A heart murmur is an extra or unusual sound heard during a heartbeat. While it can be concerning, a murmur is a sound, not a disease. Many are harmless and do not indicate a serious health problem.
Understanding Heart Murmurs
A heart murmur is a whooshing or swishing sound detected with a stethoscope. This sound occurs due to turbulent blood flow within the heart or its major blood vessels. The heart’s valves typically open and close smoothly, directing blood in a clear path.
When blood encounters an obstruction, flows rapidly, or moves backward through a valve that does not close completely, it creates vibrations heard as a murmur. The sound of a murmur can vary in pitch, timing, and intensity, providing clues about its origin and potential significance. Doctors can classify murmurs based on when they occur in the heartbeat cycle, such as during contraction (systolic), relaxation (diastolic), or continuously.
Types of Heart Murmurs
Heart murmurs are broadly categorized into two main types: innocent (or functional) and abnormal (or pathological). Innocent heart murmurs are common, especially in children. These murmurs are harmless sounds resulting from normal blood flow through a healthy heart and do not indicate an underlying heart condition.
Innocent murmurs often go away on their own as a child grows and their heart and blood vessels mature. They may also appear temporarily in adults due to conditions that increase blood flow, such as fever, exercise, or pregnancy. Innocent heart murmurs do not require treatment or lifestyle changes.
Abnormal heart murmurs, in contrast, signal an underlying heart condition. These conditions often involve structural problems within the heart, such as issues with the heart valves or congenital heart defects. Unlike innocent murmurs, abnormal murmurs do not go away on their own and usually require medical attention for the underlying cause. Treatment for abnormal murmurs focuses on managing or correcting the specific heart problem.
Causes and Accompanying Symptoms
Abnormal heart murmurs can arise from various factors, often involving structural issues or conditions impacting blood flow. Heart valve diseases are a common cause in adults, where valves may become stiff and narrow (stenosis), preventing sufficient blood flow, or fail to close completely (regurgitation), allowing blood to leak backward. Congenital heart defects, such as holes in the heart walls between chambers (septal defects) or abnormal blood vessel connections, are frequent causes of abnormal murmurs in children.
Other conditions can also lead to abnormal murmurs. These include infections like endocarditis, which can damage heart valves, or chronic inflammation from rheumatic fever. Systemic conditions that increase blood volume or speed, such as severe anemia, an overactive thyroid (hyperthyroidism), or high blood pressure, can also contribute to heart murmurs.
While innocent murmurs present with no symptoms beyond the sound itself, abnormal murmurs can be accompanied by various signs, including:
- Shortness of breath, particularly with exertion
- Chest pain
- Chronic fatigue
- Dizziness
- Fainting
- A persistent cough
- Swelling in the ankles or feet
- A bluish tint to the skin or lips
- Poor feeding and growth in infants
Diagnosis and What Comes Next
A heart murmur is typically detected during a routine physical examination when a healthcare provider listens to the heart with a stethoscope. The doctor evaluates characteristics such as the murmur’s loudness, pitch, timing within the heartbeat, and where it is best heard, which helps in differentiating between innocent and potentially concerning murmurs. Sometimes, the sound may radiate to other areas like the neck or back.
If an abnormal murmur is suspected, further diagnostic tests are recommended to determine its cause and severity. An echocardiogram, which uses sound waves to create images of the heart, is a primary tool to visualize heart valves, chambers, and blood flow patterns. An electrocardiogram (ECG) measures the heart’s electrical activity, while a chest X-ray can reveal if the heart is enlarged. In some instances, more specialized tests like cardiac catheterization may be performed to gain detailed information about heart function and blood vessels.
For innocent heart murmurs, no specific treatment is necessary, only monitoring. If the murmur is related to a temporary condition like fever or anemia, it often resolves once that condition is addressed. When an abnormal heart murmur is diagnosed, treatment focuses on the underlying cause. This can involve medications to manage symptoms or treat conditions like high blood pressure or infections. In more severe cases, particularly those involving significant valve damage or congenital defects, surgical intervention may be required to repair or replace a heart valve or correct structural issues.