Module 2: PLAX Portocol Flashcards
How should we position our patient for PLAX view?
- Lateral decubitus position (LLD)
- Drop the right shoulder back to open up the intercostal spaces
Where do we place the probe for PLAX view?
- Place probe in the left 3rd and 4th intercostal space close as possible to the sternum
- Indicator towards the patients RT shoulder or clavicle
not so close that the beam is blocked by bone
How much of the heart should take up the window in PLAX?
1/2 depth
Where should we place the focus for the PLAX protocol?
Mid
Can we see the Apex normally during PLAX?
Nope
Is FR important during PLAX?
No, it is not as important here
What can extra depth PLAX be used for? 3
Can be used to asses the surrounding structures of the heart. Including
- Pericardial fluid
- Pleural fluid
- Pericardial mass
What are some tips for PLAX cine? 4
- Reduce depth from extended view
- Focus - LVOT level
- Ensure all structures are clearly seen
- LV walls should be perpendicular to the probe
What should be seen clearly on the PLAX Cine? 5
- LV/RV endocardium
- MV
- AV
- AO
- Sinus should all be clear
Before we start taking the measurements in PLAX, what should we do? 2
- Ensure that the depth is only deeper than the posterior wall of the descending aorta
- Attempt to make the LV walls as perpendicular to the beam as possible without sacrificing image quality
What should we do for end- diastolic measurements? 2
- Scroll to the QRS complex of the beat you want to measure your diastolic measurements
- Scroll back and forth slightly until both AV + MV are closed and you have a crisp image
What should we do for End-systolic measurements? 4
- Scroll to end systole for LVID and LA
- Just after AV closes or where the LV chamber is the smallest
- MV should be closed
- Take still images every measurements
What end diastole measurement images do we take?
- IVSd (interventricular septum)
- LVIDd (LV internal dimension)
- PWd (LV posterior wall)
What are the levels of the LV?
- Base
- Mid
- Apex
Where is the base of the LV?
From the MV to the superior top of the pap muscle
Where is the Mid of the LV?
From the top to bottom of the papillary muscle
Where is the apex of the LV?
Inferior to the pap
What is the normal IVSd for men and women?
Men <10mm women <9
When doing the IVSd measurement where should we measure?
Perpendicular to the LV wall
A sliver of RV wall often sits atop of what?
The IVS
Where should we measure the IVSd from the RV and the IVS?
Measure from the fine line where the IVS switches from RV to LV to the LV chamber
IVS and LVPW thickness should be what?
Roughly equal
For the LVID measurement where should we measure to?
From endocardium of the IVS to the endocardium of the posterior wall.
don’t mistake the chordae for PW
What is the normal LVIDd measurements?
Men <58; Women <52
What is the LV posterior wall often called?
Inferolateral wall
How should we measure the LV posterior wall?
Measure from the anterior border of the PW, to the beginning of the bright echoes of the pericardium
do not include the pericardium
What are the normal measurements for the LV posterior wall?
Men <10mm; Women <9mm
What are the measurements we need to take for End systole? 2
- LVID
- LA
What are some tips for measuring LVID end systole?
Measure from posterior edge of IVS to anterior edge of LV PW
What are the normal measurements for the LA dimensions?
Men <40; Women <38
What is fractional shortening?
Is a linear calculation that gives information about the systolic function of the heart
What is the calculation for fractional shortening?
FS = ((LVIDd- LVIDs)/ LVIDd) x 100
What is the normal range for fractional shortening?
25-47%
What is ejection fraction?
A measurement used to assess systolic function by calculating the % of blood exiting the heart with each contraction
What does linear ejection fraction do?
Takes dimensions and extrapolates a volume from them
What are some general assumptions for Linear ejection fraction? 2
- The EF is reasonably accurate if there is no regional wall motion abnormalities
- Assumes the calibres are correctly placed and perpendicular to the long axis of the LV
What are some specific assumptions for EF? 3
- Ventricle is a prolate ellipse shape
- Long axis (length) is twice the short axis (width)
- Symmetric contractility
What is the teichholz formula?
Machine calculates this for you for a linear ejection fraction
But
((EDV-ESV)/ESV) X 100
How do we get a volume from a dimension? Formula
LVIDd^3 = EDV
LVIDs^3 = ESV
**convert mm to cm
What is the linear EF formula?
Linear EF = ((LVIDd^3-LVIDs^3)/LVIDd^3)x100
What is the LV mass?
The weight of the LV myocardium in grams
How do we calculate the mass of the LV?
Volume of LV walls x Myocardial density
What is the LV mass index?
The idea that absolute LV mass varies according to body size
What is the normal measurements for LV mass?
Men < 115 g/m; Women <95 g/m
What does the Relative wall thickness (RWT) assess?
The measurements of the posterior wall compared to the L chamber size
What is the formula for RWT?
RWT = (2(LVPWd))/LVIDd
What is the RWT basic principles? 2
- A bigger chamber (bigger person) will have thicker walls naturally
- When the walls hypertrophy (thicken) or the chamber dilates, this calculation becomes abnormal
What is the normal RWT ?
0.22-0.42
How do we calculate myocardial volume?
Epicardial volume - endocardial volume
What are the four types of wall thickness we might see
- Normal geometry
- Concentric remodeling
- Concentric hypertrophy
- Eccentric geometry
What does the arrows indicate?
The direction of change with disease
How can we tell the difference between the concentric and eccentric LVH?
Concentric has big thick walls and eccentric has a large chamber
How should we get AV zoom? 3
- Zoom using write zoom, by pushing in zoom dial
- Adjust size (usually doesn’t need much adjustment)
- Press zoom again
What should we see on the AV Zoom? 4
- LVOT
- Both AV cusps during syst + diast
- Some Ao
- Some LA
What are some tips to get the LVOT diameter- Mid systole? 4
- Zoom
- Measure just after the AV opened fully (mid systole)
- 5 mm inferior to AV annulus
- decrease gains this helps
What is the average measurement for LVOT mid systole diameter?
20 mm
80% of the population measure between what for LVOT - mid systole?
18-22
LVOT diameter is used in how many equations?
Many echo equations
What is the formula for Cross sectional area?
CSA = R^2
Whenever we use diameter we need to square it. This why we need to be accurate why?
Because whatever measurement we get is squared therefore it will be even more wrong
Label the parts of the heart
- Aortic annulus
- Aortic sinus of valsalva
- Sino- tubular junction
- Ascending aorta
We will only be measuring which parts of the aorta for our routine. Which ones are they?
Aortic sinus and ascending aorta (2 and 4)
When taking aortic measurements, how should we position ourselves?
Perpendicular to the long axis of the aorta
How should we measure the sinus of valsalva? (Calliper placement)
Leading to leading edge, at the widest part of the bulge
includes anterior wall
Where do we measure the ascending aorta?
> 2cm distal to the sino- tubular junction
** ideally past the PA**
Leading edge to leading edge
includes anterior Ao wall
Where does the ascending aorta sit? In relation to where we normally take the image?
The aorta sits more superiorly and medial to where we have been focused until now.
To see more of the asc aorta we must slide how?
Superiorly, and tilt medially
How should we measure the Ascending aorta? (Distance from ST junction, calliper placement, what walls do we include in the Ao, when do we measure?)
- Measure 2cm + from ST junction
- Measure LE to LE
- Includes anterior Ao wall, but not the posterior Ao wall
- Measure at End diastole
If you cannot see 2cm distal to the ST junction at end diastole, during your ascending aorta image what do you need to do?
Measure when you can see it clearly
What is the normal ASC. Ao measurement?
<3.4 cm
What is the normal measurement of the valsalva?
Normal S of V <3.7 cm
When can we measure the sinus of the valsalva?
Measured in PLAX image or ASC. Ao image
Do we need to zoom for an image of the sinus of the valsalva?
No
Where should we put the focus for the sinus of the valsalva?
At the sinus of the valsalva
Where should start and end measuring for the sinus of the valsalva? (calliper placement)
Leading edge to the leading edge including anterior wall, but not the posterior wall
When should we measure the sinus of the valsalva (in terms of heartbeat)?
End diastole
What are some tips for getting a zoom image of the MV? 3
- Make sure MV leaflet tips are clearly seen throughout the systole and diastole
- Most of the LA seen
- Part of Basal IVS seen
What are some tips to getting an image of the RT inflow (TV) view? 3
Angle towards the right hip
1. Main focus is the TV, must see both!
2. No 2D measurements taken in this view
3. Try sliding slightly laterally, then angling medially
What do we focus on during the PV (RVOT) view?
Focus of this view is the PV and the MPA