Classification of heart murmurs

Heart murmurs are caused by vibrations caused by turbulence in the blood flow as it passes through the heart and large vessels. In other words, they are sounds that appear during the cycle of heart beats that produces turbulent blood flow in or near the heart. Those sounds of heart murmurs They can be heard with a stethoscope.

In addition, this alteration can occur at birth or throughout life. In the case in which they develop at birth, they are called congenital heart murmurs. You have to be clear that murmurs are not a disease, but you have to control them because they can favor the appearance of a heart problem not diagnosed.

Characteristics of heart murmurs

The characteristics of the murmurs must be specified taking into account their intensity, sound frequency, location area in the thorax and location in the cardiac cycle, that is, if they occur during systole or diastole.

In addition, the degree of intensity of the murmur is determined by the volume of blood responsible for the turbulence in the blood flow or the pressure gradient causing such turbulence. It is important to know that the degree of the blow it does not necessarily relate to the severity of cardiac injury.

How are heart murmurs classified?

The most used classification was introduced by Levine in the year 1933. This professional was based on the intensity, a term explained above, in order to classify this cardiac alteration. According to Levine, there are 6 degrees of heart murmurs depending on whether they are more or less intense:

  • Grade 1: it’s about the soft murmurs, hard to hear. In order to listen to them, it is necessary to listen to several cardiac cycles of the patient.
  • Grade 2: they are soft murmurs, easy to auscultate.
  • Grade 3: moderate, not accompanied by thrill, that is, of palpable vibrations in the chest wall from the passage of blood.
  • Grade 4: intense murmurs that are accompanied by thrill.
  • Grade 5: these are very intense murmurs. They can be heard only with the contact of the edge of the stethoscope on the thorax.
  • Grade 6: they are so intense murmurs that they can be heard without even supporting the phonendoscope on the thoracic wall.

Another classification of heart murmurs

In murmurs, it also influences whether they occur during systole or diastole.

Apart from the classification according to the degree of intensity, they can also be grouped based on the other characteristics of heart murmurs. If we take into account the duration of it, we will classify it as diastolic or systolic.

Based on the form, they can be constant, increasing, decreasing or a mixture of these last two. Regarding its location, it refers to the place where the murmur has its greatest intensity. So, there are 6 auscultation points on the front of the thorax to identify a murmur:

  • In the second right intercostal space.
  • From the second to the fifth left intercostal space.
  • In the fifth intercostal space in mid-clavicular left line.

As well the murmurs can be classified based on their irradiation. This characteristic refers to where the breath radiates. It is usually directed in the direction of blood flow. By last, according to its tone, it can be low or high. And in terms of quality, it is a special feature that every breath can have, that is to say that it is musical, blowing or moving, among others.


The treatment will depend on the underlying cause of the murmur.

Usually the heart murmurs are harmless, therefore, they do not usually need treatment. Sometimes follow-up tests are required to make sure they are not a cause of a serious, undiagnosed heart condition.

In the case of necessity, the treatment will be oriented to treat the cause of the murmur. For example, if the functional murmurs are caused by a disease such as fever or hyperthyroidism, these will disappear once the condition is treated.

Sometimes the causes of heart murmurs can not be treated only with medications and you have to resort to surgery. According to the condition, the doctor may recommend one of these options to treat a damaged valve or perforated:

  • Valvuloplasty with balloon.
  • Annuloplasty
  • Repair of structural support.
  • Open heart surgery.
  • Repair of the valves of a valve.

In any case, and on suspicion of having heart murmurs, It is best to go to the doctor immediately. He will assess the problem and determine how to treat it.