Cardio - Echo Flashcards
What are some advantages to using echo?
Useful for assessing cardiac structure AND function, provides definitive diagnosis of most cardiac diseases, noninvasive
What are disadvantages of echo?
Requires expensive equiment and technical expertise
How does echo work?
High frequency sound waves are emitted from a transducer and are reflected/refracted/absorbed by tissues
What determines the proportion of reflected waves (returing to transducer)?
Acoustic impedance
What has the greatest to least acoustic impedance?
Fluid > soft tissue > fibrous tissue > solids (bone)
What are the 4 echo modalities?
2D, M-mode, color doppler, spectral doppler
What is M-mode?
Still image of single 1D slice throughout multiple cardiac cycle
What is color doppler?
Codes blood flow with color indicating direction
What is spectral doppler?
Measures velocity of blood flow
What are the 3 sites on which the transducer can be placed?
R parasternal, L apical, Subcostal
What orientations can you hold the transducer at?
Long-axis, short-axis
A
RV free wall
B
RV
C
tricuspid valve
D
RA
E
interventricular septum
F
LV
G
LV free wall
H
mitral valve
I
LA
The LV should be ____ the size and thickness of the RV in long-axis.
3-4x
LA and LV should be roughly the same maximum _____.
height
_____ and _____ should be roughly the same diameter.
LA and Ao
What does it mean if the doppler is showing “party colors”?
There is turbulent, high-velocity flow in that area
What does blue on the doppler mean?
away
What does red on the doppler mean?
towards
A
RV
B
Interventricular septum
C
LV
D
LV papillary muscles
E
LV free wall
A
RV
B
Interventricular septum
C
LV lumen
D
LV free wall
E
diastole
F
systole
What is fractional shortening (%FS)?
Echocardiographic index of LV systolic function;
Amount that the LV shortens in one cardiac cycle from diastole to systole
How is %FS measured?
(LVIDd - LVIDs) / LVIDd
IDd = size in diastole; IDs = size in systole
What is the normal %FS in dogs?
~28-45%
What is depicted here?
Mitral valve opening and closing
In the RP Sax, what are we looking for when then LV is in diastole?
dilation
In the RP Sax, what are we looking for when looking at the LV wall thickness?
hypertrophy
In the RP Sax, what are we looking for when we are evaluating LV systolic function?
%FS
In the RP Sax, what shape should the RV be?
Small crescent
What view is used to assess LA enlargement?
RP Sax: LA:Ao
A
tricuspid valve
B
RV
C
RA
D
aorta
E
pulmonic valve
F
LA
G
L Auricle
A
aorta
B
LA
What is the normal LA:Ao ratio in M-mode and in 2D?
< 1.5 : 1
What is considered the ratio of LA:Ao at which the LA is severely enlarged?
>2:1
What 2 things do we look for in the RP Sax heart base view (LA:Ao, PA)?
LA enlargement (LA:Ao), PA enlargement (pulmonary hypertension)
What is the normal velocity of blood flow across the pulmonic valve?
~100 cm/s
What is depicted here?
Spectral doppler view of velocity of blood flow (across the pulmonic valve)
What does the subcostal view allow for?
Allows us to align with the LV outflow tract (aorta and PV) through the diaphragm
A
RV free wall
B
RV
C
tricuspid valve
D
interventricular septum
E
LV
F
LV free wall
G
mitral valve
H
RA
I
LA
What 3 things do we look for in the L apical view?
LV should be 3-4x the size and thickness of RV, valve thickening/regurg (?), cardiac masses
