Cardio1 Flashcards
Mitral valve stenosis
The high PCWP (i.e., left atrial pressure), and the large gradient between PCWP and the LVEDP, indicated a stenoic mitral valve. Also, a stenotic mitral valve would increased the resistance to flow into the left ventricle, which would cause blood to back up in the circuit. We see this manifested in the high pulmonary artery pressure
What is the cause of this woman’s shortness of breath?
Pulmonary congestion.
The stenotic valve is increasing the resistance to flow from the left atrium to the ventricle, which is causing blood to back up in the circuit. This will lead to pulmonary congestion and increased pulmonary capillary pressure, leading to pulmonary edema and difficulty breathing.
We can also tell that pulmonary capillary wedge pressure is elevated because the pressures are elevated at the arterial and venous ends of the pulmonary circulation.
Diastolic murmur best heard at the 5th left intercostal space at the midaxillary line
mitral valve stenosis
What is the pulmonary capillary wedge pressure an estimate of?
left atrial pressure
When would you hear a murmur due to mitral regurgitation?
during diastole
What is the normal range for pulmonary capillary wedge pressure (PCWP)?
4-12 mmHg
What is indicated by a PCWP that is significantly greater than the LVEDP?
This means that there is a pressure gradient across the mitral valve, which indicates stenosis
What pressure changes would you see in someone with aortic stenosis?
Because the resistance to ejection of blood into the aorta is increased, you would see greatly increased left vantricular pressure. The systolic pressure in the aorta, however, would be normal
What type of murmur is produced by aortic regurgitation? Where can it best be heard?
Blowing, high-pitched, decrescendo diastolic murmur, best heard along the lower left sternal border
What is aortic regurgitation? How does this manifest clinically?
When blood flows back through the aortic valve into the left ventricle during diastole. This results in a blowing diastolic murmur, and a widening pulse pressure, sometimes greater than 100 mmHg
Why is the systolic pressure increased in someone with aortic regurgitation?
The systolic pressure is increased because of an increased stroke volume, which is secondary to an increased LVEDV, all due to the aortic regurgitation.
A 67 yo man comes to the physician for a physical exam required for insurance. During blood pressure measurement, systolic sounds are heard in the brachial artery with the cuff completely deflated. His BP is 170/80 mmHg. What is the most likely diagnosis? Why can these sounds be heard when the cuff is deflated?
This man likely has aortic regurgitation, evidenced by the large pulse pressure, and the systolic sounds heard with a deflated cuff.
In aortic regurg., the systolic pressure increases (the pulse pressure widens) because of increased SV. This very high volume and pressure results in turbulent flow through the brachial artery that can be heard even when the cuff pressure is zero.
Where can aortic stenosis best be auscultated?
upper right sternal border
What are the classic blood pressure findings in someone with aortic stenosis?
elevated LV peak systolic pressure, normal aortic systolic pressure = pressure gradient across aortic valve.
In aortic stenosis, there is increased resistance to blood flow through the aortic valve. In this case, the left ventricle must generate greater than normal pressure to push blood into the aorta (increased peak systolic pressure in th eleft ventricle), while the aortic systolic pressure will be normal.
A 42 yo woman comes to the ED b/c of a 1-hr hx of crushing substernal chest pain. An EKG shows critical stenosis of a cardiac valve. It is determined the stenotic valve is the aortic valve. what will be heard on auscultation?
A crescendo, decrescendo systolic murmur with an ejection click
Decrescendo diastolic murmur best heard at the lower left sternal border
aortic regurgitation
Diastolic rumble best heard in the left lateral decubitus position.
Mitral stenosis
Holosystolic murmur radiating to the apex
mitral regurgitation
What might you hear on auscultation of a pericardial effusion? Why?
Muffled heart sounds, as the fluid surrounding the heart blocks the conduction of the heart sounds.
A 70 yo man is brought to the ED b/c of a 1-month hx of worsening SOB. Auscultation shows a systolic murmur best heard at the upper right sternal border. CXR shows enlargement of the left vetnricle. Which of the following additional pathologic changes would most likely be associated with this condition?
(a) calcification of the aortic valve
(b) dilatation of ascending aorta
(c) dissection of ascending aorta
(d) rupture of aortic valve leaflets
(e) vegetations on the aortic valve
calcification of the aortic valve.
This is the most common cause of aortic stenosis in the elderly
A 70 yo man is brought to the ED b/c of a 1-month hx of worsening SOB. Auscultation shows a systolic murmur best heard at the upper right sternal border. CXR shows enlargement of the left vetnricle. What is the diagnosis? What is the relevance/connection of the enlargement of the left ventricle.
This patient has aortic valve stenosis.
Aortic stenosis –> increased afterload –> ventricular hypertrophy –> subsequent dilatation of the left ventricle
What is coarctation of the aorta?
A narrowing (stenosis) of the aorta, which increases the vessel resistance, and forces the heart to pump against a higher pressure.
What is the difference in location of the coarctation of the aorta between the infant and adult forms?
In the infant form, the coarctation lies distal to the aortic arch, but before (proximal to) the PDA
In the adult form, the coarctation lies distal to (after) the aortic arch (distal to the left subclavian artery), and is not associated with the PDA
With what genetic disorder is the infantile form of coarctatin of the aorta associated?
Turner Syndrome
How does coarctation of the aorta present in adults?
Hypertension in the upper extremities, and hypotension in the lower extremities –> a strong radial pulse and a weak femoral pulse.
Classically, notching of the inferior margins of the ribs is seen on CXR.
Increased left ventricular wall thickness (hypertrophy in response to pumping against a higher pressure)
Decreased vessel wall thickness in arteries distal to obstruction
A 3 month old girl is brought to the physician because of dyspnea, difficulty feeding, and poor weight gain. Physical exam shows a weak femoral pulse compared with the radial pulse. Pressure tracings from the thoracic and abdominal aorta are shown in the graph. Which of the following is most likely to be increased above normal values in this patient?
(a) abdominal wall thickness
(b) femoral artery wall thickness
(c) left ventricular wall thickness
(d) resting blood flow in leg muscles
(e) renal blood flow
left ventricular wall thickness
This infant has coarctation of the aorta, which increased the pressure against which the heart must pump, leading to left ventricular hypertrophy.
(The wall thickness of vessels distal to the coarctation will be decreased)
A 25 yo man comes to the physician because of episodes of headache and light-headedness. He also has pain in his calves on walking that is relieved by rest. BP is elevated in the upper extremities and below normal in the lower limbs. Diagnosis? Why the headache and light-headedness?
Coarctation of the aorta.
In this condition, there is a narrowing of the aorta just distal to the left subclavian artery. This leads to increased blood flow and hypertension in vessels proximal to the stenosis (upper extremities), and hypotension in the lower extremities. The headache and light-headedness/dizziness are manifestations of hypertension
A 25 yo man comes to the physician because of episodes of headache and light-headedness. He also has pain in his calves on walking that is relieved by rest. BP is elevated in the upper extremities and below normal in the lower limbs. Diagnosis? Why the calf pain that is relieved by rest?
Coarctation of the aorta.
In this condition, there is a narrowing of the aorta just distal to the left subclavian artery (aortic arch). This leads to decreased blood flow to and hypotension in the lower extremities. Hypotension can manifest with signs and symptoms of ischemia. This patient has claudication: pain in the legs when walking that is due to ischemia and relieved with rest.
What is the classic X-ray finding in coarctation of the aorta? Why do we see this?
Notching of the interfior margins of the ribs.
This is due to the development and enlargement of collateral arteries, in particular, the intercostal arteries. The enlargement of the arteries, which run along the inferior margin of the ribs, causes notching of the ribs
What is Eisenmenger syndrome?
A shift from a left-to-right shunt to a right-to-left shunt secondary to pulmonary hypertension
A 26 yo man comes to the physician because of a chronic cough. He has smoked 1 pack of cigarettes per day for 10 years. He also gets frequent headaches and aches in his legs when he exercises. A CXR shows irregularities and scalloping on the undersurface of his ribs. What is the likely diagnosis?
Coarctation of the aorta
Scalloping, or notching, on the undersurface of the ribs is pathognomonic for this disease.
(The headaches and aches in his legs when exercising [i.e., claudication] are also consistent with upper extremity hypertension and lower extremity hypotension that is classically seen in this condition).
Besides due to the narrowing of the aorta itself (and therefore increased blood flow to upper-extremity vessels), what is another cause of the hypertension seen in coarctation of the aorta?
Coarctation of the aorta also results in hypotension in the lower extremities. This means there will be reduced blood flow to the kidney, resulting in activation of the renin-angiotensin-aldosterone system, which will increased blood pressure.
A previously healthy 74-yo woman is brought to the ED b/c of a fall 2 days ago. The woman tripped and fell at home, injuring her right leg, and has been unable to get out of bed since the injury because of pain. 2 hours ago, she suddenly became confused and disoriented. Temp: 37 degrees C; pulse 110/min; RR 32; BP 120/70. Pulse ox shows ox saturation of 80%; CXR shows no abnormalities. Which of these is the most likely diagnosis?
(a) acute cerebral hemorrhage
(b) acute cerebral infarction
(c) MI
(d) pulmonary infection
(e) pulmonary thromboembolism
Pulmonary Thromboembolism
Hip fracture and bed rest are classic risk factors for development of a PE.
A classic clinical presentation of PE is hypoxemia (ventilation/perfusion mismatch) despite normal CXR, tachycardia, and mental status changes in older patients.
A previously healthy 74-yo woman is brought to the ED b/c of a fall 2 days ago. The woman tripped and fell at home, injuring her right leg, and has been unable to get out of bed since the injury because of pain. 2 hours ago, she suddenly became confused and disoriented. Temp: 37 degrees C; pulse 110/min; RR 32; BP 120/70. Pulse ox shows ox saturation of 80%; CXR shows no abnormalities. Why would we rule out cerebrovascular events (a and b)
(a) acute cerebral hemorrhage
(b) acute cerebral infarction
(c) MI
(d) pulmonary infection
(e) pulmonary thromboembolism
These could produce the mental status changes we see in the patient, but they would not directly cause the hypoxemia, unless the patient was hypoventilating (e.g., brainstem involvement)
A previously healthy 74-yo woman is brought to the ED b/c of a fall 2 days ago. The woman tripped and fell at home, injuring her right leg, and has been unable to get out of bed since the injury because of pain. 2 hours ago, she suddenly became confused and disoriented. Temp: 37 degrees C; pulse 110/min; RR 32; BP 120/70. Pulse ox shows ox saturation of 80%; CXR shows no abnormalities. Why would we rule out infection?
(a) acute cerebral hemorrhage
(b) acute cerebral infarction
(c) MI
(d) pulmonary infection
(e) pulmonary thromboembolism
Pulmonary infection could produce mental status changes, tachycardia, and hypoxemia, but the onset of symptoms would be slower, the patient would likely be febrile, and the CXR would be abnormal
What two processes/systems get activated in response to hemorrhage to return BP to normal?
(1) The baroreceptor reflex is stimulated, which increases sympathetic activity and decreases parasympathetic activity. This will increase HR and TPR
(2) Decreased blood flow to the kidney –> increased renin release, activating the renin-angiotensin system. This will lead to increased blood pressure and blood volume.
How does the CNS monitor arterial blood pressure?
Via arterial baroreceptors located in the carotid sinus (innervated by CN IX) and the aortic arch (CN X)
Which nerve innervated the baroreceptors in the carotid sinus? Which innervates those in the aortic arch?
Carotid sinus: CN 9
aortic arch: CN 10
Between the baroreceptors in the carotid sinus and the aortic arch, is one group more important than the other in monitoring arterial blood pressure?
Quantitatively, the carotid sinus is more important
Where in the CNS is the information from the carotid sinus and aortic arch sent to?
The nucleus solitarus in the medulla
What is the effect of decreased BP on the arterial baroreceptors?
decreased BP –> decreased stretch of arterial walls –> decreased firing of baroreceptors –> decreased parasympathetic outflow + increased sympathetic outflow –> increased HR and BP
What conducts the parasympathetic outflow in the baroreceptor reflex?
The vagus nerve, which decreases HR
In the baroreceptor reflex, what is the affect of increased sympathetic outflow?
increased HR and BP
What causes increased renin secretion?
(1) increased sympathetic activity
(2) The juxtaglomerular (JG) apparatus in the kidney monitors BP; decreased BP –> increased renin secretion
What does renin do?
converts angiotensinogen to angiotensin I
What does angiotensin II do?
(1) stimulated arteriolar vasoconstriction
(2) stimulates aldosterone release
How does sympathetic activity lead to increased total peripheral constriction? (signalling molecules, receptors)
increased sympathetic outflow –> increased norepinephrine release from postganglionic neurons –> increased stimulation of alpha-1 adrenergic receptors –> vasoconstriction
A 48 yo man is brought to the ED b/c of severe chest pain on exertion. Physical exam shows a 3/6 pansystolic murmur in the aorta with radiation to the carotids. Echocardiogram confirms the presence of aortic stenosis. There is increased blood flow through the coronary arteries. What would explain the increased blood flow?
Increased adenosine, which dilates the coronary arteries.
aortic stenosis –> increased afterload –> increased left ventricular pressure to eject blood –> increased work by left ventricle –> increased consumption of oxygen and ATP –> increased production of adenosine
In this way, coronary blood flow is coupled to, and increases in proportion to, the oxygen demand/consumption of the heart
A 48 yo man is brought to the ED b/c of severe chest pain on exertion. Physical exam shows a 3/6 pansystolic murmur in the aorta with radiation to the carotids. Echocardiogram confirms the presence of aortic stenosis. There is increased blood flow through the coronary arteries.
If there is increased coronary blood flow, why is this man experiencing angina?
Although blood flow is increased in an attempt to increase oxygen delivery to the tissue, it is not enough to meet the excessive demand. This excessive demand is likely due to increased ventricular mass.
A 60 yo man is admitted to the hospital b/c of a 2-day hx of SOB. His BP is 75/50 mmHg, and HR is 83. Phys. exam shows 3+ pitting edema of the lower extremities bilaterally. Labs show BUN is 62 mg/dL and serum creatinine is 3.0 mg/dL. A CXR shows cardiomegaly and perihylar infiltrates. What is the cause of his lab results?
prerenal azotemia
The SOB, low BP, caridomegaly, perihylar infiltrates, and pitting edema are all indicative of congestive heart failure. This will lead to decreased renal perfusion (we see his BP is low). Congestive heart failure is a common cause of prerenal aoztemia.
A BUN:Cr >20 is indicative of prerenal azotemia; in this patient, it is >20.
What is an ateriovenous fistula?
An abnormal connection between an artery and a vein.
How would CO output be affected if there is a large fistula that involves a major artery?
It would increase
The fistula means that there is an abnormal connection between an artery and vein. This would mean that oxygen concentration is decreased in the arterial blood, and increased in venous blood. To maintain oxygen delievery to the tissues, CO will increase (via an increase in HR and SV)
*The increase in CO is roughly equal to the blood flow through the fistula
How would BP be affected by a large fistula involving a major artery?
BP and systemic vascular resistance would be decreased
The fistula provides a low-resistance pathway to shunt blood from the artery to the vein, decreasing BP and systemic vascular resistance.
The solid line (A) shows a normal heart; The dashed line (B) shows a heart with valvular disease.
How does the work of the heart in patient be compare to that of patient A? How do you know?
The heart represented by B is doing increased work.
The area enclosed by the PV loop represents the work done by the heart when ejecting the stroke volume during the cardiac cycle. The area of loop B > the area of loop A
How does the oxygen consumption of heart B compare to heart A?
The oxygen consumption of heart B is increased compared to A.
We can see from the area of the loops that the work done by B is greater than A, and oxygen consumption/demand is directly related to the work.
The solid line (A) shows a normal heart; The dashed line (B) shows a heart with valvular disease.
Why is the work of patient B’s heart increased while the stroke volume is still the same?
This patient has a valvular disease that is increasing the afterload on the left ventricle, which must generate a higher systolic pressure than normal to eject the same volume of blood.
What is the typical gross and histological appearance of a cardiac myxoma?
gross: forms a pedunculated mass, most commonly in the left atrium
histological: stellate mesenchymal cells admixed with inflammatory and epithelial cells.
(scattered mesenchymal cells in a prominent myxoid background)
Why might a cardiac myxoma manifest in a person as syncope?
cardiac myxomas form a peduncuclated mass, most commonly in the left atrium. This mass can obstruct the mitral valve, inhibiting blood flow.
A 70 yo woman collapses while shopping and dies of sudden cardiac arrest. Autopsy shows a solitary pedunculated mass within the left atrial chamber. Histologically, the cells are stellate mesenchymal cells admixed with inflammatory and endothelial cells. What is the most likely diagnosis?
cardiac myxoma.
The pedunculated mass in the left atrium, and the stellate mesenchymal cells admixed with inflammatory and endothelial cells, are classic gross and histological descriptions of a cardiac myxoma.
A tumor is found in the heart. Histology shows densely-packed striated muscle. What type of tumor does this suggest?
Rhybdomyoma.
This is the most common primary cardiac tumor in children.
tumor is found in the heart. Histology shows malignant glandular tissue. What type of tumor does this suggest?
Carcinoma, which is metastatic to the heart.
What is the most common type of tumor found in the heart?
Metastatic tumors
What cancers commonly send metastases to the heart?
lung cancer
breast cancer
lymphoma
melanoma
A 55 yo woman come to the physician after several episodes of syncope. Phys exam shows a low-pitched “plopping” sound during diastole. 2D echocardiography shows a mass causing intermittent obstruction of the mitral valve. Diagnosis? What is causing the diastolic sound?
cardiac myxoma
this forms a pedunculated mass, most commonly in the left atrium. It can intermittently obstruct the mitral valve, resulting in the plopping sound (and in the syncope)
In infective endocarditis, what are the vegetations on the valvular leaflets composed of?
firbrin, inflammatory cells (neutrophils), and colonies of bacteria
What is the most common cause of infective endocarditis in IV drug users?
S. aureus
What is the most commonly affected valve in endocarditis in IV drug users?
The tricuspid valve
What is Libman-Sacks endocarditis?
non-infective (sterile) endocarditis that is associated with SLE (systemic lupus erythmatosus)
What does this image show? What does it indicate?
This shows lines of Zahn that are indicative of a premortem clot.
If a patient had an abdominal aortic aneurysm, which of the labeled structures would be affected?
A
What structures are indicated by (A) - (F)
A- aorta
B - descending colon
C - duodenum
D - inferior vena cava
E - kidney
F - ureter
A 50 yo woman comes to the ED b/c of pelvic pain. Phys exam shows several nodules within the endometirum and a diagnosis of uterine leiomyomas is made. The patient undergoes a total abdominal hysterectomy with bilateral salpingo-oophorectomy. A CT of the pelvis in a normal individual is shown. What structure is the arrow pointing to?
ovary
What is tenting of the T wave on ECG indicative of?
hyperkalemia
This is because potassium is responsible for the repolarization of cardiac cells
What is represented by (A) the positively-sloped graph, (B) the negatively-sloped graph, and (C) the intersection of (B) and the x-axis
A - cardiac output curve
B - venous return curve
C - mean systemic filling pressure
What is represented by the intersection of the curves?
In the steady state, the CO and the venous return must be equal to each other. The intersection of the graphs shows the CO, venous return, and right atrial pressure in the steady state.
Point A shows the CO in a normal individual when the right atrial pressure is 0 mmHg. Point B represents the patient’s CO and right atrial pressure (RAP). Which of the following best explains these findings?
(a) arteriovenous fistula
(b) exercise
(c) impaired left ventricular contractility
(d) narcotic overdose
(e) severe hemorrhage
arteriovenous fistula
(b), (c), and (d) would all move the cardiac output curve. Because this curve doesn’t change, these can be ruled out. Severe hemorrhage (e) would decrease the mean systemic filling pressure (shift the intersection of the venous return curve with the x-axis to the left), and so can be rule out.
How would spinal anesthesia effect the curves in the figure?
Spinal anesthesia would block the sympathetic nervous system. This would lead to systemic vasodilation –> decrease in the mean systemic filling pressure and a shift of the venous return point of x-axis intersection to the left. The decrease in sympathetic tone would also decrease resistance to venous return, causing the slope of the venous return curve to become steeper.
Finally, decreased sympathetic tone will lead to a decrease in the contractility of the heart, and cause the CO curve to shift down.
During an investigational study, two individuals volunteer for evaluation in a cardiovascular lab. When compared to the pressure-volume diagram labeled control, pressure-volume loop A most likely relfects which of the following changes?
(a) increased contractility
(b) increased end systolic pressure
(c) increased PCWP
(d) increased total peripheral resistance
(e) left ventricular dilatation
left ventricular dilatation
The LVEDPs in the control and in patient A are about the same, but the end diastolic volume in A is much greater than in the control. The only way for the pressures to be the same with different volumes is for the ventricle to dilate, which will increase its compliance.
How does the end-systolic pressure and volume compare between the two loops?
The end systolic pressures are the same for both loops; the end systolic volume is greater for loop A than for the control.
How does the contractility of the heart compare between the control and patient A?
The contractility is greater for the control than loop A. Contractility is given by the slope of the line drawn from the origin to the point of end systolic pressure:
How does the PCWP compare between the two loops?
The PCWP is often used to approximate the LV end diastolic pressure, which is the same in these two loops.
How does total peripheral resistance compare between these two loops?
Total peripheral resistance is lower in loop A than in the control.
Arterial diastolic pressure (DP) is typically proportional to total peripheral resistance; arterial DP is indicated by the pressure at which the aortic valve opens
Curve A shows a normal heart; curve B shows a heart with aortic valve disease. How does coronary blood flow during diastole in curve B compare to curve A?
It is increased.
The heart in curve B is doing increased work, as signified by the increased area in the PV loop. This increase in work increases the oxygen demand of the heart. Because 70% of the arterial blood oxygen is typically extracted by the heart, additional oxygen to the heart must be supplied by increased blood flow; increased extraction is limited. Also, the increased systolic pressure means that the coronary vessels are compressed more than normal, leading to decreased systolic blood flow through the coronary arteries. Decreased systolic blood flow + increased oxygen consumption and demand –> greatly increased blood flow during systole.
How does coronary artery oxygen content compare between curves A and B?
It would be the same.
The myocardial oxygen consumption does not affect the oxygen content of the arterial blood.
The oxygen content of the coronary venous blood would, however, be decreased in curve B–the heart that is doing greater work.
How does coronary blood flow during systole in loop B compare to loop A?
It is decreased.
The peak systolic pressure is greater in loop B, which compresses the coronary vessels even more than normal, causing blood flow to decrease.
