SYTM 5504 Week 4 Practice Questions
[4I] What is the sequence of events leading to death in a patient with cavernous hemangioma?
(1) Cavernous hemangioma of the liver (2) Trauma/rupture (3) Hemoperitoneum (4) Hypovolemic shock Cavernous hemangioma is discussed on previous card. On another note, pyogenic granuloma is benign tumor of blood vessels. It is vascular, pedunculated, red mass w/ rapid growth (1-2 cm in few wks) found on skin, gingiva, & oral mucosa. It resembles exuberant granulation tissue & ulcerates & bleeds easily. It can be caused by trauma or increased estrogen (pregnancy tumor). It spontaneously regresses. Glomus tumor is benign tumor of specialized smooth muscle cells of glomus body, i.e. arteriovenous structures involved in thermoregulation. They are painful & most commonly found under fingernails.
[4MN] What is the sequence of events leading to a stroke in mitral valve stenosis?
(1) Dilation of the left atrium (2) Blood stasis (3) Atrial thrombus (4) Systemic embolization to a cerebral artery
[4I] What is the sequence of events in Raynaud Phenomenon?
(1) Exposure to cold (2) Vasoconstriction, causing white fingers (3) Insufficient oxygen to fingers, causing blue fingers (4) Blood flow returns to fingers, causing red fingers Raynaud phenomenon is exaggerated vasomotor response to cold or emotion, affecting 3-5% of population, esp. young women. Secondary Raynaud phenomenon occurs in patients w/ SLE, scleroderma, etc.
[4I] What is the sequence of events from obstructive sleep apnea to pulmonary embolus?
(1) Hypoxemia (2) Kidneys release erythropoietin (3) Polycythemia (4) DVT, which detaches & lodges in lungs DVT is discussed on previous card. Phlebitis is inflammation of superficial veins, often caused by S. aureus infection or IV cannulation of vein w/ dirty plastic catheter. Superficial thrombophlebitis is phlebitis assoc. w/ thrombus, 10-20% of which is assoc. w/ occult DVT. Symptoms of phlebitis & superficial thrombophlebitis include pain & tenderness to palpation along course of inflamed superficial vein, which will feel like palpable cord. There will also be erythema & edema of overlying skin & subcutaneous tissue. There is also paraneoplastic syndrome called Trousseau syndrome, where pancreatic adenocarcinoma releases procoagulant factors in superficial veins leading to migratory thrombophlebitis.
[4I] What is the sequence to death in a patient with a red streak leading away from an injury site?
(1) Injury (2) Lymphangitis (3) Lymphadenitis (4) Bacteremia & sepsis Acute lymphangitis is inflammation of lymphatic vessels due to bacterial entry from injury or nearby cellulitis. It presents as red, painful, subcutaneous streaks in direction lymphatic vessel. Complications include acute lymphadenitis, i.e. tender enlargement of draining nodes. If not contained in lymph nodes, bacteria can pass into venous circulation, causing bacteremia & sepsis.
[4J] A 44-year-old woman experienced an acute episode of severe abdominal pain and suddenly vomited a large volume of bloody fluid. Her husband had her brought to the hospital by ambulance. The emergency room physician estimated that she had lost about 600 mL of blood. On physical examination, she had a blood pressure of 85/65 mm Hg and was tachycardic with a heart rate of 110 beats/min. The patient's skin was cool, moist, and pale. The physician tentatively diagnosed her to have a bleeding ulcer. What would be the effect of a drug that acted specifically to improve myocardial contractility? A. Decrease central venous pressure and increase cardiac output B. Decrease central venous pressure and decrease mean arterial pressure C. Increase central venous pressure and increase aortic pulse pressure D. Decrease central venous pressure and decrease cardiac outpu E. Increase central venous pressure and increase arterial compliance
A. Decrease central venous pressure and increase cardiac output Increased myocardial contractility would mean heart is pumping harder, which would increase cardiac output. This would decrease CVP, since more blood is pumped into system.
[4L] A study on pathogenesis of patients with essential hypertension finds hypertensive patients with normal kidney function, renal angiogram, and no abdominal mass. Which laboratory finding is most likely? A. Decreased urinary sodium B. Increased plasma renin C. Hypokalemia D. Increased catecholamines E. Reduced angiotensin converting enzyme
A. Decreased urinary sodium Essential hypertension has idiopathic causes, but one hypothesis is that kidneys fail to excrete sodium, so both sodium & water is retained in body. This leads to extra volume & hypertension.
[4B] A patient is given a drug that causes constriction of arterioles in all skeletal muscles. Assuming the arterioles in other organs are not affected, what will be the expected changes in mean arterial pressure (MAP) and capillary filtration (CF)? A. Increased MAP, decreased CF B. Increased MAP, increased CF C. Decreased MAP, decreased CF D. Decreased MAP, increased CF
A. Increased MAP, decreased CF
[4I] Which vascular tumor is associated with HHV8 infection? A. Kaposi sarcoma B. Angiosarcoma C. Bacillary angiomatosis D. Glomus tumor
A. Kaposi sarcoma Kaposi sarcoma is malignant tumor of endothelial cells infected w/ HHV8. It classically presents as multiple red-purple plaques on lower legs of older men of Mediterranean or Middle Eastern descent. Otherwise, it is assoc. w/ AIDS & transplant patients due to immunosuppression. Red-purple plaques pop up on skin, mouth, & GI tract & progress to nodules that ulcerate. One disease that mimics this tumor is bacillary angiomatosis, which is benign capillary proliferation in skin & visceral organs. It mimics Kaposi sarcoma but is actually caused by Bartonella henselae infection, esp. in AIDS patients.
[4G] The diagram depicts the relationship of left ventricular pressure and volume in the cardiac cycle. The various phases of the cardiac cycle are labeled I through IV. During which phase are the pressures in the left atrium and left ventricle most equal? A. Left ventricular filling B. Isovolumetric ventricular contraction C. Left ventricular ejection D. Isovolumetric ventricular relaxation
A. Left ventricular filling During ventricular filling, blood is rushing from atrium into ventricle, thus equalizing pressure difference. Eventually, pressure is equalized, & atrium gives extra push to squeeze remaining blood into ventricle.
[4MN] What valve pathology is associated with a mid-systolic click and a late systolic murmur? A. Mitral valve prolapse B. Mitral valve regurgitation C. Mitral valve stenosis
A. Mitral valve prolapse Mitral valve prolapse is most common cause of mitral valve regurgitation, where there is backward ejection of blood into left atrium during systole. Other causes of mitral valve regurgitation include rupture of dysfunction of posteromedial papillary muscle post-MI & functional mitral valve regurgitation due to stretching of mitral valve ring, e.g. left HF, dilated cardiomyopathy, & myocarditis. It is also caused by acute rheumatic heart disease endocarditis, infectious endocarditis, non-bacterial thrombotic endocarditis, & Libman-Sacks endocarditis. Retrograde blood flow increases pulmonary venous pressure, which causes pulmonary hypertension, right ventricular hypertrophy, & right HF. Left atrium dilates & hypertrophies, leading to S3 & S4 heart sounds. Eventually, there is decompensation & left ventricular dysfunction, leading to left HF & pulmonary edema. Pulmonary edema presents w/ dyspnea, inspiratory crackles, & cough w/ rusty sputum. Diagnosis is confirmed by ECHO.
[4C] What is the best advice for a 68-year-old male with a history of hypertension and cigarette smoking who is diagnosed with an abdominal aortic aneurysm measuring 3.0 cm? A. Observation with serial ultrasounds B. Urgent surgical repair C. Endovascular stent placement D. Begin anticoagulation E. Treat hypertension
A. Observation with serial ultrasounds
[4B] Kwashiorkor is a severe form of childhood malnutrition seen mostly in developing countries. Symptoms include hepatomegaly and pitting edema of the lower extremities. The pitting edema is most likely due to which of the following? A. Plasma protein deficit B. Inadequate cardiac output C. Excessive fluid retention D. Reduced interstitial pressure E. Decreased hematocrit
A. Plasma protein deficit There isn't enough protein inside vessels to pull fluid back in (low colloid osmotic pressure), so fluid stays outside of vessels & causes pitting edema. Liver failure produces same effect b/c liver produces albumin; not enough albumin = low colloid osmotic pressure. If kidneys are excreting too much protein, that could also cause same problem. Starling's forces are discussed in more detail on other cards. On another note, Fick's law of diffusion is J = PA(Cp - Ci), where J = rate of diffusion, P = permeability constant, A = surface area, Cp = concentration within capillary, & Ci = concentration within interstitial space. Solutes w/ high permeability, e.g. O2, CO2, & lipid soluble substances, are blood flow limited. Solutes w/ relatively low permeability, e.g. glucose, are diffusion limited.
[4MN] What can a carcinoid tumor cause? A. Tricuspid valve regurgitation B. Tricuspid valve stenosis C. Pulmonary valve regurgitation D. Pulmonary valve stenosis
A. Tricuspid valve regurgitation & D. Pulmonary valve stenosis Carcinoid heart disease is where primary carcinoid tumor small intestine metastasizes to liver. These metastases produce excess serotonin, which leaves thru hepatic vein & enters heart thru IVC. This causes fibrosis in right-sided heart valves, leading to tricuspid valve regurgitation & pulmonic stenosis.
[4A] A healthy 35-year-old man is running a marathon. During the run, there is an increase in his splanchnic vascular resistance. Which receptor is responsible for the increased resistance? A. α1 receptors B. β1 receptors C. β2 receptors D. M2 receptors E. M4 receptors
A. α1 receptors In sympathetic stimulation, NE acts on α receptors to vasoconstrict while E acts on both α & β, but β receptors cause vasodilation. In parasympathetic stimulation, ACh acts on muscarinic receptors to relax smooth muscle. ANGII & ADH act on AT1 & V1 receptors respectively to vasoconstrict.
[4I] A 74-year-old woman has suffered from a swollen arm for the last seven years, following treatment for breast cancer with a radical mastectomy and radiation therapy to the axilla. The patient is at risk for which vascular tumor? A: Angiosarcoma B: Kaposi Sarcoma C: Cavernous hemangioma D: Pyogenic granuloma E: Glomus tumor
A: Angiosarcoma Angiosarcoma is malignant tumor of endothelial cells, esp. in skin, soft tissue, breast, & liver. It is induced by radiation & presents as lymphedema, esp. several yrs after mastectomy w/ lymph node resection. Liver angiosarcoma can also be caused by exposure to polyvinyl chloride or arsenic. 5-year-survival rate is low at 30%. Lymphedema is defined as collection of lymphatic fluid in interstitial tissue or body cavities. It can be caused by post-radical mastectomy followed by irradiation of axilla, which severs lymphatic connections. Post-procedure radiation closes remaining lymphatic channels. Anything blocking lymphatic vessels, including filariasis & tumors, can also cause lymphedema. It is characterized by pitting w/ compression & is painless but progressive.
[4MN] A 27-year-old man presents to his cardiologist after two episodes of syncope. He has had several episodes of angina during the past four years. On auscultation, there is a harsh systolic ejection murmur, and a left-sided S4 heart sound. What is the most likely cause of this patient's signs and symptoms? A: Congenital aortic stenosis B: Calcific aortic stenosis C: Aortic valve sclerosis D: Aortic valve prolapse E: Aortic root dilation
A: Congenital aortic stenosis Congenital aortic stenosis presents in people < age 30. It can be due to unicuspid aortic valve or other obstruction at, below, or above level of valve. It occurs in 10% of cases w/ congenital heart disease in general, & may be assoc. w/ VSD, mitral valve abnormalities, or PDA.
[4MN] A 65-year-old previously heathy woman presents to her internal medicine physician for gradually increasing dyspnea over the past five years. Physical examination reveals bibasilar crackles, and a mid-systolic click followed by a late systolic murmur. Which of the following pathologic changes is most likely present in the patient's mitral valve? A: Myxomatous degeneration B: Dystrophic calcification C: Libman-Sacks vegetations D: Mitral annular calcification E: Congenital bicuspid valve
A: Myxomatous degeneration Patient has mitral valve prolapse, where there is bulging of 1+ mitral valve leaflets into atrium during left ventricular systole due to redundant valve tissue. It is most common mitral valve lesion (1-4% of general population) & most common cause of mitral valve regurgitation. It is also assoc. w/ Marfan syndrome, Ehlers-Danlos syndrome, & anorexia nervosa & bulimia. Excess proteoglycans in mitral leaflet causes myxomatous degeneration, where collagen fibers are absent or disorganized. This causes valve to become overly flexible & balloon.
[4MN] A 23-year-old tall, thin model collapsed on the runway suddenly and unexpectedly. He developed sudden wheezing and gasping for breath, pale skin, blue-tinged lips, and a cough that produced frothy sputum tinged with blood, followed by a rapid loss of consciousness, and death. History revealed frequent complaints of a fluttering heart, anxiety, chest pain, and dizziness. What is the most likely cause of death? A: Ruptured chordae B: Calcific aortic stenosis C: Tricuspid regurgitation D: Syphilitic aortitis E: Mitral valve stenosis
A: Ruptured chordae Patient has mitral valve prolapse secondary to Marfan syndrome. Clinically, most mitral valve prolapses are asymptomatic, but there is commonly mid-systolic click followed by murmur. This is caused by sudden restraint of prolapsed mitral valve by chordae tendineae, followed by mitral valve regurgitation. Other findings include palpitations, anxiety, & rupture of chordae, producing acute mitral valve regurgitation. There may be rapid onset forward failure, causing hypoxemia, cyanosis, & unconsciousness. There is also sudden rapid onset of pulmonary edema, including dyspnea & frothy/blood-tinged sputum. Diagnosis is confirmed by ECHO.
[4I] A 27-year-old man has recently moved to San Bernardino county. He presents to the family medicine clinic to establish primary care. On examination, the patient has a large nevus flammeus extending over the left half of his face. What is the most likely underlying condition? A: Sturge-Weber Syndrome B: Hereditary Hemorrhagic Telangiectasia C: Factor V deficiency D: Von Hippel-Lindau E: Xeroderma Pigmentosum
A: Sturge-Weber Syndrome Telangiectasia is permanent dilation of small vessels, i.e. venules, capillaries, & arterioles. First type is nevus flammeus, patch of dilated blood vessels which can present in two ways. Salmon patch aka birthmark is light pink flat lesion found on face of newborn that regresses spontaneously. Port-wine-stain aka Sturge-Weber Syndrome is nevus flammeus on face that grows during childhood.
[4MN] What are symptoms, signs, risk factors, or features of aortic valve regurgitation?
Aortic valve regurgitation is retrograde blood flow into left ventricle during early diastole. It's most commonly caused by aortic root dilation, but other causes include Marfan syndrome, aortic dissection, Ehlers Danlos syndrome, syphilitic aortitis, & primary valve diseases, e.g. infectious endocarditis & rheumatic valve disease. This clinically presents as early diastolic murmur, left-sided S3, left ventricular hypertrophy leading to S4, & signs of hyperdynamic circulation. Patient will have pounding sensation & widened pulse pressure; left ventricle must generate increased pressure to push more blood out, but diastolic blood pressure is decreased due to regurgitation.
[4MN] What pathological changes in the heart do you see with aortic stenosis?
Aortic valve stenosis is most common valve lesion in adults in Western countries. There is obstruction of blood flow from left ventricle into aorta during systole due to calcific aortic valve. This calcification is due to wear & tear, normally around age 60-80 or age 50-70 in people w/ congenital bicuspid aortic valve. Congenital aortic stenosis is discussed on another card. Normal aortic valve orifice is 3 cm^2; symptoms & signs appear when orifice is < 1 cm^2. Severe aortic stenosis is classified as orifice < 0.5 cm^2 or increased left ventricular pressure > 200 mm Hg.
[4MN] A patient has a dilated and hypertrophied left atrium. Their rhythm strip shows absence of P waves and an isoelectric baseline. What is the diagnosis?
Atrial fibrillation Mitral valve stenosis is narrowing of mitral valve orifice, resulting in left atrial dilation. Most common cause is recurrent attacks of rheumatic fever (50% of patients w/ recurrent attacks have mitral valve stenosis). It is twice as common in women than in men. Clinical findings include atria fibrillation (irregularly irregular pulse) & atrial thrombi due to blood stasis, which can systemically embolize. There is chronic backup of left atrial blood in pulmonary veins, leading to pulmonary venous hypertension, right-sided HF, & concentric right ventricular hypertrophy. This causes dyspnea & hemoptysis of rust-colored sputum (heart failure cells).
[4C] A 65-year-old man with a history of high blood pressure for 3 decades presents with an acute episode of chest pain that is tearing in nature and radiates to his back. He says the pain is excruciating and now radiates between his scapula. His respiratory rate is 22/min, pulse is 120/min, and blood pressure is 80/55 mm Hg. A dissecting aortic aneurysm is suspected. Which test should be used first to confirm the suspected diagnosis? A. Chest X-ray B. CT aortography C. EKG D. Aortic biopsy E. Serum troponin
B. CT aortography
[4H] A 36-year-old man was brought to the emergency department with suspected COVID-19 following a 3-week history of cough, fevers, and shortness of breath, worsening suddenly in the preceding 4 hours. On presentation, he was hypoxemic with an SPO2 of 88% on 15 L/min oxygen, BP of 88/56, and had no audible breath sounds on auscultation of the left hemithorax. A chest radiograph demonstrated a left-sided tension pneumothorax. What factor is most likely to be responsible for the hypotension? A. An underlying reduced heart rate B. Decreased venous return C. Cardiac tamponade D. Hypoxemia E. Hemorrhage
B. Decreased venous return ???
[4C] At a tertiary care center, a research is studying aortic aneurysms seen during the last two decades. He classifies them by etiology, location, and appearance. Which of the following is the most common type of aortic aneurysm he is likely to find? A. Saccular B. Fusiform C. Myocotic D. False E. Mixed
B. Fusiform
[4G] A number of cardiovascular outcomes are affected by deep breathing. Which of the following is a consequence of deep breathing? A. A rise in the jugular venous column B. Increased right ventricular stroke volume C. Decreased velocity of blood in the superior vena cava D. Decreased run off in the pulmonary artery E. Increased intrathoracic pressure
B. Increased right ventricular stroke volume Inspiration decreases intrathoracic pressure & thus CVP. This creates sort of vacuum that increases venous return, cardiac filling, SV, CO, MAP, & firing rate of arterial baroreceptors. This sends signals to medullary CV centers to decrease HR, contractility, venous constriction, & arteriolar constriction.
[4K] In a healthy person, the heart rate increases with inspiration and decreases with expiration, a phenomenon referred to as sinus arrhythmia. A patient with poorly controlled diabetes mellitus may develop autonomic neuropathy which manifests as a blunting of the sinus arrhythmia. What mechanism contributes to the sinus arrhythmia in a healthy person? A. Increased pressure in left atrium during inspiration B. Increased stimulation of stretch receptors in right atrium during inspiration C. Increased stimulation of stretch receptors in the IVC during expiration D. Reflex sympathetic stimulation of the SA node during expiration E. Reflex vagal stimulation of the AV node during inspiration
B. Increased stimulation of stretch receptors in right atrium during inspiration
[4J] A 44-year-old woman is diagnosed with dilated cardiomyopathy, a condition caused by impaired ventricular contractility & compensatory fluid retention. What is the advantage of compensatory fluid retention? A. Increases ventricular wall tension B. Increases ventricular stroke volume C. Decreases ventricular afterload D. Reduces cardiac workload E. Reduces the need for resting cardiac output
B. Increases ventricular stroke volume ???
[4H] A 70-year-old man with severe aortic stenosis is experiencing increasingly severe angina on exertion. He is normotensive and a recent investigation revealed normal coronary arteries. Which physiological alteration would most likely reduce the severity of the angina in this patient? A. Increasing contractility with epinephrine to increase cardiac output B. Increasing diastolic pressure without changing systolic pressure C. Increasing preload by means of fluid infusion D. Coronary angioplasty E. Diuretics
B. Increasing diastolic pressure without changing systolic pressure ???
[4L] A 75-year-old woman with significant past medical history of dyslipidemia (on atorvastatin) and diabetes mellitus (on metformin) presents to the office for an annual checkup. She quit smoking more than 5 years ago. Her blood pressure in the office was noted to be 138/72 mm Hg. Her previous blood pressure has usually been less than 130/80 mm Hg. Among the following, what is she at the highest risk for? A. Dissecting aortic aneurysm B. Myocardial infarction C. Atherosclerotic abdominal aneurysm D. Renal failure E. Cerebral hemorrhage
B. Myocardial infarction Agarwal joked that if he put this on the exam, 50% of people would get it wrong. Hint hint maybe?
[4L] A 22-year-old woman is seen at a clinic for elevated blood pressure. She appears anxious and complains of a headache since few months. This headache is dull, bilateral, and pounding, but improves with rest. Her blood pressure is 145/92 mm Hg in the right arm and 150/91 m Hg in left arm. Cardiac auscultation reveals no murmurs. However, a soft rushing noise is heard around the umbilicus on auscultation. The rest of the physical exam is noncontributory. What is the most likely cause of this woman's elevated blood pressure? A. Excessive salt in diet B. Renal artery stenosis C. Essential hypertension D. Coarctation of the aorta E. Pheochromocytoma
B. Renal artery stenosis
[4MN] Which valvular heart disease is associated with a pulsation of the liver in systole? A. Mitral valve regurgitation B. Tricuspid valve regurgitation C. Aortic valve regurgitation D. Pulmonary valve regurgitation
B. Tricuspid valve regurgitation Tricuspid valve regurgitation is due to retrograde blood flow into R atrium during systole. This incompetence causes holosystolic murmur, heard best along left parasternal border. Functional regurgitation can result from stretch of valve ring, R heart failure, & dilated cardiomyopathy. Regurgitation can also be caused by congenital heart disease in adolescents & young adults, infectious endocarditis in IV drug abusers, & carcinoid heart disease. There is right atrial dilation & hypertrophy as well as eccentric right ventricular hypertrophy. Right-sided HF leads to dependent pitting edema, ascites, congestive hepatomegaly (where liver pulsates during systole), & giant c-v wave in JVP pressure curve. Diagnosis is confirmed by ECHO.
[4B] In an experiment to determine the net flow of fluid across a systemic capillary wall, Starling's forces are measured and the following values are obtained as follows (in mm Hg). Plasma colloid osmotic pressure (PCOP) = 25 Capillary hydrostatic pressure (CHP) = 25 Venous hydrostatic pressure (VHP) = 5 Mean Arterial pressure (MAP) = 80 Interstitial fluid hydrostatic pressure (IFHP) = 2 Interstitial colloid osmotic pressure (ICOP) = 10 Capillary filtration coefficient = 10 ml/min/mm Hg Calculate the rate of net fluid movement across the capillary wall. A: 25 ml/min B: 80 ml/min C: 100 ml/min D: 120 ml/min E: 150 ml/min
B: 80 ml/min Starling's equation is Qf = K[(Pc + πi) - (Pi + πc)] = 10 mL/min/mm Hg [(CHP + ICOP) - (PCOP + IFHP)] = 80 mL/min. Positive Qf is net filtration; negative Qf is net absorption.
[4B] A marathon runner has gotten to the halfway mark of the course. What mechanism is most important in maintaining increased blood flow to the skeletal muscles during the race? A: Sustained production of nitric oxide from endothelial cells B: Increased production of lactic acid by muscle cells C: Decreased oxygen concentration in blood to the muscles D: Increased production of bradykinin by muscle cells E: Increased stimulation of arterioles by the dilator parasympathetic system
B: Increased production of lactic acid by muscle cells There are two possible mechanisms of autoregulation of blood flow to organs. In myogenic aka Bayliss hypothesis, increase in transmural pressure elicits direct contractile reflex of vascular smooth muscle, while decrease in pressure elicits relaxation. In metabolic hypothesis aka active hyperemia, dilation of arterioles results from increased metabolic activity, which is sensed thru decreased metabolic substrate (e.g. O2), increased metabolic products (e.g. CO2 & H+), increased temperature, & increased adenosine, H+, K+, prostacyclin, NO, bradykinins, & histamine. Brain, heart, & exercising skeletal muscle have mainly intrinsic control over their blood flow via metabolites, while skin & resting muscle have sympathetic control over blood flow.
[4F] When recording lead aVL on an ECG, which is the positive electrode? A: Left leg B: Left arm C: Right leg D: Left arm + left leg E: Right arm + left leg
B: Left arm Lead I measures impulses going from R arm to L arm, so R arm would be negative & L arm positive. Lead II measures impulses going from R arm to L leg, so R arm would be negative & L leg positive. Lead III measures impulses going from L arm to L leg, so L arm would be negative & L leg positive. Augmented leads are positive where they are located, so aVL is positive on left arm, aVR is positive on right arm, & aVF is positive on left foot.
[4C] A 23-year old man experiences sudden onset of severe, sharp pain. His lungs are clear on auscultation. A chest radiograph shows a widened mediastinum. Transesophageeal echocardiography confirms a dilated aortic root and arch. Which of the following diseases is the likely cause? A: Trauma B: Marfan syndrome C: Systemic hypertension D: Scleroderma, diffuse E: ANCA-associated vasculitis
B: Marfan syndrome Dissecting aortic aneurysms are assoc. w/ inherited defects of connective tissue, e.g. Marfan syndrome (fibrillin) & Ehlers-Danlos syndrome (collagen formation). It presents w/ sharp, tearing chest pain radiating to back. Complications include pericardial tamponade, which is most common cause of death.
[4A] A 22-year-old student has to have a physical examination to certify that he is able to participate in interscholastic athletics. During the cardiovascular examination, you report his heart rate as 60 beats/min and his arterial blood pressure at 128/68 mm Hg. From echocardiography, his end-diastolic volume is 150 mL and his end-systolic volume is 60 mL. What is the student's mean arterial pressure in mm Hg? A. 108 B. 98 C. 88 D. 80 E. 78
C. 88 Since duration of diastolic time is twice that of systolic time, MAP = 2/3 DP + 1/3 SP. MAP drops most in arterioles, since they have greatest resistance in peripheral circulation. Pulse pressure = Systolic pressure - Diastolic pressure. Windkessel effect is when kinetic energy from ventricular contraction is temporarily stored in aorta & arteries & upon ventricular relaxation, elastic recoil of arteries sends blood forward into rest of circulatory system during diastole. This phenomenon facilitates uninterrupted blood flow in vessels & reduces cardiac afterload.
[4L] A 50-year-old woman presents for echocardiographic evaluation. She has been diagnosed with hypertension eight years ago. Her hypertension is uncontrolled due to poor compliance. Which of the following will most likely be seen on the echocardiography of this patient? A. Dilatation of the left ventricle B. Systolic dysfunction of the left ventricle C. Decreased compliance of the left ventricle D. Systolic dysfunction of the right ventricle
C. Decreased compliance of the left ventricle Hypertension is most common primary diagnosis, defined as systemic BP > 140/90 mm Hg. It often co-exists w/ other comorbidities, e.g. metabolic syndrome, diabetes, chronic kidney disease, etc. Prevalence rises w/ age & is more common in Western countries. It would cause cardiomegaly, since L ventricle is likely pumping against increased peripheral resistance & needs to hypertrophy. There is onion-skinning (medial hypertrophy) of arterioles, causing narrowing of arteriole lumen & hyalinization of wall.
[4B] A 24-year-old pregnant female has pitting pedal edema. Her blood pressure is 118/70 and no proteinuria on urinalysis. Which of the following can best account for the edema? A. Decreased capillary permeability B. Decreased capillary hydrostatic pressure C. Increased venous hydrostatic pressure D. Increased arteriolar pressure E. Increased plasma albumin concentration
C. Increased venous hydrostatic pressure Patient's pregnancy increases venous hydrostatic pressure, which backs up fluid & increases capillary pressure. This means more fluid is filtrated out, leading to edema. Arteriolar constriction has opposite effect; since they determine how much fluid enters capillaries, arteriolar constriction decreases capillary pressure & filtration rate. Picture illustrates this concept applied to GFR.
[4C] A 59-year-old obese man presents to the ER with a 4-hour history of sudden onset of sharp radiating chest pain. The pain he says started in the chest and is now radiating to his arm and lower back. He is nauseated and feels as if he is going to die. An exam reveals a distressed male with right arm blood pressure of 210/110 mm Hg and a left arm blood pressure of 140/82 mm Hg. He is diaphoretic and extremely anxious. The ECG is unremarkable and the initial set of cardiac enzymes is negative. HIs pain is not responding to nitroglycerin. The aortic base is enlarged per radiography. What is the likely etiology or pathogenesis? A. Atherosclerosis B. Fungal infection C. Medial cystic necrosis D. Syphilis E. Trauma
C. Medial cystic necrosis Cystic medial necrosis is characterized by accumulation of basophilic ground substance in tunic media w/ cysts. It is common in connective tissue diseases, e.g. Marfan or Ehlers-Danlos syndromes.
[4MN] Which valve disease is associated with an opening snap and late diastolic murmur? A. Mitral valve regurgitation B. Mitral valve prolapse C. Mitral valve stenosis
C. Mitral valve stenosis In mitral valve stenosis, since left atrium is most posteriorly located chamber in heart, its dilation compresses esophagus, leading to dysphagia for solids. There is opening snap heard on auscultation followed by early to mid-diastolic rumble. This is b/c thickened mitral valves open w/ snap & blood remaining in L atrium rushes into L ventricle. Diagnosis is confirmed by ECHO.
[4L] A 16-year-old Dean presents for a physical. He has been healthy. His blood pressure is 145/95 mm Hg bilaterally on multiple occasions. Lower extremity blood pressure is also elevated. The patient's father has hypertension, and his father and grandfather died from chronic kidney disease. Based on this information, the clinician ordered an echocardiogram (normal) and ultrasound abdomen. What is the most likely reason for the clinician ordering an ultrasound abdomen? A. Renal artery stenosis B. Fibromuscular dysplasia C. Polycystic kidneys D. Coarctation of the aorta E. Essential hypertension
C. Polycystic kidneys
[4MN] What valve is most affected by pulmonary hypertension? A. Tricuspid valve B. Aortic valve C. Pulmonary valve D. Mitral valve
C. Pulmonary valve Pulmonic valve regurgitation is when there is retrograde blood flow into right ventricle during early diastole. It is most often functional murmur from stretching of pulmonic valve ring, e.g. from pulmonary hypertension (Graham Steell murmur). There is S3 due to right ventricle vol. overload & S4 due to eccentric right ventricular hypertrophy. This causes right-sided early diastolic murmur. Diagnosis is confirmed by ECHO.
[4C] At a family clinic, a patient's brother recently died of an abdominal aortic aneurysm. He wonders which risk factor is most strongly associated with its development... A. Family history B. Sedentary lifestyle C. Smoking D. Alcohol E. Male sex
C. Smoking
[4E] A 40-year-old man had an electrocardiogram recorded at a local emergency room after an automobile accident. His weight was 90 kg, and his blood pressure was 160/90 mm Hg. A portion of the man's ECG (three leads) is provided to you: Lead I is positive, Lead II is neutral, and Lead III is negative. What is the mean frontal electrical axis? A: -90 degrees B: -60 degrees C: -30 degrees D: +30 degrees E: +60 degrees
C: -30 degrees Dr. Addae's method of determining mean frontal electrical axis is as follows. (1) Find out which lead out of Leads I, II, or III is neutral, i.e. has equal upward & downward waves for QRS complex. In this case, that would be Lead II, which corresponds to 60 or -120 degrees on hexaxial diagram. (2) Find line that is perpendicular to that of neutral lead. In this case, that would be avL, which is -30 or 150 degrees. Mean frontal electrical axis can be either value at this point. (3) Use another lead to determine which value is correct. For example, if we choose Lead I, its positive value indicates that axis is traveling that same direction, which would confirm -30 degrees as our answer. Same result would be obtained if Lead III were chosen; since Lead III is negative, it would also point in that same direction too.
[4H] A hospitalized patient has an ejection fraction of 0.4, a heart rate of 80 beats/min, and a cardiac output of 4 L/min. What is this patient's end-diastolic volume? A: 100 mL B: 120 mL C: 125 mL D: 150 mL E: 175 mL
C: 125 mL To calculate SV: 4000 mL/min = (80 beats/min) * SV -> SV = 50 mL/beat. Plug that in to calculate EDV: 0.4 = (50 mL/beat) / EDV -> EDV = 125 mL/beat.
[4E] A mean electrical axis value of -60° would most likely be associated with which of the following conditions? A: Pulmonary hypertension B: Premature ventricular contractions C: Aortic stenosis D: Pulmonary edema E: Left ventricular infarction
C: Aortic stenosis Left axis deviation is -30 thru -90 degrees. If there is problem on left side of heart, there is left axis deviation, e.g. aortic & mitral valve problems, left ventricular hypertrophy, left bundle branch block. Right axis deviation is 100 thru 180 degrees. If there is problem on right side of heart, there is right axis deviation, e.g. cor pulmonale, right ventricular hypertrophy, etc. Extreme axis deviation is anything beyond those two ranges.
[4G] A 60-year-old woman is known to have congestive cardiac failure. At a regular visit to the cardiology clinic, a third heart sound is heard. On the pressure-volume diagram shown, when does the third heart sound occur? A: Closing of the mitral valve (Point B) B: Closing of the aortic valve (Point D) C: Between the opening and closing of the mitral valve (Points A and B) D: Between the closing of the mitral valve and the opening of the aortic valve (Points B and C) E: Between the opening and closing of the aortic valve (Points C and D)
C: Between the opening and closing of the mitral valve (Points A and B) Both S3 & S4 occur after aortic & pulmonary valves have shut (Point D) but before mitral & tricuspid valves shut (Point B). Therefore, only possible answer is b/w Points A & B.
[4L] A 17-year-old boy presents for a sports physical. He has been healthy up to this point. His blood pressure is 145/95 mmHg bilaterally on three separate occasions. Lower extremity blood pressure is also elevated. The patient's father, uncle, and grandfather all have hypertension. The patient's complete blood count, electrolytes, renal function, and urinalysis are all normal. Select the most probable diagnosis. A: Polycystic kidney disease B: Renal artery stenosis C: Essential hypertension D: Substance abuse E: Congenital heart disease
C: Essential hypertension 95% of cases are idiopathic aka primary aka essential hypertension. Risk factors include age, heredity, race (black people are at greater risk but Asians are at lower risk), obesity, high salt intake, lack of physical activity, & stress. It affects males more than females up until age 50, then females more than males after age 50.
[4K] A 55-year-old man visits his physician for an annual checkup and is asked to undertake a number of investigations. An ultrasound investigation reveals that he has renal artery stenosis. What are the expected changes in the systemic vascular resistance (SVR) and plasma aldosterone concentration (PAC)? A: No change in SVR, Increase in PAC B: Increase in SVR, Decrease in PAC C: Increase in SVR, Increase in PAC D: Decrease in SVR, Increase in PAC E: Decrease in SVR, Decrease in PAC
C: Increase in SVR, Increase in PAC Renal artery stenosis is in effect arterial vasoconstriction, so that would increase SVR. Since kidneys are receiving less blood flow, they will assume body is hypotensive & activate RAAS system, which increases aldosterone release.
[4H] Verapamil is a calcium channel blocker that reduces heart rate by affecting Phase 0 of the SA node action potential. The drug also affects Phase 2 of ventricular muscle action potentials. How would verapamil affect the preload and contractility of the ventricles? A: Decrease preload and contractility B: Decrease preload and increase contractility C: Increase preload and decrease contractility D: Increase preload and contractility E: Decrease contractility but no effect on preload
C: Increase preload and decrease contractility Reducing HR increases preload since there is more time for ventricles to fill w/ blood. Reducing intracellular Ca2+ also reduces contraction strength of muscle fibers.
[4F] A 69-year-old woman is undergoing a regular medical checkup. Based on the findings from the physical exam, the physician requested a stress ECG. Whilst exercising on the treadmill, her heart rate increased from 90 beats/min at rest to 150 beats/minute. Which of the following ECG parameters would be seen on the patients ECG during exercise? A: Increased duration of the QRS complex B: Lengthening of PR interval C: Reduced R-R interval D: Decreased P wave amplitude E: Increased R wave amplitude
C: Reduced R-R interval Exercise would cause tachycardia, which would increase HR. Only thing that should change is RR interval.
[4I] What are causes, signs, and symptoms of DVT?
Causes: stasis (extended immobilization > 3 days, long airplane/car rides, & post-op states) & hypercoagulability (inherited coagulopathy, polycythemia, & use of contraceptives) Acute signs: swelling of affected leg (> 3 cm difference in circumference relative to other leg), pain on dorsiflexion of foot (Homans sign), pain on squeezing calf, & pitting edema. D-dimer is also elevated Chronic signs: may be asymptomatic, but may see secondary varicose veins & stasis dermatitis Complications: pulmonary embolus, causing V/Q mismatch & lung infarction. Symptoms include shortness of breath, hemoptysis, pain, & sudden death
[4I] What cancer likes to form little blood vessels filled with blood in the liver?
Cavernous hemangioma Cavernous hemangioma is benign tumor of blood vessels, consisting of large, dilated, blood-filled vascular spaces separated by connective tissue stroma. They are locally destructive & found in liver & spleen. They are vulnerable to trauma & may rupture, causing hemoperitoneum & hypovolemic shock. Von Hippel-Lindau syndrome is autosomal dominant disorder where cavernous hemangiomas form in cerebellum in addition to pheochromocytomas, i.e. small vascular tumors in adrenal medulla that cause irregular secretion of E & NE & sympathetic attacks.
[4H] A 60-year-old man is seen complaining of chest pain and malaise. Assuming no change in afterload, which condition is likely to cause a shift of the cardiac function curve to the left? A. Congestive heart failure B. Decreased ventricular ejection fraction C. Increased duration of isometric contraction D. Greater stroke work capability for a given preload E. Increased parasympathetic stimulation of the SA node
D. Greater stroke work capability for a given preload ???
[4L] A 75-year-old woman presents with blood pressure of 220/150 mm Hg, retinal hemorrhages, and papilledema. She has a past medical history of dyslipidemia and diabetes mellitus. She quit smoking more than 5 years ago. Which one of the following is most likely diagnosis? A. Essential hypertension B. Uncomplicated hypertension C. Hypertensive urgency D. Hypertensive emergency E. Secondary hypertension
D. Hypertensive emergency Benign hypertension is mild or moderate elevation in BP that is clinically silent; vessels & organs are damaged over time. However, malignant hypertension is having systolic pressure > 200 mm Hg or diastolic pressure > 120 mm Hg. It causes retinal hemorrhages & renal failure (flea-bitten kidneys w/ small red hemorrhages all over). It may arise from pre-existing benign hypertension or de novo. It presents w/ acute end-organ damage, i.e. acute renal failure, headache, & papilledema, & is medical emergency.
[4G] A 60-year-old man with coronary artery disease is found to have left bundle branch block on ECG, so conduction through left branch is delayed. Which of the following findings would most likely be found on auscultation? A. Diastolic murmur B. Early systolic murmur C. Late systolic murmur D. Paradoxical split of S2 E. Physiological split of S2
D. Paradoxical split of S2 If conduction in left bundle branch is delayed, electrical signal would reach pulmonic valve before aortic valve. Therefore, pulmonic valve would close before aortic valve, resulting in paradoxical split. Upon inspiration, pulmonic valve closure is delayed as usual but still closes before aortic valve.
[4K] A 22-month-old girl had a large non-communicating cyst of the septum pellucida which blocked the foramen of Monro (in brain), increased intracranial pressure, and caused CNS ischemic response. What feature is associated with the ischemic response? A. Stimulation of central chemoreceptors by hypoxia B. Reflex decrease in stroke volume C. Reflex increase in heart rate D. Reflex decrease in renal blood flow E. Marked hypotension
D. Reflex decrease in renal blood flow Cerebral ischemia leads to increased CO2 in brain tissue, which activates chemoreceptor-mediated pressor response. Resulting peripheral vasoconstriction increases BP to very high level & severely decreases renal blood flow. Simultaneously, there is decreased HR. In Cushing reaction, increased intracranial pressure increases CSF pressure, leading to cerebral ischemia. Chemoreceptor reflex increases BP to overcome CSF pressure & restore blood flow to brain. However, chronic stimulation of pressor response leads to depressor response, where there is decreased ventricular contractility, TPR, & BP.
[4A] A study is conducted to determine the factors affecting flow rate in 5 blood vessels of the same length. Which one would have the greatest blood flow? Numbers listed are Pressure Gradient, Radius, and Viscosity respectively. A: 100, 1, 10 B: 50, 2, 5 C: 25, 4, 2 D: 10, 6, 1 E 50, 4, 10
D: 10, 6, 1 According to applied Poisseuille's law, Q = ΔPπr^4/8ηl. Original law assumes that tube is cylindrical & rigid, fluid is Newtonian (i.e. homogeneous w/o suspended particles or cells), & flow is non-pulsatile & laminar. In addition, SVR = (MAP - CVP)/CO. Blood vessels to organs, esp. in capillaries, are arranged in parallel to reduce total resistance.
[4J] Cardiac output is evaluated during catheterization in a 55-year-old man with congestive cardiac failure. Analysis of mixed venous blood from the right atrium shows an oxygen concentration of 15 mL/dL, whilst a sample of arterial blood from the brachial artery has an oxygen concentration of 20 mL/dL. Oxygen consumption is found to be 200 mL/ min. What is the patient's cardiac output? A: 1 L/min B: 2 L/min C: 3 L/min D: 4 L/min E: 5 L/min
D: 4 L/min CO = (200 mL/min) / (20 mL/dL - 15 mL/dL) = 40 dL/min = 4 L/min
[4J] A 55-year-old man is seen at the emergency department with features of myocardial infarction. His blood pressure is 120/80, pulse 44 /minute. There is no observable JVP and no evidence of pedal edema. The physical examination is normal except for the pulse. An ECG shows third degree AV block with a ventricular rate of 44/minute. Which cardiac factor is most likely to be decreased in the patient? A: Preload B: Afterload C: Contractility D: Cardiac Output E: End systolic volume
D: Cardiac Output ???
[4K] A 45-year-old woman faints when standing up following a 90-minute lecture. In a healthy person who stands up from a sitting position, what is the change that occurs in the discharge rate of baroreceptors? A: Increase discharge from the aortic sinus B: Decrease discharge from the aortic sinus C: Increase discharge from the carotid sinus D: Decrease discharge from the carotid sinus E: Increase discharge from both the carotid and aortic sinuses
D: Decrease discharge from the carotid sinus Carotid sinus responds to increase or decrease in arterial pressure, while aortic arch responds to increase only. Standing from sitting position causes blood to pool in lower extremity veins. This decreases MAP & activates baroreceptor reflex, which increases sympathetic outflow. This increases HR, contractility, CO, & constriction of arterioles & veins to restore MAP to normal. Failure of BP control mechanisms to function leads to decreased blood flow to brainstem, resulting in faintness, dizziness, & light-headedness. This is called orthostatic hypotension & occurs more commonly in elderly people or diabetics w/ autonomic neuropathy.
[4MN] A 67-year-old man is found dead in his apartment. His medical history includes several episodes of angina over the past four years, and two recent episodes of syncope. At autopsy the aortic valve is found to be abnormal. What clinical finding would have been most consistent with this valvular disease? A: Harsh diastolic murmur B: Mid-systolic click C: Pericardial friction rub D: Decreased pulse pressure E: Carditis
D: Decreased pulse pressure In aortic stenosis, there is harsh systolic ejection (crescendo-decrescendo), heard in right 2nd intercostal space, radiating into neck. There is left-sided S4 due to hypertrophied L ventricle & diminished pulse pressure, since turbulent flow & dissipation of force into aortic wall decreases systolic pressure. CO may also be decreased in severe stenosis. If patient is asymptomatic, there is excellent prognosis. If there is onset of symptoms, there is bad prognosis if not surgically corrected.
[4D] A 68-year-old gentleman working in a middle management position in the automotive industry suffers an acute myocardial infarction. During his recovery in a local hospital, where the physicians monitored him closely, he developed a slow heartbeat during the recovery period. What condition at the SA node best explains the decrease in heart rate? A: Increased opening of HCN sodium channels. B: Increased phosphorylation of T-type Ca2+ channels. C: Increased activation of beta-1 adrenergic receptors. D: Increased opening of ligand-gated potassium channels. E: Increased opening of voltage-gated calcium channels.
D: Increased opening of ligand-gated potassium channels. Increased opening HCN (funny) sodium channels would accelerate propagation of new action potential, as would increased phosphorylation of T-type Ca2+ channels. Increased (sympathetic) activation of beta-1 adrenergic receptors would increased HR, & increased opening of voltage-gated calcium channels would accelerate depolarization of action potential. However, increased opening of ligand-gated potassium channels would allow more K+ into cell, which would force nodal cell to take longer to reset & prepare for another action potential.
[4L] A 54-year-old African-American male complains of a headache and general malaise. He says he has not been feeling well for the past 48 hours. He has a history of hypertension for 24 years for which he takes a diuretic. He appears pale with a blood pressure measuring 220/110 mmHg. Soon after, he develops chest pain and dies. What is most likely to be seen at autopsy? A: Pheochromocytoma B: Splenic infarcts C: Right ventricular hypertrophy D: Renal artery stenosis E: Enlarged kidneys
D: Renal artery stenosis 5% of hypertension cases are secondary due to identifiable cause, e.g. renal artery stenosis. Stenosis decreases blood flow to affected kidney, which will respond by increasing plasma renin. However, this fails to increase blood flow to affected kidney, which eventually atrophies. This occurs due to atherosclerosis in elderly males or fibromuscular dysplasia in young females.
[4G] A physician is trying to evaluate the jugular venous pulse of a patient. However, because the patient is obese, it is difficult to identify the corresponding waves on the JVP. The physician is using the heart sounds to help identify the components of the JVP. Which component of the JVP corresponds to the second heart sound? A: a wave B: c wave C: x descent D: v wave E: y descent
D: v wave A wave corresponds to atrial contraction, so tricuspid/mitral valves are open while aortic/pulmonic valves are closed. C wave corresponds to beginning of ventricular contraction, so tricuspid/mitral valves are shut while aortic/pulmonic valves eventually open when pressure reaches certain threshold. X descent represents continuation of atrial relaxation (temporarily halted by c wave); during this time, tricuspid/mitral valves are still shut & aortic/pulmonic valves are open. Eventually, atrium fills again, so all valves are shut & therefore S2 would occur during v wave. Y descent is when tricuspid/mitral valves open & blood starts to flow from atrium to ventricle, while aortic/pulmonic valves remain shut.
[4B] An 11-year-old boy's dentist gives him N2O gas via a face mask to anesthetize him. Which of the following is the main route by which N2O reaches the brain? A. Endocytosis across the capillary wall B. Specialized endothelial transporters C. Bulk flow through fenestrations D. Diffusion through intercellular junctions E. Diffusion through the endothelial cells
E. Diffusion through the endothelial cells Pinocytosis & endocytosis provide transit for large molecules, e.g. antibodies. Bulk flow is where fenestrations & clefts b/w adjacent cells provide pathway for ions & solutes to move across capillary wall. Diffusion via gap junctions involves simple diffusion of water & small molecules. Diffusion across cells involves simple diffusion of lipid-soluble materials, including for O2 & CO2 exchange.
[4B] Researchers have found a high prevalence of lymphatic obstruction in patients with a combination of congenital heart disease and protein-losing enteropathy. Which of the following would decrease the lymph flow from tissues of such patients? A. Elevated capillary hydrostatic pressure B. Elevated interstitial fluid protein concentration C. Release of bradykinin from endothelial cells D. Release of nitric oxide from endothelial cells E. Elevated plasma oncotic pressure
E. Elevated plasma oncotic pressure Elevated capillary hydrostatic pressure would push more fluid out of capillaries & increase lymph flow. Elevated interstitial fluid protein concentration would pull more fluid out of capillaries & also increase lymph flow. Bradykinin increases lymph flow via stimulation of B1 receptors. ???
[4A] A 60-year-old man visits his family practitioner for his yearly examination. He has a blood pressure of 180/100 mm Hg, a heart rate of 78 beats/min. His plasma cholesterol level is in the upper 25th percentile. A decrease in which cardiovascular factor is the most likely explanation for the high pulse pressure in this patient? A: Stroke volume B: Arterial pressure C: Heart rate D: Total peripheral resistance E: Arterial compliance
E: Arterial compliance Compliance = ΔV/ΔP, while Distensibility = Compliance * Distending Pressure. Compliance decreases as distending pressure increases. In order of most to least compliant: veins > arteries > aging arteries. Due to their high compliance, veins act as blood reservoirs & will change their vol. most when blood is added/removed.
[4C] A 70-year-old female with a history of hyperlipidemia and hypertension dies suddenly secondary to rupture of an abdominal aortic aneurysm. Which of the following is implicated in the pathogenesis of these aneurysms? A: Proliferation of the intima forming a fibrous cap B: Calcific deposit and ossification of the tunica media C: Autoimmune damage to the endothelium with repair D: Vasa vasorum narrowing causing adventitial damage. E: Inflammation and proteolysis of medial proteins
E: Inflammation and proteolysis of medial proteins In AAAs, inflammation causes elastic tissue breakdown & decreased tensile strength. AAAs usually arise below renal arteries but above aortic bifurcation. Atherosclerosis thickens intima, preventing sufficient oxygenation of media & adventitia. AAAs are usually found in male smokers > age 60 & w/ hypertension. It often presents as pulsatile abdominal mass that grows w/ time. Complications include rupture, esp. when aneurysm is 5+ cm. Rupture presents as triad: hypotension, pulsatile abdominal mass, & flank pain.
[4D] In an experiment, the action potentials of cardiac cells were recorded whilst applying a drug that blocked the T-type calcium channels. Which phase of an action potential is most likely to be affected? A: Phase 0 of the ventricular muscle action potential B: Phase 1 of the ventricular muscle action potential C: Phase 2 of the ventricular muscle action potential D: Phase 0 of the SA node action potential E: Phase 4 of the SA node action potential
E: Phase 4 of the SA node action potential T-type calcium channels are only found in nodal cells, where they contribute to Phase 4 prepotential. Here, Na+ funny channels & T-type Ca2+ channels bring membrane potential back to threshold to trigger another action potential. This leads to Phase 0, where Ca2+ influx thru L-type calcium channels triggers depolarization. There is no Phase 1 or 2. During Phase 3, Ca2+ channels inactivate & K+ exits cell via delayed rectifier channels.
[4MN] What changes in the heart would you expect in a patient with aortic regurgitation?
Eccentric hypertrophy Aortic regurgitation is discussed on different card. On another note, pulmonic valve stenosis is uncommon valve lesion that causes obstruction to systolic blood flow from R ventricle into pulmonary artery. It results in right-sided systolic ejection murmur, concentric right ventricular hypertrophy, & right-sided HF. Diagnosis is confirmed by ECHO.
[4I] Juvenile hemangiomas should be removed surgically. True/False
False Capillary hemangioma is well-differentiated, benign tumor of capillaries. It consists of endothelial cells, i.e. thin-walled capillaries w/ scant stroma. They are found in skin, subcutaneous tissues, & mucous membranes, e.g. oral cavity or lips. Juvenile hemangioma is type of capillary hemangioma found in newborns. They are found in skin & subcutaneous tissues. They are very common & grow rapidly for few months but then regress by age 1-7.
[4MN] Aortic valve regurgitation is associated with a narrow pulse pressure. True/False
False Other signs of aortic valve regurgitation include Corrigan water-hammer pulse, when patient has bounding pulses. Patient may also present w/ de Musset sign (head nodding & bobbing w/ systole) or Quinke pulse (pulsating nail bed). Austin Flint murmur indicates severe aortic regurgitation where heavy jet of back-flowing blood hits anterior leaflet of mitral valve, preventing it from opening properly. This creates turbulence of flow from L atrium to ventricle during diastole, resulting in low-pitched diastolic rumbling. Presence of this murmur is indication for aortic valve replacement. Diagnosis is confirmed via ECHO.
[4MN] Why are schistocytes seen in valvular diseases?
RBCs passing by stenotic valve are damaged & fragment, leading to macroangiopathic hemolytic anemia.
[4MN] What are risk factors, signs, symptoms, or features of aortic valve stenosis?
Risk factors: congenital aortic stenosis, dystrophic calcification Aortic valve stenosis causes concentric left ventricular hypertrophy & dilation of aorta due to jet stream of blood impacting wall of vessel. This decreases SV & systolic function in general. Hypertrophied myocardium is non-compliant, which also impairs diastolic function. CO is decreased, eventually leading to CHF. Symptoms like angina & syncope occur w/ exercise, when reduced blood flow thru stenotic valve reduces filling of coronary arteries during diastole. Decreased perfusion of subendocardium leads to subendocardial ischemia. There are schistocytes in peripheral smear, hemoglobinemia, & hemoglobinuria (pink urine).
[4I] What distinguishes a nevus flammeus from a spider telangiectasia?
Spider telangiectasia consists of slightly raised central core (body) & radial, dilated subcutaneous arteries/arterioles (legs). They blanch w/ pressure & are caused by hyperestrogenic states, e.g. cirrhosis or pregnancy. Hereditary hemorrhagic telangiectasia is 3rd type, which is caused by autosomal dominant disorder where dilated blood vessels on skin, mucous membranes, mouth, & GI tract spontaneously rupture. Symptoms include epistaxis, iron-deficiency anemia from GI bleeds, & hematuria.
[4I] What is stasis dermatitis?
Stasis dermatitis is hemorrhagic or orange discoloration due to poor oxygen perfusion of skin. Color is due to hemosiderin depositing in skin from ruptured blood vessels. Ischemic ulcers get infected & have poor wound healing. They are often located on medial malleolus of ankle. They are caused by DVT, varicose veins, or CHF.
[4I] What are varicose veins?
Varicose veins are abnormally dilated ( > 3 mm), tortuous veins underneath skin or mucosal surface. Risk factors are being female, having family history, having multiple pregnancies, working jobs w/ prolonged standing, being obese, & being old. Increased pressure in superficial veins causes dilation & renders venous valves incompetent. They are normally found in superficial veins of upper & lower legs, esp. saphenous veins. However, they can also be found in distal esophagus due to portal hypertension, anorectal region due to internal hemorrhoids, or left scrotal sac due to varicocele. They may be secondary to DVT, since increased pressure in deep veins causes retrograde blood flow & increased pressure in superficial veins. Complications include stasis dermatitis.
