A cardiac murmur is an extra sound realized when listening to the heart with a stethoscope. As blood is pumped through the heart and passes through the valves, normal pumping sounds are heard, but an additional sound often indicates the presence of a cardiac murmur.
A murmur can be diagnosed in adults as well as children, and its presence does not always indicate the presence of cardiac disease. About two-thirds of school age children may have a heart murmur and this condition finding remains one of the most common reasons your pediatrician may refer you to a pediatric cardiologist.
The cardiac portion of the physical exam is directed towards finding early signs of cardiac disease. As congenital heart disease remains the most common birth defect, and there are various forms of acquired heart disease that may develop during a child’s lifetime. The identification and work up of a murmur is important. Fortunately for most children with this finding, there is no cardiac disease. These cases are referred to as innocent murmur or functional murmur.
A pediatric cardiologist uses features of the murmur such as location, timing, and quality to determine the likelihood of underlying cardiac disease and will consider further testing with an EKG and ultrasound of the heart known as an echo. Another important factor is the age of the patient as innocent murmurs are very common in the newborn period and school age children. Innocent murmurs are also made louder by an exacerbating condition such as dehydration, fever, infection, or acute illness, which may be the time these murmurs are found.
While innocent murmurs are the more common finding, there are certain features of a murmur that can indicate the presence of cardiac disease. Loud or harsh murmurs, murmurs that change over time, and other abnormalities in the cardiac physical exam can be associated with cardiac disease and warrant a thorough evaluation. Features such as poor feeding, bluish discoloration, difficulty with breathing, exercise intolerance, and passing out completely are other clues that there may be cardiac disease associated with the murmur. These “pathologic” murmurs typically occur in less than 1% of the population and are not usually life-threatening.
Even though your pediatrician has diagnosed your child with a murmur, he/she may not refer you to a cardiologist depending on the features of the murmur and whether it is very likely to be an innocent murmur. It is not uncommon to be referred to a pediatric cardiologist even when your pediatrician believes it’s an innocent murmur for an expert opinion and it does not mean that your child has cardiac disease. If your child is diagnosed with an innocent murmur it is important to let future physicians examining your child to know of this diagnosis and whether a workup was performed. The identification and evaluation of all the different types of murmurs of childhood is a key part of the pediatric physical exam and remains one of the timeless ways to find congenital heart disease in children and adolescents.