Cochin Cardiac Club

Health Blog by Dr.Uday Nair


What Is a Heart Murmur?

A heart murmur is an extra or unusual sound heard during a heartbeat. Murmurs range from very faint to very loud. Sometimes they sound like a whooshing or swishing noise.

The two types of heart murmurs are innocent (harmless) and abnormal.Normal heartbeats make a "lub-DUPP" or "lub-DUB" sound. This is the sound of the heart valves closing as blood moves through the heart. Doctors can hear these sounds and heart murmurs using a stethoscope.

Innocent heart murmurs aren't caused by heart problems. These murmurs are common in healthy children. Many children will have heart murmurs heard by their doctors at some point in their lives.

People who have abnormal heart murmurs may have signs or symptoms of heart problems. Most abnormal murmurs in children are caused by congenital heart defects. These defects are problems with the heart's structure that are present at birth.
In adults, abnormal heart murmurs most often are caused by acquired heart valve disease. This is heart valve disease that develops as the result of another condition. Infections, diseases, and aging can cause heart valve disease.

What Causes Heart Murmurs?

Innocent Heart Murmurs

Why some people have innocent heart murmurs and others do not isn't known. Innocent murmurs are simply sounds made by blood flowing through the heart's chambers and valves, or through blood vessels near the heart.
Extra blood flow through the heart also may cause innocent heart murmurs. After childhood, the most common cause of extra blood flow through the heart is pregnancy. This is because during pregnancy, women's bodies make extra blood. Most heart murmurs that occur in pregnant women are innocent.

Abnormal Heart Murmurs

Congenital heart defects or acquired heart valve disease often are the cause of abnormal heart murmurs.

Congenital Heart Defects

Congenital heart defects are the most common cause of abnormal heart murmurs in children. These defects are problems with the heart's structure that are present at birth. They change the normal flow of blood through the heart.
Congenital heart defects can involve the interior walls of the heart, the valves inside the heart, or the arteries and veins that carry blood to and from the heart. Some babies are born with more than one heart defect.Examples of valve problems are narrow valves that limit blood flow or leaky valves that don't close properly. Septal defects are holes in the wall that separates the right and left sides of the heart. This wall is called the septum.Heart valve problems and septal defects (also called holes in the heart) are common heart defects that cause abnormal heart murmurs.A hole in the septum between the heart's two upper chambers is called an atrial septal defect. A hole in the septum between the heart's two lower chambers is called a ventricular septal defect.

Acquired Heart Valve Disease

Acquired heart valve disease often is the cause of abnormal heart murmurs in adults. This is heart valve disease that develops as the result of another condition.
Many conditions can cause heart valve disease. Examples include heart conditions and other disorders, age-related changes, rheumatic  fever, and infections.

Heart conditions and other disorders.

Certain conditions can stretch and distort the heart valves, such as:
  • Damage and scar tissue from a heart attack or injury to the heart.
  • Advanced high blood pressure and heart failure. These conditions can enlarge the heart or its main arteries.
  • A narrowing of the aorta due to the buildup of a fatty substance called plaque  inside the artery. The aorta is the main artery that carries oxygen-rich blood to the body. When plaque builds up inside the arteries, the condition is called atherosclerosis.

Rheumatic fever

The bacteria that cause strep throat, scarlet fever, and, in some cases, impetigo also can cause rheumatic fever. This serious illness can develop if you have an untreated or not fully treated streptococcal (strep) infection.

Age-related changes.

 As you get older, calcium deposits or other deposits may form on your heart valves. These deposits stiffen and thicken the valve flaps and limit blood flow. This stiffening and thickening of the valve is called stenosis.
Rheumatic fever can damage and scar the heart valves. The symptoms of this heart valve damage often don't occur until many years after recovery from rheumatic fever.
Today, most people who have strep infections are treated with antibiotics before rheumatic fever develops. It's very important to take all of the antibiotics your doctor prescribes for strep throat, even if you feel better before the medicine is gone.

Common germs that enter the bloodstream and get carried to the heart can sometimes infect the inner surface of the heart, including the heart valves. This rare but sometimes life-threatening infection is called infective endocarditis, or IE.
IE is more likely to develop in people who already have abnormal blood flow through a heart valve because of heart valve disease. The abnormal blood flow causes blood clots to form on the surface of the valve. The blood clots make it easier for germs to attach to and infect the valve.
IE can worsen existing heart valve disease.

Other Causes

Some heart murmurs occur because of an illness outside of the heart. The heart is normal, but an illness or condition can cause blood flow that's faster than normal. Examples of this type of illness include fever, anemia, and hyperthyroidism. Anemia is a condition in which the body has a lower than normal number of red blood cells. Hyperthyroidism is a condition in which the body has too much thyroid hormone.

What Are the Signs and Symptoms of a Heart Murmur?

People who have innocent (harmless) heart murmurs don't have any signs or symptoms other than the murmur itself. This is because innocent heart murmurs aren't caused by heart problems.
People who have abnormal heart murmurs may have signs or symptoms of the heart problems causing the murmurs. These signs and symptoms may include:

  • Poor eating and abnormal growth (in infants)
  • Shortness of breath, which may occur only with physical exertion
  • Excessive sweating with no clear cause
  • Chest pain
  • Dizziness or fainting
  • A bluish color on the skin, especially on the fingers and lips
Signs and symptoms depend on the problem causing the heart murmur and its severity.

How Is a Heart Murmur Diagnosed?

Doctors use a stethoscope to listen to heart sounds and hear heart murmurs. They may detect heart murmurs during routine checkups or while checking for another condition.
If a congenital heart defect causes a murmur, it's often heard at birth or during infancy. Abnormal heart murmurs caused by other heart problems can be heard in patients of any age.
Primary care doctors usually refer people who have abnormal heart murmurs to cardiologists or pediatric cardiologists for further care and testing.

Physical Exam

Your doctor will carefully listen to your heart or your child's heart with a stethoscope to find out whether a murmur is innocent or abnormal. He or she will listen to the loudness, location, and timing of the murmur. This will help your doctor diagnose the cause of the murmur.
Your doctor also may:

  • Ask about your medical and family histories.
  • Do a complete physical exam. He or she will look for signs of illness or physical problems. For example, your doctor may look for a bluish color on your skin. In infants, doctors may look for delayed growth and feeding problems.
Ask about your symptoms, such as chest pain, shortness of breath (especially with physical exertion), dizziness, or fainting.

Evaluating Heart Murmurs

When evaluating a heart murmur, your doctor will pay attention to many things, such as:
  • How faint or loud the sound is. Your doctor will grade the murmur on a scale of 1 to 6 (1 is very faint and 6 is very loud).
  • When the sound occurs in the cycle of the heartbeat.
  • Where the sound is heard in the chest and whether it also can be heard in the neck or back.
  • Whether the sound has a high, medium, or low pitch.
  • How long the sound lasts.
  • How breathing, physical activity, or a change in body position affects the sound.

Diagnostic Tests and Procedures

If your doctor thinks you or your child has an abnormal heart murmur, he or she may recommend one or more of the following tests.

Chest X Ray

A chest x ray is a painless test that creates pictures of the structures inside your chest, such as your heart, lungs, and blood vessels. This test is done to find the cause of symptoms, such as shortness of breath and chest pain.


    An EKG (electrocardiogram) is a simple test that detects and records the heart's electrical activity. An EKG shows how fast the heart is beating and its rhythm (steady or irregular). An EKG also records the strength and timing of electrical signals as they pass through each part of the heart.
    This test is used to detect and locate the source of heart problems. The results from an EKG also may be used to rule out certain heart problems.


    Echocardiography, or echo, is a painless test that uses sound waves to create pictures of your heart. The test gives information about the size and shape of your heart and how well your heart's chambers and valves are working.
      Echo also can identify areas of poor blood flow to the heart, areas of heart muscle that aren't contracting normally, and previous injury to the heart muscle caused by lack of blood flow.
      There are several types of echo, including a stress echo. This type of echo is done before and after a stress test. During this test, you exercise (or are given medicine if you can't exercise) to make your heart work hard and beat fast.
      A stress echo shows whether you have decreased blood flow to your heart. This is a sign of coronary heart disease (also called coronary artery disease).

      How Is a Heart Murmur Treated?

      A heart murmur isn't a disease. It's an extra or unusual sound heard during the heartbeat. Thus, murmurs themselves don't require treatment. However, if an underlying condition is causing a heart murmur, your doctor may recommend treatment for that condition.

      Innocent (Harmless) Heart Murmurs

      Healthy children who have innocent (harmless) heart murmurs don't need treatment. Their heart murmurs aren't caused by heart problems or other conditions.
      Pregnant women who have innocent heart murmurs due to extra blood volume also don't need treatment. Their heart murmurs should go away after pregnancy.

      Abnormal Heart Murmurs

      If you or your child has an abnormal heart murmur, your doctor will recommend treatment for the disease or condition causing the murmur.

      Some medical conditions, such as anemia or hyperthyroidism, can cause heart murmurs that aren't related to heart disease. Treating these conditions should make the heart murmur go away.

      If a congenital heart defect is causing a heart murmur, treatment will depend on the type and severity of the defect. Treatment may include medicines or surgery.
      If acquired heart valve disease is causing a heart murmur, treatment usually will depend on the type, amount, and severity of the disease.Currently, no medicines can cure heart valve disease. However, lifestyle changes and medicines can treat symptoms and help delay complications. Eventually, though, you may need surgery to repair or replace a faulty heart valve.


      Medicines which the physician would prescribe are dependent on the particular heart issue the person has & could be any of the below explained.
      • Diuretic drugs help in removing excessive fluids from one’ system that aids in treating other issues which might be worsening heart murmurs like hypertension.
      • Anticoagulant medicines for blood clot prevention. The physician might even give prescription of anticoagulant medicines like Plavix, Coumadin or aspirin for preventing blood clot formations in the heart & leading to strokes or heart attacks.
      • ACE (Angiotensin-converting enzyme) inhibitors lessen blood pressure. Hypertension could aggravate fundamental conditions causal to heart murmur.
      • Digoxin is a drug which assists the heart in squeezing more vigorously that could assist when heart murmurs are arising from fundamental issue which is weakening cardiac muscle.
      • Statins have cholesterol-lowering effects. Presence of elevated levels of cholesterol appears to aggravate heart valve issues inclusive of heart murmur.


      Catheterization choices too are based on one’s particular heart condition. Though open heart surgeries might be necessary for these patients, but at times the reason for heart murmurs is resolved via insertion of a catheter via an artery into the groin & the catheter threaded via one’s veins to the heart for treating one’s heart problem – called as cardiac catheterization. Illustrations of methods entail:
      • A hole patched in one’s heart.
      • Valves replaced or fixed.
      • Blood vessel rebuilt.
      • Blood vessel widened which is rather constricted by insertion of a wire tube known as stents.
      Physicians earlier recommended majority of the individuals having irregular heart murmur to be taking antibiotic medicines prior to a visit to the dentists or undergoing surgical procedure. This is generally not the case now. Largely individuals having heart murmur would not require antibiotic medicines. Any doubts or queries regarding intake of antibiotic being necessary or not must be promptly addressed to one’s physician

      What are the complications of a heart murmur?
      A heart murmur is the physical finding of an underlying structural issue within the heart. A heart murmur itself has no complications. The ramifications of a heart murmur are based on the particular underlying abnormality causing the murmur, and the effect it has on cardiac physiology.

      Can heart murmur be prevented?

      It is important to remember that a heart murmur is a physical finding and is not a disease or structural heart problem. Rather it is the sound that is made because of a potential blood flow problem within the heart. Maintaining a life-long heart-healthy lifestyle may help prevent some heart valve issues. These lifestyle opportunities include keeping blood pressure, cholesterol, and diabetes under control. It is a positive choice not to smoke. Regular exercise and weight management also contribute to a healthy heart.
      Historically, rheumatic fever was a complication of strep throat (streptococcal pharyngitis). This could cause heart valve damage and the development of a heart murmur. With the advent of good screening tests for strep infections and the appropriate use of antibiotics, rheumatic fever is rarely diagnosed condition.
      Heart Murmur At A Glance

      • Turbulent blood flow within the heart causes abnormal sounds called murmurs.
      • Most murmurs are functional, or physiologic, and are normal. 
      • Some murmurs are due to abnormal function of the valves in the heart. The valves may have narrowing (stenosis) or they may leak (regurgitation). 
      • Holes in the septum or wall that divides the atrium or ventricles may cause a murmur. 
      • A murmur is a physical finding and not a structural problem within the heart itself. Treatment is aimed at the underlying condition.

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