Feline Cardiomyopathy

Question 1

List the phenotypes of feline cardiomyoopathy

Answer 1

• hypertrophic cardiomyopathy
• restrictive cardiomyopathy (endomyocardial and myocardial forms)
• dilated cardiomyopathy
• arrhythmogenic cardiomyopathy
• nonspecific phenotype

Question 2

List 6 inciting causes to develop HCM phenotype

Answer 2

• hyperthyroidism
• systemic hypertension
• glucocorticoid administration
• reduced preload
• neoplastic infiltration
• transient myocardial thickening
• acromegaly

Question 3

How are Stage B1 and B2 cardiomyopathies in cats differentiated?

Answer 3

by the risk of developing ATE or CHF and LA size is commonly used as a surrogate for this risk

other echo findings used as surrogate: LV and LA systolic dysfunction, degree of LV hypertrophy

Question 4

How is Stage D defined (i.e., cut-off value for therapeutic dose)

Answer 4

CHF unresponsive to medical management - > 6 mg/kg/day PO Furosemide required

Question 5

What is the prevalence of HCM in the general cat population versus in older cats?

Answer 5

general 15%
older 29%

Question 6

List pedigree cats predisposed to HCM

Answer 6

Ragdoll, Maine Coon, Norwegian Forest Cat, british shorthair, persian, bengal, birman

Question 7

In what gene have mutations for HCM been identified?

Answer 7

MyBPC3

Question 8

List risk factors for cats with HCM developing ATE or CHF

Answer 8

• presence of gallop sound or arrythmia
• LA enlargement moderate to severe
• severe hypertrophy of LV wall
• systolic dysfunction of LV/decreased FS%
• spontaneous echo contrast
• clot within left atrial appendage
• regional wall thinning or hypokinesis
• restrictive diastolic filling

Question 9

IS DLVOTO a negative prognostic indicator?

Answer 9

No

Question 10

How common are murmurs in cats with subclinical HCM versus healthy cats without HCM?

Answer 10

80% versus 30-45%

Question 11

How common is a gallop sound in subclinical HCM cats?

Answer 11

3-20%

Question 12

List clinical findings that make CHF more likely in a cat presenting with respiratory distress

Answer 12

• murmur
• audible arrhythmia
• temp < 37.5
• HR >200
• RR > 80

Question 13

How specific is the valentine-shaped heart for HCM in cats?

Answer 13

not specific

Question 14

How do you use pleural fluid for NT-proBNP assays?

Answer 14

have to dilute it 1:1 in saline

Question 15

What is the prognostic value of cTnI in cats with HCM?

Answer 15

prognostic for risk of cardiovascular death

Question 16

When are ECGs recommended in cats with HCM?

Answer 16

only if episodes of collapse/syncope observed

Question 17

How common is LV hypertrophy in cats with systemic hypertension?

Answer 17

85%

Question 18

Does hyperthyroidism itself cause severe HCM?

Answer 18

no, usually preexisting mild HCM that’s exacerbated

hyperthyroidism on its own will cause only mild HCM

Question 19

What is the recommendation for measuring serum thyroxine levels in cats with suspected heart disease?

Answer 19

> 6 years measure

Question 20

Describe the recommendation for how to measure left ventricular wall thickness

Answer 20

right parasternal short or long axis, measure interseptal and free wall
end-diastolic
normal: < 5 mm
> 6 mm –> hypertrophied

measure 3 times (3 cardiac cycles) and get average

Question 21

How do you assess for blood stasis on echocardiogram?

Answer 21

Doppler LA appendage flow velocity

Question 22

For a normally-sized cat, what is the normal end-diastolic LV wall thickness, what is considered indicative of hypertrophy?

Answer 22

< 5 mm normal
over 6 mm elevated

Question 23

List all measurements on echo that are part of the standard-of-care to evaluate for HCM

Answer 23

M-mode
* IVSd
* LVFWd
* LVIDd, LVIDs, FS%
* LA FS%

2D
* * IVSd
* LVFWd
* LVIDd, LVIDs
* LA/Ao
* LA diameter from RP long axis view

Question 24

What is the treatment recommendation for HCM stage B1?

Answer 24

no treatment in general
may consider beta-blocker (atenolol) if DLVOTO present

Question 25

List indications for risk of ATE in B2 cats, indicating Clopidogrel administration

Answer 25

• moderate to severe LA enlargement
• low LA FS%
• Low LA appendage velocities
• spontaneous echo contrast

Question 26

What is the recommended treatment for complex ventricular ectopy in cats with HCM?

Answer 26

sotalol and atenolol

Question 27

What is the treatment recommendation for AF in HCM?

Answer 27

diltiazem, atenolol, sotalol

Question 28

When is pimobendan recommended in HCM?

Answer 28

if no DLVOTO
* in acute CHF if systolic dysfunction/hypotension
* chronic tx

Question 29

List favorable prognostic indicators for return of function after ATE

Answer 29

only one limb affected
normal temperature
no CHF

Question 30

What can cause a transient HCM phenotype in cats?

Answer 30

very stressful event

Question 31

Of the MYBP3 gene mutations A31P and R820W, which one was identified in Maine Coons and which one in Ragdolls?

Answer 31

A31P Maine Coon

R820W Ragdoll

Question 32

What is the overall risk of CHF in cats with HCM?

Answer 32

24%

Question 33

What is the overall risk of ATE in cats with HCM?

Answer 33

11%

Question 34

What is the prevalence of DLVOTO in cats with HCM?

Answer 34

45-67%

Question 35

What is the cutoff value for vertebral heart score in cats with HCM?

Answer 35

over 9.3

Question 36

What are cut off values for LA dimension in long axis?

Answer 36

16.5 mm

Question 37

What is a normal fractional shortening in cats?

Answer 37

40% or higher