Small animal congenital cardiology + mitral valve + endocarditis Flashcards

1
Q

What is the only continuous murmur and wht does it sound like

A
  • PDA
    Louder in systole but present throughout
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2
Q

What is the different in tone of valve insufficiency/regurg murmur noise vs outflow obstruction from valve stenosis

A

Valve regurgitation = softer sound
Valve stenosis = harsher

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3
Q

Characteristics of physiological murmurs in puppies

A

Low grade and soft <3
Disappear or change when the puppy is moved around
Listen a few weeks later and will probably be gone

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4
Q

Which congenital heart diseases are more common in dogs vs cats

A

In dogs: pulmonic stenosis, subaortic stenosis, PDA
In cats: tricuspid dysplasia, ventricular septal defect

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5
Q

Signalment of pulmonary stenosis

A

Bulldogs, boxers, GSDs, small dogs … large range

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6
Q

Clinical signs of pulmonary stenosis

A

Left sided systolic heart murmur most intense at heart base
Normal pulse quality
Can lead to right sided CHF
murmur intensity correlates with stenosis severity

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7
Q

What are some consequences of severe pulmonary stenosis

A

Exercise intolerance
Syncope/collapse
Right sided congestive heart failure

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8
Q

Pathogenesis of pulmonary stenosis

A

Pulmonary valve diameter decreased so get pressure overload in the right ventricle
Leads to right ventricular hypertrophy

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9
Q

What are the three types of pulmonic stenosis and which is most common

A

Valvular stenosis is most common
ALso subvalvular/infundibular stenosis
Supravalvular stenosis very rare

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10
Q

What are the three types of pulmonic stenosis and which is most common

A

Valvular stenosis is most common
ALso subvalvular/infundibular stenosis
Supravalvular stenosis very rare

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11
Q

What are the two types of valvular stenosis

A

Type A = where there is pulmonic leaflet thickening and fusion; see parachuting movement due to fusion at the tips

Type B = where the valves and dysplastic and fused and the pulmonary artery is too narrow; this is the more aggressive phenotype

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12
Q

Which breeds do we tend to see anomalous prepulmonic coronary artery in (as a cause of subvalvular stenosis)

A

French and English bulldogs

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13
Q

What is anomalous prepulmonic coronary artery

A

Where both coronary arteries come from one orifice so one must go around the pulmonary artery to reach the correct ventricle, thereby strangling it

= Subvalvular/infundibular cause of pulmonary stenosis

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14
Q

How can we grade pulmonary stenosis

A

Via severity of right ventricular hypertrophy

Via doppler derived pressure gradients where mild is <50mmHg, moderate is 50-80 and severe is >80mmHg

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15
Q

Treatment of pulmonary stenosis based on severity

A

Mild = no treatment
Moderate; only treat if there is another associated cardiac abnormality
Severe = needs treatment; balloon valvuloplasty first line or surgery patch graft

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16
Q

When might we choose surgical patch graft rather than balloon valvuloplasty for pulmonic stenosis

A

In severly displastic valves
If they don’t respond to balloon valvuloplasty

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17
Q

How does a balloon valvuloplasty work

A

Use a balloon to dilate the stenosis and reduce obstruction
Access heart via jugular vein, measure stenosis using contrast to choose which balloon size, inflate balloon with saline and contrast so it ruptures the adhesions between valve leaflets

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18
Q

Potential complications fo balloon valvuloplasty

A

pulmonary regurgitation/insufficiency - this is less of an issue
Arrythmias

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19
Q

At what stage is it better to perform a balloon valvuloplasty for pulmonic stenosis

A

Early on in the asymptomatic phase as better outcome then when there is right sided failure

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20
Q

What is a contraindication for balloon valvuloplasty for pulmonic stenosis

A

Anomalous coronary artery due to risk of rupture

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21
Q

Whehn might transpulmonary stent implantation be indicated

A

In cases of anomalous coronary artery to keep valve leaflets open without risking coronary artery rupture

In severe cases with unsuccessful balloon valvuloplasty or re-stenosing

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22
Q

What is the pathogenesis of patent ductus arteriosus

A

When the ductus arteriosus doesn’t close after birth, blood shunts from the aorta to the pulmonary artery (from higher to lower pressure)
So goes back around lungs
Get overloading of lungs causing congestion

Issue of volume overload

Left ventricle becomes dilated to accommodate extra blood

Then get backwards congestion to capillaries and pulmonary oedema

= L sided CHF

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23
Q

What is the normal ratio of width or right to left ventricle

A

1:3

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24
Q

What do chicken fat bloot clots suggest about the animal

A

It was anaemia (or there was prolonged agony)

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25
Q

In which breed is PDA an inherited trait

A

Poodles

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26
Q

Which breeds do we commonly see PDA in

A

Poodles
Chihuahua, mlatese pom

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27
Q

What is the cause of ‘nutmeg liver’

A

Right sided CHF where there is backing up of bressure from right atrium to caudal VC and liver

= due to centrolobar congestion causing hypoxia, degeneration and necrosis of centrolobulary hepatocytes

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28
Q

Which breeds most commonly have persistent foramen ovale

A

Boxers, Dobermans, Samoyed

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29
Q

Which breeds do we see ventricular septal defects in more commonly

A

English bulldog
English springer
WHWT

30
Q

How does the heart septum form (two parts)

A

Septum membranosum comes from the base of the heart while septum muscularis is from the apex

Defect in the septum membranosum is more common

31
Q

Which breeds do we see tetralogy of fallot in most

A

Keeshonds (inherited)
English bulldogs (congenital)

32
Q

What are the primary and secondary defects in tetralogy of fallot

A

Ventricular septal defect
Pulmonic stenosis
Dextraposition of aorta

Secondary defect = hypertrophy of right ventricle

33
Q

Which breeds is pulmonic valvular stenosis inherited in

A

Beagle, English bulldog, Chihuahua

34
Q

What does the heart look like in pulmonic valvular stenosis

A

Valves are thickened white and less elastic
There is blood overload in the right venitrcle leading to right ventricular concentric hypertrophy

35
Q

What two things could happen in subaortic valvular stenosis

A

Normal response is concentric hypertrophy of left ventricle
Can get dilation instead; this is worse

36
Q

WHat breeds is subaortic valvular stenosis more common in

A

Boxer (inherited)
Newfoundland, GSD

37
Q

What signs do we notice with persistent right IV aortic arch

A

= vascular ring over oesophagus so see megaoesophagus and regurgitation at weaning

38
Q

What is the most common cardiovascular disease in dogs

A

Myxomatous mitral valve disease

39
Q

How does MMVD work

A

Get progressive degenerative lesions to the mitral valve (accumulation of proteoglycans in leaflets causing thickening)
-> Leads to mitral regurgitation and secondary volume overload of the left heart i.e increase in preload

This chronic volume overload causes eccentric hypertrophy and chamber dilates

40
Q

When does mitral valve disease progress to heart failure

A

When unable to compensate

41
Q

How does MMVD lead to pulmonary oedema

A

Get progressive LV and LA dilation via eccentric hypertrophy
Increase in left atrial pressure

When this becomes high than the pulmonary venous pressure causes congestion and pulmonary oedema `

42
Q

What are common sequelae of MMVD

A

**Left sided congestive heart failure i.e pulmonary oedema

**Arrhythmias esp atrial fibrillation following enlarged LA

Can see left atrial tears or septal defect
Pulmonary hypertension

43
Q

What are the stages of mitral valve disease

A

A = predisposed i.e cavalier king charles spaniel

B = preclinical disease
> B1 means there is mitral regurgitation but no secondary remodelling
> B2 means there has been remodelling so see LA and LV dilation

C = congestive heart failure

D = refractory CHF

44
Q

Which breeds are predisposed to MMVD

A

Mostly small breeds
Middle aged to older

Can see in large breeds where it tends to progress quicker

45
Q

What do we see in history and clinical exam of stage B MMVD dogs

A

ASymptomatic
May have a cough/resp disease that isn’t due to heart failure i.e from enlarged atrium compressing the trachea

Left apical systolic murmur

46
Q

What do we see in history of stage C CHF dog MMVD

A

Murmur in history
Now increased resp rate and effort
Cough
Exercise intolerance
Lethargy
Collapse/syncope.
+ may have weight loss etc

47
Q

What do we see on clinical exam in MMVD dogs stage C

A

Murmur
Tachynoea
Dyspnoea
Tachycardia
Tachyarrhythmias

May see signs of right sided congestive heart failure too

48
Q

What do we look for on a heart echo

A

Identify the cause of the murmur i.e assessing for mitral regurgitation

Assessing for seconadry cardiac remodelling to stage the disease

Identify any comorbidities

49
Q

What measurements do we take on a cardiac echo to assess for remodelling

A

Left ventricular size
Left atrial size (want La:Ao <1.6)

50
Q

What imaging modality is gold standard for diagnosing pulmonary oedema in stage C MMVD

A

Radiography because can look for concurrentr esp disease suggesting pulmonary oedema and stage C

+ can try to assess for cardiomegaly via vertebral atrial size and heart size to stage B1 vs B2

51
Q

What does BNP tell us about

A

Stretch on the heart
But takes a long time to get results and no cut off currently to stage between B1 and B2

52
Q

Treatment for stage B1 MMVD

A

No treatment
Recommend biannual auscultation and imaging repeated

53
Q

Treatment for stage B2 MMVD

A

Pimobendan
+ start monitoring the resting respiratory rate and effort at home; should be below 30

Take care with fluids during GAs

54
Q

How does pimobendan work

A

PDE III inhibitor, calcium sensitsor, positive inotrope, arterial and venous dilator

55
Q

What will owners report as an animal progresses from stage B2 to C

A

Slowing down, coughing, resting resp rate has increased, increase in heart rate, higher murmur intesntiy

Confirm with X rays looking for pulmonary oedema

56
Q

What should we do if we get unstable heart failure case to diagnose

A

Just avoid sedating for X rays and start treating without them

57
Q

What drug do we add in to threat MMVD stage C

A

Furosemide diuretic

58
Q

What do we see on a radiograph on stace C MMVD

A

Marked cardiomegaly with left atrial dilation

Diffuse bronchointerstitial lung pattern

Pulmonary oedema?

59
Q

What extra drugs can we add in to treat heart failure once stable on diuretics and pimobendane

A

ACE inhibitors

60
Q

What other possible condition must we excluse before starting diuretics if we se effusions and right sided CHF failure signs

A

Pericardial effusion and cardiac tamponade

61
Q

with CHF we should avoid diets high in what

A

Sodium

62
Q

What is endocarditis and what organisms are typically involved

A

Bacterial infection of endocardial surface of the heart; due to bacteraemia and endothelial damage allows bacteria to lodge

Key = CONCURRENT pathology creating risk factors for endocarditis

Involves staph, strep, E coli, pseudomonas, bartonella

63
Q

What is the typical presentation of endocarditis

A

Medium to large breed dogs
New murmur typically a red blad, arrhtyhmias, CHF

64
Q

What are some potential consequences of endocarditis

A

Thromboembolic event
Valve regurgitation
Myocarditis
Arrhtymias
Immune stimulation

Can quickly go from no regurgitation to severe regurgitation so there is a risk of sudden onset heart failrue

65
Q

Diagnosis of endocarditis

A

No definitive test: key = try blood culture, aspectially taken 3 times for 3 different veins ~30 mins apart

  • Do clinical exam
  • Haem/biochem for inflammatory markers
  • Echo
  • ECG
  • Thoracic radiographs
66
Q

What is the modified Duke’s criteria for endocarditis definitive vs possible result (in terms of number of major vs minor critera)

A

Definitive result = 2 major critera or 1 major and two minor
Possible result = 1 major and 1 minor; or 3 minor

67
Q

What are major criteria for endocarditis

A

Positive echo i.e vegetative lesions on valve

Positive blood culture on at least 2 cultures (or 3 if risk of skin contamination)

New valvular insufficiency

68
Q

What are minor criteria for endocarditis

A

Fever
Medium/large breed
Subaortic stenosis
Thromboembolic disease
Immune mediated disease
positive blood culture but not meeting major criteria
High bartonella serology

69
Q

Treatment for endocarditis

A

Antibioitics IV for a few days
Anti-thrombotics e.g clopidogrel to reduce risk of thromboembolic events
Treat the heart failure

70
Q
A