Cardiopathology Session 1 Flashcards
Describe the blood flow through the heart
- Vena cava
- Right atrium
- Tricuspid valve
- Right ventricle
- Pulmonic valve
- Pulmonary artery
- Lungs
- Pulmonary veins
- Left atrium
- Mitral valve
- Left ventricle
- Aortic valve
- Aorta
What is the ratio of ventricular wall thickness right to left? And why?
Right to left ventricular wall thickness ratio 1:3
Left much bigger because systemic pressure greater than pulmonary and has to pump blood to whole body
What are the 2 important functions of valves
- Open correctly so that blood can empty from the chamber
- Close properly so that blood doesn’t flow backwards
What is the electrical pathway through the heart
SA node—> AV node—> bundle of his—> Purkinje fibers
What are some clinical signs of heart disease
Coughing, increase respiratory effect, exercise intolerance/fatigue/collage, murmur, arrhythmia, fluid build up, cyanosis
What is a murmur
Sound of blood turbulence
What are the 3 results of heart failure
- Accumulation of blood behind failing chamber
- Decreased blood to peripheral tissues
- Decreased blood to heart itself
What are the two types of heart failure
- Sudden vs gradual
- Right vs left sided
What is sudden/acute myocardial failure
Sudden and severe pump and flow failures
What are the clinical signs of sudden/acute myocardial failure
Syncope: loss of consciousness, collapse
What type of shock is typical of sudden/acute myocardial failure
Cardiogenic shock- inability to pump as much blood as body needs
What is gradual/chronic myocardial failure
Less severe pump and flow failures and will induce cardiovascular compensatory changes
What are the compensatory changes associated with gradual myocardial failure
- Chamber dilation
- Myocardial hypertrophy
- Increased HR
- Increased peripheral resistance
- Increased blood volume
- Redistribution of blood flow
What is the goal in compensating for gradual/chronic myocardial failure
To get as much blood to vital organs as possible
Eccentric hypertrophy is a ___ overload
Volume
What type of lesions/defects are associated with eccentric hypertrophy
Valve lesions and septal defects
How does the heart change in eccentric hypertrophy
Increased ventricular lumen (dilation) with increased wall thickness (initially)
Concentric hypertrophy is ___overload
Pressure
What problems are associated with concentric hypertrophy
Stenotic valves and obstructions
How does the heart change in concentric hypertrophy
Decreased ventricular lumen with increased wall thickness
Right sided heart failure is congestion of ____circulation
Systemic
Where can congestion also occur in the body due to right sided heart failure
Hepatic and splenic congestion—> chronic leads to fibrosis
In large animals which of the 4 causes of edema results in edema in right sided heart failure and where is found
Increased hydrostatic pressure, edema in ventral subcutaneous
In dogs and cats which of the 4 causes of edema is causing edema in right sided heart failure and where is edema
Increase hydrostatic pressure
Cats: pleural effusion
Dogs: peritoneal effusion
What does the liver look like with right sided heart failure
Nutmeg like liver due to fibrosis, liver is very firm
Left sided heart failure results in congestion in ___circulation
Pulmonary
What kind of edema results from left sided heart failure and which of the 4 causes of edema causes this
Increase hydrostatic pressure resulting in pulmonary edema
Pulmonary hemorrhage results in ____ which you can use iron stain to visualize ___cells
Hemosiderosis
Use iron stain to visualize hemosiderin laden macrophages aka heart failure cells
Which sided heart failure is associated with this liver
right sided- nutmeg liver
What is wrong here and what could have caused this
Ventral SQ edema caused by right sided heart failure
What is wrong here and what caused this
pleural effusion due to right sided heart failure
What is wrong here and what could have caused this
foaming fluid in the trachea due to pulmonary edema/congestion from left sided heart failure
What does this histology slide indicate
Left sided heart failure- presence of heart failure cells
What valves are affected in right sided heart failure
Tricuspid and pulmonary
What are some examples of diseases that can cause right sided heart failure
Tricuspid dysplasia, pulmonic stenosis, Brisket disease
What valves are involved in left sided heart failure
Mitral or aortic
What are some examples of diseases associated with left sided heart failure
Mitral myxomatous degeneration (valvular endocarditis), aortic stenosis
What are some cardiomyopathies that can effect either or both sides of heart
- HCM or DCM
- Myocarditis or myocardial necrosis
What are the changes in the kidney associated with heart failure
- Hypoxia
- Drop in renal BF
- Vasoconstriction-further drop in BF— juxtaglomerular cells release renin
- Renin—aldosterone— increase sodium and h20 retention, renin release AII vasoconstriction and increase BP
- Water retention causes increased circulating volume and preload (CO increases), increased venous filling pressure- fluid accumulates in cavities and interstitium
Hypoxia also promotes erythopoiesis and extra medullary organs- polycythemia oxygen carrying capacity goes up with increased blood viscosity—> increase workload—> further decompensation
Myocardial hypoxia results in ___
Necrosis—> decreased perfusion through coronary vasculature most commonly effects papillary muscles of the left ventricle and subendocardial areas
Decreased perfusion through coronary vasculature most commonly effects where
Papillary muscles of the left ventricle and subendocardial areas
What are the histology signs of myocardial hypoxia—>necrosis
Swelling, hyperesoinophilia, vacoulization, loss of striations, pyknosis, basophilic cytoplasmic granules (calcification), inflammatory infiltrates, fibroblast proliferation and increased collagen (Scarring)
What are the 6 mechanisms of cardiovascular failure
- Ruptures
- Obstructed flow through the heart
- Regurgitant flow
- Blood shunts
- Conduction disturbances (arrhythmias)
- Pump failure- primary myocardial injury
What occurs during rupture and what are some examples
Extravasated blood—> hemorrhage or cardiac tamponade
Ex:trauma, hemangiosarcoma
What occurs when there is obstructed flow through the heart and what are some examples
Increases volume and pressure behind the obstruction
Ex: narrowed valves or vessels (Stenosis, hypertension, mass effect)
What occurs during regurgitant flow and examples
Increases volume behind the failing valve
Ex: deformed or damaged valves/chordae tendineae
What occurs during blood shunts and some examples
Heart defects that allow alterations in flow
Ex: septal detects, patent vessels
What occurs during conduction disturbances (arrhythmias)
Altered and unsynchronized cardiac contraction
Ex: cardiac glycosides (foxglove, oleander)
What occurs during pump failure- primary myocardial injury and examples
Weak contraction, incomplete emptying and reduced filling of chambers
Ex: myocardial infection, damage, necrosis, cardiomyopathies
____embryological heart defects tend to result in early loss or death
Severe
___ embryological heart defects may never show clinical signs
Mild
What are some causes of congenital diseases of the heart
Spontaneous, heritable, induced in utero (toxic, hypoxia, radiation, maternal nutritional deficiencies, excess, infectious diseases)
What is the endocardial cushion defect
Normally Two thicker areas in the cardiac tube from which the heart chambers and valves form, the defect forms one big chamber
What is patent ductus arteriosus
Failure of closure of the ductus arteriosus between the aorta and pulmonary ligament
Normally forms ligamentum arteriosum
How is the murmur sound related to the size of the defect
The smaller the defect the louder the murmur
How does blood flow in ASD and PFO
LA—>RA
What kind of hypertrophy occurs in shunts
Eccentric hypertrophy—>volume overload
What happens to the lungs during volume overload related to shunts
Increased pulmonary blood flow, enlarged pulmonary vessel, pulmonary arterial hypertension
What is the most common shunt defect across all animals, especially English bulldog, English springer spaniel
VSD
What is the most common shunt in dogs, specifically small/toy breeds
PDA
What kind of hypertrophy occurs with stenosis
Concentric hypertrophy- pressure overload
What valves does stenosis typically occur at and what is the result
Pulmonic/subpulmonic and aortic/subaortic
Resulting in hypertrophy of the ventricle that comes right before it
What breeds is pulmonic stenosis common in
English bulldogs, Boston terriers, boxers, terriers (brachycephalic)
What breeds is aortic stenosis common in
Large breed dogs (and pigs)
What are some results from tricuspid and mitral valve malformation/dysplasia
Valvular insufficiency
Volume overload
Hypertrophy of the ventricle that comes right after it
What type of hypertrophy occurs due to tricuspid and mitral valve malformation/dysplasia
Eccentric hypertrophy- volume overload
What species is more likely to get tricuspid and mitral valve malformation/dysplasia
Cats
What is tetralogy of fallout
Four abnormalities occur in the heart
1. VSD
2. Pulmonic stenosis
3. Overriding aorta
4. Right ventricular hypertrophy
R—>L shunt- dangerous because deoxygenated shunted to systemic circulation
What is the vascular ring anomaly
Aortic arch forms on the right side and pulmonary artery on the left. The ductus arteriosum/ ligamentum arteriosus comes across the esophagus and and compresses it—>cranial megaesophagus
What breeds is vascular ring anomaly common in
German shepherds, Irish setter, Great Danes
What are some common sequela of vascular ring anomaly
Regurgitation, aspiration pneumonia, poor weight gain
What is the treatment for vascular ring anomaly
Cut it
What is ectopia cordis and what species is it most common in
Heart located anywhere but in the chest
Common in calves
