Cardiology: Congenital Heart Disease Flashcards

1
Q

Use the following table to match up the following causes of murmurs
* Pulmonic stenosis
* Aortic Stenosis
* VSD
* Mitral dysplasia
* Tricuspid dysplasia
* PDA

A
  1. PDA- continuous left heart base, dorsal/forward
  2. Aortic stenosis- left base 4th IC, weak pulse
  3. Pulmonic stenosis- left base 3rd, radiates up IC space
  4. VSD- cranioventrally on right
  5. Mitral dysplasia- left MV 5th IC
  6. Tricupsid- right, 4th IC
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2
Q

What is an innocent murmur?

A

Puppies and kittens may have soft systolic heart murmur- left heart base
Should disappear by 20 weeks old

Due to change from foetal haemoglobin to adult

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3
Q
  1. What is a patent ductus arteriosus?
  2. What does it cause?
  3. What breeds are predisposed?
  4. What is the characteristic murmur sound?
A
  1. The ductus arteriosus fails to close at birth
  2. Causes a shunt between aorta (high pressure) to pulmonary trunk (low pressure)- left to right
  3. GSDs, Collies, CKCS, Bichon- females more common
  4. Waxing through systole and waning through diastole- high and cranial in the axilla (pit) left
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4
Q

Describe what happens with a PDA and therefore the effects?

A
  • Shunt from descending aorta to pulmonary artery- aortic pressure exceeds PA pressure- continuous
  • Lung field over-circulated
  • Increased volume of blood to left side of heart (L volume overload)
  • LA and LV enlargment (eccentric hypertrophy)
  • Femoral pulse may be ‘bounding’
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5
Q

What happens if a PDA is untreated?

A

Results in left sided congestive heart failure and LV myocardial failure before the dog is 7

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6
Q

What is eisenmenger’s physiology?

A
  • Rarely a PDA with pulmonary hypertension can cause the shunt to reverse
  • murmur stops being continuous
  • Animal may show cyanosis- possibly on exertion
  • Common in cats
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7
Q

What are the different diagnostic tests that can be used for heart disease?

A
  • Thoracic radiographs
  • ECG
  • Doppler Echo
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8
Q

What do the following diagnostic tests show for PDA?
1. Thoracic radiographs
2. ECG
3. Doppler Echo

A
  1. LAE, LVE, pulmonary overcirculation- ‘triple knuckle’ on DV- aortic arch, PA and left auricular appendage
  2. Often very tall R waves, Evidence of LAE, LVE
  3. Difficult- Diastolic turbulence in the PA
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9
Q

How is PDA treated?

A

Curable if early
* Surgical ligation of PDA
* Device based- keyhole, ACDO- encourage clot formation
* Do not close Eisenmengers physiology

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10
Q
  1. What is the most common congenital heart defects in dogs?
  2. What breeds are predisposed?
A
  1. Aortic stenosis
  2. Boxer and newfoundland
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11
Q
  1. What can cause aortic stenosis?
  2. What does it result in?
A
  1. Can be valvular or sub-valvular- lesions rane from ‘nodules’ to a complete or partial circumferential fibrotic band or muscular ridge
  2. Pressure overload on the LV resulting in LV concentric hypertrophy
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12
Q

What are the clinical signs of Aortic stenosis?

A
  • Syncopal episodes and excercise tollerance- consequence of obstruction
  • If coronary perfusion compromised- hypoxic myocardium- sudden death
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13
Q

Where is the point of maximal intensity of aortic stenosis?

A

Left base- murmur grade correlated with disease severity

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14
Q

What do the follownig diagnostic tests show for aortic stenosis?
Thoracic radiograghs
ECG
Doppler echo

A
  • Thoracic radiographs- unremarkalbe- aortic post-stenotic dilation sometomes
  • ECG- may be unremarkable or evidence of LVE and hypertrophy, ventricular premature complexes
  • Doppler
    2D subvalvular or valvular lesions, post-stenotic dilatoin
    Colour doppler shows turbulence in LV outflow
    Recording velocity of aortic outflow, diagnostic- normal velocity <1.7m/s, Velocities of >2 m/s
    Modified bernouilli can convery velocity into pressure gradient
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15
Q

What is the modified bernouilli equation?
What pressure gradients show different levels of stenosis?

A

PG = 4V^2
PG < 50mmHg- mild stenosis
PG 50-80 mmHg represents moderate stenosis
PG > 80mmHg indicated the presence of severe stenosis

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16
Q

With breed schemes for boxers and newfoundlands what grade of heart murmurs are allowed for breeding?

A

Boxers with no or grade 1/6 are acceptable for breeding
2/6 with echocradiography can pass if aortic velocity <2m/s

Newfoundlands- doppler aortic velocity <1.7m/s (subcostal view)

17
Q

What is the treatment/managment for aortic stenosis?

A
  • No real treatment
  • Betablockers may be effective- no evidence
  • Arteriodilators are contraindicated- increase PG
  • High pressure baloon valuloplasty have been used- no long term data
18
Q

Is pulmonic stenosis fairly common in dogs or cats?

A

Dogs

19
Q

What breeds are predisposed to pulmonic stenosis?

A

Bulldogs, boxers, bull mastiffs, cocker spaniels, west highland white, beagles

20
Q

What are the different causes of pulmonic stenosis?

A
  • Usually valvular
  • Type A- fused leaflets normal diameter
  • Type B post-stenotic dilation, dysplastic thickened leaflets
21
Q

What does pulmonic stenosis cause?
What are the presenting signs?
What murmur is often present?

A
  • Increased pressure load on the RV causes concentric RV hypertrophy
  • Increases RV pressure
  • Presenting signs- excercise intollerance, lethargy, asymptomatic
  • Systolic ejection type holosystilic murmur most intense over pulmonic valve
22
Q

What do thoracic radiographs, ECG and Doppler echocradiohraphy show for pulmonic stenosis?

A
  • Thoracic radiographs- right sided enlargment (increased sternal contact, reverse D), post-stenotic dilation of PA
  • ECG- RVE and hypertrophy (deep S waves in I, II and aVF)
  • Doppler- pressure overload in RV, IVS flattened/pushed to LV, valves (fused or dysplastic)
    Peak pulmonic velocity confirms the diagnosis
23
Q

How can pulmonic stenosis be treated?

A
  • Treatment of severely affected usually involved balloon valvuloplasty or the pulmonic valve- more successful in type A ps
  • Aim to reduce gradient by 50%
  • Some bull breeds have coronary artery abnormalities- needs to be excluded
  • Untreated leads to right sided congestive heart failure
24
Q

What two conditions have a similar pathophysiology to pulmonic stenosis?

A

Supravalvular stenosis- stenosis distal to pulmonic valves- frenchies
Infundibular stenosis or double-chambered right ventricle- stenosis below pulmonic valve and in infundibulum or RV

25
Q

Where are ventricular septal defects normally located?

A

Peri-membranous septum
‘between’ the aortic and tricuspid valve leaflets

26
Q
  1. What shunt nd murmur is caused by VSD?
  2. What species and breeds are presdisposed?
A
  1. Left to right shunt- point of max right hemithorax
  2. Most common defect in cats, not common in dogs- WHWT, cockers
27
Q

What is strange about the murmur grade of VSDs?
What are the effects on the heart with VSDs?

A

Murmur grade is inverselt proprortional to the size of the defect- smaller is louder
Left to right shunt- RV overloaded- pulmonary over-circulation, blood returns to LA/LV (overload)

28
Q

What do radiograhs, ECGs and Doppler echo show for VSDs?

A

Radiographs- LVE, LAE RVE, pulmonary overcirculation (increased size of lobar vessels)

ECG- may be normal, or show biventricular enlargment (deep Q, tall R), left atrial enlargment (P mitrale)

Echo
Colour flow detects shunt
Velocity is inversely proportional to the size of the defect (over 4m/s not associated with disease)

29
Q

What are the different sequelae to VSDs?

A
  • In many dogs/cats not significant
  • Rare reports of closure
  • Occasionally aortic valve leaflet may prolapse into defect- aortic incompetance
  • Significanct left to right shunting- left sided heart failure
30
Q

How can VSD cause Eisenmenger’s syndrome?

A
  • With significant left to right shunt, pulmonary hypertension may develop
  • Pulmonary hypertension results in increased RV pressures reversing shunt
  • Animals with right to left shunt may become polycythaemic
31
Q
  1. What breeds are predisposed to mitral valve dysplaysia?
  2. How does mitral valve disease appear grossly?
  3. Why can left atrial enlargment sometimes occur?
  4. What is the result?
A
  1. Cats and dogs- bull terriers, great danes, golden retrivers, GSD, springers
  2. Mitral valve appear grossly dysplastic
  3. Mitral valve can be stenotic
  4. Left sided heart failure- arrythmias may result

Managed the same as MDVD

32
Q

What breeds are most commonly affected by tricuspid valve dysplasia?

A
  • Can affect dogs and cats- not common
  • Labrodor most commonly affected
  • Pedigree cats more common
33
Q
  1. What causes tricuspid valve dysplasia?
  2. Describe the causes pathophysiology?
  3. How does the murmur present?
  4. What is the end effect?
  5. How is it treated?
A
  1. Tricuspid valve more apically displaced than normal
  2. Tricupsid regurgitation, right sided volume overload
  3. Right sided heart failure
  4. Treatment for CHF and arrhythmias
34
Q

What are the effects of an ASD?
How can it be diagnosed?

A
  • Not normally haemodynamically significant
  • Shunting left to right

Genuine defect using 2D shows a ‘match stick’ sign- edges of the defect are thickened and mroe echogenix

35
Q

What are the components of a tetralogy of fallot?

A
  • Pulmonic stenosis
  • Right ventricular hypertrophy
  • VSD
  • Dextrapposed aorta
36
Q

What are the effects of the tetrallogy of fallot?

A

Pulmonic stenosis- high RV pressure
Shunt from L to R when RV exceeds LV
Flow from RV may exit to dextrapposed aorta straddling the VSD
Animals cyanotic- fails to respond to O2 supplementation

37
Q

What is a vascular ring anomalie?

A

Persistent right 4th aortic arch- results in vascular ring surrounding oesophagus, patients show regurgitation and mega-oesophagus

38
Q
A