Cardiovascular Disorders Practice Questions
20 free Cardiovascular Disorders practice questions for the USMLE Step 1. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
A 58-year-old man presents with crushing substernal chest pain radiating to the left arm. ECG shows ST elevation in leads II, III, and aVF. Which artery is most likely occluded?
- A Left anterior descending artery
- B Left circumflex artery
- C Right coronary artery
- D Diagonal branch of LAD
Correct answer: Right coronary artery
ST elevation in II, III, and aVF indicates an inferior wall MI, most commonly due to occlusion of the right coronary artery.
A patient with congestive heart failure has bilateral leg swelling and jugular venous distention. Which side of the heart is failing?
- A Left ventricle
- B Right ventricle
- C Left atrium
- D Right atrium
Correct answer: Right ventricle
Right-sided heart failure leads to systemic venous congestion, causing JVD and peripheral edema.
A 63-year-old man collapses suddenly. ECG shows chaotic, irregular waveforms with no identifiable P waves or QRS complexes. What is the diagnosis?
- A Atrial fibrillation
- B Ventricular tachycardia
- C Ventricular fibrillation
- D Torsades de pointes
Correct answer: Ventricular fibrillation
Ventricular fibrillation is characterized by chaotic electrical activity with no organized rhythm and is life-threatening.
A patient presents with dyspnea and orthopnea. Lung exam reveals rales. Which condition best explains these findings?
- A Right-sided heart failure
- B Left-sided heart failure
- C Constrictive pericarditis
- D Pulmonary embolism
Correct answer: Left-sided heart failure
Left-sided heart failure causes pulmonary congestion, leading to dyspnea, orthopnea, and crackles on lung exam.
A patient with an acute MI has elevated troponin levels. How long do troponin levels typically remain elevated?
- A 12–24 hours
- B 1–2 days
- C 7–10 days
- D 2–3 weeks
Correct answer: 7–10 days
Troponins peak within 24 hours and remain elevated for 7–10 days, making them useful for detecting MI after several days.
A patient with atrial fibrillation presents with an irregularly irregular pulse. Which structure is most commonly the source of abnormal electrical activity?
- A Atrioventricular node
- B Pulmonary vein ostia
- C Bundle of His
- D Left atrial appendage
Correct answer: Pulmonary vein ostia
Ectopic foci in the pulmonary vein ostia commonly initiate atrial fibrillation through aberrant electrical activity.
A patient with heart failure is prescribed spironolactone. What is its primary benefit?
- A Directly increases cardiac contractility
- B Blocks beta-adrenergic receptor activity
- C Reduces mortality via aldosterone blockade
- D Increases venous return to the heart
Correct answer: Reduces mortality via aldosterone blockade
Spironolactone reduces mortality in heart failure patients by antagonizing aldosterone, preventing cardiac remodeling.
A patient with syncope has prolonged QT interval on ECG. Which arrhythmia is he at risk for?
- A Ventricular fibrillation
- B Atrial flutter
- C Torsades de pointes
- D AV nodal reentrant tachycardia
Correct answer: Torsades de pointes
Prolonged QT predisposes to torsades de pointes, a polymorphic ventricular tachycardia that may degenerate into ventricular fibrillation.
A patient presents with new-onset chest pain. ECG shows ST depressions in V4–V6. What is the most likely diagnosis?
- A STEMI
- B NSTEMI
- C Pericarditis
- D Hyperkalemia
Correct answer: NSTEMI
NSTEMI typically shows ST depression and T-wave inversion and is due to partial coronary occlusion.
A patient develops hypotension, distended neck veins, and muffled heart sounds after chest trauma. Which condition is most likely?
- A Cardiogenic shock
- B Cardiac tamponade
- C Aortic dissection
- D Pulmonary embolism
Correct answer: Cardiac tamponade
Beck’s triad (hypotension, JVD, muffled heart sounds) indicates cardiac tamponade due to pericardial fluid accumulation.
A 70-year-old man with atrial fibrillation develops sudden left arm weakness. Which complication is most likely responsible?
- A Carotid atherosclerotic embolism
- B Left atrial appendage thromboembolism
- C Hypertensive lacunar infarction
- D Vertebral artery dissection
Correct answer: Left atrial appendage thromboembolism
Atrial fibrillation promotes thrombus formation in the left atrial appendage, which may embolize to cerebral arteries causing stroke.
Which electrolyte disturbance increases the risk of digoxin toxicity?
- A Hyperkalemia
- B Hypokalemia
- C Hypernatremia
- D Hypercalcemia
Correct answer: Hypokalemia
Hypokalemia enhances digoxin binding to the Na⁺/K⁺ ATPase, increasing toxicity risk.
A patient presents with bounding pulses, wide pulse pressure, and a blowing diastolic murmur. Which condition is likely?
- A Aortic stenosis
- B Aortic regurgitation
- C Mitral stenosis
- D Pulmonic stenosis
Correct answer: Aortic regurgitation
Aortic regurgitation causes wide pulse pressure and a decrescendo diastolic murmur due to backflow into the left ventricle.
A patient with chronic hypertension has concentric left ventricular hypertrophy. Which mechanism explains this?
- A Increased preload
- B Increased afterload
- C Reduced contractility
- D Valve regurgitation
Correct answer: Increased afterload
Hypertension increases afterload, causing the ventricle to thicken concentrically to maintain stroke volume.
A man collapses during exercise. ECG shows a delta wave and short PR interval. Which condition is most likely?
- A Brugada syndrome
- B AV nodal reentrant tachycardia
- C Wolff–Parkinson–White syndrome
- D Sick sinus syndrome
Correct answer: Wolff–Parkinson–White syndrome
WPW syndrome involves an accessory pathway (Bundle of Kent) causing a delta wave and predisposition to tachyarrhythmias.
A patient has S3 heart sound. Which condition is this most associated with?
- A Aortic stenosis
- B Diastolic dysfunction
- C Systolic heart failure
- D Hypertrophic cardiomyopathy
Correct answer: Systolic heart failure
An S3 indicates volume overload in dilated ventricles and is commonly heard in systolic heart failure.
A woman presents with palpitations. ECG shows sawtooth flutter waves. Which arrhythmia is this?
- A Atrial flutter
- B Atrial fibrillation
- C Ventricular flutter
- D AV block
Correct answer: Atrial flutter
Atrial flutter produces characteristic sawtooth flutter waves due to a reentrant circuit in the atria.
A patient with MI develops papillary muscle rupture. What murmur is expected?
- A Aortic regurgitation
- B Mitral regurgitation
- C Tricuspid stenosis
- D Pulmonic regurgitation
Correct answer: Mitral regurgitation
Papillary muscle rupture leads to acute mitral regurgitation, causing a holosystolic murmur and pulmonary edema.
A young athlete collapses and dies suddenly. Autopsy shows asymmetric septal hypertrophy. Which condition is most likely?
- A Hypertrophic cardiomyopathy
- B Dilated cardiomyopathy
- C Restrictive cardiomyopathy
- D Arrhythmogenic RV dysplasia
Correct answer: Hypertrophic cardiomyopathy
Hypertrophic cardiomyopathy causes asymmetric septal hypertrophy and is a common cause of sudden cardiac death in young athletes.
A patient develops pulmonary edema in acute left-sided heart failure. Which mechanism is responsible?
- A Decreased pulmonary capillary hydrostatic pressure
- B Increased pulmonary capillary hydrostatic pressure
- C Increased plasma oncotic pressure
- D Increased pulmonary lymphatic drainage
Correct answer: Increased pulmonary capillary hydrostatic pressure
Left-sided heart failure raises pulmonary venous pressure, increasing hydrostatic pressure and causing pulmonary edema.