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USMLE Step 3 – High-Yield Clinical Practice Test (2026 | 2027 Style) Questions
and Answers with Rationale | Updates | 100% Correct
Domain 1: Internal Medicine – Cardiology & Critical Care
1. A 65-year-old male with a history of hypertension and type 2 diabetes
presents to the emergency department with acute, crushing substernal chest
pain radiating to his left arm. He is diaphoretic and nauseous. He took 2 aspirins
at home. His blood pressure is 145/90 mmHg, heart rate is 115 bpm. ECG shows
ST-segment elevation in leads V1-V4. The nearest cardiac catheterization lab is 3
hours away by ambulance. What is the most appropriate immediate
management?
A) Administer sublingual nitroglycerin, start a heparin drip, and prepare for
thrombolytic therapy (fibrinolysis) while arranging transfer.
B) Wait for transfer to the catheterization lab without any other interventions.
C) Administer oral beta-blockers and schedule an outpatient stress test.
D) Administer a calcium channel blocker and monitor.
Answer: A
Rationale: This is an acute STEMI. The goal is reperfusion within 90 minutes of first
medical contact. Since PCI is not available within 90 minutes, the next best option
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is fibrinolysis (thrombolytic therapy) if the patient has no contraindications.
Nitroglycerin and heparin are also immediate standard therapies.
2. A 72-year-old female with a history of heart failure with reduced ejection
fraction (HFrEF) presents with progressive dyspnea, orthopnea, and 3+ pitting
edema in the lower extremities. She has crackles in the lung bases. She is
currently on lisinopril, carvedilol, and furosemide. Her blood pressure is 90/60
mmHg and heart rate is 105 bpm. What is the most appropriate next step in
management?
A) Discontinue carvedilol and temporarily increase the furosemide dose.
B) Increase the lisinopril dose.
C) Administer an IV inotropic agent (e.g., dobutamine) and initiate non-invasive
positive pressure ventilation (NIPPV).
D) Administer oral digoxin immediately.
Answer: C
Rationale: The patient is in acute decompensated heart failure with cardiogenic
shock (hypotension, tachycardia, and signs of fluid overload). Inotropic support
(dobutamine) and NIPPV (BiPAP) are indicated for stabilization. Beta-blockers
should be held until the patient is hemodynamically stable.
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3. A 60-year-old male with a history of atrial fibrillation presents with a 1-day
history of sudden onset of severe, tearing chest pain radiating to his back. His
blood pressure is 210/110 mmHg. What is the most likely diagnosis, and what is
the immediate action?
A) Aortic dissection; immediately reduce blood pressure with IV labetalol and
order a CT angiogram.
B) Acute MI; proceed to cardiac catheterization.
C) Pulmonary embolism; start anticoagulation.
D) Pericarditis; administer NSAIDs.
Answer: A
Rationale: The classic presentation of aortic dissection is severe, tearing chest or
back pain with severe hypertension. Immediate management includes aggressive
blood pressure reduction (target systolic BP 100-120 mmHg) with IV labetalol or
nitroprusside, and emergent CT angiogram for diagnosis.
Domain 2: Internal Medicine – Pulmonology & Critical Care
4. A 68-year-old male with a 30-pack-year history of smoking and known COPD
presents with a 4-day history of increasing shortness of breath, purulent
USMLE Step 3 – High-Yield Clinical Practice Test (2026 | 2027 Style) Questions
and Answers with Rationale | Updates | 100% Correct
Domain 1: Internal Medicine – Cardiology & Critical Care
1. A 65-year-old male with a history of hypertension and type 2 diabetes
presents to the emergency department with acute, crushing substernal chest
pain radiating to his left arm. He is diaphoretic and nauseous. He took 2 aspirins
at home. His blood pressure is 145/90 mmHg, heart rate is 115 bpm. ECG shows
ST-segment elevation in leads V1-V4. The nearest cardiac catheterization lab is 3
hours away by ambulance. What is the most appropriate immediate
management?
A) Administer sublingual nitroglycerin, start a heparin drip, and prepare for
thrombolytic therapy (fibrinolysis) while arranging transfer.
B) Wait for transfer to the catheterization lab without any other interventions.
C) Administer oral beta-blockers and schedule an outpatient stress test.
D) Administer a calcium channel blocker and monitor.
Answer: A
Rationale: This is an acute STEMI. The goal is reperfusion within 90 minutes of first
medical contact. Since PCI is not available within 90 minutes, the next best option
, Page |2
is fibrinolysis (thrombolytic therapy) if the patient has no contraindications.
Nitroglycerin and heparin are also immediate standard therapies.
2. A 72-year-old female with a history of heart failure with reduced ejection
fraction (HFrEF) presents with progressive dyspnea, orthopnea, and 3+ pitting
edema in the lower extremities. She has crackles in the lung bases. She is
currently on lisinopril, carvedilol, and furosemide. Her blood pressure is 90/60
mmHg and heart rate is 105 bpm. What is the most appropriate next step in
management?
A) Discontinue carvedilol and temporarily increase the furosemide dose.
B) Increase the lisinopril dose.
C) Administer an IV inotropic agent (e.g., dobutamine) and initiate non-invasive
positive pressure ventilation (NIPPV).
D) Administer oral digoxin immediately.
Answer: C
Rationale: The patient is in acute decompensated heart failure with cardiogenic
shock (hypotension, tachycardia, and signs of fluid overload). Inotropic support
(dobutamine) and NIPPV (BiPAP) are indicated for stabilization. Beta-blockers
should be held until the patient is hemodynamically stable.
, Page |3
3. A 60-year-old male with a history of atrial fibrillation presents with a 1-day
history of sudden onset of severe, tearing chest pain radiating to his back. His
blood pressure is 210/110 mmHg. What is the most likely diagnosis, and what is
the immediate action?
A) Aortic dissection; immediately reduce blood pressure with IV labetalol and
order a CT angiogram.
B) Acute MI; proceed to cardiac catheterization.
C) Pulmonary embolism; start anticoagulation.
D) Pericarditis; administer NSAIDs.
Answer: A
Rationale: The classic presentation of aortic dissection is severe, tearing chest or
back pain with severe hypertension. Immediate management includes aggressive
blood pressure reduction (target systolic BP 100-120 mmHg) with IV labetalol or
nitroprusside, and emergent CT angiogram for diagnosis.
Domain 2: Internal Medicine – Pulmonology & Critical Care
4. A 68-year-old male with a 30-pack-year history of smoking and known COPD
presents with a 4-day history of increasing shortness of breath, purulent
