Cardiovascular Flashcards
What is the definition of congestive heart failure?
When cardiac output < venous return and heart is unable to meet the demands of the animal (an endpoint of multiple causes/diseases when compensatory mechanisms have been exhausted)
What are some of the causes of left ventricular failure?
Myocarditis
Myocardial degeneration
Aortic stenosis
Mitral valve insufficiency
Shunts
What are the effects of left ventricular failure?
Chronic passive pulmonary congestion
Edema of interstitium followed by alveolar lumen -> cough
Fibrosis of alveoli/pleural surface
Surfactants + air + edema = frothing
Reduction in cardiac output -> ischemia, renal issues
What are some of the causes of right ventricular failure?
Heartworms
Tricuspid valve insufficiency
Pulmonic stenosis
Left ventricular failure/Increased pulmonary resistance
Cardiac tamponade
What are the effects of right ventricular failure?
Systemic and portal venous system congestion, veins distended
Enlarged, congested liver (nutmeg liver) and spleen (nodules/fibrotic metaplasia), function OK
Congestion of stomach/intestines (+/- diarrhea)
Renal complications/functional loss
Epistaxis in horses
Fluid accumulation varies from species to species. Where is fluid most likely to accumulate in the cow, horse, cat and dog with right heart failure?
Cow and horse: dependent subcutaneous edema
Dog: peritoneal effusion (ascites)
Cat: thoracic effusion (hydrothorax)
What is the definition of cardiac hypertrophy?
Reversible enlargement of cardiomyocytes (volume, myofibrils) with no increase in cell number
Can myocardial muscle fibers undergo hyperplasia?
Myocytes have little capacity for cell division post-birth, so no
What are the three requirements necessary for the myocardium to undergo hypertrophy?
Time
Adequate blood supply/nutrition
Healthy myocardium
Define concentric cardiac hypertrophy.
An increase in the mass of the ventricle without accompanying increase in end diastolic volume (decrease in ventricular lumen volume) characterized by increased wall thickness.
Right side = broad at base, Left side = elongated, Bilateral = rounded
What are some causes of concentric cardiac hypertrophy (be specific)?
Caused by pressure overload:
Aortic stenosis (Left ventricular hypertrophy)
Pulmonic stenosis (Right ventricular hypertrophy)
Pulmonary hypertension (Right ventricular hypertrophy)
Define eccentric cardiac hypertrophy. What can cause eccentric cardiac hypertrophy?
Increase in myocardial mass accompanied by an increased end diastolic volume (ventricular lumen volume increased). Weight of ventricular myocardium may be only sign.
Caused by volume overload:
Valvular insufficiency
Congenital defect with shunt
Increased blood volume
What is cardiac dilatation?
Stretching of myofibers in response to increased workload that eventually leads to decreased cardiac output. Occurs instead of hypertrophy in cases where the conditions for hypertrophy are NOT met:
Insufficient time
Inadequate blood supply/nutrition
Unhealthy myocardium
What is the most likely effect on the blood flow of Atrial septal defect?
(L to R) Pulmonary hypertension +/- R to L -> cyanosis/death
What is the most likely effect on the blood flow of Ventricular septal defect?
(L to R) Pulmonary hypertension -> R to L -> cyanosis/death
What is the most likely effect on the blood flow of Tetralogy of Fallot?
(transpositional) RV directly to aorta -> cyanosis/death
What is the most likely effect on the blood flow of Persistent ductus arteriosus?
(L to R) Pulmonary hypertension +/- R to L -> cyanosis/death
What four abnormalities are found with Tetralogy of Fallot?
Ventricular septal defect
Pulmonic stenosis
Overriding aorta
Right ventricular hypertrophy
What are the effects of pulmonic and aortic stenosis?
Pulmonic stenosis -> right ventricular concentric hypertrophy, pulmonic artery dilatation, right heart failure
Aortic stenosis -> left ventricular concentric hypertrophy, LV wall fibrosis, left heart failure
What are the two right to left shunts present within the fetus which bypass the pulmonary circulation?
Foramen ovale
Ductus arteriosus
What is a patent ductus arteriosus?
Abnormal shunt between pulmonary artery and aorta that should not remain post-birth
What are the usual clinical signs found with persistent right aortic arch?
Regurgitation after eating, esophageal dilation, megaesophagus
What causes the esophagus to be constricted when a persistent right aortic arch occurs?
Vascular ring is formed from right aortic arch and ligamentum arteriosum that encircles esophagus and trachea which constricts the esophagus
What are some of the synonyms for chronic degenerative valvular disease?
Endocardiosis
Chronic valvular failure
Valvular mucoid degeneration
Myxomatous degeneration of the valves
What is the pathogenesis of chronic degenerative valvular disease?
There is a proliferation of fibroblastic tissue in the connective tissue of the valve (spongiosa), deposition of mucopolysaccharides, and weakening of the valvular collagen
How can you distinguish chronic degenerative valvular disease from endocarditis, (grossly and microscopically)?
-Grossly, CDVD will have glistening, SMOOTH nodular thickenings on valve leaflet margins/chordae tendineae, whereas endocarditis will have irregular YELLOW masses with blood, fibrin, and pus (inflammatory!) that are friable
-Microscopically, CVDV will have thickened spongiosa with loose fibroblasts and accumulation of poorly-staining mucopolysaccharide material whereas endocarditis will have bacterial colonies, fibrin, neutrophils, and granulation tissue
-CDVD more common in dogs, Endocarditis more common in large animals
-Both affect mitral valve most often
What are some of the sequelae occasionally associated with chronic degenerative valvular disease of the mitral valve?
Valvular insufficiency -> vol overload -> LV eccen hypertrophy -> LH failure -> RH failure
Rupture of chordae tendineae -> acute LH failure -> sudden death
Rupture of chordae tendineae -> chronic LH failure -> pulmonary fibrosis
Rupture of the atrial wall -> yikes
Why is the endocardium prone to mineralization and what are some causes?
High elastin content predisposes to mineralization
Endocrine disease, Toxicosis
What are some of the proposed reasons why valves are more susceptible to inflammation?
-Poorly vascularized
-Area of recurrent trauma
Rank the valves from more prone to less prone to developing bacterial endocarditis.
Mitral > Aortic > Tricuspid > Pulmonary (more pressure = more affected)
Is there a species in which the order of susceptibility to valvular bacterial endocarditis is different, how so?
Yes, in cattle Tricuspid is most common: Tricuspid > Mitral > Aortic > Pulmonary
What are the most common primary sites of infection in cases of bacterial endocarditis for cattle and horses?
Cattle: peritoneal or hepatic abscesses, metritis, mastitis
Horses: (rare) septic jugular thrombophlebitis
What is the definition of cardiomyopathy?
Disorder of heart muscle of unknown or obscure etiology, intrinsic disease that can be acute, subacute or chronic
Hypertrophic cardiomyopathy is more common in what species and what is a common and serious sequela?
CATS, so much collagen, can’t contract -> concentric hypertrophy +/- left atrial thrombosis -> saddle thrombus -> posterior paresis
Dilated cardiomyopathy is more common in what species and what kind of breed? Sequela?
Large breed dogs
Increased luminal volume, interstitial fibrosis, left heart failure -> bilateral heart failure
What is hydropericardium? How can it occur?
Excessive accumulation of serous fluid in the pericardial space
Protein-losing nephropathy or enteropathy
What is hemopericardium? How can it occur?
Accumulation of blood in pericardial space
Rupture of:
Aorta (horses, turkeys)
Atrium (dogs)
Pulmonary artery
Tumor
What is the most severe consequence of hemopericardium?
Cardiac tamponade
What is the significance of serous atrophy of fat?
Indicates inadequate nutrition/starvation
What is the usual pathogenesis of fibrinous pericarditis?
Hematogenous bacterial infection aka septicemia
What are common septicemic pathogens that cause fibrinous pericarditis?
FIP in cats, Mycoplasma felis in horses, Pasteurella in cattle/sheep/pigs, Strep, E. coli, Clostridia
What is the usual pathogenesis of purulent pericarditis?
Sharp object penetrates reticulum, diaphragm, and pericardial sac (bovine traumatic reticulopericarditis) with mixed bacterial growth
What is atherosclerosis?
Degeneration of artery wall due to buildup of lipids (cholesterol, triglycerides)
Define Periarteritis
Inflammation of adventitia
Define polyarteritis
Inflammation of many arteries
Define phlebitis
Inflammation of a vein
Define vasculitis
Inflammation of vessels (arteries and veins)
Define endarteritis
Inflammation of the intima
Define Omphalophlebitis
Inflammation of the umbilical vein
Briefly describe the pathogenesis of equine verminous arteritis.
Strongylus vulgaris larvae migrate through mesenteric artery walls -> inflammatory reaction -> aneurysm, thromboembolism, infarct (aka thromboembolic colic)
What tumor is most frequently found on the right atrium of dogs and what is the prognosis?
Hemangiosarcoma, often metastasizes to lungs or may be part of multicentric hemangiosarcoma
Sequalae: rupture -> hemopericardium -> cardiac tamponade -> death
Poor prognosis
