LA/RA/RV Flashcards
What is the function of the LA?
to collect blood from the lungs and push it into the left ventricle.
How do I measure the LA?
PLAX
taken at end Systole just prior to the opening of the Mitral Valve
What views is the LA measured using m-mode?
What are the disadvantage of measuring the LA in m-mode?
Can be do PLAX & PSAX
M-Mode can deform the natural contour
not always optimally positioned.
Lack of spatial orientation, oblique measurement line. Over estimation of LA size.
Describe the two methods to measure the LA in the 4CH & 2CH views.
- area-length approach. The area is measured by planimetry of both apical views. Then linear/length dimension is measured from the center of the mitral annulus to the superior border of chamber.
- Simpsons Biplane- tracing area and transverse obtained automatically. Volume is derived and indexed with BSA
What parameters are measured in the LA
The major and minor dimensions, area and volumes
Why do we need to take measurements in more than one tomographic view.
No single tomographic view conveys complete information about a 3-D structure. It is recommended that a combination of two or more imaging planes be used.
When do you measure LA Volume and in what views?
during end systole, just before mitral valve opening.
Apical 4CH & 2CH
What part of the cardiac cycle do I measure the LA?
End Systole – end of T-wave
What causes the IA septum to bow back and forth?
What causes it to stay bow out and what should we suspect?
Pressure gradient
a really high pressure
a PFO (patent foramen ovale)
Define end-diastole. What wave are seen?
When does contraction occur?
What happens during late diastole?
MV closes after A wave. EKG R wave
Contraction occurs after the P wave – Late diastole which is the final phase of left ventricular filling
What occurs on the EKG during A-FIB?
No p wave
here will be no A wave.
What is a missing a wave on a echo PW mitral inflow an indication of? What type of rhythm will you see on the EKG
EKG rate will be irregularly irregular
A-FIB
What does bowing of the atrial septum indicate? What view is it most easily appreciated in?
left atrial dilation (volume) and /or elevated left atrial pressure. Using the apical 4CH view.
What does contraction of the LA correspond with on the EKG?
P-wave and occurs during late diastole
On doppler of the mitral valve, what does the A-wave velocity and VTI determine?
The degree of contractility.
What is the loss of LA contractility associated with?
A-FIB. Absence of the mitral a-wave and the p-wave on EKG.
What is a PFO?
How does it occur.?
What % does it occur in adults?
Patent Foramen Ovale. Natural valve reopens because of increase pressure and volume in the LA or RA. 25 – 30% occurrence in Adults
What are congenital PFO’s commonly caused by and what is seen when using color doppler or contrast?
The Primum and Secundum membranes not properly closing,
bidirectional flow - septum appears structurally intact.
Occasionally you will see tunneling between the membranes
What is an ASD?
Atrial Septal defect. A hole in the septum.
What two membranes make up the IAS?
The septum primum – left atrial side
The septum secundum – right atrial side
Together = the foramen ovale
What happens to the foramen ovale at birth?
closes due to change in pressure also can reopen due to pressure change (PFO pressure overcomes and opens hole or the left atria gets over stretched.
What is the best method for detecting a thrombus in the LAA?
TEE- appendage can be visualized from a variety of planes.
TTE is suboptimal
What is used to distinguish the LAA from the PV?
Color doppler
What can a thrombus in the LAA get confused with?
small pectinate muscles.
What three abnormalities (deformations) are seen in the IAS
ASD, PFO, and Aneurysm of the septum
Why can a tunnel like gap be occasionally intermittently visualized in a PFO?
How often do we evaluate it?
Due to trans-atrial pressure gradient changes with respiration. Evaluate every 3-4 cycles
What are PFO’s frequently associated with?
Exaggerated mobility of the atrial septum and in the extreme form an atrial septal aneurysm.
What form of imaging is used to distinguish between an ASD and PFO and why?
TEE, because it is more sensitive and provides a more complete assessment.
What type of shunt is present when contrast crosses over > 4 sec from injection? What is the source?
transpulmonary shunting.
Usually through a arteriovenous malformation.
What is a atrial septal aneurysm?
A redundancy of the mid-portion of the septum.
What are the visual characteristics of an atrial septal aneurysm?
Excessive mobility and billowing of the tissue in the region.
What is the threshold of IA septum movement before it becomes aneurysmal?
Which modality is better at detecting it?
10 mm from septal plane
TEE is better at detecting the extent
What are the best views to see IA septum shunts?
septum subcostal viewShunts and blood flow across the
– gaps in the wall- look for flow gaps
What views can IA billowing be seen? Which is the best view?
PSAX or A4CH best seen in TEE 4CH
What is the first view we see the IAS?
PSAX at the base
What does a lipomatous infiltration involve and what shape does it create?
What should be used to distinguish between lipomatous infiltration, a malignancy or thrombus?
A fatty infiltration of the superior and inferior portions of the septum, typically sparing the fossa ovalis, creating a dumbbell shape
If there is diffuse infiltration MRI should be used
What does the motion of the IA aneurysm reflect?
The relative pressure gradient between left and right atria and thus the out-pouching will usually occur in both directions over the course of the cardiac cycle.
What are atrial septal aneurysms associated with 75% of the time? What is the combination associated with?
PFO, Substantial risk of thromboembolism
What should be used to distinguish a diffuse septal infiltration of fatty tissue from a malignancy or a thrombus?
MRI