Ultrasound of Heart SDL Flashcards
how is the patient prepared for ultrasound
clip over apical beat and apply water & gel
what is the patient position
right then left lateral recumbency
why is the echocradiogram done in lateral recumbency
- the lateral recumbency, the lower lung partially collapses under the weight of the heart and mediastinum –> this process in the lower lung is known as hydrostatic congestion and the upper most lung hyperinflates to compensate
- also the heart is fixed at the base but free at the apex so in lateral recumbency the cardiac apex falls towards the lower thoracic wall and pushes the lung out of the way
bigger area which is free from air filled lung
what transducers are best suited for imaging the heart
phased array due to small areas of contact with skin
produces a fan shaped image and allows visualization of a large structure like the heart through the small intercostal spaces
what is the B or brightness mode
and why is it used

produces the familiar real time grey scale images that represents a thin slice through the patient and vary the direction of the beam
- allows orientation of heart
- ensure that entire heart is examined systematically and no features missed
- performance of a repeatable exam and performance of standard measurements which are necessary for the comparison of findings to published results
what is the standard right parasternal view obtained
with the beam orientated at right angles to the long axis of the heart and roughly parallel with the intercostal space

what will the chambers of the heart appear
anechoic or black because blood = fluid
what does the muscular wall of the heart appear as
echogenic
what does the pericardium appear as
hyperechoic line around the outside of the heart and produces an acoustic shadow with reverberation artefact due to the air filled lung immediately beyond it
what are 3 standard right parasternal short axis views through the hear
- left ventricle
- mitral valve (fish mouth)
- heart base (aorta, pulmonic trunk and left atrium)

identify the structures on long axis view (standard right parasternal view)


how is the right parasternal long axis of the left ventricle obtained
first obtain the short axis view through the left ventricle and then rotate the transducer through 90° so the beam is orientated parallel to the long axis of the heart and roughly at right angles with intercostal space

what can be seen on the right parasternal long axis view of the left ventricle
can see the left atrium, mitral valve and left ventricles
the interventricular septum is located between the left and right ventrcles
the right side of the heart is still in the near field of image so it may not be weel imaged due to distortion of beam
it is possible to see the right atrium, tricuspid valve and right ventricle
the pericardium appears as hyperechoic line adhered to outside of heart

what are the right parasternal long axis views
- left ventricle and left atrium –> chordae tendinae
- left ventricle and aorta

what is the hyperchoic strands that can be seen running through the mtiral valve in this view
papillary muscles which represent the chordae tendinae that serve to tether the mitral valve leaflets and are therefore normal structures

what are the LPS views
- 4 chamber: left atrium, left ventricle, mitral valve, right atrium, right ventricle and tricuspid valve
- 5 chamber: directing the beam so the aortic outflow tract also appears
in these views blood is flowing either directly up the screen through the mitral valve and tricuspid valves or down the screen through the aortic valve –> useful for doppler

summarize all the views in RPS short axis, RPS long axis, LPS views
- RPS short axis: left ventricle, mitral valve, heart base (aorta, pulmonic trunk and left atrium)
- RPS long axis: left ventricle & left atrium, left ventricle & aorta
- LPS: 4 chamber, 5 chamber
what is M-mode/time-motion mode used for
performed using standard B-mode images
a cursor line is positioned through B-mode image –> displayed against time as a chart across the screen that is updated
can be used with ECG to identify the stage of the cardiac cycle

how is cardiac wall thickness measured
a standard right parasternal short axis through the left ventricle at the level of the papillary muscles immediately below the level of the chordae tendinae
M-mode cursor is positioned so it bisects a symmetrical line through the left ventricle between the papillary muscles
measured at end diastole (onset of QRS complex) and at systole (T wave)

what can the B-mode RPS long axis through LV and LA be used for
to assess
LV lumen diameter
end diastole - MV open/max area
end systole 4
what can also be used to measure LV thickness
M-mode LV function
RPS short axis through LV

what is the shortening fraction and what info does it provide (what would reduction, increase mean)
the measurements of LV lumen diameter and interventricular septum are fed into equation on machine to produce a shortening fraction
provides info regarding the function or contractility of the left ventricular wall
reduction suggests reduced cardiac function and an increase means compensatory hypercontractility (incompetent mitral valve)
what is the normal shortening fraction range in dogs and cats
dogs: 25-45%
cats: 30-55%
how is ejection fraction determined and why is it used
by calculating the ejection fraction
using B mode RPS long axis through the left ventricle and left atrium:
- image is stopped at both end diastole and end systole (using ECG or by determining the point which internal diameter of LV is at max and min)
- cursor drawn round the internal surface of the LV –> calculate the internal area at end diastole and end systole
- comparison of values gives ejection fraction





