There are two classifications of heart murmurs -- innocent and abnormal.
Innocent heart murmur symptoms are usually nonexistent, while an abnormal heart murmur may have accompanying telltale signs of a heart problem. A heart murmur is any unusual heart sound detected by a doctor using a stethoscope. An innocent heart murmur is considered harmless and may only require periodic monitoring by a doctor. An abnormal heart murmur may require surgery or other treatment to resolve an underlying problem.
An innocent heart murmur means there are abnormal sounds when the blood is flowing through the heart. This type of heart murmur is most common in children and pregnant women, and it usually resolves on its own. In fact, the Cincinnati Children's Hospital Medical Center estimates that 90 percent of children aged 4 to 7 years old have a heart murmur. Heart surgery, fever, hyperthyroidism and anemia are some of the conditions that can also cause an innocent heart murmur. This type of heart murmur usually surfaces during a routine doctor exam. The doctor may order tests like an electrocardiogram to determine whether or not the heart murmur is a sign of a more serious problem.
A child who is born with a congenital heart defect will have an abnormal heart murmur. According to the National Heart, Lung, and Blood Institute, more than half of these children have a hole in the heart, called a ventricular septal defect (VSD) or an atrial septal defect (ASD). Conditions that are more likely to damage the heart and cause an abnormal heart murmur in adults include endocarditis, rheumatic fever calcification and mitral valve prolapse (MVP).
A heart murmur may be detected in a pregnant woman during a routine exam. It is possible that the heart murmur can be due to a problem with a heart valve, but usually it is an innocent heart murmur, according to the American Heart Association. Pregnant women display innocent heart murmur symptoms because of the excess blood pumped to the heart during pregnancy to sustain the fetus and the mother. A woman who has a heart murmur due to a congenital heart problem has a higher risk of having a baby with a congenital heart defect.
The abnormal heart murmur symptoms that present themselves in adults, other than pregnant women, usually occur because of an underlying heart condition. Most often, heart disease affects the normal functioning of the heart valves. One such condition is mitral valve prolapse (MVP), also known as Barlow's syndrome or click-murmur syndrome. MVP can cause a heart murmur if blood is leaking back through the faulty valve.
According to the Mayo Clinic, symptoms of an abnormal heart murmur heart due to a heart problem can include:
An abnormal heart murmur in an adult may be due to another medical condition and have corresponding symptoms. Both anemia and hyperthyroidism are conditions that can cause a heart murmur. Anemia is when a lack of healthy red blood cells makes it difficult to get oxygen to the heart thereby causing the murmur. Hyperthyroidism is an overactive thyroid gland that increases hormones in the blood stream. However, once a doctor treats these problems, the symptoms and heart murmur will most likely disappear.
A heart murmur can be difficult to detect during a routine exam if the child is crying or will not sit still while the doctor listens with a stethoscope. If a murmur is heard, the doctor will evaluate the loudness on a scale of 1 to 6. It will also be classified into one of the following types according to when the murmur occurs:
A child with a hole in the heart may exhibit no outward symptoms and even the heart murmur can be difficult to detect with an ASD. When the hole in the heart is larger, the child may have stunted growth, lack of appetite, fatigue, shortness of breath and other lung problems.