Congenital Heart Disease Flashcards
What are the broad classification of congenital heart disease
1) Shunts: PDA, ASP/PFO, VSD
2) Valvular Malformations: Aortic/pulmonary stenosis or mitral/tricuspid dysplasia
3) Complex and Cyanotic- tetralogy of fallot, double outlet, transposition, truncus
What is the gold standard to diagnose congenital heart disease
echo
What are the three most common congenital heart diseases in dogs
1) PDA
2) Subarotic stenosis
3) Pulmonary valve stenosis
What are the most common congenital heart diseases in cats
Ventricular septal defet
patent ductus arteriosus
Tricuspid/Mitral valve dysplasia
atroventricular septal defect
What are the 3 most common congenital cardiac shunts
1) PDA: Aorta and pulmonary artery connection
2) Atrial Septal Defect
3) Ventricular Septal Defect
What are the 3 most common congenital valve disease
1) Subaortic Stenosis: obstructing outflow
2) Pulmonic Stenosis
3) MV or TV dysplasia
In the dog, PS, PDA, and SAS is the most common congenital heart disease, what is the most common in all other species?
Ventricular Septal Defect
In a dog if you hear a left apex systolic murmur, what could be occuring
mitral dysplasia (young animal) or mitral degeneration (older)
In a dog if you hear at left apex diastolic murmur, what could be occuring
1) mitral stenosis
2) Aortic insufficiency
In a dog if you hear a left base systolic murmur, what could be occuring
Pulmonary or aortic stenosis, functional/innocent
In a dog if you hear a left base diastolic murmur, what could be occuring
pulmonary or aortic insufficiency
What could be occuring if you hear a left base continuous murmur
patent ductus
arteriovenous fistulae
What could be occuring if you hear a right caudal systolic murmur
1) Tricuspid dysplasia
2) Ventricular septal defect (flow from left to right)
What could be occurring if you hear a right caudal diastolic murmur
tricuspid stenosis
Top 5 Loud Systolic Murmurs (congenital)
Subaortic Stenosis: Left heart base- poo femoral pulse
Pulmonary valve stenosis: Left heart base, normal pulse
Ventricular septal defect: right thorax
Tricuspid valve dysplasia- regurgitation: right apex
Mitral valve dysplasia- regurgitation: left apex
Why might young animals have heart murmurs
-Vibrations of normal structures
-Increased ejection velocity due to stress/anxiety
-Compression of structures by stethoscope
-Anemia and reduced viscosity
-Congenital Heart disease
T/F: Young animals with murmurs always have congenital heart disease
false: there can be nonpathologic murmurs
Nonpathological:
a) Functional: no structural heart disease is detected and there is plausible physiologic explanation for murmur (ex: anemia)
b) Innocent murmur: no physiologic explanation for murmur is identified
or
Pathological
What are the 6 S’s to consider for incidental heart murmurs
1) Sensitive: softer or absent at rest rather than exercise
2) Short: Duration is short
3) Single: no other abnormal heart sounds
4) Small: localized to 1 location and does not radiate
5) Soft: the murmur is soft or quiet, generally grade 1/6 or 2/6
6) Systolic: limited to midystole
What are some indications that a murmur might be more pathological
-Murmur is present at rest or with activity- heard at all times
-Murmur remains loud through most of systole
-Additional auscultatory abnormalities are present
-Murmur radiates from the point of maximal intensity
-Murmur is loud (grade 3/6 or louder). Murmur is continuous or a diastolic component is also audible
How do you determine if a murmur in a young animal is innocent
Age: most will be gone by 12-16 weeks of age
Intensity: innocent should not be greater than grade III/IV
Change over time: should decline in intensity with growth, not increase/ unchanged
Location: innocent murmurs are typically left basilar
Presence of other signs: no other cardiac signs are present
*Check the 6 S’s
*If it doesnt fit do an echo
Is NT-proBNP a good indicator for ruling out innocent murmurs
not perfect at discriminating but potentially, not enough evidence at this time
Most of the time, patients with congenital heart disease are (asymptomatic/symptomatic)
asymptomatic
Congenital heart disease of the atrioventricular valves is commonly (regurgitation or stenosis)
regurgitation
Congential heart disease of the aortic valve is usually due to
subaortic stenosis
Congenital heart disease of the pulmonary valve is typically due to
stenosis
Congenital atrioventricular valve dysplasia is typically characterized by
short, tick chordae
valve leaflets do not coapt, leading to severe regurgitation
What are the clinical signs of atrioventricular valve dysplasia
1) Loud systolic murmur (mitral at left apex, tricuspid on right)
2) Arrhythmias common (atrial fibrillation)
3) Heart failure typically later in life
What will occur due to mitral valve dysplasia
typically signs of left sided congestive heart failure from thick fused mitral leaflets leading to severe left atrial enlargement
How might you fix mitral valve dysplasia
it is seldom perfromed-must cross atrial septum
balloon mitral valvuloplasty to tear the fused mitral leaflets
What breed is tricuspid valve dysplasia common in?
Labrador retriever- strong genetic
What congenital heart disease is the Labrador retriever the poster child of?
tricuspid valve dysplasia
A labrador retriever with tricuspid valve dysplasia will have
right sided CHF and often atrial arrythmias such as A-fib
How do you treat tricuspid valve dysplasia
can repair or replace valve by open heart surgery
What necropsy findings will you see in a dog with AV valve dysplasia
-Fused, malformed leaflets
-Shortened chordae tendineae
-Abnormal papillary muscles
With mitral valve dysplasia you will hear
loud left apical systolic murmur
*with cough, pulmonary edema= signs of left sided CHF
With tricuspid valve dysplasia you will hear
right sided systolic murmur
*with atrial arrythmias and pleural effusion, ascites = right CHF
What lesions will you see with congenital subaortic stenosis
1) Mild (raised nodules) to a thick ridge/band to a diffuse fibrous tunnel that obstructs blood flow under the aortic valve
2) Left ventricular hypertrophy develops secondary to pressure overload
3) Intramural coronary arteries are abnormal - arteriosclerotic wall thickening and luminal narrowing
4) Subendocardial ischemia from LB hypertrophy and coronary artery narrowing
5) Dilation of ascending aorta occurs secondary to turbulent blood flow and changes in tissue of the vessel wall
What changes to the intramurmal coronary arteries will you see with congenital subaortic stenosis
Intramural coronary arteries are abnormal - arteriosclerotic wall thickening and luminal narrowing
Why do you see subendocardial ischemia with congenital subaortic stenosis
Due to the aortic outflow obstruction, this causes the LV to hypertrophy
the coronary artery narrows
decreasing oxygen relative to the demand
You have a pug with congenital subaortic stenosis. On echo, you measure the velocity to be 6m/s across this. What is the pressure difference
Modified Bernoulli Equation: 4 * 6^2 = 144mHg pressure difference between the LV and the Aorta
LV is at a high pressure to push blood through the narrowing - working really hard and will likely have subendocardial ischemia from LV hypertrophy and narrowing of coronary arteries
Clinical findings of subaortic stenosis
1) ejection murmur is loudest over the aortic or subaortic area (left)
2) Loud murmurs: often loud over right base
3) Pulses- hypokinetic (late rising)
4) Respiratory signs may be present if CHF has developed
EKG: LVH and ST-T depression
Xray: LV hypertrophy and post-stenotic aortic dilation
Echo: Subaortic obstruction + LVH + Aortic Dilation
What will you see on EKG of a patient with canine subaortic stenosis
Increased R waves (LV enlargement)
ST depression: sunendocardial ischemia
PVC= ischemia risk for syncope and sudden death
What will you see on radiography in canine subaortic stenosis
1) LV hypertrophy/ enlargement
2) post-stenotic aortic dilation
Subaortic stenosis typically occurs in
medium to large breed dogs
(golden retriever, boxer, newfoundland, german shepherd, rottweiler, bullterrier
5 negative clinical signs of subaortic stenosis
1) Exercise intolerance
2) Syncope
3) Sudden cardiac death (arrhythmias)
4) Left sided CHF
5) Bacterial endocarditis
Subaortic stenosis is a risk factor for
bacterial endocarditis
-jet of turbulent flow takes away covering
How do you treat subaortic stenosis
*Mild AS is often normal life but severe could include
1) Beta blockers (atenolol) as cardioprotection so heart doesnt have to work as hard
2) Medical therapy of CHF (furosemide, pimobendan, ACE inhibitors, etc.)
3) Balloon catheter dilation of stenosis (more useful for aortic valvular stenosis)
4) Open heart surgery (rarely done or beneficial)
5) Antibiotic prophylaxis (dental/laceration)
Pulmonary Subvalvar obstruction can occur secondary to
RV hypertrophy (muscular obstruction)
What are lesions you see with canine pulmonary stenosis
1) Valve thickening/ leaflet fusion
2) RV hypertrophy
3) Post-stenotic dilation of pulmonary artery
What kind of dogs typically get pulmonary stenosis
small dogs (Bulldogs, beagles, terrier breeds, spaniel breeds, chihuahuas)
What physical exam findings will you see in canine pulmonary stenosis
1) Jugular Pulses: A wave or C-V wave
2) Cyanotic- if open foramen ovale (right to left shunting)
3) right sided CHF
What would you see on EKG of a dog with pulmonic stenosis
right axis deviation (S waves in leads 1,2,3 +/- increased P waves due to right atrial enlargement)
Negative leads (right side is increased)
What would you see on radiograph of a dog with congenital pulmonary stenosis
1) Increased RV size
2) dilated PA (post-stenotic)
3) RA enlargement
What would you see on echo of a dog with pulmonary stenosis
thick (dysplastic) valve leaflets, often fused and doming
-right ventricular hypertrophy and post-stenotic dilation of the pulmonary artery
What would you see on doppler examination of a dog with pulmonary stenosis
Increased ejection velocity across the pulmonary valve
-Turbulence in PA
-Pulmonary regurgitation
Pathophysiologic of Canine Pulmonary Stenosis:
1) ____________ murmur over PV
2) _________ murmur over tricuspid valve from _______
3) ___________ hypertrophy
4) Post-stenotic ________ of PA
5) __________ jugular venous pulses
1) Systolic murmur over PV
2) Systolic murmur over tricuspid valve from regurgitation
3) RV hypertrophy
4) Post-stenotic dilation of PA
5) Prominent jugular venous pulses
What are the effects in moderate to severe pulmonary stenosis
1) Exercise intolerance or syncope
2) Sudden (arrhythmic) death
3) Right sided CHF (ascites, pleural effusion)
4**) Cyanosis can develop due to high right atrial pressure (foramen ovale fails to close)
T/F: Endocarditis develops in patients with SAS
true
T/F: Endocarditis develops in patients with pulmonary stenosis
false- this is unlike SAS where they do develop endocarditis
How do you treat pulmonary stenosis
1) Balloon Pulmonary Valvuloplasty: to open the valve and relieve the stenosis. this will change the pressure difference and give better life expectancy
2) Pulmonary Valve Stenting- bulldogs or really fibrotic valves that wont open with balloon
Balloon Valvuloplasty has been shown to increase life expectancy of patients with ____________ but not _____________
good: Pulmonary stenosis
no effect: subaortic stenosis
Bulldogs often have an abnormal _________
coronary artery
-left coronary wraps around the pulmonary valve
In many bulldogs, the _________coronary artery wraps around the __________
left; pulmonary valve
Why should you not do balloon valvuloplasty to fix pulmonary stenosis in bulldogs
their left coronary artery that wraps around the pulmonary valve and if you inflate the ballon to fix the pulmonary stenosis, you can burst the coronary artery
You have a bulldog with pulmonary stenosis, how do you fix this
you shouldnt do baloon valvuloplasty because often times their left coronary artery wraps around their pulmonary valve and you might bursth the artery if you do this
*You should do pulmonary valve stenting instead
Coongenital AV valve dysplasia usually causes
regurgitation and CHF
diseases of the semilumnar valves are often
congenital (especially in dog)
stenotic congenital lesions lead to
concentric hypertrophy due to pressure overload
regurgitant congenital lesions lead to
eccentric hypertrophy due to volume overload
beta-blockers are cardioprotective and used in cases of congenital _____________ lesion
stenotic
5 negative outcomes of canine pulmonary stenosis
1) Exercise intolerance
2) Syncope
3) Sudden cardiac death (arrhythmias)
4) Right sided CHF (ascites, pleural effusion)
5) Cyanosis can develop due to high RA pressure (foramen ovale not closed)
an abnormal communication that allows blood to move between cardiac chambers (systemic and pulmonary circulation)
shunt
3 types of shunts
1) Patent Ductus Arteriosus
2) Ventricular Septal Defect
3) Atrial Septal Defect
In the fetal circulation, deoxygenated blood goes from the _____________ to the ___________ via the _____________ to the reach the placenta
In the fetal circulation, deoxygenated blood goes from the pulmonary artery to the aorta via the ductus arteriosus to the reach the placenta
oxygenated blood in the placenta returns through the ____________ and then goes across the __________ to the ______________
oxygenated blood in the placenta returns through the umbilical vein and then goes across the atrial septum to the left heart and body
Normally the ____________ closes within the first week of life becoming the __________
Normally the ductus arteriosus closes within the first week of life becoming the ligamentum arteriosus
when does the ductus arteriosus typically close
within the first week of life
What allows active closure of the ductus arteriosus after birth
smooth muscle
-persistent patency is a defect in this muscle
*absent muscle limits the constriction and closure
What allows for the ductus arteriosus to persist and not close
absent/defective smooth muscle limits the constriction and closure
What happens when the ductus arteriosus persist
1) Excessive amount of blood flow out of aorta into the pulmonary artery leading to wider pulse pressure and creates hyperkinetic pulse
2) Pulmonary Overcirculation
3) Aortic dilation “ductal bump”
4) L-R Continuous murmur
5) Increased venous return
6) LA dilation
7) LV eccentric hypertrophy / dilation
A PDA creates a (hyperkinetic/hypokinetic pulse)
hyperkinetic
With PDA, you see ________ hypertrophy of the _________
eccentric hypertrophy of the LV
What murmur do you hear with PDA
Loud, continuous machinery murmur
-flow during systole and diastole
-Aorta pressure is always higher than PA pressure
What do you see in the pulse of a patient with PDA
Wide pulse pressure (systolic-diastolic)
*Diastolic is really low
(diastolic run off into PA)
-Bounding/Waterhammer/ hyperkinetic
What would you see on radiography of a patient with PDA
1) Pulmonary overcirculation (artery and vein distended)
2) Left Auricle enlargement
3) LV enlargement
4) Ao dilation
5) Perihilar edema
What would you see on echo of a patient with PDA
LA, LV, and PA dilation
continuous turbulent high velocity flow (systole and diastole) entering the pulmonary artery
An uncorrected PDA has a
high probability of premature death
What is the prognosis with a small PDA
normal life span if closed
What is the prognosis with a large PDA
progressive myocardial failure from volume overload leading to CHF
T/F: a patient can develop atrial fibrillation from LA enlargement due to a PDA
true
What should you do to medically manage a patient with PDA and is symptomatic
Diuretics, ACE-inhibitors, pimobendan (if in congestive heart failure)
How do you fix a PDA
1) Surgical ligation: through left 4th intercostal space, lung retracted, careful dissection, and dougle ligerature
2) Intervention occlusion: minimally invasive via femoral artery with device that sits at narrowing of duct and causes closure of the connection
What is the surgical approach to ligation of PDA
left 4th intercostal space
What is the risk of surgical ligation of PDA
-Ductal tear and hemorrhage out of aorta
-phrenic nerve cut
-vagus nerve cut
*only should be performed by experienced surgeons
How can a reverse PDA develop
patients develop severe pulmonary hypertension from increased transpulmonary flow
If PA pressure rises to exceed Ao pressure the shunt may reverse direction
*Now deoxygenated blood is entering the aorta and going to body, resulting in differential cyanosis
How might a patient have differential cyanosis
if the PDA reverses to be R to L, due to pulmonary hypertension, you have deoxygenated blood entering the aorta and going to the body
Cranial half is pink, Caudal half is blue
With differential cyanosis due to reversed PDA,
Cranial half:
Caudal hald:
cranial: pink
caudal: blue
How come with reverse PDA, you only see cyanosis in the caudal portion of the body
Caudal portion where ductus comes in is cyanotic
crania portion of the body does not see that ductus flow because it enters behind the right subclavian artery
incomplete closure of interventricular septum during development leading to mixing of LV and RV blood
ventricular septal defect
If the ventricular septal defect is small, there is blood flow from
Left to Right
If the ventricular septal defect is large, there is
pressure equalization or reversal of shunt direction (Right to Left)
What are the effects of a ventricular septal defect
1) Pulmonary overcirculation- blood gets pushed out straight into pulmonary artery
2) Increased venous return
3) LA dilation
4) LV eccentric hypertrophy or dilation
5) L-R shunt loud systolic murmur on right side
What murmur do you hear with ventricular septal defect
L-R shunt loud systolic murmur on right side
You see ________ hypertrophy of the ________ with ventricular septal defects
eccentric hypertrophy of the LV
With VSD, harsh holsystolic murmurs are heard loudest on the
right side
Physical exam findings with VSD
-Harsh, holosystolic murmur- loudest on the right side
-Left apical murmury from MR (LV dilation)
-Pulmonary crackles may be present if CHF
-Diastolic murmur from aortic regurgitation may rarely be heard if VSD disrupts Ao rot
-Pulse quality is normal (strong if Ao regurgitation)
What are the radiographic findings seen with VSD
1) Pulmonary overcirculation (artery and vein)
2) LA enlargement
3) LV enlargement
4) Pulmonary edema
*virtually the same as PDA but you dont see the dilated aorta
What are the echocardiographic findings you see in a VSD patient
-Color determines turbulent flow
-Doppler shows velocity to predict the LV to RV pressure difference
-LV dilation, LA dilation, MR, AR seen with large defects
what is the prognosis of patients with VSD
Small holes are well tolerated and some close as the animal grows
-Large defects can head to CHF
-Pulmonary hypertension may develop, can cause shunt reversal if RV> LV pressure
When there is pulmonary hypertension that develops causing the shunt to reverse if RV > LV pressure
Eisengmenger’s physiology
Eisengmenger’s physiology
When there is pulmonary hypertension that develops causing the shunt to reverse if RV > LV pressure
What kind of cyanosis do you get if the VSD shunt reverses to be right to left
complete cyanosis (everywhere, unlike a PDA reversal)
PDA reversal causes _______ cyanosis while VSD and ASD reversal causes _______ cyanosis
Differential Cyanosis ;
Complete Cyanosis
What are the treatment options for VSD
-Nothing (small, restrictive defects)
-Medical therapy for CHF
-Surgical banding of pulmonary trunk
-Open surgical (rarely performed)
-Interventional procedures (only for certain defects)
a band that is tied around the pulmonary artery to increase right ventricular pressure in cases of patients with ventricular septal defects
pulmonary artery banding
Pulmonary artery banding functions to
increase RV pressure to limit the shunt flow across the ventricular septal defect, but does increase work of the right heart
What is the downside to pulmonary artery banding
it does increase work on the right heart
an opening in the interatrial septim leading to mixing of the LA and RA blood
normally L to R
Atrial septal defects
How might there be movement from right to left when an atrial septal defect is present
if there is an increase in right atrial pressure
1) Pulmonary hypertension
2) Pulmonary stenosis
3) TV dysplasia
*cyanosis present if reversed
Atrial septal defects can occur at
various locations in the atrial septum
What murmur do you hear with atrial septal defects
you do not hear a murmur across the hole
(low velocity as the LA is 5mmHg and RA is 3mmHg)
you do hear a systolic ejection murmur at the left base but only relative to pulmonary stenosis from increased flow
T/F: if RA pressure increases, cyanosis occurs in patients with atrial septal defects
true, this would reverse the shunt to right to left
RA pressure can be increased due to
1) Pulmonary hypertension
2) Pulmonary stenosis
3) TV dysplasia
What are the radiographic findings of patients with ASD
1) Pulmonary Artery enlargement
2) RA and RV enlargement
3) Pulmonary overcirculation (arteries and veins are larger)
Waht are the echo findings of patients with ASD
Dilation of the right heart (RA and RV) with left to right flow (from LA to RA)
verify the shunt with color or bubbles
-expect right heart dilation
With ASD, lung injury due to overcirculation lay lead to
pulomary hypertension and a reversed shunt causing cyanosis, erythocytosis, and related complication
How do you manage patients with ASD
1) Nothing if small defect
2) Medical if significant volume overload or CHF (diuretics, pimobendan, ACE inhibitor)
3) Occlusion devices (applicable to certain types of ASDs only)
4) Surgery for definitive repair (requires cardiopulmonary bypass)
a form of atrial septal defect where the fossa ovalis doesnt close at birth due to increased RA pressure
patent foramen ovale
At birth, the foramen ovale closes at birth due to
increased LA pressure and fusion of the atrial septae
What prevents the foramen ovale from closing
increased RA pressure
of concern in patients with pulmonic stenosis, tricuspid valve dysplaisa, pulmonary hypertension or other cause of RA pressure
What might result in increased RA pressure in the fetus and prevent the foramen ovale from closing
a) Pulmonic Stenosis
b) Tricupsid valve dysplasia
c) Pulmonary hypertension
d) other causes of elevated RA pressure
Normally the foramen ovale closes between
1-2 weeks of birth but may be prevented by high RA pressure
a constellation of defects, which include large VSD, pulmonary stenosis, RV hypertrophy, and aortic malposition leading to over-riding
rare in vet species but seen in dogs, cats, camelids, and goats
tetralogy of fallot
what 4 defects are present in tetralogy of fallot
1) Large VSD
2) Pulmonary stenosis
3) RV hypertrophy
4) Aortic malposition (larger)
What are the physical findings seen with tetraology of fallot
1) Systolic murmur of PS
2) There is not usually a VSD murmur because RV and LV pressures are nearly equal
3) Clinical cyanosis
4) History of collapsing spell, and weakness
What is the consequence of tetraology of fallot
deoxygenated blood goes out the left side of the heart to the body and the body responseds with erythrocytosis (increased erythropoietin)
PCV as high as >60%
What is a laboratory finding of tetralogy of fallot
PVC is often elevated >60%
Right to left shunt causes low blood O2 and the body’s response to low O2 is to increase erythropoietin.
Epo stimulates RBC production to increase oxygen-carrying capacity
What are the radiography findings seen with tetralogy of fallot
1) Dilated Aortic arch
2) Pulmonary hypoperfusion (undercirculation)
3) RV enlargement
you will see chronic hypoxemia and progressive erythrocytosis with
tetralogy of fallot
What are the complications of hyper viscosity seen with tetralogy of fallot
exercise intolerance
CNS injury
tachypnea
systemic thromboembolism
renal disease
sudden death
How do you manage patients with tetralogy of fallot
1) Regular control of PCV- if >65% do phlebotomy and/or chemotherapy (hydroxurea)
2) Beta-blocking agents (propranolol)
3) Ballon vavuloplasty of PS
4) Palliative surgical repair (shunt to connect left subclavian artery to PA)
5) Definitive surgical repair (cardiopulmonary bypass)
palliation to connect the left subclavian artery to the pulmonary artery to treat tetralogy of fallot
Blalock-Taussig Shunt
Blalock-Taussig Shunt
the shunt diverts some aortic flow to the pulmonary artery via the left subclavian artery in patients with tetralogy of fallot
-improves pulmonary blood flow and therefore brings more oxygenated blood back to left atrium
-Improved oxygenation in left heart lessens cyanosis and clinical signs
*Functionally we surgically create a PDA
What are the outcomes of Blalock-Taussig Shunt
1) improves pulmonary blood flow and therefore brings more oxygenated blood back to left atrium
2) Improved oxygenation in left heart lessens cyanosis and clinical signs
this shunt diverts some aortic flow to the pulmonary artery via the left subclavian artery in patients with tetralogy of fallot
