Cardiovascular Flashcards
Veins always …
(a) carry blue blood
(b) carry deoxygenated blood
(c) travel towards the heart
(c) travel towards the heart
Arteries always …
(a) carry red blood
(b) carry oxygenated blood
(c) travel away from the heart
(c) travel away from the heart
Name the major blood vessels that enter the left atrium.
Pulmonary veins
Name the major blood vessels that enter the right atrium.
Cranial vena cava AND caudal vena cava
Name the major blood vessel that leaves the left ventricle.
Aorta
Name the major blood vessel that leaves the right ventricle.
Pulmonary trunk
Name the heart valve at the outflow of the right ventricle.
Pulmonic valve
Name the heart valve at the outflow of the right atrium.
Right atrioventricular valve (“tricuspid” valve)
Name the heart valve at the outflow of the left ventricle.
Aortic valve
Name the heart valve at the outflow of the left atrium.
Left atrioventricular valve (“mitral” valve)
Which is the higher pressure system: the pulmonary or systemic circulation?
Systemic circulation is higher pressure
Which is the lower pressure system: the pulmonary or systemic circulation?
Pulmonary circulation is lower pressure
Which side of the heart (right or left) propels blood through the pulmonary circulation?
Right
Which side of the heart (right or left) propels blood through the systemic circulation?
Left
There are six BASIC pathophysiologic mechanisms of cardiac dysfunction. What are they?
(1) Pump failure: Weak contractility and emptying of chambers, impaired filling of chambers.
(2) Obstruction to forward blood flow: Valvular stenosis, vascular narrowing, systemic or pulmonary hypertension.
(3) Regurgitant blood flow: Volume overload of chamber behind failing affected valve.
(4) Shunted blood flows from congenital defects: Septal defects in heart, shunts between blood vessels.
(5) Rupture of the heart or a major vessel: Cardiac tamponade, massive internal hemorrhage.
(6) Cardiac conduction disorders (arrhythmias): Failure of synchronized cardiac contraction.
There are six short- and long-term compensations that help maintain cardiac output for a while in the face of cardiac disease. What are they?
(1) Increased heart rate
(2) Increased peripheral resistance
(3) Increased blood volume
(4) Redistribution of blood flow
(5) Cardiac dilation
(6) Myocardial hypertrophy
Is dysfunction of the mitral valve more likely to cause left-sided heart failure or right-sided heart failure?
Left-sided heart failure
Is dysfunction of the aortic valve more likely to cause left-sided heart failure or right-sided heart failure?
Left-sided heart failure
Is dysfunction of the tricuspid valve more likely to cause left-sided heart failure or right-sided heart failure?
Right-sided heart failure
Is dysfunction of the pulmonic valve more likely to cause left-sided heart failure or right-sided heart failure?
Right-sided heart failure
The decreased blood flow to peripheral tissues caused by heart failure is called …
Forward failure
The accumulation or backing up of blood “upstream” from a failing heart chamber is called …
Backward failure
What does the term “forward failure” mean as it pertains to the systemic effects of heart failure?
The decreased blood flow to peripheral tissues caused by heart failure.
What does the term “backward failure” mean as it pertains to the systemic effects of heart failure?
The accumulation or backing up of blood “upstream” from a failing heart chamber
Explain the pathogenesis whereby renal HYPOTENSION (not hypoxia) caused by a failing heart can worsen heart disease.
Failing heart -> Reduced flow to peripheral tissues -> RENAL HYPOTENSION ->
Renin release from juxtaglomerular apparatus (JGA) -> Aldosterone release from adrenal cortex -> Sodium & water retention -> Increased plasma volume -> Increased workload for already failing heart -> WORSENING HEART DISEASE
Explain the pathogenesis whereby renal HYPOXIA (not hypotension) caused by a failing heart can worsen heart disease.
Failing heart -> Reduced flow to peripheral tissues -> RENAL HYPOXIA -> Erythropoietin release from kidney -> Increased erythropoiesis in bone marrow -> Polycythemia -> Increased blood viscosity -> Increased workload for already failing heart -> WORSENING HEART DISEASE
List four gross NON-CARDIAC lesions that may be caused by accumulation of blood behind a failing chamber (backward failure).
(1) Subcutaneous edema; (2) Ascites; (3) Pulmonary edema; (4) Hepatic congestion and hepatomegaly
What is the characteristic non-cardiac lesion seen in ACUTE left-sided heart failure?
Acute pulmonary congestion & edema
Pulmonary lesions are typically associated with which type of heart failure: left-sided or right-sided?
Left-sided
What are three characteristic non-cardiac lesions seen in CHRONIC left-sided heart failure?
(1) Chronic pulmonary edema; (2) Pulmonary fibrosis; (3) Pulmonary hemosiderosis (lungs appear tan-brown due to the presence of “heart failure cells” in alveoli. These are alveolar macrophages containing recycled iron pigments from red blood cells that have been “squeezed” into the alveolar lumen and phagocytosed.)
What is the characteristic non-cardiac lesion seen in ACUTE right-sided heart failure?
Acute passive congestion in liver (-> hepatomegaly)
What is the characteristic non-cardiac lesion seen in CHRONIC right-sided heart failure?
Chronic passive congestion of the liver (-> enhanced reticular pattern that, in this case, can actually be called “nutmeg liver”)
Right-sided heart failure often causes severe edema. Different domestic species manifest edema in different anatomic locations. Match each of the following animals to the most common type of edema shown in heart failure (e.g., a-1):
(a) Cat; (b) Dog; (c) Horse; (d) Ruminant
(1) Ascites; (2) Hydrothorax; (3) Subcutaneous edema
(a) Cat - (2) Hydrothorax
(b) Dog - (1) Ascites
(c) Horse - (3) Subcutaneous edema
(d) Ruminant - (3) Subcutaneous edema
Right-sided heart failure often causes severe edema. Different domestic species manifest edema in different anatomic locations. Which of the following is most typical in a CAT with heart failure?
(1) Ascites; (2) Hydrothorax; (3) Subcutaneous edema
(2) Hydrothorax
Right-sided heart failure often causes severe edema. Different domestic species manifest edema in different anatomic locations. Which of the following is most typical in a DOG with heart failure?
(1) Ascites; (2) Hydrothorax; (3) Subcutaneous edema
(1) Ascites
Right-sided heart failure often causes severe edema. Different domestic species manifest edema in different anatomic locations. Which of the following is most typical in a HORSE with heart failure?
(1) Ascites; (2) Hydrothorax; (3) Subcutaneous edema
(3) Subcutaneous edema
Right-sided heart failure often causes severe edema. Different domestic species manifest edema in different anatomic locations. Which of the following is most typical in a COW with heart failure?
(1) Ascites; (2) Hydrothorax; (3) Subcutaneous edema
(3) Subcutaneous edema
What is the term for accumulation of serous fluid (i.e., a transudate, not blood or exudate) in the pericardial space?
Hydropericardium
What does the term hydropericardium mean?
Accumulation of serous fluid (i.e., a transudate, not blood or exudate) in the pericardial space
What are three possible reasons for the development of hydrothorax, and what, briefly, is the pathogenesis of each?
(1) Hypoproteinemia (-> decreased colloid oncotic pressure): e.g., liver failure, protein-losing nephropathy, protein-losing enteropathy
(2) Heart failure (-> increased hydrostatic pressure); may also see ascites or hydrothorax
(3) Widespread vascular injury (-> leakage of plasma and plasma proteins); certain infectious diseases such as heartwater in ruminants, African horse sickness, African swine fever, bovine ephemeral fever … [many are exotic]
Hydropericardium and hydrothorax are synonyms. True or false?
False. Fluid accumulates in the pericardial cavity in hydropericardium but in the pleural cavities in hydrothorax.
What does the term hemopericardium mean?
The accumulation of whole blood in the pericardial cavity
What is the term for the accumulation of whole blood in the pericardial cavity?
Hemopericardium
Which is more likely to be rapidly fatal: hemopericardium or hydropericardium? And why?
Hemopericardium is more likely to be rapidly fatal as blood accumulation is typically sudden and caused by a bleeding vessel or chamber. The pericardium cannot distend, resulting in the heart being compressed by accumulated blood within the fibrous pericardial sac and failing acutely. This is called cardiac tamponade.
PLEASE NOTE THAT AT THIS POINT ONLY HALF THE ANSWER REQUIRED HAS BEEN PROVIDED. THE REMAINDER IS BELOW. PLEASE FINISH YOUR ANSWERS IN EXAMS.
In contrast, fluid accumulates slowly and at low pressure in hydropericardium, allowing the pericardium time to expand to some degree. This avoids compression of the heart.
By far the most common cause for hemopericardium in dogs is “leaking” cardiac hemangiosarcomas. What are three other, less common causes?
(1) Idiopathic; (2) Spontaneous atrial rupture; (3) Blunt force thoracic trauma (e.g., by car); (4) Intracardiac injections; (5) Other cardiac neoplasm (e.g., aortic body tumor AKA chemodectoma)
What is the most common cause for hemopericardium in dogs?
“Leaking” cardiac hemangiosarcomas. Typically these are located on the right auricle.
What is the most common cause for hemopericardium in horses?
Spontaneous aortic rupture. [NOT hemangiosarcoma; you’re thinking of dogs.]
You are performing a necropsy on a horse. As you peel the pericardial sac off the heart you are reminded of the appearance of soft butter when two slices of bread are peeled apart. What are you dealing with? And what is the most likely cause?
Fibrinous or fibrinosuppurative pericarditis; either is fine. [NOT fibrous pericarditis, hemopericardium, hydropericardium, or intrapericardial injection of spreadable dairy products.] In horses this is typically caused by bacterial septicemia, e.g., Streptococcus equi
You are performing a necropsy on a pig. As you peel the pericardial sac off the heart you are reminded of the appearance of soft butter when two slices of bread are peeled apart. What are you dealing with? And what is the most likely cause?
Fibrinous or fibrinosuppurative pericarditis; either is fine. [NOT fibrous pericarditis, hemopericardium, hydropericardium, or intrapericardial injection of spreadable dairy products.] In pigs this is typically caused by bacterial septicemia, e.g., Haemophilus parasuis
You are performing a necropsy on a cow. As you peel the pericardial sac off the heart you are reminded of the appearance of soft butter when two slices of bread are peeled apart. What are you dealing with? And what is the most likely cause?
Fibrinous or fibrinosuppurative pericarditis; either is fine. [NOT fibrous pericarditis, hemopericardium, hydropericardium, or intrapericardial injection of spreadable dairy products.] In cattle this is typically caused by bacterial septicemia, e.g., Histophilus somni. It can also be caused by “hardware disease” AKA traumatic reticulopericarditis, where the pericardium is penetrated by a nail or wire from the gut.
What is indicated by serous atrophy of epicardial fat?
A negative plane of energy. e.g., anorexia, starvation, cachexia, GIT parasitism etc.
You are performing a necropsy on a bison. You notice that the epicardial fat is grey to clear and gelatinous. What is the term for this and what does it suggest?
Serous atrophy of fat. It suggests a negative plane of energy. e.g., anorexia, starvation, cachexia, GIT parasitism etc.
You are performing a necropsy on a bison. You notice that the epicardial fat is white to yellow and abundant. What is the term for this and what does it suggest?
Normal epicardial fat. It suggests that the animal was maintaining its energy requirements and was not anorexic, starved, cachexic etc.
What is the most common pericardial neoplasm?
Mesothelioma (a malignant tumor of mesothelial cells)
Mesothelioma is the most common pericardial neoplasm. Is it benign or malignant?
Malignant, despite its -oma name. There is no benign form of mesothelioma.
Mesothelioma may arise within the pericardial cavity from pericardial mesothelial cells. Where else in the body can mesothelioma arise?
The pleural cavities and the peritoneal cavity.
Mesothelial cells are the flattened cells that line serous body cavities and produce a small amount of lubricating fluid. What are the names of the (a) benign and (b) malignant neoplasms that arise from mesothelial cells?
(a) Trick question. There is no such thing as a benign mesothelial tumor. (b) Mesothelioma is the malignant neoplasm arising from mesothelial cells.
Which vessels are connected in the congenital cardiac abnormality “PDA” (patent ductus arteriosus)
The aorta and pulmonary trunk
Name two normal fetal cardiac shunts AND their names postnatally.
(1) Foramen ovale -> fossa ovalis
(2) Ductus arteriosus -> ligamentum arteriosum
In which domestic species is the congenital cardiac abnormality “PDA” (patent ductus arteriosus) most commonly seen?
Dogs
In which direction (left to right or right to left) does blood flow in a patent ductus arteriosus? And why?
Left to right (postnally). This is because the pressure in the aorta exceeds the pressure in the pulmonary trunk. Blood takes the “path of least resistance” and a proportion of aortic blood is sent via the PDA into the pulmonary trunk. This causes overperfusion of the lungs.
Which organs “suffer the most” in an animal with a patent ductus arteriosus?
The lungs. A proportion of aortic blood is sent via the PDA into the pulmonary trunk. This causes overperfusion of the lungs.
In which direction (left to right or right to left) does blood flow in a patent foramen ovale? And why?
Left to right (postnatally). This is because the pressure in the left atrium exceeds the pressure in the right atrium.
In which direction (left to right or right to left) does blood flow in an atrial septal defect? And why?
Left to right (postnatally). This is because the pressure in the left atrium exceeds the pressure in the right atrium.
You are performing a necropsy on a dog and find that the right ventricle has a markedly thickened wall. In addition, its outflow valve is malformed and has a band of fibrous tissue immediately proximal to it. What are you most likely seeing?
Pulmonic stenosis. This is a congenital malformation of the pulmonic valve. The resulting narrowing (stenosis) causes concentric hypertrophy of the right ventricular wall.
Aside from the valvular malformation itself, what is the most prominent lesion you would expect in the heart of a dog with congenital pulmonic stenosis?
Right ventricular concentric hypertrophy
You are performing a necropsy on a dog and find that the left ventricle has a markedly thickened wall. In addition, its outflow valve has a band of fibrous tissue immediately proximal to it. What are you most likely seeing?
Subaortic stenosis. This is a congenital malformation where a ring of fibrous tissue encircles the left ventricular outflow tract beneath the aortic valve. The resulting narrowing (stenosis) causes concentric hypertrophy of the left ventricular wall.
Aside from the valvular malformation itself, what is the most prominent lesion you would expect in the heart of a dog with congenital subaortic stenosis?
Left ventricular concentric hypertrophy
Describe the (a) appearance and (b) function of an AV valve affected by congenital atrioventricular valve dysplasia.
(a) AV valve leaflets and chordae tendineae are short and thickened; (b) Incompetent valve function -> regurgitation of blood [-> heart failure]
You are performing a necropsy on a calf and find a dark purple 7 mm diameter spherical cyst on the free edge of the left AV valve. What is this and what is its significance?
A valvular hematocyst. These are bulging blood-filled cysts along the free edges of AV valves, most commonly seen in young ruminants. They cause no functional abnormalities and regress spontaneously. They should not be misinterpreted as valvular endocarditis.
You are performing a necropsy on a calf and find a clear 7 mm diameter spherical cyst on the free edge of the left AV valve. What is this and what is its significance?
A valvular lymphocyst. These are bulging lymph-filled cysts along the free edges of AV valves, most commonly seen in young ruminants. They cause no functional abnormalities and regress spontaneously. They should not be misinterpreted as valvular endocarditis.
What are valvular hematocysts, where are they most commonly found, and in which domestic species?
These are bulging blood-filled cysts along the free edges of AV valves, most commonly seen in young ruminants. They cause no functional abnormalities and regress spontaneously. They should not be misinterpreted as valvular endocarditis.
Which canine congenital cardiac developmental anomaly is associated with esophageal obstruction?
Persistent right aortic arch
What is the most common vascular ring anomaly in dogs?
Persistent right aortic arch
Which canine congenital cardiac developmental disorder is most likely in a stunted young dog with frequent regurgitation of food?
Persistent right aortic arch
From which aortic arch should the aorta develop normally?
Left fourth
In cases of persistent right aortic arch, from which aortic arch did the aorta develop?
Right fourth
What clinical sign is noticed first by owners of dogs suffering from persistent right aortic arch (PRAA)? What are three other, less spectacular but still important clinical effects or lesions of PRAA?
Frequent regurgitation of food is the most obvious clinical sign.
(1) Cranial megaesophagus; (2) Aspiration pneumonia; (3) Stunting
In the condition persistent right aortic arch, what specific structure causes esophageal entrapment and stenosis?
The ligamentum arteriosum
Describe the pathogenesis of the condition persistent right aortic arch, from causal developmental abnormality to production of the most common clinical signs and lesions.
Aorta develops abnormally from the right 4th aortic arch instead of the left 4th aortic arch -> this creates a vascular ring with the ligamentum arteriosum (which developed normally from the left 6th aortic arch) -> the esophagus passes through and is entrapped by this vascular ring -> esophageal narrowing at this point -> frequent regurgitation of food [+/- cranial megaesophagus, aspiration pneumonia and stunting]
What is ectopia cordis?
A developmental anomaly where the heart develops at an abnormal site outside of the thoracic cavity. The most common ectopic location is subcutaneously in the caudoventral neck, just cranial to the thoracic inlet.
What is the term for the developmental anomaly where the heart develops at an abnormal site outside of the thoracic cavity?
Ectopia cordis. The most common ectopic location is subcutaneously in the caudoventral neck, just cranial to the thoracic inlet.
What are three specialized histologic features of cardiac myocytes that set them apart from other types of muscle cells?
(1) They branch; (2) They have intercalated discs; (3) Some of them are specialized (e.g., Purkinje cells) to form a conducting system
Do cardiac myocytes undergo (a) hyperplasia or (b) hypertrophy in response to increased workload?
(b) Hypertrophy
Describe the appearance of a transversely sectioned heart with biventricular concentric hypertrophy.
The ventricular myocardium is marked thickened (hypertrophied) and the volume of the ventricular chamber lumen on each side is reduced and sometimes slit-like.
Describe the appearance of a transversely sectioned heart with biventricular eccentric hypertrophy.
The ventricular myocardium is thickened (hypertrophied) but this is overshadowed by marked enlargement (dilation) of the ventricular chamber lumen on each side. Because of this chamber dilation the myocardium may appear relatively thinned, but it is still hypertrophied.
Fill in the blank: ventricular concentric hypertrophy is a result of __________ overload.
Pressure
Fill in the blank: ventricular eccentric hypertrophy is a result of __________ overload.
Volume
Fill in the blank: cardiac ventricular pressure overload results in __________ hypertrophy.
Concentric
Fill in the blank: cardiac ventricular volume overload results in __________ hypertrophy.
Eccentric
Which type of ventricular hypertrophy (concentric or eccentric; left, right or biventricular) would be expected in aortic valvular stenosis? And why?
Concentric and left. Aortic stenosis causes PRESSURE overload in the left ventricle. Pressure overload results in CONcentric hypertrophy. (In contrast, eccentric hypertrophy is associated with VOLUME overload).
Which type of ventricular hypertrophy (concentric or eccentric; left, right or biventricular) would be expected in pulmonic valvular stenosis? And why?
Concentric and right. Pulmonic stenosis causes PRESSURE overload in the right ventricle. Pressure overload results in CONcentric hypertrophy. (In contrast, eccentric hypertrophy is associated with VOLUME overload).
Which type of ventricular hypertrophy (concentric or eccentric; left, right or biventricular) would be expected in chronic systemic hypertension? And why?
Concentric and left. Systemic hypertension causes PRESSURE overload in the left side of the heart. Pressure overload results in CONcentric hypertrophy. (In contrast, eccentric hypertrophy is associated with VOLUME overload).
Which type of ventricular hypertrophy (concentric or eccentric; left, right or biventricular) would be expected in chronic pulmonary hypertension? And why?
Concentric and right. Pulmonary hypertension causes PRESSURE overload in the right side of the heart. Pressure overload results in CONcentric hypertrophy. (In contrast, eccentric hypertrophy is associated with VOLUME overload).
Which type of ventricular hypertrophy (concentric or eccentric; left, right or biventricular) would be expected in hyperthyroidism in cats?
Concentric and biventricular.
Which type of ventricular hypertrophy (concentric or eccentric) would be expected in aortic or pulmonic valvular insufficiency (“leakiness”)? And why?
Eccentric. Valvular insufficiency (“leakiness”) results in backflow of blood into an already full heart chamber. This is VOLUME overload. Volume overload leads to chamber dilation, or ECCENTRIC hypertrophy. (In contrast, concentric hypertrophy is associated with PRESSURE overload).
Which type of ventricular hypertrophy (concentric or eccentric; left, right or biventricular) would be expected in a ventricular septal defect? And why?
Eccentric and right. Ventricular septal defects result in blood crossing into an already full right ventricle. Blood moves left to right rather than right to left because the pressure in the left ventricle exceeds pressure in the right ventricle. This is VOLUME overload. Volume overload leads to chamber dilation, or ECCENTRIC hypertrophy. (In contrast, concentric hypertrophy is associated with PRESSURE overload).
Chronic pulmonary hypertension may result in right ventricular concentric hypertrophy. What is a fairly common disease that causes this in (a) dogs, (b) cattle and (c) horses?
(a) Dogs: “Heartworm disease” (dirofilariasis), where nematodes live in the pulmonary arteries, pulmonary trunk and right atrium.
(b) Cattle: “Brisket disease” (high altitude disease), where cattle above 7000 feet develop right-sided heart failure.
(c) Horses: “Heaves” (chronic alveolar emphysema), which is an asthma-like condition.
What does the term cor pulmonale mean?
Right-sided heart failure caused by chronic pulmonary hypertension
What is the term for right-sided heart failure caused by chronic pulmonary hypertension?
Cor pulmonale