Diagnostic approach - echocardiography Flashcards
What can you determine using echocardiography?
STRUCTURE: chamber size, valve structure, other lesions FUNCTION: systolic function, diastolic function, valve function, intracardiac pressures
What is echo the test of choice for?
Defining TYPE of heart disease
What is echo not the best test for?
Identifying HF
How are 2D images generated?
Fan-shaped beam of ultrasound Reflected waves are reconstructed (in real time) to produce tomographic image of the heart.
Define tomography
= imaging by sections using any kind of penetrating waves.
What are the types of echocardiography?
M Mode (motion mode, single point source) 2D (standard, fan shape) Colour Flow Doppler Spectral Doppler (velocity and direction of BF)
Describe M-mode echo. Use?
Basic method, good time resolution, standard way for measuring ventricular size. =distance-time graph
Outline 2D echo
Easiest to understand, therefore standard method. Image depends on where probe is pointing and the angle of the probe.
What is ‘BART’?
Acronym for understanding Colour Flow Doppler Echocardiography. Stands for: Blue Away from the transducer Red Towards the transducer (nothing to do with oxygenation, blood flow is superimposed on a B&W image)
What type of graph does a Spectral Doppler echo produce?
Velocity/time graph (i.e. velocity and timing of BF)
How to achieve the best echo images?
Most cats/dogs need no sedation. Best in lateral recumbency (air in dependent/underneath lung lobe is absorbed –> better image)
What view would this produce?
Right parasternal, long axis, 4 chamber (note the LV is a bullet-shape)
Define LVOT
Left Ventricular Outflow Tract
What view would this produce?
Right parasternal, long axis, LVOT (i.e. slightly rotated to the right parasternal, long axis, 4 chamber )
What is this image of?
Short axis, papillary muscles
What does this show?
Short axis mitral valve
What does this show?
short axis left atrium/aortic valve
T/F: mitral and aortic valve are in contact with each other
True (short axis, pulmonary artery echo view)
What does this show?
left apical 4 chamber (note the characteristic LV bullet shape)
What is LA enlargment a risk marker for?
Dogs - acquired heart disease Cats - cardiomyopathy Since it suggests increased LA pressure. Potential for CHF to follow with pulmonary oedema.
What is the RV free wall thickness supposed to be?
1/3 the thickness of the LV free wall
What measurements can be made on echo?
LA diameter: short axis LA/Ao (normal <1.6 in cats) LV: diameter and LV wall thickness (systole and diastole) LV systolic function (FS%)
Describe the shape of a normalLA
square. As the LA enlarges, it becomes more rounded.
What is FS%?
Fractional shortening % = the % change in LV diameter (i.e. an assessment of contractility). Equation: FS% =(LVDd - LVDs)/LVDd ]* 100
What does a LV FS% of >55% suggest?
The LV is HYPERkinetic
What does a LV FS% of
The LV is HYPOkinetic
What characterises abnormal BF? 3
Direction Velocity Turbulence (On echo, green indicates abnormal BF)
Causes of LA dilation - 3
VOLUME OVERLOAD: MVD, and L-R shunts SYSTOLIC DYSFUNCTION: DCM DIASTOLIC DYSFUNCTION: HCM
Causes of LV dilation - 2
VOLUME OVERLOAD: MR, L-R shunts, AR SYSTOLIC DYSFUNCTION: DCM, chronic volume overload
Causes of LV hypertrophy - 2
PRESSURE OVERLOAD: aortic stenosis, systemic hypertension IDIOPATHIC: HCM
Causes of mitral valve abnormalities
Myxomatous valve disease (–> eccentric hypertrophy)
Cause of aortic valve abnormality
Endocarditis
Causes of RV hypertrophy - 2
PRESSURE OVERLOAD: pulmonic stenosis or pulmonary hypertension (can’t differentiate these with echo images)
Most likely diagnosis?
MVD
Most likely diagnosis?
DCM
Most likely diagnosis?
Pericardial effusion (free fluid is also present on the other side of the pericardium)
Define cardiac tamponade
Pressure on the heart that occurs when blood/other fluid builds up in the space between the myocardium and the pericardium.
