AuscultifyDiastolic Murmurs: Types, Causes and Grading
A diastolic murmur is heard between S2 and the next S1, while the ventricles fill. Unlike systolic murmurs, diastolic murmurs are almost always pathologic: there is no innocent diastolic murmur in adults, so each one needs an explanation and usually an echocardiogram. There are three types by timing: early diastolic decrescendo murmurs (aortic and pulmonic regurgitation), mid-diastolic rumbles (mitral and tricuspid stenosis, plus flow rumbles) and late diastolic or presystolic murmurs.
This page goes deeper than the systolic vs diastolic overview: what each diastolic murmur sounds like, where to put the stethoscope, and how the 1 to 4 grading scale works.
Why diastolic murmurs are almost always pathologic
In systole, blood is ejected across normal semilunar valves at high velocity, which is why healthy young hearts often generate a soft flow murmur. In diastole the semilunar valves should be shut and blood should cross the open AV valves under a very small pressure gradient. Sound during diastole therefore means one of three things: a semilunar valve is leaking (regurgitation), an AV valve is narrowed (stenosis), or a normal AV valve is carrying abnormally high flow because of a shunt or severe regurgitation upstream. None of those is normal.
The three types of diastolic murmur
1. Early diastolic decrescendo (aortic and pulmonic regurgitation)
Aortic regurgitation begins immediately after A2, is loudest at its onset and fades as aortic and ventricular pressures equalize. It is high-pitched and blowing, so use the diaphragm. Listen at the left lower sternal border (3rd to 4th intercostal space) for valvular AR, and at the right upper sternal border when the cause is aortic root dilation. The position matters more than for any other murmur: sit the patient up, lean them forward and have them hold their breath in end-expiration. A soft AR murmur is often audible only in that position.
Pulmonic regurgitation from pulmonary hypertension produces the Graham Steell murmur: a high-pitched early diastolic decrescendo at the left 2nd to 3rd intercostal space that gets louder on inspiration, usually with a loud P2.
2. Mid-diastolic rumble (mitral and tricuspid stenosis)
Mitral stenosis is a low-pitched rumble that starts after an opening snap and follows a loud S1. Use the bell, lightly, at the apex with the patient in the left lateral decubitus position, at end-expiration. In sinus rhythm the murmur gets louder just before S1 as the atrium contracts (presystolic accentuation); this disappears in atrial fibrillation. Severity tracks the length of the murmur and how early the opening snap falls after S2, not the loudness.
Tricuspid stenosis is rare, almost always rheumatic and coexists with MS. It rumbles at the lower left sternal border and, like other right-sided murmurs, increases on inspiration.
Three rumbles mimic MS across a normal mitral valve:
- Austin Flint murmur: a mid-to-late diastolic apical rumble in severe AR, caused by the regurgitant jet pushing the anterior mitral leaflet toward closure. No opening snap, no loud S1.
- Carey Coombs murmur: a soft mid-diastolic apical murmur in acute rheumatic fever from mitral valvulitis. It disappears as the inflammation resolves.
- Flow rumbles: short mid-diastolic murmurs from torrential flow across a normal valve. Severe MR, VSD and PDA cause a mitral flow rumble; ASD and severe TR cause a tricuspid flow rumble. They usually come with an S3.
3. Late diastolic or presystolic
A presystolic murmur sits just before S1 and is produced by atrial contraction driving blood across a stenotic AV valve. It is essentially the presystolic accentuation of MS or TS heard on its own in mild disease, and it requires sinus rhythm.
| Murmur | Timing | Pitch | Chest piece | Site | Position | Cause |
|---|---|---|---|---|---|---|
| Aortic regurgitation | Early diastolic decrescendo | High, blowing | Diaphragm | LLSB 3rd to 4th ICS; RUSB if root dilated | Sitting forward, end-expiration | Bicuspid valve, rheumatic, endocarditis, root dilation, dissection |
| Pulmonic regurgitation (Graham Steell) | Early diastolic decrescendo | High, blowing | Diaphragm | Left 2nd to 3rd ICS | Supine, louder on inspiration | Pulmonary hypertension |
| Mitral stenosis | Mid-diastolic rumble, presystolic accentuation | Low, rumbling | Bell | Apex | Left lateral decubitus, end-expiration | Rheumatic heart disease |
| Tricuspid stenosis | Mid-diastolic rumble | Low | Bell | LLSB | Supine, louder on inspiration | Rheumatic (with MS), carcinoid |
| Austin Flint | Mid-to-late diastolic rumble | Low | Bell | Apex | Left lateral decubitus | Severe AR |
| Flow rumble | Short mid-diastolic | Low | Bell | Apex (mitral) or LLSB (tricuspid) | Supine | Severe MR, VSD, PDA, ASD, severe TR |
Grading diastolic murmurs: 1 to 4, not 1 to 6
Systolic murmurs are graded 1 to 6 on the Levine scale, where grades 4 to 6 are defined by a palpable thrill and by how far the stethoscope can be lifted off the chest. Diastolic murmurs almost never produce a thrill, so by convention they are graded 1 to 4:
- Grade 1: very faint, heard only after you tune in, and may not be present in every position.
- Grade 2: faint, but heard immediately once the stethoscope is placed.
- Grade 3: moderately loud, no thrill.
- Grade 4: loud, usually with a thrill. Rare in diastole.
Some institutions use 1 to 6 for every murmur, so state which scale you are using when you document. More importantly, intensity is a poor guide to severity in diastole. Acute severe AR often gives a short, soft murmur because ventricular pressure rises quickly and cuts the gradient off.
Why diastolic murmurs are easy to miss
Three properties work against you. They are low intensity (most are grade 1 to 2), often low pitched (the MS rumble sits near the lower limit of hearing) and short (an early AR murmur may last only a fraction of diastole). Each also depends on a specific position and chest piece, so a routine supine sweep with the diaphragm can miss both AR and MS in the same patient.
Practical fixes: palpate the carotid so you know which gap is diastole, then listen deliberately to the silence after S2 rather than waiting for something to jump out. Do the sitting-forward, end-expiration listen at the left sternal border on every cardiac exam, and the left lateral decubitus bell listen at the apex. Pressing the bell hard turns it into a diaphragm and filters out a rumble; see the bell vs diaphragm guide.
Continuous murmurs are not diastolic murmurs
A patent ductus arteriosus produces a continuous "machinery" murmur that peaks around S2 and spans both systole and diastole because aortic pressure exceeds pulmonary pressure throughout the cycle. Do not confuse these with the to-and-fro murmur of combined aortic stenosis and regurgitation, which is two separate murmurs with a clear gap at S2.
Hear real diastolic murmurs in Auscultify
Descriptions only get you so far. Auscultify's library includes real clinical recordings of aortic regurgitation and mitral stenosis, and the Heart Sounds quiz mode plays them without labels so you have to commit to a timing before you see the answer. Murmurs you miss are weighted to come back sooner, and the Spectrogram view (Pro) shows the decrescendo of AR and the low-frequency band of an MS rumble so you can see exactly where each murmur sits after S2.
Practice murmurs free →FAQ
What is a diastolic murmur?
A diastolic murmur is a murmur heard between S2 and the next S1, while the ventricles are filling. It comes from a leaking semilunar valve, a narrowed AV valve, or unusually high flow across a normal AV valve.
Are diastolic murmurs always pathologic?
In practice, yes. There is no innocent diastolic murmur in adults, so every diastolic murmur should be assumed to reflect valve disease or a significant volume load and usually needs an echocardiogram.
What are the types of diastolic murmurs?
Three types by timing: early diastolic decrescendo murmurs (aortic and pulmonic regurgitation), mid-diastolic rumbles (mitral and tricuspid stenosis, Austin Flint, Carey Coombs and flow rumbles), and late diastolic or presystolic murmurs from atrial contraction across a stenotic AV valve.
How are diastolic murmurs graded?
Diastolic murmurs are conventionally graded 1 to 4 on the Levine scale because they almost never produce a thrill. Grade 1 is very faint, grade 2 is faint but heard immediately, grade 3 is moderately loud, and grade 4 is loud with a thrill. Systolic murmurs use the full 1 to 6 scale.
What does a soft diastolic murmur mean?
A soft diastolic murmur still needs to be explained. Intensity correlates poorly with severity in diastole: severe acute AR can produce a short, soft murmur, and early MS is typically a faint rumble. Confirm it in the correct position and arrange an echocardiogram.