Heart Sounds Lab
Put your headphones on. Only one sound plays at a time, every sound loops until you stop it, and the quiz at the bottom will ask for all of it back.
Step 1 · Rhythms and gallops
Learn the beat before the murmurs
These four are synthesized live in your browser, so S1, S2 and the extra sounds land at exactly the right point in the cycle every time. Loop them until 'ken-tuc-KY' and 'TEN-nes-see' are automatic.
S1 + S2
Lub-Dub. AV valves close (S1), semilunar valves close (S2).
- Timing
- S1 opens systole, S2 closes it
- Best heard
- All four areas, diaphragm
- Differentiate
- S1 coincides with the carotid pulse, S2 follows it
BaselineDiaphragmAll 4 areas
Exam pearl: Time with the radial pulse: hear-feel-hear = S1-pulse-S2. Diaphragm, all four areas.
Physiologic Split S2
Normal on inspiration. Delayed pulmonic closure.
- Timing
- S2 splits on inspiration, merges on expiration
- Best heard
- Pulmonic area (LSB 2nd ICS)
- Traps
- Fixed split suggests ASD; paradoxical split suggests LBBB or severe AS
InspirationPulmonic areaFixed split = ASD
Exam pearl: Normal on inspiration. A fixed split points to ASD; a paradoxical split to LBBB or severe AS.
S3 Gallop
Early diastole. Rapid filling. "ken-tuc-KY".
- Timing
- Early to mid diastole, just after S2
- Best heard
- Bell at the apex, left lateral decubitus
- Think of
- CHF, severe mitral regurgitation, dilated cardiomyopathy
BellApexCHF
Exam pearl: Bell, left lateral decubitus, at the apex. Points to CHF and dilated cardiomyopathy.
S4 Gallop
Late diastole. Atrial kick. "TEN-nes-see".
- Timing
- Late diastole, immediately before S1
- Best heard
- Bell at the apex, left lateral decubitus
- Think of
- LV hypertrophy from hypertension, aortic stenosis, HCM; ischemia
BellStiff ventricleHTN / AS / HCM
Exam pearl: Bell, left lateral decubitus. A non-compliant ventricle: hypertension, AS, HCM.
Step 2 · Murmurs
Systolic or diastolic is the first question
Time every murmur against the carotid pulse. A murmur between S1 and S2, with the pulse, is systolic; some systolic murmurs are innocent. A murmur after S2, against silence, is diastolic, and diastolic murmurs are always pathological.
Systolic
Between S1 and S2, while the ventricles eject. Stenosis of the outflow valves (aortic, pulmonic) and regurgitation through the inflow valves (mitral, tricuspid) all murmur here.
Diastolic
After S2, while the ventricles fill. Regurgitation through the outflow valves and stenosis of the inflow valves murmur here. Never innocent; always work it up.
Systolic murmurs
Aortic Stenosis
Crescendo-decrescendo. Harsh, high-pitched.
- Location
- RSB 2nd ICS
- Radiation
- To the carotids
- Shape
- Crescendo-decrescendo (diamond)
- Maneuver
- Valsalva decreases intensity
RSB 2nd ICSCarotidsValsalva decreases
Exam pearl: RSB 2nd ICS radiating to the carotids. The peak moves later as severity increases.
Mitral Regurgitation
Holosystolic. Blowing, high-pitched.
- Location
- Cardiac apex
- Radiation
- To the left axilla
- Shape
- Holosystolic (pansystolic)
- Maneuver
- Isometric hand grip increases intensity
ApexLeft axillaHand grip increases
Exam pearl: Heard at the apex, radiating to the left axilla. Isometric hand grip makes it louder. Diaphragm.
Pulmonic Stenosis
Crescendo-decrescendo. Harsh, medium to high.
- Location
- LSB 2nd ICS
- Radiation
- Does not radiate (occasionally neck or left shoulder)
- Shape
- Crescendo-decrescendo (diamond)
- Maneuver
- Intensity increases during Valsalva release
LSB 2nd ICSNo radiationValsalva release
Exam pearl: LSB 2nd ICS. Does not radiate. Intensity rises during Valsalva release.
Diastolic murmurs
Aortic Regurgitation
Early decrescendo. Blowing, high-pitched.
- Location
- LSB, 2nd to 4th interspaces
- Position
- Sitting, leaning forward, breath held in exhalation
- Shape
- Early decrescendo
- Maneuver
- Isometric hand grip increases intensity
LSBLean forward + exhaleAlways pathological
Exam pearl: Sit the patient forward, exhale, LSB with the diaphragm. Hand grip makes it louder.
Mitral Stenosis
Mid-diastolic rumble. Low-pitched.
- Location
- Apex, 5th ICS at the midclavicular line
- Position
- Bell, left lateral decubitus
- Shape
- Mid-diastolic decrescendo-crescendo rumble
- Maneuver
- Isometric hand grip increases intensity
ApexBellLeft lateral decubitus
Exam pearl: Left 5th ICS at the MCL. Bell, left lateral decubitus. Hand grip makes it louder.
Step 3 · At the bedside
Where to put the stethoscope, and which side of it
APTM from the right sternal border around to the apex. The diaphragm hears high frequencies: S1, S2, and most murmurs. The bell hears low frequencies: S3, S4, and the rumble of mitral stenosis.
Aortic
RSB 2nd ICS
Best for: AS, AR, ejection click
Pulmonic
LSB 2nd ICS
Best for: PS, split S2
Tricuspid
LSB 4th to 5th ICS
Best for: TR, VSD, S3/S4
Mitral
Apex, 5th ICS MCL
Best for: MR, MS, S3/S4
Step 4 · Side by side
The five murmurs in one table
This is the table to be able to reproduce from memory in an exam corridor.
| Feature | Aortic Regurgitation | Aortic Stenosis | Mitral Regurgitation | Mitral Stenosis | Pulmonic Stenosis |
|---|---|---|---|---|---|
| Timing | Diastole | Systole | Systole | Diastole | Systole |
| Shape | Decrescendo | Cresc-decresc | Holosystolic | Decresc-cresc | Cresc-decresc |
| Quality | Blowing | Harsh | Blowing | Rumbling | Harsh |
| Pitch | High | High | High | Low | Medium-high |
| Location | LSB and RSB 2nd ICS | RSB 2nd ICS | Apex | Apex 5th ICS MCL | LSB 2nd ICS |
| Radiation | Rarely | Carotids | Left axilla | Localized | None |
| Special test | Hand grip louder | Valsalva softer | Hand grip louder | Hand grip louder | Valsalva release louder |
Guess the sound
Nine heart sounds, blind
Shuffling the deck…