Heart Murmurs: Step 1 review notes and self-test
Notes for the Heart Murmurs rapid review: the clue that separates each of its 6 confusion pairs, with timestamps and a self-test.
October 21, 2026
The video covers confusion pairs for AS, AR, HCM, MR, MS, MVP, right-sided regurgitation, and rheumatic disease. Watch the video, then use these notes to test yourself.
Aortic stenosis vs Aortic regurgitation
Name the timing first: systole means aortic stenosis, while diastole means aortic regurgitation. AS has a harsh crescendo-decrescendo systolic murmur at the right upper sternal border that radiates to the carotids, with a weak delayed pulse. AR has an early diastolic decrescendo murmur with wide pulse pressure, bounding pulses, and LV volume overload. Both can cause LV hypertrophy and heart failure symptoms, so murmur timing and pulse pressure decide.
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 →Aortic stenosis vs Hypertrophic cardiomyopathy
Use the response to preload and the pulse: Valsalva or standing makes HCM louder and AS softer, while squatting or handgrip makes HCM softer and AS louder. AS has a right upper sternal border systolic murmur that radiates to the carotids with pulsus parvus et tardus, while HCM has a brisk bifid pulse. Both can cause crescendo-decrescendo systolic ejection murmurs and exertional syncope, so murmur shape does not decide.
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 →Mitral regurgitation vs Mitral stenosis
Timing separates them: MR causes a holosystolic apical murmur that radiates to the axilla, while MS causes an opening snap followed by a low-pitched diastolic rumble at the apex. Atrial fibrillation, dyspnea, and a loud apical murmur can occur in both, so they do not decide. Listen for the opening snap in MS, and remember that a shorter A2-to-opening-snap interval means more severe MS.
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 →Mitral valve prolapse vs Mitral regurgitation
Listen for a click: MVP has a midsystolic click followed by a late systolic murmur, while MR has a holosystolic blowing apical murmur that radiates to the axilla with no click. Standing or Valsalva moves the MVP click earlier and lengthens the murmur, while squatting or handgrip moves the click later and shortens the murmur. MVP can progress to or coexist with MR, so the auscultatory pattern is the discriminator.
Mitral valve prolapse vs Mitral regurgitation MVP is click plus late systolic murmur; MR is holosystolic apical murmur radiating to axilla. Open the comparison and video →Tricuspid regurgitation vs Pulmonary regurgitation
Timing is the fastest separator: tricuspid regurgitation is holosystolic at the lower left sternal border, while pulmonary regurgitation is early diastolic at the left upper sternal border. Tricuspid regurgitation often comes from right-sided dilation or endocarditis, while pulmonary regurgitation often comes from pulmonary hypertension. Both are right-sided murmurs and can increase with inspiration, so inspiration alone does not decide.
Tricuspid regurgitation vs Pulmonary regurgitation Tricuspid regurgitation is holosystolic at the lower left sternal border; pulmonary regurgitation is early diastolic at the left upper sternal border. Open the comparison and video →Acute rheumatic fever vs Rheumatic heart disease
Use the timeline: acute rheumatic fever is an active post-group A strep immune syndrome, while rheumatic heart disease is chronic valve scarring years later. Acute rheumatic fever can include migratory polyarthritis, carditis, chorea, erythema marginatum, and subcutaneous nodules. Carditis can occur during acute rheumatic fever, but mitral stenosis or mixed mitral disease years later points to chronic rheumatic heart disease.
Acute rheumatic fever vs Rheumatic heart disease Acute rheumatic fever is the active post-strep inflammatory syndrome; rheumatic heart disease is chronic valve scarring. Open the comparison and video →Quick self-test
Name the diagnosis from the clue, then tap to check.
Crescendo-decrescendo systolic murmur at the right upper sternal border radiating to the carotids.
Aortic stenosis · Aortic stenosis vs Hypertrophic cardiomyopathy
Holosystolic murmur at the apex radiating to the axilla.
Mitral regurgitation · Mitral regurgitation vs Mitral stenosis
Post-group A strep immune syndrome with Jones criteria features such as migratory polyarthritis, carditis, chorea, erythema marginatum, and subcutaneous nodules.
Acute rheumatic fever · Acute rheumatic fever vs Rheumatic heart disease
Holosystolic blowing murmur at apex radiating to axilla, often worse with handgrip or acute after papillary muscle dysfunction.
Mitral regurgitation · Mitral valve prolapse vs Mitral regurgitation
Early diastolic decrescendo murmur with wide pulse pressure, bounding pulses, and LV volume overload.
Aortic regurgitation · Aortic stenosis vs Aortic regurgitation
Dynamic systolic murmur that increases with Valsalva or standing and decreases with squatting.
Hypertrophic cardiomyopathy · Aortic stenosis vs Hypertrophic cardiomyopathy
Chronic valve scarring years later, especially mitral stenosis or mixed mitral disease.
Rheumatic heart disease · Acute rheumatic fever vs Rheumatic heart disease
Holosystolic murmur at lower left sternal border that increases with inspiration, often from right-sided dilation or endocarditis.
Tricuspid regurgitation · Tricuspid regurgitation vs Pulmonary regurgitation
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
Opening snap followed by a low-pitched diastolic rumble at the apex.
Mitral stenosis · Mitral regurgitation vs Mitral stenosis
Midsystolic click with late systolic murmur; standing/Valsalva moves click earlier and lengthens murmur.
Mitral valve prolapse · Mitral valve prolapse vs Mitral regurgitation
Keep going
Every pair in this review has a free page in the library with a side-by-side comparison and a practice question. Work through the ones you missed in the self-test first.