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Small Animal Final Year > SA Endocardial Disease > Flashcards

SA Endocardial Disease Flashcards

1
Q

Why is valvular disease important?

A
  • The most common cause of heart failure in the dog
  • Will likely see this everyday!
  • 90% + of heart disease and failure will be due to degenerative valve disease
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2
Q

What is the most common cause of heart failure in the dog?

A

Valvular disease

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3
Q

Describe what can be seen on this radiograph

What is the cause?

A
  • Acute decompensated patient
  • Can see enlarged cardiac silhouette – it’s a progressive disease, valves degenerate and they will get worse and worse but this animal will compensate for a long time often before it develops clinical signs of congestive heart failure
  • Air bronchograms
  • Acute onset pulmonary oedema associated with valve disease
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4
Q

What is the acquired form of valvular disease?

A
  • Chronic degenerative valvular disease (CDVD) – most common thing we see. Called lots of different things
  • Endocarditis (rare) – covered later. Is seen from time to time but they don’t usually present as a dog with heart disease, just present as sick animal with heart murmur
  • Traumatic injury (very rare)
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5
Q

What is the congential form of valvular disease?

A

•Valve dysplasia

–Insufficient valve

–Stenotic valve

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6
Q

What are some other names for chronic degenerative valvular disease (CDVD)?

A

•Chronic (mitral) valvular disease (CVD)

–It affects tricuspid valve as well usually!

  • Chronic degenerative valve disease (CDVD)
  • Endocardiosis
  • Myxomatous mitral valve disease

–Myxomatous describes pathological change histologically, infiltrated with this myomatous tissue

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7
Q

What is the pathology of chronic degenerative valvular disease (CDVD)?

A
  • Myxomatous degeneration of Mitral valve and/or Tricuspid Valve
  • 60% MV only, 30% both, 10% TV only
  • Rarely affects aortic / pulmonic valves
  • Thickening and redundancy of heart valve leaflets

–More of valve leaflets gets incorporated over time

  • Most pronounced at the free margins of the valves
  • Area becomes thickened
  • Prominent nodular thickenings
  • CDVD results in valve leaflet and CT abnormalities. Lengthening of the CT and redundancy of the CT and laxity of the valve leaflets. This leads to MV prolapse. 1st see prolapse then thickening of the leaflet edges which then curl on themselves.
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8
Q

What is the histopathology of the valve structure?

What happens when they are diseased?

A
  • Valve structure – 4 distinct layers histologically to the valve, thin layer on top and bottom – bulk of valve consists of 2 internal layers, dibrosa more robust part of valve and is continuous with chordinae tendonea.
  • Once disease develops, it can go on to affect cordinae tendonae as well
  • The elastic fibres between the spongiosa and atrialis spilt and separate. Spongiosa increases in size while the fibrosa layer of the valve degenerates. Increase in ECM. Fibroblasts in the spongiosa proliferate forming swirls and small nodules. In the fibrosa layer the collagen bundles become swollen and hyalinised fragment and vanish. In severe cases only scattered remnants of the fibrosa remain. Similar changes in the CT.
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9
Q

What nerves are within heart valves?

A

Autonomic nerves within the valves

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10
Q

What is the Whitney classification of valvular disease?

A

•Whitney classification

–Class I – small discrete nodules along edge of valve

–Class II – thickened free edges and irregular

–Class III – valve edges are grossly thickened and nodular with extension of lesions to the base of CT

–Class IV – Further severity of Class III lesions

•Whitley classified the progression of the disease into 4 classes. Class I lesions are small, discrete nodules along the edge of the valve leaflet. The lesions coalesse to form larger deformities toward the free edges of the leaflet. Class II the free edges are thickened and the edges become irregular and more thickened as the disease progresses. Some thickened CT are thickened where they attach to the valve. Class III valve edges are grossly thickened and nodular the thickening extends part way and sometimes all the way to the base of the CT . In class 4 further severity of class 3 lesions

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11
Q

What is wrong with this heart?

A

Typical nodular thickenings, this is severe, advanced pathology – this valve wont be very effective as big gaps in it! As blood regurgitates to atrium as a result, we get damage to atrial wall and causes jet lesions which weaken the wall and this atrial wall may rupture

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12
Q

What does stroke volume = ?

A

Stroke volume = End Diastolic Volume – End Systolic Volume

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13
Q

How is the stroke volume regulated?

A
  • Pre-load – degree of stretch on the heart before it contracts (amount of blood coming back)
  • Contractility – forcefulness of contraction of the individual ventricular muscle
  • After-load – pressure that must be exceeded before ejection of blood from ventricles
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14
Q

What are some factors that can increase stroke volume?

A

Increased pre-load

Increased contractiliy

Decreased afterload

  • leads to increased stroke volume which then goes on to increase cardiac output -
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15
Q

What are some things that can cause increased heart rate?

A

ANS (increased sympathetic activity, decreased parasympathetic activity

Hormones - catecholamines, thyroid hormones

Other factors - low physical fitness, age, increased body temperature, female

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16
Q

What are some things that can increase pre-load?

A

Increased end-diastolic volume (stretches heart)

Cardiac muscle fibres contract more forcefully

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17
Q

What are some things that can increase contractility?

A

Positive inotropic agents - increased sympathetic stimulation, adrenaline, increased extracellular calcium

This leads to an INCREASED FORCE OF CONTRACTION

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18
Q

What can decrease after-load?

A

Decreased arterial blood pressure during diastole

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19
Q

When are systolic murmurs often heard?

A

S1 and S2

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20
Q

What is the signalment for valvular disease?

A
  • Middle to old age
  • Small breeds

–Cavalier King Charles

–Poodles

–Maltese etc.

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21
Q

Which heart disease are small breeds dog more disposed to?

A

Chronic valvular disease?

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22
Q

Which heart disease are large breeds dog more disposed to?

A

Dilated cardiomyopathy

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23
Q

What is the typical congestive heart failure history?

A
  • Increased respiratory rate and effort
  • Coughing (often during night / early morning)
  • Exercise intolerance
  • Often one of the first things the owners will describe
  • Decreased appetite
  • May have had a heart murmur for years, technically it has heart failure at this point! But we treat congestive heart failure which is when oedema starts falling. These dogs become a problem when they develop congestive heart failure
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24
Q

What is the initial diagnostic work up for a dog with suspected heart disease?

A
  • Should have high index of suspicion
  • Auscultation:
  • Murmur
  • Systolic
  • Is valve disease to cause heart failure they will have a very loud murmur
  • Tachycardia
  • Arrhythmias
  • Pulmonary crackles
  • Oedema
25
Q

What are the grades of heart murmurs?

A
  • Grade I – quiet only heard after few minutes in a quiet room
  • Grade II – quiet but easily audible
  • Grade III – same intensity as the heart sounds – easy to hear
  • Grade IV – a murmur louder than heart sounds but no precordial thrill
  • Grade V – very loud murmur and precordial thrill present. Precordial thrill vibration felt on chest wall due to transmission from turbulent blood flow.
  • Grade VI – murmur audible when stethoscope removed from chest wall
26
Q

Where are you most likely to hear a murmur of mitral insufficiency?

A
  • Point of maximum intensity will be over the left apex (MV area)
  • Radiates dorsally and to right thorax
  • Confuses TR identification
27
Q

Does murmur grade indicate severity?

A

Murmur grade approximately indicates severity (but there are exceptions) – as disease gets worse, murmur gets louder until right at the end when it gets really bad and often goes more quiet again

28
Q

What kind of things should you be checking to check whether there is significant heart disease or not?

A
  • Grade III murmur or louder (without anaemia)
  • Heart rate >120bpm
  • Loss of sinus arrhythmia

–Resp sinus arrhythmia. Small breed dog, murmur and coughing but still has sinus arrhythmia, its not in heart failure

  • Precordial thrill
  • Dysrhythmia +/- pulse deficits
  • Weight loss?
29
Q

What are some things that would cause heart disease to be on your differential diagnosis lidt?

A
  • Cough
  • Breathlessness

–Pleural effusions

–Cats typically present acute onset as breathlessness as they hide their earlier clinical signs well

  • Exercise intolerance
  • Dogs with LHS heart failure will cough.
  • Cats with heart failure rarely cough!
30
Q

What things should you do as part of your diagnostic work up for heart disease?

A
  • Depends largely on what the owner wants to do…
  • Thoracic Radiographs

–See what changes there are in the heart as a consequence of the disease

  • Echocardiography
  • Electrocardiogram
  • CBC, Biochemistry is important
  • Urinalysis can be helpful
  • Bronchoscopy

–Wont usually! But if not sure if there is an airway involvement you might do this

31
Q

What is essential for the diagnosis of congestive heart failure?

A

RADIOGRAPHS

  • ESSENTIAL for dx of CHF
  • Cardiac enlargement
  • Engorged pulmonary vessels
  • Pulmonary oedema (L-CHF)
32
Q

Describe this radiograph

What is a likely clinical sign?

A

Is patient with a cough, must be some form of airway irritation

Enlarging LA in this disease compresses left stem bronchus, that’s what causes the cough.

LHS heart failure causes a cough

Left mainstem bronchus compression due to enlarged LA

33
Q

Describe what is going on in this radiograph

A

Acute left sided failure

Elevated trachea

Oedema (alveolar pattern) causing loss of line of diaphragm, border obliteration – notice how it is almost all in the diaphragmatic lung lobe – little oedema in cranial lungs, interesting that when dogs develop pulmonary oedema due top LHS failure its almost always here

34
Q

What are some radiographic abnormalities of left sided cardiomegaly?

A

–Straightening of distal trachea

–Increased cardiac silhouette height

–Straightening of caudal border of the heart and loss of cardiac waist

–Tenting of LA

–Splitting of mainstem bronchi

–Bulge on cardiac silhouette at 2-3 o’clock

35
Q

What are some radiographic abnormalities of right sided cardiomegaly?

A

–Dorsal deviation of trachea

–Increased sternal and diaphragmatic contact

–Reverse ‘D’ shape on DV

–May see generalised cardiomegaly as usually concurrent with MR

–Signs of RCHF eg ascites, pleural effusion

–Right sided changes will ALWAYS be in associated with left sided changes

36
Q

When does heart disease become heart failure?

A

–Cant have heart failure without heart disease

–Dogs must have a murmur or a dysrhythmias or a gallop etc. – tells us we have underlying disease

–Cardiac output will be compomirsed with significant heart disease, then compensatory mechanisms set in. body does not like BP falling, detected by baroreceptors and activation of renin-angiotensin system etc. to try and get it back up

–Disease gets worse with time and eventually get congestive heart failure:

  • Left sided – pulmonary oedema
  • Right sided – ascites, pulmonary effusion
  • Animal has been in failure since it has been compensating for the heart disease – will be spoken about at another point more so
37
Q

What radiographic abnormalities can you see with right sided enlargement?

A

•Right sided heart enlargement

–Dorsal deviation of trachea

–Increased sternal and diaphragmatic contact

–Reverse ‘D’ shape on DV

–May see generalised cardiomegaly as usually concurrent with MR

–Signs of RCHF eg ascites, pleural effusion

–Right sided changes will ALWAYS be in associated with left sided change

38
Q

When would you use echocardiography?

A
  • Use this if you want to diagnose type and extent of underlying heart disease
  • Function analysis
  • Does NOT dx CHF! It will tell you how well it is functioning and allow us to identify the failing part
39
Q

How can we use ultrasonography to see if the heart atria have increased or not?

A

Heart base where aorta is bang in the middle view witll allow us to determine if atrial size has increased or not

40
Q

What can be seen on this echo image?

What view is it?

A

Echo image of thickened mitral valve

41
Q

How can we tell is the atrium is big on US?

What should the ratio from the aorta to the atrium be?

A

Is the LA big? We want to know that! With this view, we can get aorta right in the middle. Comparing size of aorta to size of LA, in normal animal the ratio is that the LA should not be bigger than 1.4x the size of the aorta.

42
Q

Describe the problem here

A

Dilated Cardiomyopathy

DCM

This sort of picture in dog with chronic valve disease, this is a poor prognostic sign

43
Q

Describe the problem here

A

Chronic Mitral Valve Disease

CVD

Right parasternal short axis view. M mode – allows us to measure size of ventricle in diastole and systole.

44
Q

If the animal has a dysrhythmia, what diagnostic test should you use?

A

If animal has a dysrhythmia, then probably need an ECG!

45
Q

What would you use electrocardiography to see?

A
  • +/- tachycardia
  • sympathetic stimulation with CHF
  • +/- arrhythmia
  • APCs, atrial fibrillation are common complications of valve disease
  • Changes in complex morphology
  • If animal has a dysrhythmia, then probably need an ECG! Atrial premature
46
Q

Describe what is going on with this ECG

A
  • HR 160bpm
  • Irregularly irregular
  • P for every QRS
  • QRS for every P wave
  • Complex 8 arrived early
  • Same QRS morphology
  • P wave buried in preceding T wave
  • Tall R waves – LV enlargement
  • Wide P waves – P mitrale – LAE Dx
  • APC secondary to CDVD most likely
  • Its following the conducting system so it’s a supra-ventricular premature complex
47
Q

With heart disease, what would you use blood tests for?

A
  • Haematology
  • Anaemia, polycythaemia, WBC count
  • Biochemistry
  • Renal, liver disease, other systemic Dx
  • Once we start treating these cases biochem becomes very important
  • Cardiac biomarkers
    • ANP, BNP, Troponins
48
Q

Name some complications of heart disease

A

•Ruptured chordae tendonae

–If they do, the animal will go into severe left sided congested failure. Will be coughing up pulmonary oedema, froth, and needs acute treatment

•Intractable cough

–Can be difficult to manage

•Pulmonary Hypertension

–RV trying to eject blood into vascular bed weith higher pressure than usual, so RV struggled to deliver blood to lungs

•Pericardial effusion due to left atrial tear

–This complication becoming more commonly seen as these dogs are living a lot longer

–These dogs often die suddenly

•Tussive syncope

–When they cough, changes in pressure of thorax

–They faint

•Resp difficult with big heart – simply acts as space occupying lesion and restricts ability to breathe! Not always pulmonary oedema

49
Q

How do ruptured chordae tendonae often present?

A

•Frequently present as an acute emergency, severe fulminant LCHF

–Severe dyspnoea

–Stressed – panicking (owner and dog!)

–Cyanotic

–Life threatening

50
Q

What is your diagnosis?

What view is it?

A

Right parasternal long axis view

Flailing mitral valve leaflet, everytime ventricle contracts, valve flicks up into atrium, so a massive regurgitation

51
Q

What are the main causes of pulmonary hypertension?

A

1.Alveolar hypoxia with pulmonary vasoconstriction / remodelling

–Severe respiratory disease e.g IPF, neoplasia etc

2.Pulmonary vascular obstructive disease

–Pulmonary thromboembolism

–Heart worm disease

3.Pulmonary overcirculation

–Large congential shunts

4.High pulmonary venous pressure

–Left sided heart failure of various causes

–Chronic exposure of RV to high venous pressures because of LHS failure

5.Idiopathic

52
Q

What is wrong on this specimen?

A
  • Pericardial effusion
  • Can present with acute tamponade
  • Avoid pericardiocentesis if possible as risk of moving clot
  • Atrial tear
53
Q

Wha tis tussive syncope?

What breeds is it most common in?

A
  • Usually small breed dogs associated with COPD, CDVD, Brachycephalic syndrome, collapsing trachea
  • Syncope associated with coughing or occasionally with wretching / gagging etc
  • Decreased cerebral blood flow due to increased intra cranial pressure
  • Increased intrthoracic pressure
54
Q

What are the 3 proposed mechanisms of tussive syncope?

A

–3 proposed mechanisms:

  • Increased intrathoracic pressure leading to reduced venous return
  • Decreased cerebral blood flow due to increased cerebral pressure
  • Tachyarrhythmias
55
Q

What is the treatment for tussive syncope?

A

•Treat underlying cause as need to reduce the amount of coughing! Very diffiuclt as these often have some degree of airway disease along side the heart disease also

56
Q

What is endocarditis?

How do they present?

A
  • Bacterial infection of endocardium
  • Typically affects 1 or more valves
  • Access of bacteria rarely documented
  • Dental disease often blamed!
  • Normally presented with very sick dogs, that’s developed a heart murmur or a variable heart murmur. Rarely document how bugs got in there – lots of theories
57
Q

How signs does a patient with endocarditis present with?

A
  • Rarely present as cardiac patient
  • Sick patient with variable murmur – one that they didn’t have before!

–Comes and goes – can change throughout the day!!

–Can be diastolic murmur – semilunar insufficiency

  • If aortic valve is disease, it becomes insufficient
  • Dog>>cat
  • Other systemic signs

–Variable pyrexia/PUO

–Shifting lameness because the lesion on valve is chycking out infected thrombi and they lodge in joints and kidneys – just generally very sick animals

–Lethargy, anorexia, weight loss – not specific

58
Q

What things would you find on clinical exam with endocarditis?

A
  • Haematology and biocehm suggests inflammatory disease
  • Dysrhythmias
  • Other systems involved?
  • Urinalysis – renal damage
  • Echo – valve lesions – variable valves
  • US – infarcts elsewhere – kidneys
  • Blood culture for causative organism – but not the easiest to do and don’t always grow something
  • Survival – CHF due to valve damage

–Can be months/years later if you get them over the infectious stage

Small Animal Final Year (317 decks)

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