AuscultifyGallop vs Murmur: How to Tell an Extra Heart Sound From a Murmur
A gallop is a brief, discrete, low-pitched extra heart sound, either an S3 or an S4, that lasts a few hundredths of a second and gives the beat a three-part cadence. A murmur is a prolonged sound produced by turbulent blood flow, lasting long enough to have a duration, a shape and a pitch of its own. S3 and S4 are not murmurs, and "S3 murmur" or "S4 murmur" are misnomers. This page explains the difference, lists the other short sounds that get confused with both, and gives a four-step method for any extra sound you cannot name.
Gallop vs murmur: the core differences
| Gallop (S3, S4, summation) | Murmur | |
|---|---|---|
| Duration | Very short, a single thud of roughly 0.03 to 0.05 s | Prolonged, occupies part or all of systole or diastole |
| Pitch | Low, near the limit of hearing | Low, medium or high depending on the lesion |
| Chest piece | Bell, light pressure; fades with firm pressure | Diaphragm for most; bell for the low rumble of mitral stenosis |
| Timing | Diastole only: S3 just after S2, S4 just before S1 | Systolic, diastolic or continuous |
| Cause | Vibration of the ventricular wall during filling | Turbulent flow across a valve, defect or vessel |
| Shape | None; a point in time | Crescendo, decrescendo, plateau, crescendo-decrescendo |
| Description words | Thud, bump, dull, gallop, Kentucky, Tennessee | Blowing, harsh, rumbling, musical, machinery |
| Grading | Not graded; described as present, soft or loud | Graded 1 to 6 for systolic, 1 to 4 for diastolic |
The single most useful test is duration. Ask yourself whether the extra noise is a point or a stretch. A point is a sound; a stretch is a murmur. The second most useful test is chest-piece behaviour: press the bell firmly and a gallop disappears, while most murmurs get clearer.
Why S3 and S4 are not murmurs
Murmurs need turbulent flow, which needs a pressure gradient across a narrowed, leaking or abnormal opening sustained over a period of the cycle. Gallops need neither. An S3 is the ventricular wall and mitral apparatus vibrating once when rapid inflow decelerates abruptly; an S4 is the same structures vibrating once when atrial contraction pushes into a stiff chamber. Each is a single event, not a flow state, which is why they have no shape and no grade. The distinction matters for documentation and for reasoning: a gallop tells you about ventricular compliance and filling pressure, while a murmur tells you about a valve or a shunt. The two often coexist, for example an S3 following the pansystolic murmur of severe mitral regurgitation, but they are recorded separately. Read the mechanism in detail in S3 heart sound and S4 heart sound.
What "gallop rhythm" means
A gallop rhythm is the triple cadence you hear when S3 or S4 is added to S1 and S2, particularly at a fast rate, where the three sounds resemble hoofbeats. An S3 gallop is the "Ken-TUCK-y" rhythm and an S4 gallop is the "TEN-nes-see" rhythm, unpacked in S3 Kentucky, S4 Tennessee. When both are present and diastole shortens, they merge into a loud mid-diastolic summation gallop. In an adult, a gallop rhythm is a heart failure finding until proven otherwise.
Other short extra sounds that are neither gallops nor murmurs
Several brief sounds are high-pitched and click-like rather than dull, so they are heard best with the diaphragm and can be mistaken for a split S1 or S2 or for the start of a murmur.
- Ejection click: early systole, just after S1, at the base. Bicuspid aortic valve, pulmonic stenosis, dilated aortic root.
- Mid-systolic click: mid to late systole at the apex, often followed by a late systolic murmur. Mitral valve prolapse; moves earlier with standing.
- Opening snap: early diastole, high-pitched, apex to lower left sternal border. Mitral stenosis; followed by the rumble.
- Pericardial knock: early diastole, loud, lower left sternal border. Constrictive pericarditis.
- Split S2: two crisp components at the pulmonic area that move with respiration.
- Tumor plop: early diastole, low-pitched, variable with position. Atrial myxoma, rare.
Extra sound after S2: the differentials
| Sound | Interval after S2 | Pitch | Best site and chest piece | Clue |
|---|---|---|---|---|
| Split S2 | 0.03 to 0.06 s | High | Pulmonic area, diaphragm | Widens on inspiration; fixed in ASD; paradoxical in LBBB |
| Opening snap | 0.04 to 0.12 s | High, sharp | Apex to LLSB, diaphragm | Followed by diastolic rumble; shorter interval means tighter stenosis |
| Pericardial knock | 0.06 to 0.12 s | Medium to high, loud | LLSB, diaphragm or bell | Raised JVP, Kussmaul sign, constriction history |
| S3 | 0.12 to 0.18 s | Low, dull | Apex, bell, left lateral | Heart failure or volume overload; normal in the young |
| Tumor plop | Variable, early diastole | Low | Apex, bell | Changes with position; constitutional symptoms |
The intervals are commonly taught approximations and overlap at the edges, so use pitch and chest piece to break ties. Anything crisp that the diaphragm brings out is not an S3.
How to work through an unknown extra sound in 4 steps
- Fix S1 and S2. Palpate the carotid; S1 comes just before the upstroke. Decide whether the extra sound is in systole (between S1 and S2) or diastole (between S2 and the next S1). Gallops are always diastolic.
- Decide point or stretch. A discrete thud or click is a sound; anything with a beginning, a middle and an end is a murmur. If it is a murmur, move to grading, shape and radiation and see systolic vs diastolic murmurs.
- Judge pitch with the chest piece. Switch between bell and diaphragm. A sound heard with the bell that vanishes on firm pressure is low-pitched: S3, S4, tumor plop. A sound clearer with the diaphragm is high-pitched: click, opening snap, split S2, most knocks.
- Localize and provoke. Find where it is loudest, then change something: inspiration for right-sided sounds and S2 splitting, left lateral decubitus for apical gallops, standing and squatting for clicks, leg raising for a faint S3. Match the behaviour against the tables above.
Write down the result in that order: timing, character, pitch, site, provocation. "Low-pitched early diastolic sound at the apex with the bell in left lateral decubitus, disappears with firm pressure, consistent with S3" is a finding a colleague can act on. "Extra sound, ?murmur" is not.
Practice tips
- Learn the gallops and the clicks as pairs of opposites: dull and low versus crisp and high, bell versus diaphragm.
- Listen to a recording of an S3 immediately followed by an opening snap. Once you have heard them back to back the pitch difference is hard to forget.
- Time yourself on the point-or-stretch decision. You should be able to make it in two cycles.
- Whenever you hear a murmur, listen deliberately for a gallop as well. Missing the S3 that accompanies a regurgitant murmur means missing the ventricle's response to the lesion.
Hear gallops and murmurs side by side in Auscultify
Auscultify's library holds real recordings of S3, S4, opening snaps, clicks, split S2 and the common systolic and diastolic murmurs, all captured at the sites where they are best heard. Six quiz modes mix sounds and murmurs together so you have to make the point-or-stretch decision under realistic conditions, missed items return through spaced repetition, and the Spectrogram view (Pro) shows a gallop as a brief low-frequency blip and a murmur as a sustained band, which makes the difference obvious.
Train heart sounds free →FAQ
Are S3 and S4 murmurs?
No. S3 and S4 are heart sounds, brief low-pitched vibrations of the ventricular wall during filling. Murmurs are prolonged sounds produced by turbulent blood flow across a valve or defect. The terms S3 murmur and S4 murmur are misnomers.
What is a gallop heart sound?
A gallop is an extra low-pitched diastolic heart sound, S3 or S4, that gives the heartbeat a three-beat cadence like a galloping horse. When S3 and S4 merge at fast rates the result is a summation gallop.
What is a gallop rhythm?
A gallop rhythm is the triple cadence produced when an S3 or S4 is added to the normal S1 and S2, usually with a fast heart rate. In an adult it most often indicates heart failure, either a volume-loaded ventricle (S3) or a stiff ventricle (S4).
Is there such a thing as an S3 murmur?
No. An S3 is a discrete sound lasting a fraction of a tenth of a second, not a murmur. It can coexist with a murmur, for example an S3 after the pansystolic murmur of mitral regurgitation, but the S3 itself is a sound and is documented as one.
What is the difference between a pericardial knock and S3?
Both are early diastolic sounds. A pericardial knock is earlier, usually 0.06 to 0.12 seconds after S2, higher pitched and often loud, best heard at the lower left sternal border in constrictive pericarditis. An S3 is later, softer and lower pitched, apical, and points to a volume-loaded ventricle.
What is an extra heart sound after S2?
The main possibilities are a widely split S2, an opening snap of mitral stenosis, a pericardial knock, an S3, or rarely a tumor plop. They are separated by how soon after S2 they fall, their pitch, and whether the bell or diaphragm brings them out.