Feline Cardiomyopathies

Question 1

What is the dominant form of heart disease in cats?

Answer 1

CMOs, usually hypertrophic

Question 2

Outline some causes for dilated feline CMO

Answer 2

Taurine deficiency (no longer common)

Question 3

Hyperthyroidism is a very likely occurrence in older cats. What causes it to appear like HCM?

Answer 3

Regional vasoconstriction

Question 4

Outline the aetiology of feline HCM

Answer 4

Idiopathic, but a strong genetic predisposition in some breeds

Question 5

Which breeds have a strong genetic predisposition to HCM?

Answer 5

Maine coon (autosomal dominant; mutation in myosin-binding protein C)
Persian
Ragdoll (different mutation in myosin-binding protein C)
American shorthair

Question 6

What viral disease is though to relate to feline HCM?

Answer 6

Parvovirus

Question 7

Explain the pathophysiology behind HCM

Answer 7

Thickening of LV wall and septum, small lumen
Stiff ventricular walls, diastolic dysfunction, poor LV filling, low SV, neurhohormonal activation, tachycardia, even poorer LV filling.
Progressively high LV filling pressures, enlarged LA

Question 8

Possible common consequences of HCM as a result of the pathophysiology?

Answer 8

Pulmonary congestion
Thrombus formation in LA or LV
Arterial thromboembolism

Question 9

List some pathophysiology cal complications of HCM

Answer 9

LV outflow tract obstruction
Myocardial ischaemia
Mitral insufficiency
Atrial fibrillation (uncommon)
Biventricular failure with pleural effusion

Question 10

What are the clinical features of HCM cats (age, progression, signs, etc).

Answer 10

middle aged, male cats (can occur at any age and sex)
subclinical for years, murmur possible
Mostly present with resp. Signs or aortic thromboembolism.
Tachyponoea, panting with mild exertion, dyspnoea

Question 11

List a common condition affecting the posterior of a cat with HCM following thromboembolism lodgement

Answer 11

Saddle thrombus.

Question 12

Is a saddle thrombus painful? How does it present? What is the result?

Answer 12

Painful within the first hour and then ceases. Pulses become weaker, footpads cyanotic, muscles begin to feel tight and stiff. Support these animals, but expect a plantar grade stance with limited functionality (can’t jump well, aren’t happy).

Question 13

Clinical features of HCM?

Answer 13

Disease onset may seem acute despite development of pathological changes
Acute development of CHF and or sudden death possible
Possible systolic (usually mitral) murmur
+/- gallop. Sound/rhythm +/- arrhythmia
Usually good pulses, strong precordial impulse (apex beat)
Maybe pulmonary crackles
Maybe muffling (if pleural effusion)

Question 14

What leads you to a diagnosis of HCM (what findings)?

Answer 14

Radiograph:
Echocardiography
ECG
Ruling out secondary causes (hyperthyroidism, systemic hypertension, SAS, taurine deficiency)
Valentine shaped heart (not always present)

Question 15

You radiograph a suspect HCM and notice a bronchoinsteretitial pattern heading towards becoming alveolar. After giving Frusemide and taking another RadX a few hours later, the substance disappears. hat time of substance was it likely to be? What do you suspect?

Answer 15

Low protein, watery fluid. Still HCM. Frusemide is good at fixing waterlogged lungs in HCM cases.

Question 16

What are the aims of treatment of asymptomatic. HCM

Answer 16

Prevent CHF from developing
Prevent arterial thromboembolism
Prevent sudden death
Prevent or reverse myocardial abnormalities
DON'T TREAT A MURMUR EMPIRICALLY

Question 17

Is treatment of HCM before the onset of any clinical signs beneficial?

Answer 17

We are unsure about this too. Is anyone sure of any fucking empirical CMO treatment in anything? Fuck

“Theoretically, it makes sense”

Question 18

How might you manage asymptomatic HCM

Answer 18

anti-thrombus therapy
Beta blocker
Ca2+ channel antagonist
ACEI

Question 19

What are some problems with Ca channel antagonists?

Answer 19

Anorexia, weight loss, skin lesions.

Question 20

How do we treat HCM with evidence of clinical signs

Answer 20

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

Question 21

How do you treat acute CHF in cats?

Answer 21

Avoid stress
O2 supplementation
Diuresis
Sedation
Ventilation
Drain pleural effusion (butterfly catheter, just in front of 8th rib).

Question 22

How is HCM treated at home?

Answer 22

Depends on the stage, but generally

• Frusemide
• ACEI
• Beta blocker
• Anti-thrombic therapy
• Exercise restriction!
• Salt-restricted diet (if the animal eats it)

Question 23

What are some common beta blockers for treating HCM in cats?

Answer 23

atenolol or diltiazem

Question 24

When do we use atenolol and diltiazem in HCM cats?

Answer 24

Diltiazem first if no outflow tract obstruction, tachycardia or arrhythmia. Use atenolol first in cats with outflow obstruction, tachycardia, or arrhythmias. Swap over if response is or becomes suboptimal.

And then panic like a motherfucker if that doesn’t work.

Question 25

What is the prognosis for HCM cats?

Answer 25

Good for those not showing signs
Poor for those with aortic thromboembolism
THe larger the LA, the older the animal, presence of AF and refractory R-sided CHF = worse prognosis

Question 26

List 3 CMOs in cats (don’t use HCM)

Answer 26

Restrictive
Dilated
Secondary

Question 27

What does “smoke” in the LA (grey swirling material) on echocardiography suggest?

Answer 27

Use of clopidogram

Question 28

Feline CMOs are classified how?

Answer 28

According to their morphological appearance (hypertrophic, dilated, restrictive)