Pulmonic stenosis is a common ___________ of __________.
congenital heart disease; dogs
Pulmonic stenosis is typically ___________ due to... (3)
valvular obstruction; fusions, thickening, or hypoplasia.
What causes secondary pulmonic stenosis?
subvalvular obstruction due to RV hypertrophy
Pulmonic stenosis is often accompanied by _________.
patent foramen ovale
What are characteristic lesions of pulmonic stenosis? (4)
post-stenotic dilatation of PA, RV hypertrophy, +/- patent foramen ovale, +/- tricuspid regurg and RA enlargement
What are Type A and Type B pulmonic stenosis?
- Type A: fusion of valve leaflets
- Type B: dysplasia of valve
Describe the adjunct murmur that may be present with pulmonic stenosis.
tricuspid regurg: holosystolic murmur low on the left
What are historical findings common with pulmonic stenosis? (4)
young dog, exercise intolerance, syncope, +/- asymptomatic
What are PE findings common with pulmonic stenosis? (5)
- ejection murmur loudest at left heart base
- +/- systolic ejection sound (valve doming)
- +/- murmur of TR on the right
- jugular pulses
- [if R-CHF] ascites
Describe the murmur that is most commonly found with pulmonic stenosis. (3)
- diamond-shaped (crescendo-decrescendo) phonocardiogram
- left heart base area
What are ECG findings common with pulmonic stenosis? (5)
- right-axis deviation, small R wave, prominent S wave, RBBB, +/- increased P wave (if RA enlargement)
- [only occur with moderate to severe disease!!! not consistent]
What are radiographic findings that may be present with pulmonic stenosis? (2)
RV enlargement, dilatation of main PA (post-stenotic)
What echo abnormalities may be noted with pulmonic stenosis? (7)
- thick dysplastic valve leaflets or leaflet fusion
- post-stenotic dilatation of PA
- RV hypertrophy +/- RA enlargement
- dynamic RVOT obstruction
- flow turbulence in RVOT and MPA
- increased velocity of flow on Doppler
- +/- pulmonary and TV regurg
Why might there be RVOT obstruction with pulmonic stenosis?
d/t muscle hypertrophy and "squeezing"
Where is the MPA normally seen on radiography?
MPA is at 1 o'clock on VD
Why might S waves be prominent with pulmonic stenosis?
RVH pattern- ESPECIALLY IN LEAD I
RV and RA enlargement with pulmonic stenosis is suggestive of concurrent ____________.
patent foramen ovale
What is the PW Doppler flow pattern of the RVOT with pulmonic stenosis? (3)
- severely increased peak flow velocity (estimate pressure gradient with Bernoulli)
- turbulent blood flow (not laminar)
- often pulmonary regurg
How is mild to moderate pulmonic stenosis managed?
often no treatment, mild exercise restriction, do very well
What are management options for high moderate to severe pulmonic stenosis? (6)
exercise restriction, balloon catheter dilation (vavuloplasty), beta-blockers (atenolol), medical therapy of CHF, stenting of hypoplastic valve, DON'T BREED THESE DOGS
In contrast to aortic stenosis, dogs with pulmonic stenosis DO NOT develop ____________.
Why do we give beta-blockers to dogs with high moderate to severe pulmonic stenosis? (2)
decreases dynamic RVOT obstruction, cardioprotective
What breeds often have coronary anomalies concurrently with pulmonic stenosis, and what are the clinical implications of this?
- Bulldogs, Frenchies, Boxers
- cannot balloon dilate the stenotic PV
What coronary anomaly can sometimes be present (in certain breeds) concurrently with pulmonic stenosis?
only 1 single right coronary ostium and the left coronary artery comes off the right and wraps around the pulmonary valve [this is why we can't balloon dilate pulmonic stenosis in these cases--> would cut off the left coronary artery]
With atrial septal defect, __________ may develop.
cyanotic heart disease
What gross lesions are associated with congenital aortic stenosis? (5)
- fibrous/ fibromuscular or fibrocartilagenous tissue below the aortic valve [i.e. subaortic stenosis]
- concentric LV hypertrophy (chronic pressure overload)
- LV fibrosis (chronic)
- dilatation of ascending aorta (d/t to turbulent blood flow and dissemination of kinetic energy)
- intramural coronary arteries often sclerotic (wall thickening, luminal narrowing)
What causes the post-stenotic dilatations?
turbulent blood flow through the stenotic lesion and dissemination of kinetic energy (blood flowing at high velocity)
Why might a dog with aortic stenosis die suddenly?
intramural coronary arteries--> arteriosclerosis with wall thickening and luminal narrowing--> ischemia--> arrhythmias--> death
ECG indicator of myocardial ischemia.
ST segment depression
With aortic stenosis, the _____________ is proportional to the _____________ (which is why we can use Bernoulli to estimate severity).
velocity of flow across the stenosis; pressure gradient b/w the 2 chambers
What pressure gradient, as calculated by Bernoulli's, is considered severe aortic stenosis?
Describe the murmur associated with aortic stenosis. (4)
- [indistinguishable from pulmonic stenosis- differentiate based on pulse quality]
- left hear base area
- ejection murmur/ systolic
- diamond-shaped/ crescendo-decrescendo
What are PE findings with aortic stenosis? (2)
left heart base ejection murmur with hypokinetic pulses
What ECG findings are common with aortic stenosis? (3)
increased R amplitude(LVH), ST segment depression, ventricular ectopy (VPCs)+/- bigeminal distribution
Where is the aorta located on radiographs?
11-1 o'clock is aortic valve/aorta on VD
What are radiographic findings common with aortic stenosis? (2)
LV enlargement, post-stenotic dilatation
What are echo findings common with aortic stenosis? (7)
subaortic obstruction, LV hypertrophy, aortic dilatation, progressive LV systolic dysfunction (if severe), aortic regurgitation, turbulent flow (not laminar) in LVOT, aortic insufficiency, may be normal with mild disease
What historical findings may be present with canine subaortic stenosis? (3)
no signs, +/- exercise intolerance, +/- syncope
When does aortic stenosis develop?
it is heritable and they are born with it, but it is not detectable at birth; subaortic stenosis is NOT detectable at birth or within the first 3 weeks of life; you might not find it until a few months old
What are outcomes of aortic stenosis? (5)
exercise intolerance, syncope, sudden cardiac death, L-CHF (rarely), bacterial endocarditis
What is the management for mild to moderate aortic stenosis?
none, maybe exercise intolerance
What is the management for high moderate to severe aortic stenosis? (5)
exercise restriction, beta-blockade (atenolol), medical management of CHF, prophylactic antibiotics (to avoid bacterial endocarditis), +/- cutting balloon
Aortic valve degeneration is most common in __________.
Describe the murmur associated with aortic valve degeneration. (3)
- left mid-thoracic
- holodiastolic heart murmur
- musical/ decrescendo
What gross lesions are associated with aortic degeneration? (3)
- severe aortic valve thickening and degeneration
- valve prolapse
- linear beads/bands
Describe the pathophysiology of aortic regurgitation.
insufficiency of aortic valve leading to LV volume overload
Describe the diagnosis of aortic valve degeneration in horses. (3)
- arterial pulses often hyperkinetic
- holodiastolic heart murmur over aortic valve area
- confirm with echo
Describe the management of aortic degeneration in a horse.
- rarely a clinical problem (only if severe)
- exercise restriction
What is the Bernoulli Equation? (actual values)
pressure gradient = 4(peak velocity)²
What is the main difference in arterial pulse quality between SAS and PS?
- with PS, femoral pulses are normal
- with SAS, femoral pulses are weak/ hypokinetic