Cardio - Hypertrophic CM

Question 1

What is HOCM?

Answer 1

Disease of the myocardial sarcomere caused by/characteristic of:

genetic mutations in MyBPC, dietary/environmental factors, impaired LV myocardial relaxation, and concentric hypertrophy

Question 2

What cat breeds are prone to HOCM?

Answer 2

Maine Coons and Ragdolls

Question 3

HOCM is a disease of _____ dysfunction.

Answer 3

diastolic

Question 4

What do HOCM hearts look like?

Answer 4

Myofiber disarray, replacement fibrosis, arteriosclerosis (small vessel disease)

Question 5

What does the O in HOCM stand for?

Answer 5

obstructive

Question 6

Where is the obstruction in HOCM?

Answer 6

At area where blood leaves LV as it crosses the aorta

Question 7

What role does the MV play in HOCM?

Answer 7

It is anatomically near the obstruction location, and can swing and get in the way of the outflow tract, contributing to HOCM

Question 8

What is the signalment for HOCM?

Answer 8

Cats (Maine Coons, Ragdolls), males (75%), middle-age (~6 yr)

Question 9

What is the prevalence of HOCM in cats?

Answer 9

15%

Question 10

What is part of the breeder screening for HOCM?

Answer 10

Echo and genetic testing

Question 11

What is part of the veterinarian screening for HOCM?

Answer 11

Murmur, arrhythmia, cardiac biomarkers (NT-proBNP)

Question 12

What can HOCM be a complication of?

Answer 12

CHF, ATE

Question 13

How is HOCM definitively diagnosed?

Answer 13

Echo

Question 14

What are signs of HOCM seen on echo?

Answer 14

LV hypertrophy, LV diastolic function, +/- LA enlargement

Question 15

What are DDx for LV hypertrophy in cats?

Answer 15

4H/4 “hypers”

HCM, hypertension, hyperthyroidism, hypersomatotropism (acromegaly)

Question 16

How does hypertension cause LV hypertrophy?

Answer 16

Ventricle is working harder to pump blood out due to increased afterload

Question 17

How can hyperthyroidism cause LV hypertrophy?

Answer 17

Thyroid hormone can directly cause hypertrophy –> hypertension

Question 18

What causes a heart murmur in HOCM?

Answer 18

Dynamic LVOT obstruction +/- mild mitral regurg

Question 19

What is easier to diagnose, HOCM or HCM? Why?

Answer 19

HOCM because most HCM cats don’t have murmurs and HOCM cats do

Question 20

What are DDx for murmurs in adult cats?

Answer 20

HOCM, hyperthyroidism/SHT, physiologic, anemia

Question 21

What are the 3 complications of HOCM and which is most common?

Answer 21

L-CHF (most common), ATE, sudden cardiac death

Question 22

What CS come with HOCM due to L-CHF?

Answer 22

Dyspnea, tachypnea, inappetance, ADR, hiding

Question 23

What CS come with HOCM due to ATE?

Answer 23

acute paresis/pain, bilateral hindlimb > other

Question 24

Where does fluid go in cats with L-CHF?

Answer 24

Pulmonary edema, pleural eff, pericardial eff

Question 25

T/F: Most cats with HOCM are never diagnosed or treated

Answer 25

True

Question 26

___% of cats who are diagnosed will progress and experience a complication.

Answer 26

50

Question 27

What is the average survival in asymptomatic HOCM cats?

Answer 27

~5 years

Question 28

What is the average survival of HOCM cats following an episode of CHF?

Answer 28

6 months - 2 years

Question 29

What is the average survival of HOCM cats following an ATE?

Answer 29

3-6 months

Question 30

What are negative prognostic indicators of HOCM?

Answer 30

Severe LA enlargement, severe LV hypertrophy, older age

Question 31

Do HOCM cats or HCM cats have better prognosis?

Answer 31

HOCM because they have murmurs and so get detected earlier

Question 32

What drugs are important in HOCM and why?

Answer 32

Clopidogrel, aspirin, heparin, tPA

(Anti-coagulants bc HOCM cats love to form clots)

Question 33

What meds are used in asymptomatic (stage B) HOCM?

Answer 33

Atenolol, ACEi, clopidogrel

Question 34

What meds are used in CHF HOCM (stage C)?

Answer 34

Acutely = sedation, oxygen, +/- thoracocentesis

Furosemide, ACEi, Pimobendan, Spironolactone

Question 35

What meds are used in ATE?

Answer 35

Analgesia (opioids), clopidogrel, heparin/low mol weight heparin, tPA for thrombolysis