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Cardiology

Heart Murmurs Explained

Timing, character, and radiation for the murmurs you will hear most, plus the bedside maneuvers that help tell them apart.

Systolic Murmurs

MurmurCharacterRadiation
Aortic stenosisCrescendo-decrescendo, harshCarotids
Mitral regurgitationHolosystolic, blowingAxilla
Hypertrophic obstructive cardiomyopathy (HOCM)Crescendo-decrescendoVariable; increases with Valsalva

Diastolic Murmurs

MurmurCharacterNotes
Aortic regurgitationDecrescendo, blowingBest heard leaning forward, expiration
Mitral stenosisLow-pitched, rumblingOpening snap; best heard at apex, left lateral position

Grading Scale

Systolic murmurs are graded 1-6 by intensity, with grade 4 or higher typically having a palpable thrill. Diastolic murmurs are graded 1-4.

Bedside Maneuvers

For the full physical exam sequence, see the OSCE Cheat Sheets.

Related Topics

Frequently Asked Questions

Why does Valsalva increase the HOCM murmur but decrease others?

Valsalva reduces venous return and left ventricular filling. In HOCM, a smaller ventricle worsens the dynamic outflow obstruction, making the murmur louder — the opposite of most other murmurs, which soften with less blood to generate turbulent flow.

What does a thrill indicate?

A palpable thrill generally corresponds to a louder murmur (grade 4 or higher) and reflects more turbulent, forceful flow across the valve.

Is every murmur pathological?

No — innocent (functional) murmurs are common, especially in children, and are typically soft, early systolic, and not associated with other abnormal findings.