YR3 10 CVS HO1 Flashcards
List the types of myocardial hypertrophy and dilation
Left, Right and Bi Ventricular hypertrophy and Bilateral Dilation
Pump failure is due to
Weak contractility and impaired empting and filling of chambers
Obstruction of blood flow is due to
Valvular stasis, vascular narrowing, systemic or pulmonary hypertension
Regurgitant blood flow is due to
Volume overload of chamber behind failing affected valve
Shunted blood flow from congential defects occur in
Septal defects and shunts between blood vessels
Rupture of the heart or a major vessels occurs in
Cardiac tamponade or massive internal haemorrhaging
Cardiac conduction disorders (arrhythmias) is
Failure of synchronized cardiac contraction
Pericardium serous fluid postmortem appearance
Blood tinged
Euthanaisa lesson in the endocardium
Red-brown staining +/- crystalline pricipitates
Myocardial necrosis
Caused by: Focal ischemic necrosis > myocardial infarct
Causes: arrhythmia and death
Toxic myocardial necrosis causes
Monensin toxity esp. in horses, gossypol toxicity in pigs, cassia occidentalis or avocado leaves in small ruminants, ractopamine in greyhounds
Myocardium VitE/Selenium deficiency
White Muscle Disease - young ruminants, necrosis & mineralisation
Mulberry Heart Disease - young pigs, necrosis and haemorrhage
Repair of necrotic myocardium
Inflammation in response to dead tissues - granulation tissue > fibrosis +/- mineralization
Myocardium does not regenerate
Inflammation of the myocardium is
Myocarditis
Viral myocarditis e.g.
Canine parvovirus myocarditis
Protozoal mycarditis e.g.
Neopsora caninum, Toxoplasma gondii, Sarcocystis spp.
Granulomatous myocarditis
Hairy vetch or citrus pulp toxicity in cattle
Define Cardiomyopathy
Myocardial disease of unknown cause
Cardiomyopathy e.g.
Dilated Cardiomyopathy - rare in large animals, in past caused by taurine deficient diet in cats, Hypertrophic cardiomyopathy, Feline endomyocarditis/endocardial fibrosis
Canine dilated cardiomyopathy
Strong breed predisposition w/ slight male predominance. Giant breeds esp. Great Danes & Irish Wolfhouds > Histo - attenuated wavy fibers. Large breeds esp. Doberman Pinschers & Boxers > Histo - degeneration and fatty infiltration.
Arrythmogenic right ventricular cardiomyopathy - Boxers > Histo - fatty infiltration of right ventricular wall
Juvenile onset cardiomyopathy - Portugese Water Dogs and Toy Manchester Terrier
Hypertrophic cardiomyopathy (HCM)
Feline idiopathic hypertrophic cardiomyopathy.
Common in all breeds, adult male predisposition.
Thickened interventricular septum & left ventricular free wall, enlarged left atrium. End stage HCM is fibrotic and relatively thin walled but will still weigh more than normal
Feline thyrotoxic cardiomegly
Seen in older cats associated with functional adenomatous hyperplasia of thyroid - NOT the same as HCM, which is IDIOPATHIC
Feline endomyocarditis/endocardial fibrosis
Idiopathic but infectious suspected. Inflammatory stage in young cats enlarged heart +/- discolouration of aortic outflow tract. Acute - left ventricular haemorrhage and inflammation, Chronic - left ventricular fibrosis (restrictive cardiomyopathy)
Inflammation of the pericaridum is called
Pericarditis
Pericarditis e.g.
Fibrinosuppurative pericarditis, Canine idiopathic pericarditis/pericardial effusion/haemorrhage, Equine pericarditis
Fibrinosuppurative pericarditis
Systemic disease in any species but common in cattle due to traumatic reticulopericarditis aka hardware disease. Bread and butter appearance
Canine idiopathic pericarditis/pericardial effusion/haemorrhage
Large breed dogs w/ slow onset but fair prognosis. May predispose to mesothelioma
Equine pericarditis
Coincides w/ mare reproductive loss syndrome. Great risk factor is exposure to tent caterpillars
Epicardial haemorrhage
May be petechial, ecchymotic or diffuse associated w/ septicaemia, anoxia, endotoxaemia. Very common in horses post mortem
Serous atrophy of epicardial fat
Coronary grooves normally contain fat, loss of this fat indicated severe emaciation. Atropied fat is gelantinous and resembles serum hence “serous”
Congestive heart failure causes
1)Pulmonary congestion and edema 2)Pulmonary hemosiderosis (brown induration) - esp. w/ heart worms 3)Oedema > Acites in dogs, Pleural effusion (hyrothorax/chylothorax) in cats, Dependant subcutaneous oedema in cattle and horses 4)Chronic passive congestion of liver (nutmeg liver)
Saddle thromboembolus pathogenesis
Feline cardiomyopathy (commonly HCM) > turbulence in left atrium > left atrium thrombus forms > embolizes to aortic bi/trifurcation > ischemia and necrosis of hind limbs
Endocardiosis
Degenerative change of valves. Common aging chance in dogs, esp. small breeds > congestive heart failure. Gross lesion - smooth white-grey nodules on AV valve esp. left
Inflammation of the endocardium
Endocarditis, typically bacterial and valvular
Endocarditis in Dogs
Large breeds >5yrs. Endocardiosis is not a predispoing factor. Left side of heart is mostly affected. Agents - Bortonella (aorta), Streptococcus (mitral valve, polyarthritis, Gram neg (E.coli, Salmonella etc) any valve
Endocarditis in Horses
Left side most often affected (aortic > mitral)
Endocarditis in Ruminants, camelids
Righ side most often affected (tricupid > pulmonary)
Endocarditis lesion (m&m)
Gross - Verrucous rough tan to red material adhered to valves (vegetative)
Histo - Fibrin and bacteria (a septic thrombus)
Endocarditis pathogenesis and sequelae
Circulation bacteria attach to the valve/damage to endothelium > fibrin and neutrophils form septic thrombus on valve > pieces break off and embolize.
Conseq a)Valvular insufficiency > congestive heart failure b)Septic emboli > multi organ infarcts
Valvular cysts
Congenital lesion most common in cattle filled with serum or blood
Types of AV valvular disease
Hematocyst, lymphocyst, calcification, endocardiosis, endocarditis and ruptured chordae tendinae
Parasites of the heart
Dirofilariasis (Dirofilaria immitis)
Dirofilariasis
Nematodes found in the pulmonary arteries and right heart. Huge worm load can extend into the vena cava = vena caval syndrome. Pulmonary artery endothelium gets rough. Lungs can be brown due to hemosiderosis
Heart Neoplasms
Hemangiosarcoma, chemodectoma, lymhoma, mesothelioma
Heart hemangiosarcoma
Very common in dogs esp. Golden Retriever and German Shepherd. Right atrial appendage is the most common site. Rupture or oozing results in hemopericaridium and cardiac tamponade.
Chemodectoma
Heart base tumour = aortic body tumour
Most common in dogs (esp. brachycephalic), but seen in cats and cattle. Arise from aortic body (chemoreceptor) bet. the aorta and pulmonary artery
Heart lymphoma
Myocardial location more common in cattle but also occurs in cats and dogs
Mesotheliom
Malignant neoplasm of mesothelial cells which line the serosal surfaces including the pericardium > pericardial effusion
Congenital heart anomalies list
Failure of closure of atriovenous communication, failure of valve formation, Tetralogy of Fallot, PRAA, Ectopia cordis, Analomous coronary artery
Congenital heart anomalies - Failure of closure of arteriovenous communication
Patent ductus arterious, Atrial Septal defect, Ventricular Septal defect, Atrioventricular canal
Patent ductus arteriosus (PDA)
Normally patent in fetus and in foals up to 5days. Persistent patency due to hyoplasia of smooth muscle wall of ductus
Atrial septal defect (ASD)
Differentiate from foramen ovale (which has a flap)
Ventricular septal defect (VSD)
Common in all domestic animals
Atrioventricular canal defect
Open communitcation between all 4 chambers
Congenital heart anomalies - Failure of valve formation
Pulmonic stenosis, aubaortic stenosis, mitral valve dysplasia, tricupid valve displasia
Pulmonic stenosis (PS)
Relatively common in dogs. May be subvalvular, valvular or supravalvular. Results in right ventricular hypertrophy DO NOT CONFUSE W/ HCM
Subaortic stenosis (SAS)
Common in dogs and some strains of pigs. Fibrous tissue below aortic valve. Results in marked left ventricular hypertrophy. Myocardial necrosis and death is common
Mital valve dysplasia
Common in cats. Thickened, nodular and fused valve leaflets. Results in valvular insufficiency > left ventricular hypertrophy and dilated left atrium
Tricuspid valve dysplasia
Most common in cats. Thickened, nodular and fused valve leaflets. Results in valvular insufficiency > right ventricular hypertrophy
Congenital heart anomalies - Tetralogy of Fallot
1.Ventricular septal defect 2.Overriding aorta 3.Pulmonic stenosis 4.Right ventricular hypertrophy
Congenital heart anomalies - Persistent right aortic arch (PRAA)
Common in dogs esp. German Shepherds. Caused when the aorta formed from the right arch instead of the left hence how the aorta is on the right. To connect the aorta w/ the pulmonary artery, the ductus arteriosus must pass dorsally over the oesophagus and trachea, all this constricts the oesophagus
Congenital heart anomalies - Ectopia cordis
Heart located anywhere but the chest
Congenital heart anomalies - Anomalous coronary arteries
Seen in calves can result in ischemic myocardial necrosis
Disorders of the blood vessels
Inflammation, Arteriosclerosis and Aortic rupture
Inflammation of vessels is
Vasculitis; not common
Fibrinoid vasculitis
Necrotic smooth muscle replaced by fibrin causes include viruses, bacteria, endotoxin, type III hypersensitivity and uremia
Fibrinoid vasculitis disease e.g.
Mulberry heart disease
Inflammation of the arteries
Arteristis
Arteritis e.g.
Canine meningeal polyarteritis, verminous arteritis
Canine meningeal polyarteritis
Beagle Pain Syndrome - most common in 6-9mth old lab beagles but other breeds affected. Present with fever, depression and neck pain. Severe necrotizing arteritis of meningeal vessels
Verminous artertitis
Weaking of the vessel wall by larvae and inflammation. Occurs in the cranial mesenteric artery and less commonly in the aorta.
1) Strongylus vulgaris larvae migration in horses
2) Thrombosis of cranial mesenteric artery results in ischemia of intestions > colic
3) Aneurysm can develop
Inflammation of veins
Phlebitis
Phlebitis e.g.
Omphalophlebitis - inflammation of the umbilical vein and Latrogenic phlebitis - due to traumatic venipuncture
Thickening or harding of arteries is called
Arteriosclerosis
Arteriosclerosis e.g.
Fibrosis & mineralization and artherosclerosis
Fibrosis and Mineralization of arteries
Common aging change in dogs of the caudal abdominal aorta. Prediposes to aortic thrombosis
Artherosclerosis of arteries
Intramural depostion of lipid. Occasionaly seen in diabetic and hypothyroid dogs
Aortic rupture
Most often due to trauma. Uncommon in animals but most often on horses during racing
Neoplasms of vacular origin
Hemangioma, hemangiosarcoma, lymphangiosarcoma
Vascular Hemangioma
Benign tumour of endothelial cells. Dermal - sometimes accoicated w/ sun exposure, Subcutaneous - common bening tumour in dogs
Vascular Hemangiosarcoma
Malignant tumor of endotheil cells. Most common in Golden Retrievers and German Shepherds. Primary sites - spleen, right atrium, liver. Metastic sites - lungs, liver, kidney, brain, speel, right atrium
Vascular Lymphangiosarcoma
Malignant tumour of lymphatic endothelial cells. Cats - caudal ventral abdominal subcutis > poor prognosis. Rare in other species
