraction (%FS)
What is fractional shortening measuring?
- Index of contractility
How do you determine fractional shortening?
- (LV Diastole - LV systole)/(LV diastole * 100%)
What is normal FS% in dogs?
- 25-40%
What is normal FS% in cats?
- 35-50%
What does a decreased FS mean?
- Reduced systolic function
What does color Doppler measure?
- Turbulence and direction of flow (qualitative)
What does spectral Doppler measure?
- Pulsed or continuous wave
- Flow speed/velocity (quantitative) in m/sec
- Can identify pressure gradient across a stenotic valve or shunt (and calculate cardiac chamber pressures)
Which color is away and which is towards on Doppler?
- Blue is away and red is towards (BART)
What does green/yellow mean on Color Flow Doppler?
- Turbulence and high velocity
How do you calculate pressure gradient across a stenotic valve or shunt based on spectral Doppler?
- Modified Bernoulli Equation
- 4x[(velocity)^2] = Pressure gradient
Can you overestimate velocity with spectral Doppler?
- NOPE
- You can only underestimate if you are not well-aligned with the flow
Which view would you use to measure aortic valve velocity?
- Subcostal view
What is normal velocity across the aortic valve?
- 1.5 m/sec
- Approximately
What is normal velocity across the pulmonic valve?
- 1.5 m/sec
What is right ventricular pressure if pulmonary arterial flow is 1.1 m/sec?
- 4 x (1)^2 = 4 mm Hg difference between Pulmonic artery vs RV
- If normal pulmonic artery is 20 mmHg, then RV is 24 mmHg
- Normal range of RV is 15-30
What is the RV pressure if PA flow is 5M/sec
- 4*(5^2) = 100 mmHg
- normal PA is 20, meaning that RV is 120 mmHg
- Make sure you know what this would mean for the aorta and left ventricle too
