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Normal systolic LV pressure in the resting dog.
LV pressure is at all times higher than RV pressure during the cardiac cycle. T or F
RA pressure is always lower than LA pressure during the cardiac cycle. T or F
What structural abnormalities can be identified by echocardiography? (6)
dilatation, hypertrophy, valve thickening, septal/vascular defects, pericardial abnormalities, abnormal chamber contents
What functional abnormalities can be identified by echocardiography? (3)
myocardial dysfunction (systolic/ dysfunction), valve dysfunction (stenosis/ insufficiency), abnormal flow (shunts)
What information should be obtained from an echocardiography study? (4)
underlying disease/ lesion, current functional status, disease progression, response to therapy
What is the driving force of flow?
What are causes of LA dilatation? (5)
volume overload (valve regurg, shunts), mitral valve disease (endocardiosis, stenosis, endocarditis), LV systolic dysfunction (DCM), LV diastolic dysfunction (HCM), idiopathic (LA cardiomyopathy)
What are causes of LV dilatation? (6)
- volume overlad: mitral regurg, aortic regurg, chronic RAAS activation
- LV systolic dysfunction: DCM, taurine deficiency, repeated doxorubicin administration
Causes of LV concentric hypertrophy. (6)
- LV pressure overload: aortic stenosis, systemic hypertension
- abnormal myocardial growth: hypertrophic cardiomyopathy, hyperthyroidism
- infiltrative disease
How is LV hypertrophy identified on echo?
feline HCM= wall thickness in diastole ≥ 6mm and reduced chamber dimension
What is pseudohypertrophy?
dehydration causes collapse of the chambers, so even though the chamber is normal, it measures thicker
Segmental hypertrophy is almost always indicative of __(2)__; symmetrical hypertrophy is almost always __________.
infiltration of cells or HCM; pressure overload
What are causes of mitral valve abnormalities? (3)
- endocardiosis (thickening, prolapse, flail leaflets)
- dysplasia (thickening, abnormal motion, elongated chordae, displace PPM)
- vegetative endocarditis (thickening, vegetation)
Endocardiosis (DVD) looks almost the same as _________ on echo; tell them apart by...
endocarditis; dogs with endocarditis are systemically ill, DVD occurs in older small breed dogs WITHOUT systemic illness
What are causes of aortic valve, LVOT abnormalities? (4)
- aortic stenosis (discrete subaortic ridge, LV hypertrophy, post-stenotic dilatation)
- aortic root dilatation
- vegetative endocarditis
- hypertrophic obstructive cardiomyopathy (cats)
What is restrictive VSD?
small defect, high flow velocity (but the small size restricts flow)--> very loud systolic heart murmur
What is non-restrictive VSD?
large VSD, low flow velocity (large size does not restrict flow)--> less loud or no heart murmur [more severe]
What is cardiac tamponade?
tamponade= collapse of the RA +/- RV due to elevated intrapericardial pressure--> weakness, collapse, death
How can cardiac tamponade be diagnosed via 2D echo and ECG?
large effusions lead to typical "swinging motion" of the heart in the fluid--> electrical alternans on ECG (alternating R wave amplitudes); collapse of RA +/- RV on echo
PDA causes overload of... (4)
pulmonary artery, left atrium, left ventricle, aorta
What pericardial abnormalities can be identified by echocardiography? (4)
pericardial effusion, pericardial mass/cyst, pericardial thickening, peritoneo-pericardial diaphragmatic hernia
In what species is "smoke" normal on echo?
Define spontaneous echocardiographic contrast.
"smoke"- sign of blood stasis in cats and dogs and a precursor of TE disease (normal in horses)
How is LV systolic dysfunction diagnosed? (3)
subjective assessment, LV shortening fraction, other indicies
What is a normal SF in dogs?
How is LV diastolic dysfunction diagnosed? (4)
subjective assessment, LA size, LV filling patterns (Doppler), other indicies
How does a LV relaxation abnormality appear on PW Doppler?
small E wave, large A wave
How does restrictive LV filling (decreased distensibility) appear on PW Doppler?
tall E, small A
What are causes of RA and RV dilatation? (5)
- volume overload: tricuspid regurg, chronic stimulation of RAAS
- tricuspid valve disease
- RV systolic dysfunction
- complete AV block
What are causes of RV hypertrophy? (2)
- pressure overload (pulmonic stenosis, pulmonary hypertension, cor pulmone)
- infiltrative disease (neoplasia)
What are causes of pulmonary artery abnormalities? (3)
- pulmonary artery dilatation: post-stenotic dilatation in pulmonic stenosis, pulmonary hypertension, cor pulmone, left-to-right shunt
- abnormal content
- pulmonary atresia
Pulmonary dilatation can be caused by... (3)
pulmonic stenosis, pulmonary hypertension, overflow conditions (L-to-R shunts)
How is RV systolic dysfunction diagnosed? (2)
subjective assessment, Doppler indices
Heartworms are always...
on the right side
What do mature heartworms look like on echo?
macaroni-like tubular structures with a lumen; seen on right parasternal long axis 4-chamber view
Doppler echo is used to assess... (4)
valve function, systolic and diastolic function, severity of valve lesions, and intra- and extracardiac pressures.
What is the Bernoulli equation? What is it used for?
change in pressure= 4 x Vmax2; we can use the velocity of blood flow across a valvular lesion to estimate the severity of a stenotic lesion--> assess severity of aortic stenosis, pulmonic stenosis, and pulmonary hypertension
The tricuspid regurg velocity in a dog with chronic lung disease is measured by Doppler at 4.5 m/s. Give a close estimate of the systolic pulmonary artery pressure.
- Δp (mmHg)= 4 x Vmax² (m/s)
- = 4 x (4.5m/s)² = 81mmHg [way too high]
The peak velocity across a left to right shunting PDA is measured by Doppler at 2.5m/s. The dog's systolic BP is 150mmHg. Estimate the dog's main pulmonary artery systolic pressure. Based on this info, is the PDA restrictive or non-restrictive?
- PA systolic pressure= 4 x (2.5m/s)²= 25mmHg
- non-restrictive- this is a normal PA pressure so the velocity must not be that much higher than normal
In a dog with VSD, the peak flow velocity through the defect is 5.5m/s. The systolic arterial BP is 140mmHg. Calculate the systolic RV pressure. Is this VSD restrictive or non-restrictive?
- RV systolic pressure= 4 x (5.5m/s)²= 121mmHg
- Restrictive VSD b/c RV pressure is way too high, therefore blood must be flowing at a higher velocity; there is also most likely concurrent pulmonary hypertension