Cardiovascular Disease Flashcards
What is the number one form of heart disease in dogs?
Valve disease
How does the heart usually respond to stress?
Hypertrophy
(concentric, eccentric, mixed)
What causes concentric hypertrophy?
Examples?
Increased afterload
-resistance the heart must overcome to pump blood
Subaortic stenosis, high BP
What causes eccentric hypertrophy?
Examples?
Response to increased preload
-vol of blood distending heart before contraction
Valve regurge, congenital shunts
How do cardiomyocytes regenerate?
Once lost, cardiomyocytes cannot be replaced
What causes ischemic necrosis of the myocardium?
Impaired coronary blood flow
arteriosclerosis (narrowing), coronary thrombus, impaired flow
What causes nutritional/oxidative damage to the myocardium?
Vitmamin E/ selenium deficiency
Cattel, sheep, pigs
What causes toxic damage to the myocardium?
Doxorubicin (chemo), ionophores (monensin), cardiac glycosides (digoxin), gossypol, thallium, blister beetle
What can cause myocarditis?
Virus, bacteria, protozoa, autoimmune, response to ischemia, myocardial disease
What can cause myocardial fibrosis?
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
What are consequences of myocardial fibrosis?
Impaired contractile function
Impaired relaxation
Disrupted electrical activity
Decreased perfusion
What is the most common cardiac disease of the cat?
Hypertrophic cardiomyopathy
Diastolic disfunction
Reduced compliance = impaired filling
Maine coon, ragdoll, sphynx
What type of hypertrophy is dilated cardiomyopathy?
Eccentric hypertrophy
dilated champers = poor function
What are the types of DCM?
Primary: genetic/familial, dobermans
Secondary: taurine deficiency -cats; grain-free diets -dogs.
What is arrythmogenic right ventricular cardiomyopathy?
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.
What is atrial myopathy?
Replacement fibrosis in atria, loss of atrial activity leading to AV node takeover (slower rate), progresses to heart failure
Rare, english springer spaniels
What is secondary cardiomyopathy?
secondary myocardial changes due to systemic disease:
anemia, hyperthyroidism, systemic hypertension, acromegaly, diabetes mellitus, cor pulmonale, steroid admin
Do arrhythmias cause structural disease?
They can cause structural disease and they can be secondary to structural disease.
How does a degenerative AV valve present?
Thick valve, laxity of chordae, regurgitation
SYSTOLIC murmur
Very common in dogs
How does a degenerative aortic valve present?
DIASTOLIC murmur
Common in older horses
What is infective endocardiosis?
large, vegetative growths on affected valves
Fibrin (yellow) and hemorrhage (red) fresh post-mortem
Right sided valves: cattle
Left sided (aortic): other species
Where does hemangiosarcoma usually manifest in the heart?
Right auricle
canine
Where is a chemodectoma found?
Heart base (aorta)
canine
What is the main issue of a left to right shunt?
Volume overload
What is the main issue of a right to left shunt?
Hypoxia
deox blood into arterial circulation
ACVIM Stages of Heart Disease:
A: at risk for heart disease (predisposed)
B: Structural disease, no CHF
C: past or current CHF
D: CHF refractory to standard therapy
