PSSSST!!! murmur, murmur, murmur

Understanding heart murmurs is fairly simple. There are diastolic and systolic murmurs, quiet and loud murmurs, innocent and problematic murmurs. Learning what are the causes and what is problematic is as easy as 1, 2, 3. Here is a guide to the basics.

PSSSST!!! murmur, murmur, murmur

What is a murmur?

A murmur is a "whoosh" sound heard with a stethoscope. Normal hearts make the "lubb-dubb" sound (or Lubb-dupp) when the heart valves close. Murmurs make a "whoosh-whoosh" sound.

What causes a murmur?

Murmurs are not caused by a disease, but may indicate a heart problem. If the murmur is present at birth, it is congenital. Murmurs that are problematic are usually related to a defective heart valve. This can be due to stenosis or regurgitation problems. In a stenosis murmur, the heart valve has a smaller than normal opening, and cannot open completely. In a regurgitation murmur, the valve may be unable to completely close and blood leaks backward through the valve.

What is an innocent heart murmur?

Often, a newborn will have a murmur caused by the open PDA, which should close on it's own, and the murmur will go away. Innocent murmurs are not usually a problem and may not require any treatment because it will usually go away on it's own. The patient will likely not experience any signs or symptoms.

What causes an innocent heart murmur?

When blood flows more rapidly through the heart than it normally does, you may hear a murmur. Causes of rapid blood flow that can result in an innocent murmur include pregnancy, physical activities / exercise, fever, anemia, hyperthyroidism, and rapid growth phases (example, adolescence).

What is an abnormal or problematic heart murmur?

An abnormal murmur can be serious. Congenital disease is the cause in newborns and children. In adults, murmurs that are abnormal are usually caused by acquired heart valve problems.

What causes an abnormal heart murmur?

The most common cause is congenital heart defects in babies born with structural heart problems. In babies and children, this can include:

  • Holes in the heart that cause shunts (septal defects). This is not always a serious problem, depending on where the hole is and the size of the hole.
  • Abnormal blood flow can occur between the chambers or the blood vessels
  • Valve abnormalities that do not allow enough blood to flow through (stenosis) or that do not close properly or leaks back into the chamber it just came from (regurgitation)

In adults, common causes include infections or conditions that damage the valve structures such as:

  • Endocarditis (infection in the inner lining and valves of the heart)
  • Valve calcification (hardening/thickening of valves) that can cause mitral or aortic valve stenosis
  • Rheumatic fever can damage heart valves if left untreated (caused by strep throat infection)

What types of medical conditions or illness can cause a murmur?

Conditions that can temporarily cause a murmur due to a blood flow increase can include fever, anemia, pregnancy, or thyrotoxicosis (overactive thyroid gland).

What are the signs and symptoms of a problematic heart murmur?

Sometimes the patient may not exhibit any signs or symptoms other than the murmur heard with the stethoscope. However, we need to be aware of the following S/S that may show up:

  • Cyanosis
  • Edema or sudden weight gain
  • JVD
  • Chest pain
  • Poor appetite & failure to thrive (INFANTS)
  • Shortness of breath
  • Sweating with no or minimal exertion
  • Dizziness
  • Chest pain
  • Fainting
  • Chronic cough
  • Enlarged liver

What types of murmurs are there?

There are two basic types of murmurs: Systolic and diastolic.

What is a systolic murmur?

A murmur that is heard when the heart contracts is a systolic murmur. The murmur is "graded" by how loud it is, from a 1-6. For example, a 1/6 murmur is very faint, and a 6/6 is extremely loud and can be heard even if the stethoscope is not touching the chest.

What does a systolic murmur indicate?

A systolic murmur can indicate mitral valve prolapse or regurgitation, or aortic stenosis. Other possible conditions can include cardiomyopathy. If there are no abnormal findings, the murmur is considered innocent. Quiet, short systolic murmurs are usually innocent and are commonly harmless. Long murmurs may indicate a heart problem that needs treatment.

What is a diastolic murmur?

A murmur that is heard when the heart relaxes between beats.

What does a diastolic murmur indicate?

Diastolic murmurs can indicate mitral or triscuspid stenosis, or aortic or pulmonary regurgitation. Like systolic murmurs, a long and continuous diastolic murmur indicates a possible problem that needs treatment, although there are continuous diastolic murmurs that are considered harmless as well.

How is the murmur diagnosed?

Aside from grading the murmur (1-6/6 example provided earlier), there are other tests the physician may order, including a chest xray, EKG, echocardiogram, or a heart cath.

How is the heart murmur fixed?

Innocent heart murmurs do not generally require treatment unless the murmur is a result of illness (hyperthyroidism or fever). The murmur will usually go away.

Abnormal murmurs may be monitored over time by a physician or specialist. Sometimes treatment is necessary: endocarditis requires long term antibiotics, some valve problems may require surgery.

Additionally, other medications may be prescribed, including anticoagulants, diuretics, ACE inhibitors, beta blockers, or statins.

How are valves fixed?

Valve repair can be done through repair of the structural support, leaflet repair, balloon valvuloplasty, or annuloplasty. In cases where valves cannot be repaired, a replacement can be done through open heart surgery and removing the damaged valve. It can be replaced with a mechanical or tissue valve. Additionally a transcatheter aortic valve replacement (TAVR) may be done because it is less invasive.

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Julie Reyes

About Julie Reyes, DNP, RN

Julie Reyes, DNP, RN

14 Articles   260 Posts

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Specializes in cardiac ICU.

Very interesting topic, especially the murmurs presenting in endocarditis caused by bacterial infection such as borrelia burgdorferi (lyme disease), where the murmurs arise out of all kinds of issues with autonomic nervous system.

A lot of times these murmurs are ignored and altogether dismissed as being benign, especially in athletes, who may go untreated for years.

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Specializes in Pediatrics, developmental disabilities.

Great review Julie! Thank you!

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