What Is a Heart Murmur?

DrSugar Answers: Heart Murmur?

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Dear DrSugar,
A few years ago, I started going to a new primary care physician, who I really like. But I was surprised when she listened to my heartbeat and told me I had a heart murmur. She said it was nothing to worry about, just something you "have," and that it probably wouldn't ever lead to any complications. I've never had a doctor tell me I had a heart murmur before, but she was so casual about it, it made me think it's very common. What exactly is a heart murmur, and is it something to be worried about?
— Telltale Heart

This is a fantastic question, considering the heart is one of the most important organs in the body and its main function is to supply all the other organs in the body (and even itself!) with oxygen-rich blood. Learn more about the heart and this issue when you keep reading.

First, let's review some heart mechanics. It’s a muscular organ that is divided into four chambers: right and left atria, and right and left ventricles. Blood flows from the right side of the heart to the lungs for oxygenation and from the lungs to the left side of the heart. From the left side of the heart, the blood is then pumped to the body through an intricate series of arteries. Between each chamber of the heart are valves that provide for the one-way forward flow of blood through the heart, and as you’ll see below, these valves are the cause of certain types of heart murmurs.

The US Department of Health’s National Heart Lung and Blood Institute defines a murmur as an extra or unusual sound heard during a heartbeat. Murmurs can range from faint to very loud and can sound like a whooshing or swishing noise. Physicians or other medical professionals can hear heart murmurs using a stethoscope. Heart murmurs can be present at birth or can develop later in life.

There are two types of heart murmurs: innocent (harmless) and abnormal. People who have innocent murmurs have normal hearts (which seems to be what you reported that your primary care physician had diagnosed you with). People with innocent heart murmurs usually have no signs or symptoms of heart problems. The sounds of the innocent heart murmur are made when the blood flows through a normal heart. An innocent murmur can also occur when the blood flows more rapidly through the heart.

Conditions that cause rapid blood flow through the heart, thus causing an innocent murmur are: physical activity or exercise, pregnancy, fever, anemia (low levels of healthy red blood cells), and excessive thyroid hormone production (hyperthyroidism). Innocent heart murmurs may disappear over time or may last one’s entire life without causing further health problems. This type of heart murmur usually doesn’t require treatment because the heart is normal. However, if the innocent murmur is caused by hyperthyroidism or fever/illness, the murmur will go away once the condition is treated.

The most common cause of abnormal murmurs in children is congenital heart disease (which means they were born with structurally abnormal hearts) and includes heart valve abnormalities or holes between chambers in the heart. Other causes of abnormal heart murmurs include infections and conditions that damage the structures of the heart (notably the heart valves) and are more common in older children and adults. Both the Mayo Clinic website and the National Heart Lung and Blood Institute have wonderful information regarding the causes and treatment of abnormal heart murmurs. One important cause that I will discuss is rheumatic fever, because it is a serious consequence of untreated or not fully treated strep throat infections. Thus, it is very important that you take all of the antibiotics prescribed to you for a strep throat infection, even if you feel better before the medication runs out.

To check whether a murmur is innocent or abnormal, your physician or medical professional will listen to the heart murmur with a stethoscope and determine how loud the murmur is, where in the heart it is heard, what pitch it is, and when during the heart cycle it occurs. They will also look for other signs and symptoms of heart problems and ask about whether any family members have a history of heart murmurs or other heart conditions. If the doctor thinks the heart murmur is abnormal, additional tests may be ordered like a chest x-ray, electrocardiogram (ECG), echocardiogram (an ultrasound of the heart), or various other tests.

While there is not much one can do to prevent a heart murmur, it is reassuring to know that heart murmurs are not a disease and are, more often than not, harmless. Innocent murmurs do not cause symptoms or require you to limit physical activity. Although an innocent murmur may be a lifelong condition, your heart is normal and you most likely will not need treatment. As I always say, if you have any concerns or questions regarding your health, please seek evaluation and consultation with your physician or medical professional!

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DrSugar's posts are for informational purposes only and should not be considered medical advice, diagnosis, or treatment recommendations. Click here for more details.

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