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)