Cardio Concepts Flashcards
Normal function of the right heart
Takes O2 POOR blood from body to lungs
Function of the left heart
Takes O2 RICH blood from lungs to body
Causes of LHF (4 major themes)
Loss of contractility: myocarditis, myocardial necrosis, CM
Valvular insufficiency: mitral, aortic = incr. preload
Valvular stenosis: aortic = incr. afterload
Systemic hypertension = incr. afterload
Sequelae of LHF
Pulmonary congestion, edema and fibrosis
Hemosiderosis
Causes of RHF
Valvular insufficiency: tricuspid, pulmonic = incr. preload
Pulmonary hypertension = incr. afterload
Valvular stenosis: pulmonic = incr. afterload
Sequelae of RHF
Hepatic passive congestion Pleural/pericardial effusion Congestion of GI tract > diarrhea Ascites = dogs Hydrothorax = cats SQ edema = horses, ruminants
Cor pulmonale
RHF secondary to pulmonary disease
Ex: chronic obstructive pulmonary disease, HWD, PTE, neoplasia
Describe cardiac skeleton composition in each of the following species: pigs, cats, dogs, horses and ruminants
Pigs/cats = dense, fibrous connective tissue Dogs = fibrocartilage Horses = hyaline cartilage Ruminants = bone
What is heart failure?
End point of numerous diseases in which compensatory mechanisms have been exhausted leading to:
decr contractility, decr compliance, dys/arrhythmias
Hypertrophy is due to chronic ____ overload, and dilation is due to chronic ___ overload.
Hypertrophy = pressure Dilation = volume
Cardiac syncope
Acute HF
Arrhythmias, necrosis, changes in BP/HR leading to collapse, loss of consciousness and death
Congestive heart failure
Chronic loss of pumping ability
Forward or backward failure - then eventually full failure
Cycle of cardiac decompensation
Decompensation leads to hypoxia
Hypoxia > RAAS/renin release > Na/H2O retention > incr plasma vol > edema
Hypoxia > EPO > polycythemia > incr viscosity
Pathologic consequences of hypertrophy
Decreased contractility, ventricular relaxation and compliance
Leads to increased end-diastolic pressure
Concentric hypertrophy: definition, main cause, examples
Def: incr in mass WITHOUT incr in end-diastolic volume
Cause: incr afterload
Ex: aortic stenosis, pulmonic stenosis, pulmonary hypertension with PDA, cats with hyperthyroidism (systemic hypertension)
Eccentric hypertrophy: definition, main cause, examples
Def: incr in mass w/ dilation WITH incr end-diastolic volume
Cause: incr preload
Ex: AV/semilunar valvular insufficiency, AV shunt
Congenital abnormalities in dogs
PDA
Pulmonic stenosis
Sub-abortion stenosis
Congenital abnormalities in cows
A/V septal defects (VSD)
Transposition of main vessles
Congenital abnormalities in pigs
Sub-aortic stenosis
Endocardium cushion defects = AV septum
Congenital abnormalities in cats
Endocardium cushion defects = AV septum
Left AV valvular insufficiency (mitral)
Congenital abnormalities in horses
Uncommon
After how many days is the ductus arteriosis considered “patent”?
If no closure after 5 days
In general, valvular insufficiencies result in ______ ______ in ventricles.
Increased preload
In general, semilunar valvular stenosis, outflow tract stenosis and hypertension _______ _______ in the ventricle.
Increase afterload
In general, AV valvular stenosis and pericardial disorders _______ _______ in the ventricles.
Decrease preload
Which chamber and species does uremic endocarditis affect?
Left atrium in dogs
Vegetative valvular and mural endocarditis: most common cause and valve involved
Cause: bacterial - usually concurrent extra-cardiac disease (sepsis, uremia)
Valve: mitral
Endocardiosis: definition, signalment, valve most commonly involved
Def: myxomatous valvular degeneration
Signalment: small/toy breeds, Cavalier King Charles Spaniel; middle aged to older
Valve: mitral
Sequelae of endocardiosis
Valvular incompetency Atrial dilation Jet lesions CHF LA rupture Hemopericardium
Name three causes of nutritional myocardial necrosis
Vitamin E/selenium = lambs, calves, horses, pigs (mulberry heart dz)
Thiamine = carnivores
Copper
Brain-heart syndrome
Sunendocardial necrosis post acute brain/CNS injury
Ex: coronary spasm, massive release of catecholamines, fxnl pheo
How does myocarditis generally result?
From hematogenous spread or direct extension from endo or pericardium (rarely primary!)
What are the four categories of causes of myocarditis?
Bacteria, viral, protozoan, helminths
DCM: general cause, dysfunction, gross findings
Cause: genetic abnormalities in cytoskeleton proteins and mitochondrial genes
Dysfunction: systolic
Grossly: A + V dilated, V hypertrophied, thin walls +/- subendocardial fibrosis
DCM has been reported in what three species?
Feline - taurine deficiency
Canine - genetic
Bovine - Holsteins, Japanese Blk Cattle
Canine DCM signalment
Young to middle aged large or giant breeds
Short onset of clinical signs > LHF/BV failure
HCM: dysfunction, gross findings
Dysfunction: diastolic = impaired filling
Grossly: concentric hypertrophy (cats)
HCM has been reported in what two species?
Feline
Bovine - Holsteins
Signalment/inheritance for feline HCM
Maine coons and Ragdolls
Autosomal dominant inheritance
RCM: dysfunction, gross findings, species
Dysfunction: diastolic = impaired filling
Grossly: fibrosis
Species: cats
RCM has been associated with what two conditions in cats?
Hypereosinophilic syndrome
Bartonella infection
Signalment of excessive moderator bands
Older cats - congenital disease that manifests in older
Wooly coat myopathy: signalment, lesions
Signalment: Hereford calves with tightly curled wooly coat
Lesions: fibrosis, necrosis, mineralization
Which one rapidly results in death vs the other and why? Hydropericardium or hemopericardium?
Hemopericardium rapidly results in death
NOT hydropericardium because fluid accumulation is usually slow
Usual cause of fibrinous pericarditis?
Hematogenous microbial infection
What does purulent pericarditis indicate? What is the most common etiology in cats, horses and cattle?
Presence of pyogenic bacteria
Cats/horses = pyothorax
Cattle = traumatic reticulopericarditis (perforating FB in reticulum)
Name two heart base tumors in the dog
Chemodectoma (primary HB tumor)
Ectopic thyroid/parathyroid tumors
Which species are rhabdomyomas most common in and their origin in this species?
Swine = Purkinje cell origin
