MadSci Network: Medicine

Re: what is a heart-murmur?

Date: Thu Jul 29 20:08:43 1999
Posted By: Rhonda E. Lowe, Undergraduate, Biology, UNF
Area of science: Medicine
ID: 933033920.Me

Hello Matt--

A heart murmur is a sound made because the blood that circulates through the heart's chambers and valves or through its vessels makes a sound. The heart is divided into four chambers: two on the left and two on the right. As the heart pumps blood with oxygen into the lungs and throughout the body, it eventually returns (deoxygenated blood ) to the heart & enters its chambers.

The murmur happens as the blood goes through the heart's chambers or valves. The (stenotic) valve doesn't open completely, so blood may be ejected through a smaller than normal opening or the valve may not close completely which then lets some of it "leak" back into the chamber that it just left. Then, the murmur or swishing sound can be heard. As the heart contracts and relaxes during its beating cycle, the abnormal noise is heard. Sometimes, the valve is simply too tight or holes in the chambers can cause them too.

Other causes of heart murmurs result from bacterial infections that can cause the lining of the heart to inflame or swell & these cause other general illness symptoms like fever and chills; heart disease resulting from heart attacks, high blood pressure or heart muscle disease. Even pregnancy which may cause birth defects in the heart of the baby either heard upon exam at birth or later during infancy and these are known as genetic defects; rheumatic fever which inflames joints throughout the body as well as the heart muscle itself; defects like the holes in the chambers or valves; blood disorders such as anemia; and also environmental factors such as exposure to a harmful industrial chemical. Most often, the murmur, or "leaky valve" or swishing sound that is made is rated on a scale of 1 to 6. One is a very faint murmur and 6 is a very loud one. In fact, 9 out of 10 children will be identified with a heart murmur at some point in their lives. Most of the time, heart murmurs do not cause any problems with a person's health. These are called "benign" murmurs. Here are the various types of murmurs:

The benign murmurs are usually not associated with any other condition and most people lead normal and productive lives and still have normal cardiac function that usually does not cause future problems. In essence, the heart is a healthy one but just has irregular flow of blood that makes the murmur sound. Most people with this type do not have to restrict activities like eating, exercise, or other ones. Often doctors hear murmurs during a physical exam as they use the sthethoscope to listen to the sounds of the heart and these are usually heard between 2 to 4 years of age. Then, they can have further tests to determine the type of murmur it actually is. They may have echocardiograms, which is where a device is placed on the body over the heart and moved around to "paint" (record) a picture of the heart on a machine & it shows what's going on as the heart pumps blood out from its chambers and valves; and in severe murmurs, doctors may need to do heart catheterizations where a very fine tube is inserted into an artery or vein in the groin of in the arm or leg and moved up towards the heart...then a special dye is injected through the catheter and s-rays are taken in the cath procedure which shows the ehart and any defects (like holes in the chambers). They can even use the EKGs and chest X-rays to evaluate for murmurs, and determine if further testing is needed.

Doctors listen for many things when they discover a murmur or use the echocardiogram to aid in identifying these factors: finding out the exact location or where the murmur actually is at in the heart; listening to its loudness or intensity (1 to 6 scale); deciding on its frequency or whether it is low, medium, or high; listening to its quality such as harsh, rough, rumbling; and timing of the murmur which is deciding where in the heart's beating cycle the murmur occurs such as at the beginning of the beating cycle (known as S1 and S2 heart sounds) or in the middle or near the end, and other things.

So, remember most heart murmurs do not require any treatment--no medicine, surgery, or anything like that; but doctors do like to periodically evaluate the murmur just to make sure the heart murmur hasn't changed and that the heart is still functioning well. But, it's always important to try to use your healthy lifestyle habits like proper nutrition, no smoking, regular exercise to keep the heart strong and healthy. BUT, if the murmur is caused from a birth defect or the valves become severly diseased, then other treatments are needed including medicines, surgery to replace the "leaky" valve or to repair any holes in the heart cuasing the murmur. Most of the time, even with "normal" murmurs (no treatment needed), you do have to take antibiotics for procedures such as such as when you go to the dentist for routine cleanings, fillings, and other things or any type of other surgery.But, remember that most murmurs are not serious and many people have them and lead normal lives. Just if you are identified with a murmur, your doctor will certainly monitor it throughout your life. In fact, i found out I had a "normal" murmur when i was about 20 years old, and I'm healthy and have never had any problems. So, I hope this answered your question, and if you too have a murmur, try not to worry and just let your doctor evaluate it and determine if any treatment is necessary. BUT, keep in mind, very few people have serious heart murmurs resulting from major defects and very few people need treatment.

Thanks for your question--

Rhonda (graduate science and education student in biology)

Harrison's Principles of Internal Medicine, 14th ed.

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