Heart Murmur

A heart murmur is an extra sound, heard through a stethoscope, that occurs somewhere within the normal cycle of a heartbeat. Rather than a smooth "lub-dub" sound alone, a murmur adds a whooshing, blowing, or rushing quality, produced by blood moving through the heart's chambers and valves in a way that creates audible turbulence. Heart murmurs are extremely common in children and are usually discovered incidentally during a routine checkup rather than because a child has any noticeable symptoms. Murmurs fall into two broad categories that mean very different things for a child's health:

• Innocent, or functional, murmurs — the sound of blood flowing through a completely normal, healthy heart; do not indicate any underlying heart disease and are, by far, the most common type found in children
  
  
• Abnormal, or pathologic, murmurs — reflect an actual structural issue with the heart, such as a congenital heart defect, which is why any newly discovered murmur is evaluated carefully to determine which category it falls into

• Innocent murmurs arise simply from the normal, sometimes brisker, flow of blood through a structurally healthy child's heart and blood vessels; they often become more noticeable during fever, illness, or periods of rapid growth, when blood flow through the heart naturally increases, and they may come and go over time as a child grows, without this variation being a cause for concern
  
  
• Abnormal murmurs are caused by an actual structural problem, most often a congenital heart defect such as a hole between heart chambers or a narrowed or malformed valve, which creates turbulent blood flow that a trained clinician can often distinguish from an innocent murmur based on its specific sound characteristics, timing within the heartbeat, and location
  
  
• Newborn-period murmurs — because congenital heart defects are present from birth, a murmur detected in the newborn period, or one accompanied by other signs such as poor feeding, rapid breathing, or a bluish tint to the skin, is evaluated with a higher degree of caution than one first noticed incidentally in an older, otherwise well child
  
  
• Family history of congenital heart disease can also inform how thoroughly a newly found murmur is investigated

• Most heart murmurs found during a routine checkup do not require urgent action, and a pediatrician who identifies a murmur will typically evaluate its specific characteristics to judge whether it appears innocent or warrants further testing
  
  
• Referral to a pediatric cardiologist is common practice whenever there is any uncertainty, and this evaluation, which may include an echocardiogram, can definitively distinguish an innocent murmur from one caused by a structural heart problem
  
  
• Prompt medical evaluation is especially important, rather than a routine wait-and-see approach, if a murmur is accompanied by other symptoms such as difficulty breathing, poor feeding or weight gain in an infant, unusual tiredness or shortness of breath during activity, fainting, or a bluish tint to the lips or skin, since this combination raises the likelihood that the murmur reflects an underlying heart condition
  
  
• Once a murmur has been formally evaluated and determined to be innocent, no further cardiology follow-up or activity restriction is generally needed, and parents can be reassured that the finding does not indicate any heart disease