The Cardiovascular confusions that cost the most Step 1 points

Cardiovascular look-alikes cost points because two conditions can share symptoms, murmurs, or hemodynamic findings. Each pair below focuses on the clue that should drive your answer.

Septic shock vs Cardiogenic shock

Both can cause shock, and late septic shock can produce cold, mottled extremities that resemble cardiogenic shock. Separate them with SVR, cardiac output, and filling pressures. Septic shock has low SVR with normal or high cardiac output early and low-to-normal PCWP, while cardiogenic shock has high SVR, low cardiac output, and high PCWP. Do not choose based on skin temperature alone.

Septic shock vs Cardiogenic shock Septic shock is low-SVR vasodilation; cardiogenic shock is pump failure with high filling pressures. Open the comparison and video →

Mitral regurgitation vs Mitral stenosis

Both can present with atrial fibrillation, dyspnea, and a loud apical murmur. Mitral regurgitation produces a holosystolic murmur at the apex that radiates to the axilla, while mitral stenosis produces an opening snap followed by a low-pitched diastolic rumble. Time the murmur before using its location. Do not let shared symptoms decide which valve lesion is present.

Mitral regurgitation vs Mitral stenosis MR: blowing holosystolic apical murmur radiating to the axilla; MS: low-pitched mid-diastolic rumble after an opening snap. Open the comparison and video →

Stable angina vs Acute coronary syndrome

Both involve ischemic chest pain, but the pattern separates them. Stable angina causes predictable exertional chest pressure relieved by rest or nitroglycerin, while new, worsening, or rest pain requires an acute coronary syndrome framing. A normal first troponin or ECG does not make an unstable pattern stable. Use ECG and serial troponins to classify acute coronary syndrome only after you recognize the pattern.

Stable angina vs Acute coronary syndrome Stable is predictable demand ischemia; new, worse, or rest pain is ACS until biomarkers and ECG classify it. Open the comparison and video →

Left-sided heart failure vs Right-sided heart failure

Both can cause dyspnea, especially because right-sided failure commonly follows left-sided failure. Left-sided failure produces pulmonary congestion with orthopnea, crackles, and pulmonary edema. Right-sided failure produces systemic venous congestion with JVD, hepatomegaly, ascites, and peripheral edema. Ask whether the congestion is visible in the lungs or the systemic veins.

Left-sided heart failure vs Right-sided heart failure Left-sided failure: pulmonary congestion (dyspnea, crackles, S3); right-sided failure: systemic congestion (JVD, edema, ascites). Open the comparison and video →

Aortic stenosis vs Hypertrophic cardiomyopathy

Both produce crescendo-decrescendo systolic ejection murmurs and can cause exertional syncope. Aortic stenosis is a fixed obstruction with a weak delayed carotid pulse, while hypertrophic cardiomyopathy is a dynamic obstruction with a brisk bifid pulse. Valsalva or standing makes the hypertrophic cardiomyopathy murmur louder and the aortic stenosis murmur softer. Do not use murmur shape alone to separate them.

Aortic stenosis vs Hypertrophic cardiomyopathy AS is fixed obstruction with pulsus parvus et tardus; HCM is dynamic obstruction with brisk/bifid pulse and louder murmur when preload falls. Open the comparison and video →

Cardiac tamponade vs Tension pneumothorax

Both can cause obstructive shock with hypotension, JVD, and pulsus paradoxus. Cardiac tamponade has muffled heart sounds with bilateral breath sounds, while tension pneumothorax has absent unilateral breath sounds with hyperresonance. Those shared bedside signs do not separate them. Listen to the heart and lungs before choosing the emergency procedure.

Cardiac tamponade vs Tension pneumothorax Tamponade is muffled heart sounds and effusion; tension pneumothorax is absent unilateral breath sounds with hyperresonance. Open the comparison and video →

Restrictive cardiomyopathy vs Constrictive pericarditis

Both cause diastolic failure with preserved ejection fraction, biatrial enlargement, Kussmaul sign, and right-sided congestion. Restrictive cardiomyopathy comes from stiff ventricular muscle, while constrictive pericarditis comes from a rigid pericardial shell. Pericardial calcification or thickening, a pericardial knock, and respiratory variation in ventricular inflow point to constriction. A normal pericardium with biventricular wall thickening points to restriction.

Restrictive cardiomyopathy vs Constrictive pericarditis Restrictive is stiff myocardium; constrictive is stiff pericardium with exaggerated ventricular interdependence. Open the comparison and video →

Aortic stenosis vs Aortic regurgitation

Both can cause left ventricular hypertrophy and heart failure symptoms. Aortic stenosis produces a harsh systolic murmur that radiates to the carotids with a weak delayed pulse. Aortic regurgitation produces an early diastolic decrescendo murmur with wide pulse pressure and bounding pulses. Name the murmur timing first because systole points to stenosis and diastole points to regurgitation.

Aortic stenosis vs Aortic regurgitation AS is systolic obstruction with carotid radiation; AR is diastolic leak with wide pulse pressure. Open the comparison and video →

Quick self-test

Name the diagnosis from the clue, then tap to check.

1. Holosystolic murmur at the apex radiating to the axilla.

   Mitral regurgitation · Mitral regurgitation vs Mitral stenosis

2. Crescendo-decrescendo systolic murmur at the right upper sternal border radiating to the carotids.

   Aortic stenosis · Aortic stenosis vs Hypertrophic cardiomyopathy

3. New, worsening, or rest chest pain requiring ACS framing: unstable angina, NSTEMI, or STEMI.

   Acute coronary syndrome · Stable angina vs Acute coronary syndrome

4. Diastolic dysfunction from rigid pericardium, often with pericardial calcification or knock.

   Constrictive pericarditis · Restrictive cardiomyopathy vs Constrictive pericarditis

5. Predictable exertional chest pressure relieved by rest or nitroglycerin.

   Stable angina · Stable angina vs Acute coronary syndrome

6. Diastolic dysfunction from stiff myocardium, often due to infiltrative disease.

   Restrictive cardiomyopathy · Restrictive cardiomyopathy vs Constrictive pericarditis

7. Dynamic systolic murmur that increases with Valsalva or standing and decreases with squatting.

   Hypertrophic cardiomyopathy · Aortic stenosis vs Hypertrophic cardiomyopathy

8. Early diastolic decrescendo murmur with wide pulse pressure, bounding pulses, and LV volume overload.

   Aortic regurgitation · Aortic stenosis vs Aortic regurgitation

9. Dyspnea, orthopnea, crackles, pulmonary edema, and reduced forward output.

   Left-sided heart failure · Left-sided heart failure vs Right-sided heart failure

10. Opening snap followed by a low-pitched diastolic rumble at the apex.

    Mitral stenosis · Mitral regurgitation vs Mitral stenosis

11. Harsh crescendo-decrescendo systolic murmur at the right upper sternal border radiating to carotids with weak delayed pulse.

    Aortic stenosis · Aortic stenosis vs Aortic regurgitation

12. Hypotension, JVD, muffled heart sounds, pulsus paradoxus, and electrical alternans.

    Cardiac tamponade · Cardiac tamponade vs Tension pneumothorax

How to make these stick

Practice each pair with fresh questions until you identify the separating clue automatically. Keep returning to the one distinction that decides the pair.