Cardiovascular Disease

Question 1

What is the number one form of heart disease in dogs?

Answer 1

Valve disease

Question 2

How does the heart usually respond to stress?

Answer 2

Hypertrophy
(concentric, eccentric, mixed)

Question 3

What causes concentric hypertrophy?
Examples?

Answer 3

Increased afterload
-resistance the heart must overcome to pump blood
Subaortic stenosis, high BP

Question 4

What causes eccentric hypertrophy?
Examples?

Answer 4

Response to increased preload
-vol of blood distending heart before contraction
Valve regurge, congenital shunts

Question 5

How do cardiomyocytes regenerate?

Answer 5

Once lost, cardiomyocytes cannot be replaced

Question 6

What causes ischemic necrosis of the myocardium?

Answer 6

Impaired coronary blood flow
arteriosclerosis (narrowing), coronary thrombus, impaired flow

Question 7

What causes nutritional/oxidative damage to the myocardium?

Answer 7

Vitmamin E/ selenium deficiency
Cattel, sheep, pigs

Question 8

What causes toxic damage to the myocardium?

Answer 8

Doxorubicin (chemo), ionophores (monensin), cardiac glycosides (digoxin), gossypol, thallium, blister beetle

Question 9

What can cause myocarditis?

Answer 9

Virus, bacteria, protozoa, autoimmune, response to ischemia, myocardial disease

Question 10

What can cause myocardial fibrosis?

Answer 10

Replacement fibrosis: common response to lost cardiomyocytes, replacement of muscle with fibrous scar tissue
Interstitial fibrosis: interstitial deposition of collagen between/around cardiomyocytes
HCM/DCM

Question 11

What are consequences of myocardial fibrosis?

Answer 11

Impaired contractile function
Impaired relaxation
Disrupted electrical activity
Decreased perfusion

Question 12

What is the most common cardiac disease of the cat?

Answer 12

Hypertrophic cardiomyopathy
Diastolic disfunction
Reduced compliance = impaired filling
Maine coon, ragdoll, sphynx

Question 13

What type of hypertrophy is dilated cardiomyopathy?

Answer 13

Eccentric hypertrophy
dilated champers = poor function

Question 14

What are the types of DCM?

Answer 14

Primary: genetic/familial, dobermans
Secondary: taurine deficiency -cats; grain-free diets -dogs.

Question 15

What is arrythmogenic right ventricular cardiomyopathy?

Answer 15

Replacement of cardiomyocytes with fat and fibrous tissue (mostly in RV). The abnormal tissue causes arrythmias resulting in collape and sudden death or CHF
Common in boxers and bulldogs.

Question 16

What is atrial myopathy?

Answer 16

Replacement fibrosis in atria, loss of atrial activity leading to AV node takeover (slower rate), progresses to heart failure
Rare, english springer spaniels

Question 17

What is secondary cardiomyopathy?

Answer 17

secondary myocardial changes due to systemic disease:
anemia, hyperthyroidism, systemic hypertension, acromegaly, diabetes mellitus, cor pulmonale, steroid admin

Question 18

Do arrhythmias cause structural disease?

Answer 18

They can cause structural disease and they can be secondary to structural disease.

Question 19

How does a degenerative AV valve present?

Answer 19

Thick valve, laxity of chordae, regurgitation
SYSTOLIC murmur
Very common in dogs

Question 20

How does a degenerative aortic valve present?

Answer 20

DIASTOLIC murmur
Common in older horses

Question 21

What is infective endocardiosis?

Answer 21

large, vegetative growths on affected valves
Fibrin (yellow) and hemorrhage (red) fresh post-mortem
Right sided valves: cattle
Left sided (aortic): other species

Question 22

Where does hemangiosarcoma usually manifest in the heart?

Answer 22

Right auricle
canine

Question 23

Where is a chemodectoma found?

Answer 23

Heart base (aorta)
canine

Question 24

What is the main issue of a left to right shunt?

Answer 24

Volume overload

Question 25

What is the main issue of a right to left shunt?

Answer 25

Hypoxia
deox blood into arterial circulation

Question 26

ACVIM Stages of Heart Disease:

Answer 26

A: at risk for heart disease (predisposed)
B: Structural disease, no CHF
C: past or current CHF
D: CHF refractory to standard therapy