Term
| Specific Compensatory Mechanisms of the Cardiovascular System |
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Definition
Cardiac dilation
Myocardial hypertrophy
Increased heart rate
Increased peripheral resistance (vasoconstriction)
Increased blood volume (renal response-angiotensin II-ADH-aldosterone)
Redistribution of blood flow |
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Term
| Compensation Mechanism for the Heart |
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Definition
| Decreased cardiac output-->juxtaglomerular apparatus senses -->renin release-->angiotensin II and aldosterone release-->ADH release from angiotensin II (increased renal tubular absorption of water) and increased resorption Na+/increased excretion K+ by renal tubules (from aldosterone) -->increased water resorption in the kidney-->increase in plasma-->maintenance of cardiac filling pressure BUT increased hydrostatic pressure-->Edema, also increased afterload on heart (BAD for the heart!) |
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Term
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Definition
normal left ventricular wall thickness to right ventricular wall thickness about mid-way up the ventricles is 3:1
myofibers are more susceptible to ischemia |
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Term
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Definition
response to systolic pressure overload
occurs as a response to increased pressure on the myofibers
myofibers become bigger in size and increase muscle mass
stenosis |
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Term
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Definition
response to diastolic volume overload
chamber dilation
muscle mass is increased
myofibers are stretched which increased contractile force (Frank-Starling)
septal defect |
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Term
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Definition
shunts L to R, can switch R to L
Eccentric, right ventricle (shift, concentric) |
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Term
| Ventricular Septal Defect |
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Definition
shunts L to R, can switch R to L
Eccentric, right ventricle (shift, concentric) |
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Term
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Definition
shunts L to R, can switch R to L
Once shifts, Concentric right ventricle |
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Term
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Definition
no shunting
Concentric, right ventricle |
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Term
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Definition
no shunting
Concentric, left ventricle |
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Term
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Definition
shunts L to R, can switch R to L
Concentric, right ventricle (stenosis most important) |
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Term
| Mitral Valve Insufficiency |
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Definition
no shunting
Dilated left ventricle, maybe eccentric |
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Term
| Tricuspid Valve Insufficiency |
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Definition
no shunting
Dilated right ventricle, maybe eccentric |
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Term
| Acute Right Sided Heart Failure |
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Definition
congestion of the systemic circulation, liver, spleen, GIT
hepatomegaly, splenomegaly |
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Term
| Acute Left Sided Heart Failure |
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Definition
pulmonary congestion and edema
brown tinted lung due to hemosiderin |
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Term
| Chronic Right Sided Heart Failure |
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Definition
chronic hepatic congestion
nutmeg liver
subcutaneous edema in horses and ruminants, as ascites in dogs, and as hydrothorax in cats |
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Term
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Definition
very dark red-brown with an enhanced lobular pattern centered on central veins
finding of chronic right sided heart failure
blood has backed up into the centrilobular areas and pooled, and extravasated erythrocytes have been phagocytized and the hemoglobin processed into hemosiderin by macrophages
fibrosis also occurs |
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Term
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Definition
Hemoglobin imbibition-inkish to reddish coloration imparted to tissues due to the lysis of red blood cells
intracardiac injections-focal area of hemorrhage/necrosis
intracardiac euthanasia-tissue destruction and crystal precipitation |
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Term
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Definition
occurs if there is rapid filling of the pericardial sac
impedes venous return in the heart due to compression of veins and the right side of the heart |
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Term
| Causes of Hemopericardium |
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Definition
Rupture of a large vessel (aortic tear in horses, trauma)
Coagulopathy
Neoplasia (right atrial hemangiosarcoma) |
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Term
| Causes of Hydropericardium |
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Definition
Increased hydrostatic pressure (heart failure)
Decreased oncotic pressure (cachexia)
Increased vascular permeability (pleuritis)
Obstruction of lymphatics (neoplasia) |
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Term
| Causes of Fibrinous Pericarditis in Cattle |
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Definition
Blackleg (Clostridium chauvoei)
Mannheimia haemolytica |
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Term
| Causes of Purulent Pericarditis |
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Definition
| Traumatic reticuloperitonitis (pericarditis) in cattle |
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Term
| Causes of Fibrinous Pericarditis in Sheep |
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Definition
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Term
| Causes of Fibrinous Pericarditis in Pigs |
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Definition
Haemophilus parasuis
Mycoplasma hyorhinis
Streptococcus suis
Actinobacillus suis
Edema disease (E. coli)
Vitamin E/Se deficiency (mulberry heart disease) |
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Term
| Causes of Fibrinous Pericarditis in Horses |
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Definition
Streptococcus equi (strangles) septicemia
African horse sickness |
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Term
| Causes of Fibrinous Pericarditis in Dogs |
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Definition
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Term
| Causes of Fibrinous Pericarditis in Cats |
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Definition
| Feline infectious peritonitis virus |
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Term
| Causes of Polyserositis in Pigs |
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Definition
Actinobacillus suis
Haemophilus parasuis
Steptococcus suis
Mycoplasma hyorhinis |
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Term
| Traumatic Reticuloperitonitis/Pericarditis |
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Definition
Cow eats a nail/wire-->Nail lodges in reticulum-->Reticulum contracts and pokes the nail into the diaphragm and pericardium-->Bacteria on nail now present in pericardial sac-->Purulent pericarditis
Fibrinous to Fibrous to Constrictive Pericarditis
or septicema |
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Term
| Constrictive Pericarditis in Dogs |
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Definition
fibrosis of the pericardium with fusion of the visceral and parietal layers
inhibits right sided filling
develops right sided congestive heart failure |
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Term
| Epicardial Petechial and Ecchymotic Hemorrhages |
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Definition
| occur due to septicemia, endotoxemia, anoxia, or electrocution especially in large animals |
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Term
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Definition
occurs in animals with cachexia
clear-gray and gelatinous epicardial fat
mineralization may also be observed |
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Term
| Calcium Deposition on Epicardium |
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Definition
in vitamin E/selenium deficiency in ruminants or vitamin D toxicity
gritty, white material |
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Term
| Urate Deposition on Epicardium |
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Definition
aka gout
occurs in birds and reptiles
gritty, white material |
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Term
| Hypertrophic Cardiomyopathy |
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Definition
idiopathic primary condition
thickening of any combination of the right and left ventricular wall and interventricular septum
heart does not fill well because the ventricular chamber volume is decreased
common in cats
gross diagnosis is best
can see myofiber disarray |
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Term
| Feline Hypertrophic Cardiomyopathy Mechanism of Sudden Death |
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Definition
| Feline hypertrophic cardiomyopathy-->decreased ventricular volume-->stress (increased physiologic demands on the heart)-->cardiac hypoxia/arrhythmia-->sudden death |
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Term
| Feline Hypertrophic Cardiomyopathy Mechanism of Thromboembolism |
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Definition
| Feline hypertrophic cardiomyopathy-->decreased ventricular volume-->increased blood turbulence through the heart-->thrombus formation-->thromboembolism (often lodges in the iliac bifurcation—a “saddle thrombus”) |
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Term
| Feline Hypertrophic Cardiomyopathy Mechanism of Congestive Heart Failure |
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Definition
| Feline hypertrophic cardiomyopathy-->decreased ventricular volume-->poor ventricular filling-->compensatory mechanisms-->congestive heart failure |
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Term
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Definition
can cause myocardial hypertrophy but as a secondary change
stimulation of myocytes by thyroid hormones
sequelae are the same |
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Term
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Definition
primary disease
dilation of ventricular chambers with thin walls
can interfere with the closure of the atrioventricular valves and valvular insufficiency results
results in congestive heart failure, sudden death, thromboembolism (cats)
common in dogs |
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Term
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Definition
cause dilated cardiomyopathy in cats
Taurine modulates tissue calcium influx through calcium channels |
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Term
| Dilated Cardiomyopathy in Dogs |
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Definition
affects large breed dogs and is often heritable
make this diagnosis grossly
globoid shape or hearts that look like they have a double apex due to both left and right side ventricular dilation
endocardium is thickened |
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Term
| Feline Restrictive Cardiomyopathy |
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Definition
lesions in endocardium with marked fibrosis
endocardium is thick and white
constricts proper filling of the heart leading to congestive heart failure |
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Term
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Definition
caused by toxin
end in sudden death when it interferes with conduction
or can end in congestive heart failure
most frequent areas are the left ventricular papillary muscles and the subendocardial myocardium |
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Term
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Definition
originate from the aortic body which is a chemoreceptor organ
affects brachyocephalic dogs
due to stimulation of the aortic body by chronic hypoxia
benighn but can compress and lead to congestive heart failure |
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Term
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Definition
| agonal lesion in large animals |
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Term
| Endocardial Mineralization |
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Definition
caused by Vitamin D toxicosis, Johne's disease
occurs especially in the endocardium because of the high amounts of elastic fibers |
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Term
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Definition
common in neonatal ruminants
hematocyst or lymphocyst |
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Term
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Definition
Myxomatous degeneration of the valve
mucous filled connective tissue
Smooth, shiny, nodular thickenings on valves
affects mitral valve dogs only
jet lesion may be present |
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Term
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Definition
Inflammation of the valve
Rough, friable, yellow-white masses (fibrin + usually bacteria)
affects mitral and aortic valves of cows and pigs
uremia, heart disease, and migrating worms predispose animal to this disease |
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Term
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Definition
Valvular insufficiency-->Congestive heart failure
Right side emboli-->Pulmonary abscess
Left side emboli-->infarction (especially renal, myocardial, or splenic)
Stenosis of the valve |
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Term
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Definition
narrowing of the valves
causes dilation of vessel distal to it
or causes concentric hypertrophy |
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Term
| Congenital Valvular Stenosis |
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Definition
| pulmonic and aortic valves are most commonly affected |
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Term
| Ventricular Septal Defect |
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Definition
most common congenital cardiac defect in cattle
often high on the heart
VSD-->dilated right ventricle--> eccentric hypertrophy-->pulmonary hypertension-->pressure overload--> concentric hypertrophy-->shunts from R to L
hypoxia |
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Term
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Definition
failure of closure of foramen ovale
sequelae similar to VSDs |
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Term
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Definition
Endothelial injury
Alterations in blood flow
Hypercoagulability
Enhanced platelet activity (malignant neoplasia, uremia, diabetes mellitus)
Increased clotting factor activation |
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Term
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Definition
erythrocytes separate from the plasma and fibrin
seen commonly in horses
may be due to severe anemia, systemic
inflammatory disease, leukemia, or a prolonged agonal period |
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Term
| Post Mortem Clot vs. Thrombus |
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Definition
Post mortem clots are smooth and not adherent to vessels
True thrombi are adherent to the vessel wall and granular looking |
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Term
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Definition
immune mediated, septicemia, toxemia, and viruses
leukocytes infiltrating the vessel wall
may not see grossly
fibrinoid degeneration-presence of fibrin in the vessel wall that gives it a pink, smudgy appearance microscopically |
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Term
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Definition
right sided heart failure
worms in pulmonary artery and right ventricle
induces hypertrophy of the pulmonary vessels and leads to pulmonary hypertension
concentric hypertrophy of the right heart
dead worms can embolize to the lung |
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Term
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Definition
presentation of HW disease
obstructs the venous return to the heart
shock and acute right heart failure |
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Term
| Cranial Mesenteric Arteritis in Horses |
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Definition
due to Strongylus vulgaris L4 larvae
migrate into intima
proliferation, inflammation, and fibrosis in the intima
thrombus and aneurism formation
ischemia/infarcts in the supplied gastrointestinal tract. |
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Term
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Definition
possible immune mediated vasculitis
vessels appear grossly thickened
fibrinoid necrosis, inflammation, and fibrosis in the vessel wall
Beagle Pain Syndrome |
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Term
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Definition
age related change
arterial wall has fibrosis and is thickened by increased smooth muscle
loss of elasticity
grossly as raised, firm, white plaques on the tunica intima of the vessel |
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Term
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Definition
accumulates lipid in smooth muscle cells and macrophages
myocardial infarction
necrosis and fibrosis can also occur secondary to this accumulation
dogs with hypothyroidism or diabetes mellitus
stout, thick, white vessels or if the vessel is opened, white plaques on the intimal surface |
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Term
| Arterial Medical Calcification |
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Definition
vitamin D toxicosis, calcinogenic plants, and Johne’s disease
raised white plaques on the intimal surface |
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Term
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Definition
local dilation of a vessel
happen when there is there is turbulence and hemodynamic alterations in high pressure vessels
blood enters the wall of the artery because the tunica intima is torn |
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Term
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Definition
patent vessel between the pulmonary artery and aorta
bypasses lungs |
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Term
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Definition
heritable in Keeshonds and English bulldogs
Ventricular septal defect (high)
Pulmonic stenosis
Dextroposition of the aorta (more specifically, an overriding aorta where aorta straddles VSD and can receive blood from both ventricles)
Right ventricular hypertrophy |
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Term
| Persistent Right Aortic Arch |
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Definition
embryonically two aortic arches, but one (the right side) disappears and the left one remains to become the aorta
in this disease the right one instead goes on to develop into the aorta
ligamentum arteriosum that connects the pulmonary artery to the aorta entraps the esophagus and trachea, forming a ring
megaesophagus, regurgitation, aspiration pneumonia |
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Term
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Definition
dilated lymphatic vessel
idiopathic or obstruction |
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Term
| Intestinal Lymphangectasia |
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Definition
seen in dogs
dilated lacteals in the intestine are leaky and this leads to hypoproteinemia |
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