What is a Heart Murmur?

A heart murmur is a swishing or a whistling sound that the doctor hears when he listens to your child's heart with a stethoscope. The heart beat normally makes two sounds: the first is Lub and the second is Dub, these two sounds follow each other (Lub Dub) and are not separated by any extra sounds. A heart murmur will be heard as a swishing or a whistling sound in addition to the normal Lub-Dub sound. The moving blood sounds like the running water in your garden hose. A heart murmur may indicate that there is a heart problem or may be due to normal blood flow. A heart murmur is not a diagnosis or disease, it is a sign to alert our attention to check if there is anything wrong.

Most of the time heart murmurs are normal and do not indicate that there is anything wrong with the heart. However, sometimes they may result from a hole in the heart or a narrowed valve. A hole in the hose allows water to squirt out producing a whistling sound. Heart murmurs come in different sounds which may help indicate whether the murmur is normal or abnormal. Click the sound icon to listen to the different heart murmur sounds on this page.  Musical  Harsh  Machine-Like

Listen to the difference between a small hole in the heart and a large hole.  Small Hole

The fact that a heart murmur sounds softer may indicate that the hole is larger.  Large Hole

nnocent Causes:
Fever During fever the blood flows faster to meet the body's higher energy needs, this is similar to a fast flowing stream. This murmur could be heard in any child with fever and disappears when the fever is over. Anemia When the concentration of red blood cells is low, as may happen with poor nutrition, the blood will flow faster, making a murmur. This murmur resolves after treating the anemia.	A thin chest wall and a straight back Simply because the heart is closer to the chest wall, the blood flow sound will be easily heard without indicating there is anything wrong with the heart.
Venous Hum Venous hum is a common innocent murmur heard during childhood. This murmur is heard as a soft humming sound at the base of the neck just above the collarbone. It results from the normal blood flow in the large neck veins (jugular veins). The doctor may lightly compress the neck vein to make the murmur transiently disappear, or he may turn your child's head to one side or another, so as to make the murmur sound louder. These simple maneuvers help the doctor to differentiate a Venous Hum from the murmurs resulting from heart disease.	Venous Hum
Still's Murmur This heart murmur is named after the doctor who described it. It is heard most frequently in active, healthy 3 to 7-year old children. The murmur represents the normal sound of blood gushing out into the aorta during heart contraction. It has a musical tone to it and thus is frequently described as "musical murmur"; it usually sounds softer during sitting and may sound very loud during fever, anxiety, or exercise.
Not-Innocent Causes:
A narrow valveIf you press on your garden hose, the sound of the flowing water becomes louder, as the caliber of the garden hose becomes narrower. As the blood encounters a narrowed valve it becomes turbulent, and faster to squeeze itself through, thus producing a heart murmur. A narrow valve is called valve stenosis. The importance of the situation depends on what valve is involved and the degree of the narrowing.	A narrow arteryIf the arteries going to the lungs from the heart (Pulmonary Arteries) are narrow they may produce a heart murmur. This is a defect called Branch Pulmonary Artery Stenosis. To learn more about Branch Pulmonary Artery Stenosis,
A leaking valve As the heart valve closes some blood leaks back making a blowing sound (murmur). A leaking valve is called insufficient or regurgitating. Its importance depends on how much blood is leaking, what valve is involved, and how long it has been going on.	Regurgitation
A hole in the heart Because the pressure in the heart chambers is not the same, the blood will flow from the high to the low-pressure chamber, producing a murmur sounding like a waterfall. If the hole is small, it will make a very loud sound. If the hole is large it may make a faint murmur that may go unnoticed for some time; therefore a faint murmur may sometimes indicate a serious problem. A hole in the heart is called septal defect. If it is between the upper cardiac chambers, it is called Atrial Septal Defect (ASD), and is called Ventricular Septal Defect (VSD) if it is between the lower cardiac chambers. The importance of septal defects depends on their size and site.	Small Hole Large Hole