Heart murmurs are typical whooshing or swishing sounds made by the blood in or near the heart during a heartbeat cycle. Generally, a heartbeat makes a ‘lubb-dupp’ sound upon the closing of the heart valves, which can be heard via a stethoscope. However, in a heart murmur, the sound of the heartbeat is abnormal.
Murmurs can be benign or could indicate a potentially serious heart condition. These could be present at birth (congenital) or can occur later in one’s life. However, heart murmurs are not a disease but can be an indication of an underlying issue. That said, most of the heart murmurs are harmless and do not require any form of treatment. However, in some cases, the condition would need to be monitored to check the underlying heart condition.
Causes of heart murmurs
Heart murmurs are vibrations or sounds of turbulence, caused by the blood when it flows through the heart. This happens when the valves, which typically make a valve sound, start to make a heart murmur because they do not open or close properly, thereby causing the blood to leak backwards or restrict going forward.
This can occur due to various causes, which also can be described as the type of murmur, such as:
Innocent heart murmur: This type is very common in newborns and children; the person with an innocent heart murmur usually has a normal heart. However, in this condition, the blood flows more rapidly than the normal speed through the heart, causing a murmur. Some factors which can trigger innocent heart murmurs include:
- Physical activity or strenuous exercise
- Lack of healthy blood cells
- Excessive levels of thyroid hormones in the body
- Rapid growth phases, such as adolescence
Innocent heart murmurs can be temporary and go away on their own or could be life long, while not causing any further complications.
Abnormal heart murmurs: Abnormal heart murmurs in children are caused because of structural problems of the heart at the time of birth. These are also known as congenital heart defects. Some common congenital defects include:
- Holes in the heart or cardiac shunts: Also called septal defects, the holes in the heart can cause abnormal heart murmurs and could potentially be serious. For cardiac shunts, the heart experiences an abnormal flow of blood between the heart chambers or the blood vessels, causing a murmur.
- Heart valve abnormalities: Heart valve abnormalities can cause the valves to restrict the blood flow (known as stenosis) and in other cases, some valves do not close properly or cause a leakage, resulting in a murmur (called regurgitation).
That said, causes of abnormal heart murmurs in adults include infections and several other factors which damage the structure of the heart. Such as:
- Valve calcification: This condition causes hardening and thickening of valves can happen as one age. This can cause the valves to become narrow, making it harder for blood to flow through the heart, thereby causing abnormal heart murmurs.
- Endocarditis: This state is the one in which the inner lining of the heart and valves are infected because of bacteria and other germs from other parts of the body such as the mouth. These bacteria travel through the bloodstream and accumulate in the heart. The condition, if left untreated, can destroy the valves.
- Rheumatic fever: This type of fever develops when a person with a strep throat infection is not treated properly. Rheumatic fever can permanently affect the heart valves and restrict the normal flow of blood through the heart, thereby causing abnormal heart murmurs.
Risk factors of heart murmurs
Some people are at more risk of developing heart murmurs than others. These risk factors include:
- Family history of a heart defect
- Certain medical conditions such as high blood pressure, rheumatoid arthritis, weak heart muscles, history of rheumatic fever, etc.
- Illnesses during pregnancy
- Taking illegal drugs or specific medications during pregnancy
Symptoms of heart murmurs
For people who have innocent heart murmurs, there may be no prominent symptoms or signs. These are harmless murmurs which do not need any specific treatment. Also, in case of an abnormal heart murmur, the major symptom would be the unusual sound of the heart, detected by the doctor with a stethoscope.
However, the below signs are also an indication of heart murmurs.
- Blue-appearing skin, especially on the fingertips and lips
- Swelling in the legs or abdomen
- Sudden and unexplained weight gain
- Enlarged liver
- Chronic and consistent cough
- Acute shortness of breath
- Heavy sweating without exertion or with minimal exertion
- Enlarged neck veins
- Poor appetite
- Chest pain
That said, in a newborn baby, the symptoms of a heart murmur will include:
- Difficulty in feeding
- Stunted growth
- Bluish skin during feeding or even while the minimal activity
- Breathing problem
- Cranky and fussiness
Diagnosis of heart murmurs
Foremost, the doctor will study the symptoms and then check for abnormal sounds via a stethoscope. To confirm the analysis, further tests of the heart’s function including blood pressure checks, oxygen level determinant, pulse rate, etc. – will be conducted. Moreover, an echocardiogram will be done to obtain pictures of the heart valves.
Based on the test results and findings, the doctor will assign a grade to the heart murmur. The scale of grading is 1-6, where 1 is extremely mild and 6 is very loud murmur. Also, for murmurs which occur during the relaxation state, the grading scale is 1-4, where 4 is the maximum pitch.
In some cases, the doctor might also conduct a stress echocardiogram, chest X-ray and cardiac catheterization.
Overall, not all heart murmurs are serious and need treatment. However, they need to be consistently monitored and in cases of severity, appropriate treatment should be sought as per the underlying disease and the intensity of the problem.