Auscultation Lab

Heart sounds

Normal S1 and S2

View

Expiration

Echo view

Schematic color Doppler and continuous-wave Doppler, synced to the sound

Teaching schematic, not a real echo. Turbulent jets show as a mosaic and a filled, speckled Doppler envelope; laminar flow is smooth red (toward the probe) or blue (away). Peak gradient ≈ 4v².

Focus — choose what you hear

Keys 1–8 switch focus · Space plays

Other layers

Play only

Tempo · heart rate

Slows the timing only. Pitch stays true, so a 40 ms split becomes 160 ms at 0.25×.

Heart rate72/min

Sound

Teaching contrast (exaggerates murmur shape and extra sounds) Speaker boost (makes S1, S3, S4 and rumbles audible on laptop and phone speakers) Ear-training tones: S1 = drum, S2 = chime, murmur = a pitch that rises and falls with its shape

Stethoscope · breathing

Room noiseoff

Volume80%

Bedside maneuvers

Maneuvers change murmur intensity and timing the way they do at the bedside.

Compare side by side

The two sounds alternate on the same time axis, so the difference falls exactly where your ear should look.

Classic confusions

A

B

Playback

Switch every

Same heart rate for both

Tempo

Stethoscope head, breathing, maneuvers and volume follow the settings on the Listen tab.

Dynamic auscultation

Run a maneuver the way you would at the bedside and hear the murmur change beat by beat. Then change how a murmur responds and hear the difference.

Murmur

Play as

Tempo

Maneuver

Murmur loudness, beat by beat (dashed line = at rest)

Edit how this murmur responds

Behave like

100% = loudness lying down at rest. Your changes also apply on the Listen and Compare tabs and are saved in this browser. Quizzes always use textbook behavior.

Which way does each murmur go?

Tap any cell to hear that murmur before and during the maneuver.

Virtual chest

Drag the stethoscope anywhere on the chest. Every sound gets louder or softer depending on how far you are from where it is best heard, and murmurs carry along their real radiation paths.

Sound

Show

Tempo

How loud each sound is here

Disease spectrum

Slide a lesion from mild to severe and hear the murmur, the extra sounds and S2 change together, with the Doppler velocity alongside. Or mix a systolic and a diastolic lesion.

Lesion

Severity

Breathing cycles automatically

Sculpt the murmur

Read the case, then draw the murmur you expect to hear, pick its quality and any extra sounds. Listen to your model, then check it against the answer.

Case

Pen

Quality

Extra sounds

Train your ear

Three drills, from finding S1 at a fast heart rate to naming murmurs blind with room noise.

Press Start. Listen to at least four beats, then choose.

Take apart a real recording

Load any heart-sound file — from your digital stethoscope, or an openly licensed library such as the University of Michigan Heart Sound & Murmur Library (CC BY-SA). The decomposition engine finds every S1 and S2, separates the recording into S1, S2, murmur and noise tracks, and measures the murmur's timing and shape. Then focus, slow down and loop exactly as on the Listen tab.

Demo loaded: synthesized VSD, 8 sDrop an audio file here (WAV, MP3, M4A, OGG) or choose one. Files stay on your device.

Choose audio file

Or try a demo recording

Decomposition

Waiting for a recording…

Play

Play only

Speed

Filter

Loop selection Normalize to 60/min

0.00 s

What the engine measured

Rhythm

Systole

Diastole

Explain with AI

Age Listening site

Claude reads the engine's measurements and explains what pattern they suggest, what else it could be, and which focus settings to use next. It runs on your own Claude account and asks your permission the first time.

Measurements come from automated signal processing (envelope segmentation and spectral masking) and can be wrong — especially with noise, irregular rhythms or very fast rates. They are for learning, never for diagnosis.

Spectrogram · 0–1000 Hz

Valve closures appear as narrow vertical columns; murmurs as broader bands of energy between them. A musical Still's murmur shows stacked harmonic lines.

A method you can use on every patient

Find S1 with the pulse
Place a finger on the carotid or brachial pulse. S1 comes just before the upstroke and opens the shorter interval. At infant rates, rely on the pulse rather than the interval lengths.
Study S2 alone
At the left upper sternal border, ignore everything else for five breaths. Is it single, split only on inspiration, split all the time, or split on expiration?
Hunt for extra sounds
Listen in systole for clicks, then in diastole for a snap, S3 or S4. Switch to the bell at the apex for S3 and S4.
Listen to systole, then diastole
For each, decide: is there sound? Does it start with S1 or after a gap? What shape is it — diamond, plateau, decrescendo?
Describe it, then change something
Grade, location, radiation, pitch, quality. Then sit, stand, squat or hold a breath, and note what changes.

Timing cheat sheet

Sound	When	Pitch · head	Best heard	Tell
S1	Start of systole	Low–mid · diaphragm	Apex, LLSB	Just before carotid upstroke
S2	End of systole	Higher, crisper · diaphragm	Base	A2 then P2 on inspiration
Ejection click	40–70 ms after S1	High · diaphragm	Apex (aortic), LUSB (pulmonary)	Pulmonary softens on inspiration
Midsystolic click	Mid–late systole	High · diaphragm	Apex	Moves earlier on standing
Opening snap	60–100 ms after A2	High · diaphragm	Apex, LLSB	Followed by a rumble
S3	120–180 ms after A2	Low · bell	Apex, left side down	Normal in children; “Ken-tuck-y”
S4	Just before S1	Low · bell	Apex	Always abnormal in children; “Ten-nes-see”
Pericardial rub	1–3 parts: atrial, systolic, diastolic	High, scratchy · diaphragm	LLSB, sitting forward	Changes with position

About these sounds

Every sound in the library is synthesized live from published timing, frequency and envelope characteristics. That is what lets you slow time without changing pitch, isolate each layer and apply maneuvers. They are teaching models: confirm your ear on real patients and real recordings, using the libraries below and the Real recordings tab.

Real S1, S3, S4 and rumbles sit below 150 Hz, which laptop and phone speakers barely reproduce. Speaker boost (on by default) adds audible harmonics above them; headphones still sound most natural.

Ear-training tones replace each sound with an unmistakable cue — a drum for S1, a chime for S2, and a pitch that traces the murmur's shape (rising–falling for ejection, a flat drone for holosystolic, a falling glide for aortic regurgitation). Use them to learn the pattern, then switch back to natural sound. In the quiz they are available at Level 1 only.

Real-recording libraries

Michigan Heart Sound & Murmur Library

University of Michigan. Openly licensed (CC BY-SA 4.0), so files can be loaded here.

Easy Auscultation reference guide

Large catalog with phonocardiograms, organized by listening area. Listen on their site.

UW Physical Diagnosis: heart sounds & murmurs

University of Washington teaching module with examples.

Blaufuss Multimedia heart sounds tutorial

Classic tutorial on describing murmurs.

CirCor DigiScope dataset (PhysioNet)

5,272 annotated recordings from 1,568 mostly pediatric patients; open for research and teaching.

FSU library guide to heart & lung sounds

Curated list of further collections.

Auscultation Lab

Normal S1 and S2

Echo view

Focus — choose what you hear

Compare side by side

Dynamic auscultation

Edit how this murmur responds

Which way does each murmur go?

Virtual chest

Disease spectrum

Sculpt the murmur

Train your ear

Student, new APN

Resident, pediatrician

Fellow, cardiologist

60/min, pulse cue on

95/min, no cue

140/min, S2 louder

Take apart a real recording

Decomposition

Rhythm

Systole

Diastole

Explain with AI

A method you can use on every patient

Find S1 with the pulse

Study S2 alone

Hunt for extra sounds

Listen to systole, then diastole

Describe it, then change something

Timing cheat sheet