What are the six reasons for pump/flow failure?
Primary myocardial injury Obstructed flow Regurgitant flow Blood shunts Conduction disturbances Ruptures
What occurs with primary myocardial injury?
Weak contraction + Incomplete emptying/filling of chambers
What occurs with obstruction of flow?
increased volume and pressure behind obstruction
What can cause obstruction to flow?
Stenotic valves
Narrowed vessels
Systemic/pulmonary hypertension
What is regurgitant flow?
increases volume behind failing valve
What are aneurysms?
Localized dilation in blood vessels. Making them thin and weak and in turn prone to rupture
Where do aneurysms most commonly occur?
Large elastic arteries in thoracic or abdominal cavities
What occurs with an incomplete tear?
Blood dissects along smooth muscle or adventitial planes, slowing the speed of blood loss
What is the common location of aneurysm in turkeys?
Abdominal aorta
Why to turkeys get aneurysms in a specific location?
related to rapid growth
What is the common location of an aneurysm in a stallion?
Proximal aorta
Why are stallions predisposed to aneurysms in a specific location?
Breeding associated
What is the cause of abdominal aorta aneurysms in horses?
Strongylus vulgaris
What are the two places dogs are prone to have aneurysms?
Thoracic aorta + Proximal aorta
Why do dogs tend to get aneurysms in their thoracic aorta?
Spiro lupi
Why do dogs tend to get aneurysms in their proximal aorta?
Underlying CT disorder
Why do pigs tend to get aneurysms?
Copper deficiency
What are the three types of degenerative vascular disease?
Arteriosclerosis + Atherosclerosis + Arterial medial calcification
What is arteriosclerosis?
Large elastic arteries with intimal fibrosis
What can cause arteriosclerosis?
Turbulence + Age
What is atherosclerosis?
Elastic + Muscular arteries, intima + media lipid deposits
When is atherosclerosis seen?
Pigs, birds, and dogs with high cholestrol
What is arterial medial calcification?
Elastic + muscular arteries, mineral deposition
What are the possible causes in arterial medial calcification?
Calcinogenic plants
Vit. D toxicosis
Uremia/renal disease
Johne’s disease
What causes brisket disease?
High altitude creates hypoxic environment that triggers pulmonary hypertension in cattle
What is the mechanism by which brisket disease occurs?
Hypoxia - Vasoconstriction - Work induced hypertrophy of arterial walls - increased pressure + resistance - dilation/hypertrophy of right ventricle = CHF
What gives brisket disease it’s name?
Ventral edema
What areas are affected most with myocardial hypoxia + necrosis?
Papillary muscles of LV
Subendocardial areas
What are the histological presentation of myocardial injury?
Swelling, hypereosinophila + vacuolar degeneration
Loss of striations
Nuclear pyknosis
Inflammatory infiltrates
What is the progression of heart failure?
Primary pump failure
Backward failure
Forward failure
What is backward failure?
Accumulation of blood behind failing chamber
What is forward failure?
Loss of cardiac reserve, reduction of blood flow to peripheral tissues
What occurs if heart failure progresses gradually?
Cardiovascular compensatory changes
What happens with cardiovascular compensatory changes?
Chamber dilation + Myocardial hypertrophy = increased SV
Increased HR + BV + Peripheral resistance
Redistribution of BF
What does hypoxia induce in bone marrow?
Erythropoiesis
What does hypoxia induce in the spleen?
Polycythemia
What does polycythemia + erythropoiesis do to the composition of blood?
Oxygen carrying capacity increase as well as viscosity
Therefor workload on the heart also increases
What clinical symptoms do you see with right sided heart failure?
Hepatic + Splenic congestion
Ventral subcutaneous edema
Ascites
Hydrothroax
What occurs with left sided heart failure?
Pulmonary edema + Congestion
How does hypoxia effect the kidneys?
Juxtaglomerular cells are stimulated to release Renin
Renin stimulates aldosterone + AngII
What does AngII do?
Thrist + ADH release
What does aldosterone do?
Water retention + potassium loss
What are the two types of cardiomyopathy?
Dilated + Hypertrophic
What are the two major reasons for left sided heart failure?
Myocarditis + Myocardial necrosis
Mirtal/Aortic valve disease
What are two major reasons for right sided heart failure?
Pulmonary hypertension
Triscuspid + Pulmonic stenosis
What part of the heart is good for detecting nutritional status of the animal?
Fat on the heart
What are jet lesions?
Fibrosis under endocardium above or below abnormal valve due to turbulence
What is an atrial septal defect?
Incomplete closure of atrial septum or failure of closure of foramen ovale
Where is ASD seen most commonly?
Boxer + Doberman + Samoyed breeds
What occurs with ASD?
LT to RT shunting of blood Increased volume of blood to lungs Enlarged pulmonary vessels Pulmonary arterial hypertension RA ventricular dilation
What is a ventricular septal defect?
Incomplete closure anywhere along ventricular septum
Where is VSD seen most commonly?
English bulldogs + English springer spaniels + West Highland white terriers
What occurs with VSD?
LT to RT shunting
LARGE DEFECTS lead to: Cardiomegaly + LA enlargement + pleural effusion + pulmonary edema
What is patent ductus ateriosus?
Failure of closure of fetal connection formed by 6th aortic arch between aorta and pulmonary artery
What would the connection responsible for PDA normally form?
Ligamentum arteriosum
What occurs with PDA?
LT to RT shunting
LV preload + enlargement
Pulmonary vessel dilation
Pulmonary hypertension
What is clincally heard with a PDA?
Continous murmur
What are the most common heart defects seen in horses?
VSD - PDA - Persistent truncus arteriosus
What are the most common heart defects seen in ruminants?
Valvular hematomas
Patent foramen ovale
VSD
Transposition of aorta + pulmonary artery
What are the most common heart defects seen in pigs?
Subaortic stenosis
Endocardial cushion defects
What are the most common heart defects seen in dogs?
PDA Pulmonic stenosis Subaortic stenosis PRAA VSD
What are the most common cardiac defects seen in cats
Endocardial cushion defects Mitral malformation VSD Endocardial fibroelstosis PDA
What are the four conditions of tetralogy of fallot?
Narrowing of pulmonary valve
Thickening of RV wall
Displacement of aorta over ventricular septal defect
Ventricular septal defect
Where is tetralogy of fallot most commonly seen?
Keeshond + English bulldogs
What occurs with tetralogy of fallot?
RT to LT shunt via VSD
RV outflow obstruction due to pulmonic stenosis
RV hypertrophy
What clinical signs are seen with tetralogy of fallot?
Cyanosis
What are the two types of valvular stenosis?
Pulmonic + Aortic
What is valvular stenosis?
Bands of firm CT form just below the valve (“Subvalvular stenotic ring”)
– or –
Narrowing formed by deformed/thickened valve
What occurs with pulmonic stenosis?
Concentric RV hypertrophy from pressure overload in this chamber
What occurs with aortic stenosis?
LV concentric hypertrophy
Varying degrees of LV necrosis
Fibrosis + Intraventricular arterial hypertrophy + hyperplasia
What is hydropericardium?
Fluid in the pericardial sac
What is hemopericardium?
Bleeding to into the pericardial sac
What is cardiac tamponade?
When either hydropericardium or hemopericardium occur to a severe enough extent causes restriction on the heart. Leading to reduced ventricular filling + Pulmonary edema + Cardiogenic shock
What is pericarditis?
Fibrinous w/ acute inflammation
What occurs with hardware disease?
Migration of linear metal from reticulum
Penetrates pericardial sac
Introduction of gut/environmental bacteria
Pericarditis
What is brain-heart syndrome?
Association between neurologic injury + myocaridal necrosis
Associated w/ SNS stimulation of myocardial beta receptors
What is selenium a key component of?
Glutathione peroxidase
Why are myocardial cells the most sensitive to selenium or Vit E deficiencies?
Increased activity + high oxygen demand makes these cells particularly sensitive to oxidative damage
What age is selenium and vitamin E deficiencies seen?
Young
What disease do you see in pigs due to selenium deficiency?
Mulberry heart disease
What disease do you see in cows with selenium deficiencie?
White muscle disease
What is a major function of copper?
Promoting cross-linking of collagen
What do you see with copper deficiencies?
Lesions in a number of organs
Weakened vascular integrity
Predisposes animal to aneurysmal dilations or tears
What are three deficiencies that cause myocaridal necrosis, besides copper?
Thiamine + Magnesium + Potassium
What animal is most commonly known for ionophore coccidiostat toxicity?
Horses
What is anthracycline?
Antineoplastic drug used to treat lymphosarcoma in dogs
What does anthracycline toxicity cause?
Acute myocardial necrosis via oxidative damage
Cytokine release + inhibition of protein synthesis
When is gossypol toxicity seen?
Horses, ruminants, + swine fed a cottonseed diet
What occurs with gossypol toxicity?
Lesions on organs similar to ionophore toxicity