Pediatric Cardiology

Heart Murmurs: Types, Symptoms, Causes and Diagnosis

Posted on by Prof. Dr. İbrahim Cansaran TANIDIR

Heart murmur is the reflection of turbulence that occurs as blood passes through the heart chambers or major vessels as an additional blowing or humming sound heard with a stethoscope. The most typical symptoms of a heart murmur appear in babies as getting tired quickly during sucking, bluish discoloration of the lips, and growth retardation; in older children, chest pain with exercise, palpitations, and a feeling of fainting are notable. These sounds, which are frequently encountered in childhood and are generally defined as an “innocent murmur,” are critical clinical findings that provide information about the structural health of the heart and blood flow velocity.

What Is a Heart Murmur?

You can think of the heart as a magnificent muscle pump located at the very center of our body, working nonstop and enabling us to survive. Within this magnificent system, there are four chambers that allow blood to collect, strong one-way valves that ensure blood moves only in the correct direction, and wide vascular networks that carry this life fluid to all tissues. In a healthy and calm body, blood flows through these anatomical pathways extremely smoothly, in its own layers, and completely silently. We can compare this perfect flow pattern to a deep river with a smooth bed flowing peacefully and slowly without making any sound.

However, sometimes a natural or acquired obstacle appears in front of this river, its bed narrows, or the flow rate of the water suddenly increases significantly. Just as water makes a humming sound by hitting rocks and foaming in such moments, the blood inside our heart also becomes turbulent under similar physical conditions. When the normal and silent flow pattern of blood is disrupted, the accelerated fluid strikes vessel walls or heart chambers and creates various mechanical vibrations. The entirety of these vibrating sounds in the form of blowing or humming, which reach the chest wall and are heard by physicians with the help of a stethoscope, is called a heart murmur.

Why Is Heart Murmur Heard So Frequently in Children?

While hearing a murmur in an adult is a rare situation, these sounds are encountered in more than nearly seventy percent of individuals in infancy and childhood during a certain stage of growth. Behind this lies not a frightening heart disease, but completely age-related natural bodily differences. An adult’s rib cage is quite thick; the bones have enlarged, muscle tissue has become denser, and a distinct, thick fat layer has formed under the skin. These thick tissue layers act almost like a strong sound insulation material for sounds coming from inside the heart and prevent mild vibrations from reflecting outward.

In children, however, the situation is completely different. The chest walls of children and especially newborn babies are extremely thin. When the stethoscope is placed on the chest, even the slightest and most innocent vibration created by blood passing through the heart or the major vessels very close to the heart easily passes through this thin wall and reflects outward. Since there is no thick barrier to filter or block sound waves, even the completely normal flow sound of blood becomes easily audible. As the child grows and steps into adolescence, the body develops, and the rib cage widens and thickens. This normal physical growth process is the main reason why most of these benign sounds heard during childhood disappear or become inaudible as age advances.

Which Conditions Lead to the Formation of a Heart Murmur?

There are several basic physical conditions that cause the flow of blood inside the heart to become turbulent and therefore turn into an audible sound. The first and most common scenario is a temporary excessive increase in blood flow velocity. Think of moments when a child has a high fever, experiences severe anemia, or runs around in the park for hours and becomes breathless. The body suddenly needs much more oxygen, and the heart begins to pump much faster and much more strongly to meet this demand. Although there is no problem in the structure of the heart, blood passing through narrow valves at twice the normal speed alone creates a strong sound wave.

Another condition is the narrowing of the anatomical pathway through which the blood must pass. If the valves at the entrance of the main vessels leaving the heart are congenitally narrow, blood has to gush through them with great pressure. Imagine how water gushes out with pressure and sound when you squeeze the end of a narrow hose; this is exactly what happens in narrowed heart valves. In addition, congenital openings or holes in the walls separating the chambers of the heart are also an important cause. As blood rapidly passes through this hole from the high-pressure side to the low-pressure side, it causes a very distinct, harsh sound. Finally, faulty heart valves that do not close completely and allow blood to leak backward after moving forward are also among the main factors involved in the formation of this sound.

What Does an Innocent Heart Murmur Mean?

A very large portion of the cases we encounter in clinics and hospitals fall into the safe category we call “innocent.” When families hear the word “innocent” from the physician, they can take a deep breath and feel relieved, because this term definitively indicates that there is no anatomical or structural problem in the child’s heart. Innocent sounds are vibrations that occur only during the natural flow of blood in a completely healthy, perfectly functioning, strong heart with no holes or narrowings.

There is no need to change anything in the daily life or habits of children who receive this diagnosis. They are healthy individuals with completely normal physical capacity. There can be no medical restriction whatsoever on their participation in physical education classes at school, involvement in a professional sports branch in clubs, running and playing with peers on the street, or continuing their normal lives. They absolutely do not need to use any heart medication, undergo surgery, or follow a special diet. The flow sound of the river inside is heard a little more clearly only because their chest structure is thin and their blood flow is fast.

What Are the Common Types of Innocent Heart Murmur?

Innocent sounds are named with different medical terms according to the age group in which they are heard, the tone of the sound perceived with the stethoscope, and the region of the heart from which they reflect outward. Some sounds resemble the vibration of a guitar string, while others are like a light breeze or the hum of a seashell. Especially the lightening or complete disappearance of these sounds with a change in the child’s body position, for example when quickly standing up from a lying position, is their most important distinguishing feature.

The benign sound types we most frequently encounter in routine examinations are as follows:

  • Still’s murmur
  • Venous hum
  • Pulmonary flow murmur
  • Carotid murmur
  • Newborn pulmonary flow

Which Diseases Can a Pathological Heart Murmur Indicate?

Although the vast majority of sounds detected in children are innocent, sometimes this sound heard with a stethoscope may be a strong whisper of a physical defect or organic problem in the heart. These undesirable conditions, which we call pathological, arise from concrete defects in the general structure of the heart. These defects are serious structural problems that directly affect the health of the heart muscle and the body’s oxygenation balance and require careful treatment.

At the forefront of these problems are septal defects, commonly known among the public as “a hole in the heart.” The presence of a congenital opening in the inner walls between the ventricles or atria of the heart causes blood to make unnecessary extra rounds inside the heart and incredibly increases the workload of the heart. As the high-pressure blood of the left ventricle rapidly passes to the right side, it creates a very loud and harsh sound wave on the stethoscope. Similarly, serious narrowings in the aortic and pulmonary artery valves, which carry blood to the entire body or the lungs, are also included in this risky category. In addition, the continued openness of certain special bridge vessels that are open in the womb but should close immediately when the baby is born and begins to breathe also indicates the presence of a structural problem in the heart.

What Are the Symptoms of Heart Murmur in Babies?

If the extra sound heard is not innocent but truly originates from a diseased structure, the body will definitely show this to the family in other ways as well. Especially since babies cannot speak and explain their problems, it is necessary to read their body language and physical reactions very well. For a baby, sucking breast milk or feeding from a bottle is an activity that requires as much effort as running a marathon for an adult. While a healthy baby can easily tolerate this effort, a baby with a heart problem becomes exhausted in a short time. When the increased oxygen need during exertion cannot be met, the body enters serious stress and the autonomic nervous system begins to give emergency warnings.

The main signals that families should carefully observe during infancy are as follows:

  • Getting tired quickly during sucking
  • Frequently pausing feeding
  • Excessive sweating in the forehead area
  • Inability to gain weight
  • Bluish discoloration around the lips
  • Rapid breathing

What Are the Symptoms of Heart Murmur in Older Children?

As childhood progresses, physical activity and expectations from physical movement increase exponentially. School-age children constantly run around in the yard, climb stairs quickly, and participate in various sports activities. When there is a pathological disease in the heart, the increased oxygen and fresh blood demand of the working muscles can no longer be met by the heart. This manifests as the child getting tired much earlier than peers during play and having to stop games halfway while breathless. Insufficient blood flow to the heart during exertion may cause a feeling of pressure in the chest, while rhythm disorders may cause the heart to beat violently as if it will jump out of the chest. One of the most frightening and urgent symptoms is sudden loss of consciousness that occurs as a result of insufficient blood flow from the heart to the brain during heavy exertion.

The main complaints requiring urgent evaluation in school-age children and adolescents are as follows:

  • Getting tired quickly
  • Shortness of breath
  • Chest pain
  • Feeling of palpitations
  • Fainting
  • Swelling in the legs

How Is the Intensity of a Heart Murmur Graded?

As physicians, when listening to the chest, we do not simply define the sound we hear as present or absent; we assign that sound an objective numerical grade. For this sensitive analysis, a special six-step grading system accepted by medical authorities worldwide is used. This system both ensures that a clear and understandable record is kept in the patient’s file and gives us very important initial clues about the severity of the current problem in the heart.

Grade one refers to very mild, fleeting sounds that can be noticed only in an extremely quiet room and only when the physician listens very carefully. Grade two refers to soft tones that can be heard easily and immediately as soon as the stethoscope touches the chest. Grade three refers to sounds that are moderate in intensity, clearly audible, but do not create a vibration that can be felt by touching the chest wall. When grade four is reached, the situation becomes more serious; here, in addition to the sound heard through the stethoscope, the physician feels a mechanical vibration resembling a cat’s purr when placing their hand on the child’s chest. Grade five refers to sounds so clear that they can fill the room even when only a tiny edge of the stethoscope touches the chest. The sixth and final grade is the most severe; these are intense storm-like sounds that can be heard from outside with the naked ear even when the stethoscope is completely removed from the chest and lifted into the air.

How Is a Heart Murmur Analyzed by Specialists?

Deciphering the complex sounds reflected from the rib cage requires extremely careful expertise. The stethoscope is actually only a tool that enhances hearing; the actual detailed analysis takes place in the physician’s experienced mind. While listening to this sound, physicians examine its character, rhythm, and interaction with the child’s other bodily factors piece by piece. The fine line between a completely innocent sound and a diseased, pathological sound is largely clarified thanks to this detailed acoustic analysis. Whether the sound appears during the contraction or resting phase of the heart, and whether its tone is musical or harsh, are vital for diagnosis.

The main criteria that doctors mentally evaluate during auscultation are as follows:

  • The focus where the sound is heard most clearly
  • Its timing in the cardiac cycle
  • The intensity grade of the sound
  • The tone of the sound
  • The spread of the sound in the chest
  • Its change with position

Which Modern Methods Are Used in the Diagnosis of Heart Murmur?

Although physical examination provides excellent clues to an experienced physician, in modern medicine, we need to clearly see inside the heart in order to speak definitively and make the most accurate decision. Today, at the heart of this process lie echocardiography devices, which provide extremely reliable and detailed information. This system, which works with exactly the same sound wave logic as harmless ultrasound devices used to monitor the baby in the womb during pregnancy follow-up, instantly reflects a moving and detailed map of the heart onto a color screen. During the procedure, the child is absolutely not pricked with a needle, does not feel pain, and no harmful rays or radiation are given to the body. With the help of a warm gel applied to the child’s chest and a small probe moved over it, the thin valves, wall structures, contraction capacity, and all chambers of the heart are examined precisely.

In addition, electrocardiographies taken with small adhesive pads attached to the child’s chest are of great importance to understand whether there is a disorder in the heart’s electrical cable system, that is, in its general rhythm. If the problem occurs only when the child runs or exerts intense effort, dynamic examination methods such as an exercise test performed by making the child run in a controlled manner may be used. Holter devices may be attached to the patient to monitor rhythm disorders throughout the day. In much more complex heart diseases, angiography procedures performed by reaching inside the heart with very thin wires through vessels in the groin area both completely confirm the diagnosis and clarify the treatment plan perfectly.

What Treatment Path Is Followed When a Heart Murmur Is Detected?

The solution method to be applied is shaped specifically according to the root cause of the problem detected in the heart, the degree of the disease, and the general condition of the patient. In innocent cases, the word treatment is not used medically, because there is no disease that needs to be corrected or treated. However, if there is an anatomical defect, the most appropriate tools are carefully selected from the wide range offered by medicine. In babies showing signs of heart failure, the first step is usually special and regular drug treatments that will reduce the heavy workload on the heart, remove excess fluid accumulated in the lungs from the body through the kidneys, or regulate the disturbed rhythm of the heart.

Thanks to the dizzying point reached today by medical technology and medical instruments, many heart holes that in the past necessarily required major open surgeries can now be successfully closed without opening the rib cage at all. Thanks to umbrella-like smart devices delivered directly into the heart by entering through a vessel in the groin with a tiny needle, the holes are completely blocked from inside, and the child can cheerfully walk home the next day. However, in the presence of much more complex congenital defects in which multiple major anomalies coexist, valves have completely lost their form, or the vessels of the heart are reversed, open operations performed by expert cardiovascular surgeons are the strongest path that brings definitive and permanent health.

What Should Families Pay Attention to Regarding Heart Murmur?

Being told during your child’s routine health check that an extra sound is heard in the heart can naturally create a great storm of fear in every parent. However, the most reassuring and scientific fact you should keep in mind during this process is that the vast majority of these sounds are only temporary, ordinary, and completely benign melodies of growing fresh bodies. What matters is not to panic unnecessarily at the first moment you hear it, but to manage the process logically with correct and calm steps.

If your child does not have visible complaints such as difficulty feeding, bluish discoloration of the lips, getting exhausted very quickly compared with peers, or fainting while moving, the possibility that the sound heard with the stethoscope is innocent is very high. Evaluation with echocardiography is necessary for a definitive diagnosis.

Güncellenme Tarihi: 13.10.2026

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