10 USMLE Cardiology Questions with Answers and Explanations (Set 3)

These 10 USMLE cardiology and vascular practice questions (Set 3) cover myocardial infarction, hypertension choices in diabetes and asthma, atherosclerosis, cyanotic congenital heart disease, Marfan syndrome, atrial flutter, varicose veins and vascular erectile dysfunction. Each question includes the correct answer and an explanation.

Written by Dr. Ray Makar, MD, author of the Repeated USMLE Questions eBook series.

Prefer video? Watch daily USMLE case questions on MedFocus by Dr. Ray on YouTube.

How to use this page: read the question, pick your answer, then tap Show Answer and Explanation.

Questions

Question 1. A 67-year-old man is brought to the emergency room by his colleagues for a possible heart attack. One hour ago, he felt excruciating chest pain, shortness of breath and nausea. ECG shows elevation of ST segment in leads II, III and aVF. Therapy is initiated and the patient starts feeling better. ER physician explains to the patient mechanism of action of different drugs used in the treatment. Which of these drugs is responsible for rapid reperfusion in this patient?

A- Aspirin
B- Tissue plasminogen activator (tPA)
C- Ticlopidine
D- Argatroban

Tissue plasminogen activator (tPA) is the only drug of the above choices which mechanism of action is mainly reperfusion of the affected site. It is given intravenously to dissolve the blood clot and improve the blood flow to the part of the heart that deprived of blood. Other drugs work mainly on platelets to stop accumulating and acting on the injured site.
The correct answer is B

 

Question 2. A 56-year-old man presents to the emergency room complaining of severe chest pain, nausea and excessive sweating for 30 minutes. ECG and laboratory tests confirm the diagnosis of acute myocardial infarction. What is the most likely reason of diaphoresis in this patient?

A- Parasympathetic stimulation
B- Sympathetic stimulation
C- Decreased peripheral resistance
D- Decreased sodium and water retention
E- Elevated parathyroid hormone

Myocardial infarction especially inferior MI leads to shock. Shock results in sympathetic stimulation which leads to excessive sweating. All other options are not associated with MI.
The correct answer is B

 

Question 3. A 57-year-old man with a long history of type 2 diabetes visits the clinic for follow up. He takes metformin, aspirin and pravastatin. His blood pressure was high in the last 2 visits. He made lifestyle changes in the form of diet and exercise but they did not help in lowering his blood pressure. His BMI is 25 kg/m2 and his blood pressure today is 150/92 mmHg. What is the most appropriate treatment for this patient’s hypertension?

A- Lisinopril 10 mg daily
B- Metoprolol 25 mg daily
C- Hydralazine 50 mg daily
D- Minoxidil 30 mg daily
E- Continue lifestyle modification for 3 months

The rule of thumb in treating hypertension in diabetic patients is using ACE inhibitors such as Lisinopril to delay renal problems. Other antihypertensive drugs do not help to delay the development of diabetic neuropathy. Lifestyle modification is not enough for this patient at this time.
The correct answer is A

 

Question 4. A 59-year-old man visits his physician for his yearly routine examination. He mentions that his exercise tolerance had been reduced over the last year. He also notes that he experiences shortness of breath and chest pain when he is ascending his home stairs although he lives on the second floor. He smokes 1-2 packs of cigarettes every day for 35 years. He drinks socially and uses recreational drugs occasionally. On examination, his vital signs are as follows: pulse 86/min, blood pressure 138/86 and his BMI is 30. His cardiac examination is unremarkable. He has family history of hypercholesterolemia and coronary disease. His laboratory tests show abnormal lipid profile (LDL Cholesterol: 230 mg/dL and HDL: 32 mg/dL). What is the most likely vascular pathology in this patient?

A- Atherosclerosis
B- Deep venous thrombosis
C- Hyperplastic arteriosclerosis
D- Medial calcific sclerosis

This patient has hypercholesterolemia and most probably angina revealed by exertional dyspnea and chest pain. At his age and due to other factors such as smoking and familial hypercholesterolemia, coronary artery disease is mostly precipitated by atherosclerosis. Deep venous thrombosis is suspected if the patient complains of pain, tenderness and swelling of one or both of his legs and/or shortness of breath and pleuritic pain. Hyperplastic arteriosclerosis and medial calcific sclerosis usually occur in smaller arteries and arterioles in patients with diabetes and/or hypertension which is not the case in this patient.
The correct answer is A

 

Question 5. A 16-month-old boy is brought to the clinic by his mother who is concerned that her boy turns blue and becomes short of breath several times during last three months. During these episodes, he becomes irritable and stays in squatting position until he relieves. Cardiac examination reveals systolic ejection murmur over the upper right sternal border. X-ray shows boot-shaped heart. What is the most likely diagnosis?

A- Tetralogy of Fallot
B- Total anomalous pulmonary venous return
C- Transposition of the great arteries
D- Tricuspid atresia
E- Truncus arteriosus

This is a case of cyanotic heart disease. As we may all know, congenital heart diseases are classified into cyanotic and non-cyanotic heart diseases. Also, cyanotic heart diseases are further classified into early and late cyanotic depending upon if they are diagnosed early in the neonatal period or later. Total anomalous pulmonary venous connection, transportation of the great vessels, tricuspid atresia and truncus arteriosus are examples of early cyanotic congenital heart diseases which show right after birth. Tetralogy of Fallot is usually revealed later on or after the neonatal period due the development of right-to-left shunt through the ventricular septal defect.
Fallot of Tetralogy is characterized by ventricular septal defect, pulmonary stenosis, right ventricular hypertrophy and overriding aorta. Sometimes, as in this case, it appears later after the neonatal period and it causes “tet spells” which are episodes of cyanosis, dyspnea, irritability and loss of consciousness. Some kids develop natural relief by squatting which increases venous return to the heart leading to relief of these episodes.
The correct answer is A

 

Question 6. A 23-year-old man with a history of Marfan syndrome presents to the ER complaining of sharp pain on the upper back. He is admitted to intensive care unit (ICU) for the risk of aortic dissection. Which of the following proteins are responsible for the probable development of aortic aneurysm and dissection in this patient?

A- Myosin and actin
B- Fibrin and actin
C- Fibrillin and elastin
D- Myosin and fibrin

Marfan syndrome is a connective tissue disorder caused by FBNI gene mutation on chromosome 15 which results in defective fibrillin. It affects bones, heart, large vessels and eyes. Patients are tall with long extremities, hypermobile joints and long tapering fingers and toes. Aortic aneurysm develops due to cystic medial necrosis of the aorta.
Myosin and actin are not directly affected in Marfan syndrome. It affects fibrillin which forms a sheath around elastin.
The correct answer is C

 

Question 7. A 49-year-old man who is recently diagnosed with hypertension and has a history of bronchial asthma and Raynaud syndrome visits his physician for initiation of his treatment plan. In selecting the appropriate antihypertensive drug, which of the following is the best treatment for this patient?

A- Atenolol
B- Captopril
C- Amlodipine
D- Metoprolol
E- Hydrochlorothiazide

A dihydropyridine calcium channel blocker such as amlodipine (or nifedipine) is the best choice. It lowers blood pressure and also relieves Raynaud phenomenon by dilating peripheral arteries. Beta-blockers such as atenolol and metoprolol should be avoided because they can cause bronchospasm in asthma and can worsen Raynaud vasospasm. ACE inhibitors and thiazides lower blood pressure but do not help Raynaud.
The correct answer is C

 

Question 8. A 78 year-old patient is admitted to the hospital for treatment of pneumonia. On the third day, the nurse noticed that his heart rate is 150/min. and blood pressure is 116/86 mmHg. The patient is stable with no chest pain or shortness of breath. His ECG shows saw tooth pattern with no other abnormalities. What is the most appropriate next step of management of this patient?

A- Start heparin
B- Start metoprolol
C- Order cardiac enzymes
D- Perform electric cardioversion
E- Refer to a cardiologist

This patient has atrial flutter which is common in elderly hospitalized patients. He needs urgent rate control by metoprolol before conducting any further investigations.
The correct answer is B

 

Question 9. A 43-year-old cashier visits her physician with a complaint of severe pain for 3 months and a new onset of itching in her right leg. Examination reveals multiple varicosities on the medial side of the right thigh and leg and an erythematous patch on the medial side of the knee. What is the most common precipitating factor for this condition?

A- Alcohol intake
B- Excessive sweating
C- Prolonged exposure to the sun
D- Prolonged standing
E- Strenuous exercise

Prolonged standing is the most common precipitating factor for varicose veins. Prolonged standing can cause blood to accumulate in the leg veins leading to increasing the venous pressure. Increase in the pressure within the veins leads to weakness of the walls of veins and damage of the valves. Varicose veins are dilated superficial veins which are commonly found in the lower extremities. Notice that this person’s job is cashier which is usually related to prolonged standing. Other factors are not causing varicose veins.
The correct answer is D

 

Question 10. A 53-year-old man visits his physician with a complaint of erectile dysfunction. He is married for 20 years and they have two kids. He had never complained of his sexual performance until last month when he found out that he could not induce a full erection. He has no major health conditions and does not take any medications. He smokes one pack of cigarettes daily for 25 years. He does not drink alcohol or takes recreational drugs. What is the most likely etiology for this patient’s condition?

A- Endocrine
B- Infection
C- Pure psychogenic
D- Trauma
E- Vascular

In men older than 50 years, vascular diseases such as atherosclerosis, peripheral vascular diseases, hypertension and coronary vascular diseases are considered the main causes of new onset of erectile dysfunction. Other etiologies are common but not as common as vascular diseases, which account for 50% of all cases of erectile dysfunction occurs after 50 years of age.
The correct answer is E

 

High-yield points from this set

  • STEMI: tPA dissolves the clot by converting plasminogen to plasmin (primary PCI is preferred when available quickly).
  • Sweating during an MI comes from sympathetic stimulation.
  • Hypertension in a diabetic patient: an ACE inhibitor or ARB is first choice.
  • High LDL, low HDL, smoking and exertional chest pain = atherosclerosis.
  • Cyanotic spells relieved by squatting with a boot-shaped heart = tetralogy of Fallot.
  • Marfan syndrome = fibrillin-1 defect; risk of aortic root aneurysm and dissection.
  • Hypertension with asthma and Raynaud: a dihydropyridine calcium channel blocker.
  • Stable atrial flutter with a fast rate: rate control with a beta-blocker.
  • Prolonged standing is the main precipitating factor for varicose veins.
  • New erectile dysfunction in an older smoker is usually vascular.

Keep practicing

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