Heart Murmur in Children: Innocent vs. Pathological Murmurs, Causes, and Treatment

Heart murmurs in children are additional sounds heard during cardiac auscultation and are often innocent (physiological) in origin. Innocent murmurs occur without structural heart disease and may disappear during the growth process. Pathological murmurs, on the other hand, develop due to congenital or acquired heart diseases and require detailed cardiological evaluation.

Symptoms of innocent murmurs are usually characterized by the child being in good general condition, and cyanosis, shortness of breath, or developmental delay do not accompany them. These murmurs often become more noticeable during periods of fever, anemia, or rapid growth. During physical examination, they are soft in intensity and may change with position.

Conditions that support findings of pathological murmurs may include feeding difficulties, easy fatigue, sweating, and cyanosis. Such murmurs are associated with structural heart anomalies, valve diseases, or septal defects. Severe, continuous, or back-radiating murmurs require further investigation and are evaluated with echocardiography.

The diagnostic and treatment process for heart murmurs in children is planned by a pediatric cardiology specialist. In addition to auscultation, echocardiography, ECG, and advanced imaging methods when necessary are used in diagnosis. Innocent murmurs do not require treatment, whereas medical or surgical intervention may be applied in pathological causes.

What is a heart murmur and how does it occur during blood flow?

To understand a murmur, one must first imagine how the heart functions as a pump and how the fluid inside it, namely blood, moves. In an adult and healthy heart, blood flows extremely regularly, silently, and in layers within the vessels and heart chambers. You can compare this to water flowing calmly in a wide riverbed. Water remains silent as long as it does not encounter an obstacle or the riverbed suddenly narrows. However, if the river narrows, the speed of the water increases, or rocks appear in its path, the flow is disturbed, whirlpools form, and a rushing sound begins to be heard. We call the turbulent, vortex-like movement of blood flow in the heart heard through a stethoscope a “murmur.”

Hearing this sound in children is much easier than in adults, and this is entirely related to the physical characteristics of children. The chest wall of children is thin; therefore, the distance between the heart and our ears is much shorter compared to adults. A thick layer of muscle or fat that would isolate the sound between the heart and the stethoscope has not yet developed. In addition, children’s metabolism works very rapidly. Their hearts beat much more frequently per minute than adults, and blood circulates through their vessels much faster. According to the laws of physics, the faster a liquid flows, the greater the likelihood of producing sound. For this reason, hearing a murmur in a child does not necessarily mean that the child has heart damage; most of the time it is simply the natural result of fast blood flow, a strong heart, and a thin chest wall.

What are the differences between an innocent murmur and a pathological murmur?

When a physician places a stethoscope on a child’s chest and hears that blowing sound, the first and most critical question that arises in their mind is: “Is this sound innocent or pathological?” This distinction is the fundamental crossroads that determines the direction of everything that will follow. Innocent murmurs, which we also call “functional” or “physiological” murmurs, are sounds heard when there is no structural problem in the heart. The heart valves are intact, there are no holes between the chambers, and the vessels are of normal width. The only source of the sound is the dynamics of blood flow at that moment. This situation is so common that more than half of school-age children may have this sound heard at some point in their lives.

Pathological murmurs, on the other hand, are a sign of an underlying “organic” problem. In other words, there is an error in the architecture of the heart. This may be a hole between the ventricles (VSD), a valve stenosis or insufficiency (blood leaking backward because the valve does not close properly), or abnormal placement of vessels. These structural disorders force blood flow and cause a harsh and rough noise. However, the reassuring statistic is this: the vast majority of murmurs heard in childhood, more than ninety percent, are innocent and not a sign of disease. The prevalence of congenital heart diseases is around one percent. In other words, the likelihood that a murmur is innocent is much higher than the possibility that it indicates disease.

What are the characteristics of innocent murmurs and why are they called the “music of the heart”?

Innocent murmurs have a unique and almost “benign” character that can be easily recognized by an experienced ear. When describing these sounds, physicians often use the term “musical.” This is because they are not harsh or machine-like sounds that irritate the ear; rather, they resemble the vibration of a string, a gentle hum, or a soft blowing sound. They last for a short time and are heard only in the middle of the contraction phase of the heart before disappearing. They are never very intense and do not create a vibration (thrill) on the chest wall that can be felt with the hand.

The most common type in this group is the “Still’s Murmur,” especially heard in children between the ages of 2 and 7. It is thought to occur when blood pumped from the left ventricle into the aorta causes thin chordae or valve structures to vibrate like the string of a musical instrument. The most fascinating and diagnostic feature of Still’s murmur is that it varies according to the child’s position. When the child lies on their back, the return of blood to the heart increases and the sound becomes more pronounced; however, when the child stands up, the amount of blood returning to the heart decreases due to gravity, and the murmur becomes softer or even disappears completely. A murmur that disappears with position is one of the strongest proofs that it is innocent.

Another commonly encountered innocent sound is the “Venous Hum.” This sound actually comes not from the heart but from the blood flow in the large veins of the neck. It is usually heard near the collarbone as a continuous wind-like hum. If the sound disappears when the child turns their head to the side or when gentle pressure is applied to the neck, this proves that it is not related to the heart and is a completely harmless vascular sound.

The general characteristic features of innocent murmurs are as follows:

• Short duration
• Soft tone
• Musical character
• Changes with position
• Minimal radiation
• Systolic timing

Do fever, anemia, or exercise increase the intensity of murmurs?

Yes, they definitely do.

This is exactly why we call innocent murmurs “functional”; the intensity of the sound can change depending on the current function and working tempo of the heart. Any condition in which the body’s oxygen demand increases or blood circulation accelerates may cause an innocent murmur that is normally unheard or very faint to become noticeable. This does not indicate that the heart is diseased but simply that it is responding to the current condition.

For example, the metabolism of a child with a febrile infection accelerates and the heart beats much faster than normal. During this time, the speed of blood flow increases and turbulence intensifies. The sound we hear during examination may disappear completely once the fever subsides and the child calms down. Similarly, in anemia, the density of the blood decreases, meaning the blood becomes more fluid. A thinner fluid forms vortices more easily. In addition, in anemia the heart must pump more blood to carry sufficient oxygen to body tissues.

After exercise, intense excitement, fear, crying episodes, or conditions where the thyroid gland works rapidly may also increase cardiac output and cause “flow murmurs.” Sometimes we may even hear a temporary murmur in a child whose heart is beating rapidly simply due to fear of the examination. For this reason, when evaluating a murmur, physicians consider not only the sound heard at that moment but also the child’s overall condition.

Situations that temporarily increase murmur intensity include:

• High fever
• Intense exercise
• Excitement
• Fear
• Anemia
• Thyroid diseases
• Rapid growth periods

Which murmurs are a sign of danger (heart disease)?

Although most are innocent, some murmurs immediately alert us the moment we place the stethoscope. For physicians, there are certain warning signs, or “red flags,” that prompt immediate further investigation rather than a “wait and see” approach. These features are strong evidence of a structural problem in the heart, such as a hole or narrowing.

The most important red flag is the timing of the murmur. Murmurs heard during the relaxation phase of the heart, when it fills with blood—called the “diastolic” phase—are always considered pathological in children until proven otherwise. Innocent murmurs occur only during the contraction phase (systole). The second important criterion is intensity. If a murmur is very loud and we can feel a vibration (thrill) when placing our hand on the child’s chest, similar to the vibration of a purring cat, this definitely indicates an organic problem. Innocent murmurs never produce vibrations strong enough to be felt by hand.

The character of the murmur and the area where it radiates also provide valuable clues. If the sound is not soft and musical but harsh, rough, and noisy like a machine, pathology should be suspected. Furthermore, if the sound does not remain only over the heart but spreads strongly to the back, armpit, or neck, this indicates blood being forcefully ejected from one place to another.

Risky features suggesting a pathological murmur include:

• Diastolic timing
• Very high intensity
• Palpable vibration
• Harsh character
• Machine-like sound
• Radiation to the back
• Continuous character

What symptoms accompanying murmurs can families observe at home?

Making the diagnosis is of course the physician’s task, but a parent’s observation at home can sometimes provide clues more valuable than the most advanced devices. This is because a murmur is only the visible part of the iceberg. If there is a significant hole or narrowing in the heart, it will inevitably affect the child’s daily life, nutrition, and energy. Children with innocent murmurs, however, are completely symptom-free and experience no disruption in their lives.

In infants, the earliest and clearest sign of heart failure appears during feeding. For a baby, sucking requires effort comparable to running for an adult. If your baby becomes tired quickly while feeding, frequently stops sucking to rest, and beads of sweat appear on their forehead at that moment, this is an important sign that the heart is struggling to supply the body. Failure to gain weight or falling significantly behind peers in growth also raises suspicion.

In older children, performance during play is a key indicator. If your child becomes tired much faster than peers, leaves games early, becomes breathless while climbing stairs, or complains of chest pain, it is important to be cautious. Bluish discoloration of the lips or fingertips indicates reduced oxygen levels in the blood and requires urgent evaluation. However, if a child runs tirelessly in the park, sweats but never seems to tire, and has a healthy pink complexion, the murmur heard in their heart is highly likely to be innocent.

Symptoms to pay attention to in infants include:

• Becoming tired quickly during feeding
• Excessive sweating during feeding
• Rapid breathing
• Failure to gain weight
• Frequent lung infections
• Cyanosis
• Rapid heartbeat

Symptoms to pay attention to in older children include:

• Easy fatigue during exercise
• Chest pain
• Fainting
• Palpitations (rapid heartbeat)
• Cyanosis
• Need to squat

Symptoms to pay attention to in adolescents include:

• Fatigue compared to peers (with or without exercise)
• Chest pain
• Fainting, dizziness, darkening of vision
• Palpitations

What does the doctor do during the examination and how is the diagnosis made?

When you enter the examination room, the process is not limited to listening to the heart. In fact, the physician begins observing the child the moment they enter the room. The child’s color, vitality, breathing pattern, and movements provide the first clues. The stage of listening to the heart, known as auscultation, is a delicate art that requires silence. If the child is crying or restless, it becomes impossible to distinguish those subtle sounds. For this reason, sometimes calming the mother, examining the child while they are in a parent’s arms, or distracting them with toys may be necessary.

With the stethoscope, we listen not only to one area of the chest but to four main auscultation points, the armpits, and even the back. However, another step that is just as important as listening is the examination of pulses. Especially checking the pulses in the groin area (femoral pulses) is vital to avoid missing narrowing in the aorta (coarctation). If the femoral pulses are weak, the diagnosis may point in a completely different direction.

During the examination we may ask the child to lie down, sit up, squat, or perform a straining maneuver if they are older. These simple movements change the amount of blood returning to the heart and reveal the character of the murmur. For example, an innocent Still’s murmur decreases when standing, while murmurs from some serious heart muscle diseases increase when standing. These maneuvers allow us to approach the correct diagnosis without the need for complex technologies.

Is echocardiography necessary for every murmur?

In medical practice, performing echocardiography (ECHO) for every child with a murmur or referring every child to a pediatric cardiologist is not always necessary. However, when human life is involved and we do not want to leave any margin of error, physicians usually act cautiously. If an experienced physician is completely certain during examination that the murmur has one hundred percent innocent characteristics, the child has no symptoms, and the electrocardiography (ECG) is normal, they may inform the family and only follow the child periodically.

However, if there is even the slightest suspicion, uncertainty in the character of the sound, or unresolved intense anxiety in the family, ECHO is the gold standard for definitive diagnosis. Echocardiography is a method of visualizing the inside of the heart, valves, walls, and vessels in real time using sound waves. It does not contain radiation, does not cause pain, does not involve needles, and provides definitive results. If there is a hole in the heart, it can measure its diameter, location, and the amount of blood passing through it with millimetric precision. Therefore, ECHO is the most powerful tool for eliminating uncertainty.

Sometimes an ECG may also be requested to evaluate the electrical activity of the heart, or a chest X-ray may be performed to see the size of the heart within the chest cavity. However, it should be remembered that the ECHO, ECG, and chest X-ray of a child with an innocent murmur will all appear completely “normal.” Normal test results do not mean the murmur does not exist; they prove that the murmur is “innocent.”

Situations requiring ECHO and advanced examinations include:

• Newborn period
• Suspicious examination findings
• Presence of symptoms/complaints
• Syndromic facial appearance or diagnosis of a syndrome
• Family history of heart disease
• High anxiety in the family

Why are murmurs in newborn babies evaluated differently?

The newborn period, the first 28 days of life, is a very special stage in which the greatest physiological change in human life occurs. While in the womb the baby receives oxygen from the mother through the placenta, at birth with the first cry they begin using their lungs. This transition means a complete change in the blood flow pathways inside the heart. Certain vessels and openings that must remain open in the womb begin to close in the first days after birth once they have completed their function.

This closure process does not occur at the same time in every baby. Many murmurs heard during the first one or two days are “transitional murmurs” caused by temporary vessel openings and usually disappear spontaneously within a few days. However, this period is also a sensitive window in which serious congenital heart anomalies may present symptoms.

One of the situations that concerns us most in newborns is the “silent period” paradox. Large holes in the heart (for example a large VSD) may not produce examination findings (murmurs) immediately after birth. This is because in the first weeks the pressure in the baby’s lung vessels is still high and blood flow from the left side of the heart to the right side is minimal. Without a pressure difference, there is no sound. When the baby is 2–6 weeks old, lung pressure decreases, blood flow begins, and the murmur can then be heard very loudly. Therefore, the absence of a murmur when a baby is discharged from the hospital does not mean that one will not appear in the following weeks. For this reason, routine check-ups in the first months are vitally important.

Does a child diagnosed with an innocent murmur need restrictions?

As a physician, I must answer this question very clearly and loudly: No, absolutely not. An innocent murmur is not a heart disease; it is the sound of a healthy and strongly functioning heart. A child with this confirmed diagnosis should not have any physical activity restrictions. They can fully participate in physical education classes, become licensed athletes, run on the football field, swim, and sweat.

Unfortunately, sometimes due to misunderstandings or overly protective parental attitudes, these children are labeled as “sick” and raised as if in a glass jar. Constantly telling a child “don’t run, don’t get tired, you have a heart condition” can lead to a psychological condition we call “cardiac neurosis.” This not only prevents the child’s physical development and increases the risk of obesity but also damages their self-confidence. The physician’s greatest responsibility here is to reassure the family and emphasize that the child is “normal.” Innocent murmurs do not require medication, special check-ups (beyond routine annual visits), or a special diet.

Do murmurs disappear over time and what are the treatment options?

The natural course of innocent murmurs is usually toward disappearance. As the child grows, the chest wall thickens, muscle and fat tissue increase, and the heart rate slows with age. All these factors make it more difficult for the sound to be heard from outside. Most innocent murmurs are no longer audible by adolescence. In some very thin individuals or those with a slender chest structure, they may still be faintly heard in adulthood, but this does not create a health problem.

In pathological murmurs, however, treatment varies depending on the severity of the underlying condition.

Not every “hole in the heart” requires surgery or angiography. For example, small holes in the muscular part of the heart may produce very loud murmurs but tend to close spontaneously as the child grows. In such cases, patient follow-up alone is sufficient.

However, large defects, severe valve stenosis, or diseases causing cyanosis require intervention. Today, thanks to technological advances, some of these interventions can be performed without surgery, using catheter-based techniques through the groin. In cases requiring surgery, pediatric cardiac surgery produces remarkable results. In summary, even if a murmur is pathological, it does not mean hopelessness but simply a condition that must be managed correctly.

General treatment approaches include:

• Regular follow-up (Observation)
• Medication therapy
• Closure via catheterization
• Open-heart surgery