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Q. During a recent checkup, my doctor told me I have a heart murmur. Should I be worried?
Dr. Marianne Legato: Most patients are quite alarmed when their doctor tells them they have a heart murmur -- and usually unnecessarily so. A "heart murmur" is the sound a physician hears through her stethoscope. It is caused by rough or turbulent blood flow. This can be due to any one of several things.
One cause is a problem with one of the valves that allow blood to flow from one chamber of the heart to the next without backflow. Guiding blood in the right direction is achieved by an ingenious system of these valves, each of which opens to allow blood to flow forward and then closes to ensure that that blood does not leak backward into the chamber from which it has just come.
In the normal heart, the delicate leaflets of tissue that make up the valve -- as thin as tissue paper -- open and close smoothly and completely -- like swinging doors that guard the entrance to a store. If those leaflets are thickened, as they are in older people or in people who have had some injury to the valve (like rheumatic fever, for example), they do not open completely (or may not close snugly) and the smooth flow of blood is disturbed, creating a unique sound that your doctor learns to interpret. The most expert physicians are able to tell simply by listening which valve is involved, and what is wrong with it.
Another common cause of turbulent blood flow has nothing to do with inadequate or diseased heart valves. Sometimes either the speed of blood flowing through the heart or the volume of blood passing through it is increased. These conditions create turbulence -- a lot like a stream after a heavy rain that races and foams along its course, or a car that races along a road at high speed. These are things that we expect to happen in pregnancy (when blood volume increases) or with fevers (when the speed at which blood flows through our heart increases). Other temporary -- and treatable -- conditions that cause heart murmurs are anemia and hyperthyroidism. Some murmurs are simply "innocent" or "functional"; many young people have soft murmurs that are not of any consequence because they are simply the result of the vigorous beating of their hearts. These are more apparent in thin people.
When your doctor hears a murmur for the first time, she will decide whether its character warrants imaging of your heart; this is done with an echocardiogram. In this examination, sound waves are bounced off the heart to create an accurate picture of its structure so that the physician can "see" the details of the heart's anatomy, including that of its valves. Because valves can stiffen with age, murmurs may appear as we grow older. But they can, as I've explained, be the result of a temporary condition like a fever or anemia. Of course, if you were born with a developmental defect in your heart's anatomy (like a hole between the chambers of the heart, called a septal defect), your murmur would have been present since you were born. Most murmurs, though, are what we doctors term "acquired," and are heard only later in life.
Hearing -- and interpreting the cause of -- heart murmurs is an acquired ability; it takes long training and good tutors. Sometimes you may have had a faint murmur all your life, but doctors may not have heard it until you met a particularly careful and well-trained listener. In any case, don't jump to conclusions until your physician has explained its cause. It may not mean anything important at all!
If you are told you have a heart murmur, ask your doctor if you need an echocardiogram. If the answer is "no," make sure she can explain why not and why she believes the murmur to be "functional" or "innocent."
Originally published on LHJ.com, December 2005.
Do you have a health question, concern, or worry? E-mail your questions to Dr. Legato at AskDrLegato@lhj.com, and the answer (but not your name) may be featured in an upcoming issue of Ladies' Home Journal or on LHJ.com.