Feline cardiomyopathies Flashcards

1
Q

How are CMO’s in cats classified?

A

By their morphological appearance

Hypertrophic, dilated, restrictive

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2
Q

What is the most common type of CMO in cats?

A

Hypertrophic (HCM)

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3
Q

What is the aetiology of feline HCM?

A

Idiopathic
Strong genetic presiposition in some breeds
Parvovirus maybe has some roll?

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4
Q

What 4 cat breeds have a strong genetic predisposition for developing Hypertophic CMO? (HCM)

A

Maine Coon
Persian
Ragdoll
American Shorthair

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5
Q

Describe the pathophysiology of HCM?

A
(Hypertrophic CMO)
Thickening of LV wall and septum
Lumen becoming smaller
Stiff ventricular walls
Diastolic dysfunction - muscles don't relax properly so it can't fill 
Poor LV filling
Low stroke volume
Neurohormonal activation
Tachycardia
Worsening LV filling
Increased LV filling pressures
Enlarged left atrium
\+/- pulmonary congestion, thrombus formation in Left side, arterial thromboembolism
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6
Q

Why are you less likely to see atrial fibrillation in cats compared to dogs?

A

Cats are smaller and therefore have less cells
Less cells the electro-message need to pass through to get the muscle fibers to all get ready to contract at the exact same time
(Less parts=less chance of fuck up)

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7
Q

What are the 5 pathophysiological complications of feline hypertrophic CMO?

A

Left ventricular outflow tract obstruction (from increased muscularity)
Myocardial ischaemia
Mitral insufficiency
Atrial fibrillation (uncommon)
Biventricular failure with pleural effusion

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8
Q

What are some clinical features of a cat with HCM?

A

Signalment - middle-aged, more commonly male
May be asymptomatic for years
Maybe a murmur - systolic, usually mitral
+/- gallop sound
+/- arrhythmia
Usually good pulses and strong apex beat (precordial impulse)
Mostly present with respiratory signs or aortic thromboembolism
Tachypnoea, panting with mild exertion, dyspnoea
Maybe muffled lung sounds - pleural effusion
Coughing is Uncommon!

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9
Q

What are some clinical features of a cat with an aortic ‘saddle’ thromboembolism?

A

Very painful for a while (hour or so) and then no feeling in hind limbs
Cold back limbs
Cyanotic foot pad
Muscles are ischaemic - go into rigor

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10
Q

Although feline HCM develops over time, why do many present acutely?

A

Cats are very sensible about exercise and can hide the development of pathological changes
Therefore may present with acute development of CHF or sudden death

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11
Q

How do you diagnose a cat with a suspected HCM?

A

Compatible history and physical exam
Echocardiography is the best way to distinguish*
Radiograph for a ‘valentine’ shaped heart - changes not always present
ECG most will have changes
Always rule out secondary causes

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12
Q

List 4 secondary causes of HCM that you need to rule out when diagnosing?

A

Hyperthyroidism (common in cats)
Systemic hypertension
SAS
Taurine deficiency

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13
Q

What are the 4 principle aims of treating asymptomatic HCM?

A

Prevent CHF from developing
Prevent arterial thromboembolism
Prevent sudden death
Prevent or reverse myocardial abnormalities

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14
Q

What makes treatment of feline HCM so difficult?

A

Very hard to diagnose in the first place

-Don’t treat a murmur empirically

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15
Q

How do you treat a cat with asymptomatic HCM?

A

Anti-thrombotic therapy
Beta blocker
Calcium channel antagonist - diltiazem (but can get anorexia, weight loss, skin lesions)
ACEI
-Treatment in asymptomatic phase theoretically makes more sense in this disease

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16
Q

What are the 5 principle aims for treating a cat with symptomatic HCM?

A
Enhance ventricular filling
Relieve congestion
Control arrhythmias
Minimise tissue ischaemia
Prevent thromboembolism
17
Q

How do you treat a cat with an acute present of CHF?

A
Avoid stress! - including clinical exam 
O2 supplementation
Diuresis - furosemide 
Sedation - butorphanol - improve efficiency of breathing 
Venodilation - nitroglycerin ointment
Drain pleural effusion if present
18
Q

What do you need to keep in mind when treating a cat with nitroglycerin ointment?

A

They become tolerant extremely quickly

19
Q

How do you treat a cat with HCM when released back home?

A
Depends on stage presented
Furosemide at minimal effective dose
ACEI
Beta blocker OR diltiazem
Anti-thrombotic therapy - clopidogrel, asprin every 72hours maybe
Exercise restriction
Salt-restricted diet if cat will eat it
20
Q

When doing a contrast study in a cat with DCM, what will happen to the dye once it reaches the heart?

A

It will stay there for longer than usual

Have very weak contractions