Heart murmur: definition, causes, symptoms, diagnosis and treatment

By Cristiano Antonino Last updated Jun 18, 2023

The term ‘heart murmur’ is generically defined as a clinical sign related to alterations in blood flow within the cardiac chambers

This sound, which can be detected during an objective cardiological test, is a very frequent sign in the general population, particularly in adults.

This condition can be totally asymptomatic, which is why detection can be difficult.

A heart murmur can also be found in children, although it is rarer

All that is needed to recognise this sign is a simple phonendoscope and the expert advice of a doctor, such as a cardiologist or general practitioner.

What are the causes of a heart murmur? Here is all the information on the subject.

What is a heart murmur

A heart murmur is a particular noise perceived by the doctor during cardiac auscultation when performing an objective test.

This term is used to define a particular noise caused by the flow of blood being pushed by the contracting heart muscle.

When alterations or obstructions to the blood flow are present, turbulent flows can be generated which, contrary to what normally happens, produce a noise.

To understand what a heart murmur is, it is necessary to delve into the mechanism of blood flow within the heart.

Normally, the blood circulation is silent, but certain conditions can alter the flow, which will be noisy.

The noise of the blood flow pushed by the heart muscle is similar to that produced by air conditioners.

Several events occur during the cardiac cycle: the heart muscle contracts and relaxes and the heart valves open and close.

When alterations occur in the proper functioning of these systems, turbulent blood flow is generated that causes a medically detectable noise.

The murmur can be benign (innocent or functional) or pathological (organic).

Benign heart murmur: what it is

A distinction is usually made between benign and pathological heart murmur.

In both cases, a noise is usually not present but there are differences between these two conditions:

Benign heart murmur is also called physiological. In this case, this clinical sign is not related to the presence of a heart disease, so it is not synonymous with a heart-related pathology.

It is possible that certain factors such as stress or lifestyle can cause a heart murmur to emerge.

In this case, in fact, the blood, pushed by the movement of the heart in the arterial vessels, passes through the heart valves, generating small turbulent flows that generate this noise.

In this case, the murmur may disappear on its own.

During pregnancy, heart murmurs are not infrequently detected, which disappear on their own after childbirth, without medication.

Factors related to the patient’s life, such as diet, posture, exercise and stress can lead to cases of benign and momentary heart murmurs.

A pathological or organic heart murmur is indicative of heart disease.

It is difficult to distinguish a benign from a pathological murmur and, therefore, further investigations such as a cardiac ultrasound or other imaging test should be performed to verify that the heart is functioning properly.

Symptoms

Diagnosing a heart murmur can be complex because very often the sufferer is unaware of the condition.

In fact, many people have no symptoms but discover this sign during check-ups such as a medical certificate for non-competitive sports activities.

The noise produced by the blood flowing inside the heart chambers and through the valves can be detected using a phonendoscope.

Since it cannot be perceived by the patient himself, it cannot be defined as a symptom but as a clinical sign.

When symptoms are perceived and a heart murmur is detected, it is likely to be caused by organic disease.

In this case, the most common symptoms are:

Shortness of breath during exercise or everyday activities such as climbing stairs;
Chest pain;
Dizziness;
Fainting;
Excessive sweating;
Cyanosis;
Growth delays.

Causes of heart murmur

A heart murmur can be caused by several factors. Again, causes can be distinguished according to the type of heart murmur, whether benign or pathological.

Causes of benign heart murmur can include common factors such as:

Pregnancy
Stress
Sedentary lifestyle
Strong emotions
Childhood

The causes of pathological heart murmur are many more, as this sign can occur in different diseases.

Among the most common causes are:

Problems with the functioning of the heart valves, such as rheumatic fever or valve infections;
hypertension or heart failure;
atherosclerosis;
ageing, which leads to deposits of substances such as calcium that harden the valves and make blood circulation difficult;
congenital cardiac malformations, which can lead to circulatory abnormalities;
anaemia, i.e. a shortage of haemoglobin in the blood;
hyperthyroidism, the excessive production of thyroid hormones.

Diagnosis

The only way to diagnose a heart murmur is to be examined by a doctor, as no sound is perceived by the patient.

The murmur is usually recognised during general examinations, during which the doctor may objectify this sign and prescribe a specialist examination or an imaging test to detect any concomitant heart disease.

It is usually the general practitioner who recommends the type of examination best suited to the perceived noise.

It is usually advisable to visit a cardiologist who can accurately diagnose the type of problem and, if necessary, set up an appropriate treatment.

During a cardiologist’s examination for the diagnosis of a heart murmur, it is not uncommon for the doctor to ask about the patient’s medical history.

Among the most frequent questions are:

Is there any history of cardiological disease in the family?
Have you experienced symptoms such as chest pain, dizziness, fainting or shortness of breath?
Did these symptoms occur at rest or during physical activity?

With these questions and a careful objective test, the doctor will be able to assess the severity of the heart murmur, recognising its intensity, the heart tone affected and its duration.

Following the examination, specific tests such as chest X-ray, electrocardiogram or echocardiography may be requested.

The colour Doppler echocardiogram

To detect the type of heart murmur, an echocolordoppler of the heart at rest is often requested.

This test is non-invasive and relies on the use of an ultrasound mechanism to reconstruct the static and dynamic morphology of the heart.

This test takes about 20 minutes and involves placing a probe on the chest (called a transducer) that sends all the information on the blood circulation and movements of the heart to the echocardiograph.

Through this particular type of ultrasound it is possible to detect the presence of problems in the heart muscle and to check the state of the heart valves .

In this way, it is possible to investigate the health of the heart and understand whether the murmur is related to a heart disease.