Nothing, for an innocent murmur
No medication and no restrictions, including on sport. An innocent murmur stays harmless.
Medically Reviewed By: Dr Paul Lim – MBBS, M.Med (Int Med), MRCP (UK), FAMS (Cardiology)
Heart Examination Finding
Dr Paul Lim Chun Yih
Senior Consultant Cardiologist & Electrophysiologist
Heart Murmur (Whooshing Heart Sound: Innocent or Abnormal?)
A heart murmur is a whooshing sound made by blood flowing through the heart, heard through a stethoscope, and not necessarily a sign of heart disease. Just been told you have one? Sit down with Dr Paul Lim, who takes things at your pace, and find out whether yours is innocent or needs a closer look.
Dr Paul Lim Chun Yih
Senior Consultant Cardiologist & Electrophysiologist
22+
Years of
Clinical Experience
Clinical Experience
Your Cardiologist
Assessed by Dr Paul Lim
Senior Consultant Cardiologist & Cardiac Electrophysiologist
Dr Paul Lim is a Senior Consultant Cardiologist who subspecialises in heart rhythm disorders. He investigates murmurs with echocardiography, follows valve conditions over time with repeat scans, and treats the atrial fibrillation that a narrowed or leaking mitral valve can bring with it. He completed advanced fellowship training at Barts Heart Centre, London under Singapore’s HMDP award.
UK & SG
Fellowship Training
10,000+
Patient Consultations
1,000+
Ablation & Device Procedures
The Basics
What Is a Heart Murmur?
A heart murmur is a blowing, whooshing or rasping sound caused by turbulent blood flow through or near the heart. A healthy heart makes two short sounds with each beat, the familiar lub-dub. The first (S1) is the valves between the upper and lower chambers closing; the second (S2) is the valves that let blood out of the heart closing. A murmur is an extra sound during or between them, made when blood stops flowing smoothly and starts to swirl.
You will not usually hear or feel a murmur yourself. A doctor picks it up through the stethoscope, often at a routine check-up, a health screening, a pre-operative assessment or an antenatal visit.
A murmur is a sign, not a diagnosis. It tells the doctor that blood is flowing turbulently somewhere, and the next step is to find out where and why. Each type has its own shape and its own place in the heartbeat:
Normal heart sounds: two short sounds per beat, S1 and S2 (the “lub” and the “dub”), with silence between them
Innocent (flow) murmur: soft, short, and typically early-systolic or midsystolic, the shaded part of the beat. Everything else sounds normal
Ejection systolic murmur: rises and falls between the two sounds in a diamond shape, and the second sound can soften. The pattern of a narrowed aortic valve (aortic stenosis)
Pansystolic murmur: the same loudness from the first sound right up to the second. The pattern of a leaking mitral valve (mitral regurgitation) or a hole between the pumping chambers (VSD)
Early diastolic murmur: starts straight after the second sound and fades away. The pattern of a leaking aortic valve (aortic regurgitation)
Doctors describe a murmur by when it happens (systolic, during the squeeze; diastolic, during refilling; or continuous), where on the chest it is loudest, how loud it is on a scale of 1 to 6, and whether it changes when you stand, squat or breathe in. Together, those details point to the likely cause. Diastolic murmurs are far more likely than systolic murmurs to signal underlying valve disease and generally warrant further evaluation. They are also the terms a referral letter uses, so if you have one, the decode table will help.
Red Flags
Is a Heart Murmur Serious? When to Worry
Most murmurs are harmless. Whether yours matters depends less on the murmur itself than on what comes with it: symptoms, your age, and what the echocardiogram shows.
Emergency: call 995 or go to A&E
Do not wait for an appointment if you have a murmur, or a known valve problem, together with:
- Chest pain, tightness or pressure
- Fainting, near-fainting or collapse, particularly during exertion
- Severe breathlessness at rest, or when lying flat
- In a baby: blue or grey lips or skin, fast and laboured breathing, or being too breathless to feed
Book a cardiologist appointment
Arrange a review soon if your murmur:
- Is new, and has never been checked with an echocardiogram
- Comes with breathlessness on exertion, tiredness, dizziness, palpitations or swollen ankles
- Is described in your letter as grade 3 or louder, diastolic, pansystolic or continuous
- Sits alongside an abnormal ECG or an enlarged heart on a chest X-ray
- Comes with a fever that will not settle, night sweats or weight loss, and you have a valve problem or an artificial valve. See a doctor the same day
- Runs alongside a family history of valve disease, cardiomyopathy, or sudden death at a young age
- Was found before an operation, a new sport or a pregnancy, and you need clearance to go ahead
- Worries you, or you would simply like a second opinion
Usually harmless, but worth confirming
These are usually innocent, though a doctor should still confirm it:
- A soft (grade 1 or 2) systolic murmur in a child or young adult who feels well
- A murmur that appears during pregnancy, a fever or anaemia, and fades once that settles
- A murmur already checked with an echocardiogram and confirmed as innocent
Not sure which applies to you? Speak to a cardiologist for a proper assessment and peace of mind.
Been told you have a murmur? Find out what is behind it.
Telling Them Apart
Innocent vs Abnormal Heart Murmurs
An innocent murmur, also called a flow or functional murmur, is the sound of blood moving briskly through a normal heart. An abnormal (pathological) murmur has a structural cause: a valve, a hole, or thickened heart muscle.
| Feature | Innocent murmur | Abnormal murmur |
|---|---|---|
| Cause | Brisk blood flow through a normal heart | A narrowed or leaking valve, a hole between chambers, or thickened heart muscle |
| Timing | Systolic, during the squeeze | Systolic, diastolic or continuous |
| Loudness | Usually soft, grade 1 or 2 | Often grade 3 or louder, though not always |
| Sound | Soft, musical or vibratory | Often harsh or blowing |
| With position | Often changes or fades when you sit up, stand or lie down | Steadier; a few, such as HCM, get louder on standing |
| Symptoms | None | Sometimes breathlessness, chest pain, dizziness or tiredness |
| Echocardiogram | Normal heart and valves | Shows the valve or structural cause |
| Treatment | None needed | Depends on the cause, and is often monitoring first |
Doctors have a memory aid for innocent murmurs in children, the “seven S’s” of an innocent murmur: sensitive to position, short, single, small, soft, sweet and systolic. In adults, a soft systolic murmur in someone with no symptoms and an otherwise normal examination is very likely to be innocent. Where there is any doubt, an echocardiogram settles it.
Reading Your Letter
Heart Murmur Grades and What Your Letter Means
Murmurs are graded for loudness on a scale of 1 to 6, known as the Levine scale, and written as a fraction: 2/6 (sometimes II/VI) means grade 2 out of a possible 6. The scale was originally developed for systolic murmurs; it can also be applied to diastolic murmurs, though a palpable thrill (grades 4–6) is uncommon with diastolic flow, so diastolic murmurs are less often graded that high in practice.
| Grade | What the doctor hears |
|---|---|
| 1/6 | Very faint; heard only with careful listening |
| 2/6 | Soft, but heard as soon as the stethoscope is placed |
| 3/6 | Easily heard and moderately loud, with no vibration felt on the chest |
| 4/6 | Loud, with a vibration (a thrill) that can be felt with a hand on the chest |
| 5/6 | Very loud; heard with the stethoscope only just touching the chest |
| 6/6 | Loud enough to hear with the stethoscope lifted off the chest |
A loud murmur is not always a serious one
Loudness reflects how fast the blood is moving, not how much is wrong. A small hole between the pumping chambers can make a loud murmur and do no harm at all, while a badly narrowed valve can grow quieter once the heart muscle tires. Grade 3 or louder is more often abnormal, but the grade is a prompt to scan rather than a verdict.
The other words on a referral letter
Letters describe a murmur in shorthand. These are the terms you are most likely to see, as they are written.
| Term on the letter | What it means |
|---|---|
| Ejection systolic murmur (ESM) | A murmur that rises and falls during the squeeze. The innocent flow murmur is one. Others come from a narrowed aortic or pulmonary valve, thickened heart muscle (HCM), or the extra flow from a hole between the upper chambers (ASD). |
| Pansystolic or holosystolic murmur (PSM) | A murmur at an even loudness through the whole squeeze. Usually a leaking mitral or tricuspid valve, or a hole between the pumping chambers (VSD), and always worth a scan. |
| Early diastolic murmur (EDM) | A soft, blowing murmur straight after the second heart sound, usually from a leaking aortic valve (aortic regurgitation). |
| Mid-diastolic murmur | A low rumble while the heart refills. Classically a narrowed mitral valve (mitral stenosis). |
| Continuous murmur | Heard through both the squeeze and the refill. A patent ductus arteriosus is one cause; a venous hum in a child is an innocent one. |
| Thrill | A vibration felt through the chest wall. It makes a systolic murmur at least grade 4. |
| Click | A short, sharp extra sound. A click midway through the squeeze is typical of mitral valve prolapse; an early one can come from a bicuspid aortic valve. |
| Radiates to the carotids / to the axilla | Where the sound travels. Towards the neck suggests the aortic valve; towards the armpit, the mitral valve. |
| Apex, left sternal edge, aortic area | Where on the chest the murmur is loudest, which hints at the valve involved. |
| Flow, innocent or functional murmur | Three names for a harmless murmur with no structural cause. |
Why It Happens
What Causes a Heart Murmur?
The causes fall into two groups: extra blood flow through a healthy heart, which makes an innocent murmur, and a structural problem, which makes an abnormal one.
Note: this is not an exhaustive list. If you have been told you have a murmur, an echocardiogram is how to find out which of these, if any, applies.
Innocent (flow) murmurs
- Childhood, when innocent murmurs are very common and most fade with age
- Pregnancy: the heart pumps a much larger volume of blood
- Fever or an infection
- Anaemia, which makes the heart pump faster to carry enough oxygen
- An overactive thyroid speeds up the whole circulation
- Exercise or stress
Heart valve problems
- Aortic stenosis. The aortic valve stiffens and narrows, usually from calcium build-up with age. It makes an ejection systolic murmur, and is a common reason for a murmur to appear later in life.
- Aortic sclerosis: thickening and stiffening of the aortic valve that still lets blood through freely. Common with age, and worth monitoring
- Mitral regurgitation, a leak back through the mitral valve, which can follow mitral valve prolapse, a heart attack or an enlarged heart
- Mitral valve prolapse (MVP), where the valve flaps bow backwards as they close. Often mild, sometimes with a click and a murmur late in the squeeze
- Aortic regurgitation is a leaking aortic valve, heard as a soft blowing murmur after the second sound
- Mitral stenosis, a narrowed mitral valve, most often a late effect of rheumatic fever in childhood
- Tricuspid regurgitation, a leak on the right side of the heart, often from raised pressure in the lungs
- A bicuspid aortic valve has two flaps instead of three from birth, and is the commonest cause of aortic stenosis before the age of 70, accounting for roughly 60% of valve replacements for severe aortic stenosis in patients under 70 (versus about 40% in those 70 or older, where degenerative calcific disease of a normal trileaflet valve predominates)
Heart muscle, holes and infection
- Hypertrophic cardiomyopathy (HCM), an inherited thickening of the heart muscle whose murmur often gets louder on standing. Worth ruling out in young athletes and in anyone with a family history of sudden death
- Atrial septal defect (ASD): a hole between the upper chambers. It can go undiagnosed until adulthood
- Ventricular septal defect (VSD), a hole between the pumping chambers. Small ones are loud but often harmless, and many close during childhood
- Patent ductus arteriosus. A blood vessel that should close after birth stays open, making a continuous murmur
- Endocarditis, an infection of the heart’s inner lining, which can cause a new murmur alongside a fever
- After a heart attack, damage to the muscle that anchors the mitral valve can make it leak
In Context
Heart Murmurs in Adults, Pregnancy and Children
When a murmur turns up, and in whom, changes what it is likely to be.
Found at a check-up, with no symptoms
This is how most adult murmurs come to light: at a health screening, an insurance or employment medical, or a pre-operative check. A soft systolic murmur in someone who feels well is usually innocent. If it has never been scanned, one echocardiogram gives a definite answer, and a normal result needs no follow-up.
Appearing later in life
A murmur that is new in your sixties or beyond is more often due to wear on a valve, usually thickening or narrowing of the aortic valve. Many of these are mild and only need watching. Breathlessness, chest tightness or dizziness on exertion should not be put down to getting older: once a narrowed valve causes symptoms, it needs treating promptly.
Told you had a murmur as a child
Many adults remember being told about a murmur at school or as a baby, and never heard any more about it. Most were innocent and faded long ago. A few were the first sign of a valve problem or a hole that can persist quietly into adulthood, such as a bicuspid aortic valve or a small hole between the chambers. If yours was never checked with a scan, one echocardiogram as an adult closes the question.
During pregnancy
Blood volume rises substantially in pregnancy, and the extra flow makes innocent murmurs common. Most disappear after delivery. Pregnancy can also unmask a valve problem that was there before, so a murmur that is loud or diastolic, or that comes with breathlessness, fainting or chest pain, needs an echocardiogram. It uses ultrasound and is safe in pregnancy.
In babies and children
Innocent murmurs are very common in healthy children and usually fade by adulthood. Newborns are different: between 0.6% and 8.6% of newborns have a heart murmur, and among those with an asymptomatic murmur, roughly 37% are found to have congenital heart disease on echocardiogram, with about 2.5% having a severe or critical lesion requiring immediate intervention. Paediatric cardiology referral, rather than echocardiography as a first step, is the recommended initial approach for a newborn with a murmur. At any age, the warning signs are poor feeding, sweating or tiring during feeds, slow weight gain, fast breathing, a blue tinge to the lips, and fainting or chest pain on exertion. Babies and children are assessed by a paediatric cardiologist, and your child’s doctor will advise whether a referral is needed.
Before surgery or sport
An untested murmur often comes to light at a pre-operative check. Most people go ahead as planned, but a significantly narrowed valve matters to the anaesthetist, so it is worth having the scan before the operation date. The same applies before starting strenuous sport, where the aim is to rule out the less common causes such as HCM. A cardiac clearance assessment covers both.
What You Might Notice
Does a Heart Murmur Cause Symptoms?
An innocent murmur causes none. An abnormal one causes symptoms only once the problem behind it starts to affect how well the heart pumps, and these are the ones to watch for.
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Breathlessness On stairs or exertion that used to be easy, or when lying flat at night.
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Chest pain or tightness on exertion A narrowed aortic valve can leave the thickened heart muscle short of blood during effort.
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Fainting or dizziness on exertion A warning sign with aortic stenosis or HCM, and a reason for prompt review.
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Tiredness A gradual drop in how much you can do, which is easy to put down to age.
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Palpitations A leaking or narrowed mitral valve stretches the upper chamber, which can set off atrial fibrillation.
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Swollen ankles Fluid that collects when the heart is struggling to keep up.
Talk to Dr Paul Lim about your murmur and what, if anything, it needs.
Sound, Feeling or Rhythm
Heart Murmur vs Palpitations, AFib and Irregular Heartbeat
These terms get mixed up, but each describes something different.
A murmur is a sound, made by blood flowing through the heart’s valves and chambers. Palpitations are a sensation: the feeling of your own heartbeat. An irregular heartbeat, such as atrial fibrillation (AFib), is an electrical problem with the heart’s rhythm.
They do overlap. Valve disease, particularly of the mitral valve, stretches the upper chambers and is a common route into atrial fibrillation, so someone with a murmur may later develop palpitations. A murmur and an irregular pulse found together are worth assessing as one picture.
Two more mix-ups are worth clearing up. A murmur is different from a bruit, a similar whooshing sound heard over an artery, such as the one in the neck. And although some murmurs come from a hole in the heart, most do not.
A murmur also cannot be seen on an ECG, which records the heart’s electrical activity rather than its sound. The ECG can show knock-on effects such as thickened muscle, but the cause of a murmur is found on an echocardiogram. There is more on how an ECG and an echocardiogram differ.
Getting a Diagnosis
Echocardiogram for a Heart Murmur: How It Is Diagnosed
The question is always the same: is the heart structurally normal? Listening narrows it down, and an echocardiogram answers it.
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1
History and examination
Your symptoms, family history, and any earlier letters or scans. The murmur is then listened to in several positions, such as lying on your left side, sitting forward, standing and squatting, because the way it changes points to its cause.
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2
2D echocardiogram
A painless ultrasound scan of the heart, taking about 20 to 45 minutes and carried out by our female professionals. It shows each valve opening and closing, measures how narrowed or leaky a valve is, and checks the chambers and pumping strength. For most murmurs, this is the test that settles the question. See the 2D echocardiogram page for what to expect.
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3
Electrocardiogram (ECG)
A quick 12-lead ECG checks the rhythm and looks for strain on the heart muscle. It cannot detect the murmur itself.
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4
Blood tests and chest X-ray
A full blood count and thyroid test where a flow murmur from anaemia or an overactive thyroid is suspected, and a chest X-ray if the heart may be enlarged.
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5
Further tests, where needed
A treadmill stress test can show whether a valve problem limits you on exertion when symptoms are unclear. A transoesophageal echocardiogram, cardiac MRI or CT gives a closer look where the standard scan leaves questions.
A first consultation with Dr Paul Lim is S$130.80 at Jurong or S$218 at Orchard, and a 2D echocardiogram is S$436 at Jurong or S$545 at Orchard, all NETT and inclusive of GST. An echocardiogram can also go ahead with a referral letter from another doctor. See all cardiology fees.
What Happens Next
Heart Murmur Treatment
A murmur is not treated in itself; its cause is. For most people, that means no treatment at all.
Treating a flow cause
Where anaemia, an overactive thyroid or a fever is driving extra blood flow, treating it usually quietens the murmur.
Watching a mild valve problem
Mild valve disease without symptoms may need no treatment. It is followed with repeat echocardiograms, alongside good blood pressure control, and those scans guide the timing of any procedure. Medication eases symptoms such as fluid build-up, and blood thinners are used if atrial fibrillation develops.
Repairing or replacing a valve
When narrowing or leaking becomes severe, or starts to cause symptoms, the valve can be repaired or replaced. That is done by open-heart or keyhole surgery or, for the aortic valve, through a catheter passed up from a blood vessel in the leg (TAVI). TAVI is now an established alternative to surgery whatever the surgical risk, and the usual choice for people too frail for an open operation. Age, the shape of the valve and general health all shape the decision, which a heart team makes with you.
Holes between the chambers are handled case by case: many small ones need nothing, and some can be closed with a device passed up through a vein rather than by open surgery. Endocarditis is treated with several weeks of antibiotics, usually four to six. They are started by drip in hospital, and some people can finish the course with tablets once they are stable.
Next Steps
When to See a Cardiologist for a Heart Murmur
If your murmur has never been scanned, a consultation and a 2D echocardiogram can give you some answers. A normal scan needs no follow-up; an abnormal one finds the problem early, with time to plan.
See a cardiologist sooner if the murmur is new, comes with breathlessness, chest discomfort or dizziness, or you have an operation or a new sport ahead. For a broader check at the same visit, four of the five heart screening packages include an echocardiogram.
Get in Touch
Book a Consultation for a Heart Murmur
See Dr Paul Lim to find out whether your murmur is innocent, and what to do if it is not.
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Common Questions
Heart Murmur FAQ
Answers to the questions people most often ask after being told they have a heart murmur.
What does a heart murmur sound like?
Through a stethoscope, a murmur is a whoosh, swish or rasp during or between the two normal heart sounds, the “lub” and the “dub”. An innocent murmur is usually soft and musical. A narrowed valve tends to make a harsher sound, and a leaking one a softer, blowing sound. You will not usually hear or feel a murmur yourself; it takes a stethoscope to pick it up.
Is a heart murmur serious?
Usually not. Many murmurs are innocent: the sound of normal blood flow through a healthy heart, especially common in children and during pregnancy. A murmur is more likely to matter if it is new in adulthood, grade 3 or louder, diastolic, or accompanied by breathlessness, chest pain, dizziness or fainting. Call 995 or go to A&E if a murmur comes with chest pain, fainting or severe breathlessness. Otherwise, an echocardiogram tells an innocent murmur from an abnormal one.
Can a heart murmur go away?
Often, yes. Innocent murmurs in children commonly fade as they grow, and flow murmurs caused by pregnancy, fever or anaemia usually disappear once the cause settles. A murmur from a structural problem, such as a narrowed or leaking valve, generally stays, and some grow louder as the valve changes over time. That is why a murmur from valve disease is followed with repeat scans.
Does a heart murmur show up on an ECG?
No. An ECG records the heart’s electrical activity, not its sounds, so it cannot detect a murmur. It can show indirect clues, such as thickened heart muscle from a narrowed aortic valve, and it checks the rhythm. The test that shows the cause of a murmur is an echocardiogram, an ultrasound scan of the heart.
Is a grade 2 heart murmur serious?
A grade 2 murmur, written 2/6, is soft but heard as soon as the stethoscope is placed, and most soft systolic murmurs in people without symptoms are innocent. The grade describes loudness, not severity, so it is a guide rather than a verdict. Murmurs of grade 3 or louder are more often abnormal and are usually checked with an echocardiogram, as is a murmur of any grade that comes with symptoms.
Is a heart murmur normal in pregnancy?
Soft murmurs are common in pregnancy because the heart pumps a much larger volume of blood, and most disappear after delivery. Mention it at your antenatal review. A murmur that is loud or diastolic, or that comes with breathlessness, fainting or chest pain, should be checked with an echocardiogram, which uses ultrasound and is safe in pregnancy.
Can I exercise with a heart murmur?
With an innocent murmur, yes, and without restriction. With a murmur caused by a valve or heart muscle problem, it depends on the cause and its severity, so it is sensible to have the murmur assessed before starting hard training or competitive sport. Stop and seek advice if you feel faint, have chest pain or become unusually breathless during exercise.
Do I need antibiotics before dental treatment if I have a heart murmur?
Not for an innocent murmur. Antibiotics before dental work are now reserved for a small group of people at the highest risk of endocarditis, an infection of the heart’s inner lining. That group includes people with an artificial heart valve (including one placed by catheter) or a valve repaired with artificial material, a previous episode of endocarditis, and some congenital heart conditions, particularly those not fully repaired. If you have a known valve or heart condition, ask your cardiologist whether this applies to you, and keep up regular dental check-ups, since healthy teeth and gums lower the risk.
How much does it cost to check a heart murmur in Singapore?
At our clinics, a first consultation with Dr Paul Lim is S$130.80 in Jurong or S$218 in Orchard, and a 2D echocardiogram is S$436 in Jurong or S$545 in Orchard. All prices are NETT and inclusive of GST. An echocardiogram can also go ahead with a referral letter from another doctor. Any further tests are billed separately.
Which doctor should I see for a heart murmur in Singapore?
An adult with a murmur is assessed by a cardiologist, who will arrange an echocardiogram where it is needed. Dr Paul Lim is a Senior Consultant Cardiologist in Singapore, with clinics at Orchard and Jurong, and subspecialises in heart rhythm disorders, including the atrial fibrillation that valve disease can bring. Babies and children are assessed by a paediatric cardiologist.