SA Endocardial Disease

Question 1

Why is valvular disease important?

Answer 1

• 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

Question 2

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

Answer 2

Valvular disease

Question 3

Describe what can be seen on this radiograph

What is the cause?

Answer 3

• 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

Question 4

What is the acquired form of valvular disease?

Answer 4

• 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)

Question 5

What is the congential form of valvular disease?

Answer 5

•Valve dysplasia

–Insufficient valve

–Stenotic valve

Question 6

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

Answer 6

•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

Question 7

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

Answer 7

• 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.

Question 8

What is the histopathology of the valve structure?

What happens when they are diseased?

Answer 8

• 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.

Question 9

What nerves are within heart valves?

Answer 9

Autonomic nerves within the valves

Question 10

What is the Whitney classification of valvular disease?

Answer 10

•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

Question 11

What is wrong with this heart?

Answer 11

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

Question 12

What does stroke volume = ?

Answer 12

Stroke volume = End Diastolic Volume – End Systolic Volume

Question 13

How is the stroke volume regulated?

Answer 13

• 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

Question 14

What are some factors that can increase stroke volume?

Answer 14

Increased pre-load

Increased contractiliy

Decreased afterload

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

Question 15

What are some things that can cause increased heart rate?

Answer 15

ANS (increased sympathetic activity, decreased parasympathetic activity

Hormones - catecholamines, thyroid hormones

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

Question 16

What are some things that can increase pre-load?

Answer 16

Increased end-diastolic volume (stretches heart)

Cardiac muscle fibres contract more forcefully

Question 17

What are some things that can increase contractility?

Answer 17

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

This leads to an INCREASED FORCE OF CONTRACTION

Question 18

What can decrease after-load?

Answer 18

Decreased arterial blood pressure during diastole

Question 19

When are systolic murmurs often heard?

Answer 19

S1 and S2

Question 20

What is the signalment for valvular disease?

Answer 20

• Middle to old age
• Small breeds

–Cavalier King Charles

–Poodles

–Maltese etc.

Question 21

Which heart disease are small breeds dog more disposed to?

Answer 21

Chronic valvular disease?

Question 22

Which heart disease are large breeds dog more disposed to?

Answer 22

Dilated cardiomyopathy

Question 23

What is the typical congestive heart failure history?

Answer 23

• 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

Question 24

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

Answer 24

• 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

Question 25

What are the grades of heart murmurs?

Answer 25

* 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

Question 26

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

Answer 26

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

Question 27

Does murmur grade indicate severity?

Answer 27

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

Question 28

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

Answer 28

* 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?

Question 29

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

Answer 29

* 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!

Question 30

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

Answer 30

* 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

Question 31

What is essential for the diagnosis of congestive heart failure?

Answer 31

RADIOGRAPHS * ESSENTIAL for dx of CHF * Cardiac enlargement * Engorged pulmonary vessels * Pulmonary oedema (L-CHF)

Question 32

Describe this radiograph What is a likely clinical sign?

Answer 32

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

Question 33

Describe what is going on in this radiograph

Answer 33

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

Question 34

What are some radiographic abnormalities of left sided cardiomegaly?

Answer 34

–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

Question 35

What are some radiographic abnormalities of right sided cardiomegaly?

Answer 35

–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

Question 36

When does heart disease become heart failure?

Answer 36

–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

Question 37

What radiographic abnormalities can you see with right sided enlargement?

Answer 37

•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

Question 38

When would you use echocardiography?

Answer 38

* 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

Question 39

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

Answer 39

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

Question 40

What can be seen on this echo image? What view is it?

Answer 40

Echo image of thickened mitral valve

Question 41

How can we tell is the atrium is big on US? What should the ratio from the aorta to the atrium be?

Answer 41

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.

Question 42

Describe the problem here

Answer 42

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

Question 43

Describe the problem here

Answer 43

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

Question 44

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

Answer 44

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

Question 45

What would you use electrocardiography to see?

Answer 45

* +/- 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

Question 46

Describe what is going on with this ECG

Answer 46

* 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

Question 47

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

Answer 47

* 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

Question 48

Name some complications of heart disease

Answer 48

•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

Question 49

How do ruptured chordae tendonae often present?

Answer 49

•Frequently present as an acute emergency, severe fulminant LCHF –Severe dyspnoea –Stressed – panicking (owner and dog!) –Cyanotic –Life threatening

Question 50

What is your diagnosis? What view is it?

Answer 50

Right parasternal long axis view Flailing mitral valve leaflet, everytime ventricle contracts, valve flicks up into atrium, so a massive regurgitation

Question 51

What are the main causes of pulmonary hypertension?

Answer 51

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

Question 52

What is wrong on this specimen?

Answer 52

* Pericardial effusion * Can present with acute tamponade * Avoid pericardiocentesis if possible as risk of moving clot * Atrial tear

Question 53

Wha tis tussive syncope? What breeds is it most common in?

Answer 53

* 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

Question 54

What are the 3 proposed mechanisms of tussive syncope?

Answer 54

–3 proposed mechanisms: * Increased intrathoracic pressure leading to reduced venous return * Decreased cerebral blood flow due to increased cerebral pressure * Tachyarrhythmias

Question 55

What is the treatment for tussive syncope?

Answer 55

•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

Question 56

What is endocarditis? How do they present?

Answer 56

* 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

Question 57

How signs does a patient with endocarditis present with?

Answer 57

* 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

Question 58

What things would you find on clinical exam with endocarditis?

Answer 58

* 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