Are Heart Murmurs Genetic? Understanding Inheritance, Causes, and Risks

Uncover the genetic and non-genetic factors contributing to heart murmurs, their causes, warning signs, and management options.

By Medha deb

Created on Sep 26, 2025

Uncover the genetic and non-genetic factors contributing to heart murmurs, their causes, warning signs, and management options.

Heart murmurs are commonly heard as extra or unusual sounds during a heartbeat. These murmurs can be harmless, or they might indicate underlying heart conditions, some of which are influenced by genetic factors. This article provides an in-depth look at heart murmurs, their causes, the extent to which genetics may contribute, and what you should watch for if you or your family has a history of heart problems.

What Is a Heart Murmur?

A heart murmur is a distinct ‘whooshing’ or swishing sound heard between heartbeats, usually detected with a stethoscope. These sounds are caused by turbulent blood flow through the heart’s valves and chambers. Heart murmurs are categorized into two primary types:

Innocent (or functional) murmurs: Harmless sounds caused by increased blood flow or typical physiological factors.
Abnormal murmurs: Sounds linked to structural or functional heart problems, such as congenital defects or acquired valve disease.

Heart murmurs are most frequently identified in children. In many cases, the murmur is benign and resolves naturally without treatment. Research indicates up to 8.6% of infants and as many as 80% of all children experience a murmur at some point, but less than 1% of pediatric murmurs seen by a cardiologist are due to congenital heart disease.

How a Murmur Sounds

During a routine exam, a healthcare provider may hear the abnormal sound and distinguish it from a normal heart’s “lub-dub.” Innocent murmurs produce a soft, short, vibratory sound. Abnormal murmurs may be louder, longer, or associated with other concerning heart sounds.

How Are Genetics Involved in Heart Murmurs?

The role of genetics in heart murmurs is usually indirect, influencing the underlying condition rather than the murmur itself. Heart murmurs are considered signs—detected on physical examination—rather than diseases. Abnormal heart murmurs may indicate a genetic heart condition or inherited structural abnormalities in the heart.

Genetic inheritance comes into play when murmurs are caused by:

Congenital heart diseases, such as septal defects (holes in the chamber walls) or inherited valve abnormalities.
Familial heart valve disease, where issues such as mitral valve prolapse are observed across generations.
Heredity of risk factors, such as a parent having a heart defect or certain inherited syndromes affecting heart structure.

A 2021 study of pediatric patients found that the absence of congenital heart disease risk factors—including no family history—was key in distinguishing innocent from pathologic murmurs. Family history remains an important risk element for abnormal heart murmurs.

What Causes Heart Murmurs?

Heart murmurs have varied causes, which may be entirely benign or signal more serious conditions. Understanding the underlying reason is crucial for management.

Common Causes of Innocent Murmurs

Innocent murmurs generally have a temporary or self-resolving cause and are not a sign of heart disease. Typical causes include:

Young age: Innocent murmurs are common in infants and children due to their developing cardiovascular systems.
Fever: Raised body temperature increases blood flow, which can generate extra heart sounds.
Physical activity: Exercise or exertion can transiently raise blood flow velocity.
Pregnancy: Higher blood volume in pregnancy may lead to harmless murmurs.
Anemia: Reduced red blood cells prompt the heart to pump faster, occasionally causing murmurs.
Thyroid disease: Hyperthyroidism increases metabolism and cardiac output.
Growth spurts: Children experiencing rapid growth may temporarily develop innocent murmurs.

Causes of Abnormal (Pathologic) Murmurs

Abnormal murmurs usually point toward structural or acquired heart disease. Common causes include:

Congenital heart defects:
- Ventricular septal defect (VSD): Hole between the ventricles.
- Atrial septal defect (ASD): Hole between the atria.
- Bicuspid aortic valve: Aortic valve with two instead of three cusps, which can be inherited.
- Patent ductus arteriosus (PDA): Failure of the arterial duct to close post-birth.
- Tetralogy of Fallot: Four combined defects disrupting normal heart function.
- Coarctation of the aorta: Narrowed segment of the aorta.
Degenerative valve disease: Age-related changes that cause thickening or calcification of heart valves (e.g., mitral or aortic stenosis).
Infective endocarditis: Infection of the heart valves or lining.
Rheumatic heart disease: Previous untreated strep infections leading to valve damage.
Carcinoid syndrome: Rare tumors that release hormones affecting heart valves.
Cardiomyopathy: Disease of the heart muscle, which might be genetic.
Other: Tumors, cardiac amyloidosis, and high blood pressure in the lungs (pulmonary hypertension).

Genetic Conditions and Their Impact on Heart Murmurs

Genetic conditions related to heart murmurs often involve inherited abnormalities in heart structure or function. Notable examples include:

Mitral valve prolapse: Up to 35–50% of cases have a genetic component. Families may share similar mitral valve structure abnormalities, predisposing them to murmurs and valve problems.
Ventricular septal defect: The American Heart Association cites genetic factors playing a role, particularly when other family members are affected.
Bicuspid aortic valve: This congenital condition tends to run in families and can be inherited from parents to children.
Hypertrophic cardiomyopathy (HCM): Frequently inherited, HCM thickens the heart muscle and often presents with a murmur.
Cardiac amyloidosis and tumors: Some rare hereditary syndromes increase risk for these conditions, which may lead to murmurs.

Genetic Condition	Potential Murmur Presentation	Inheritance Pattern
Mitral Valve Prolapse	Click-murmur syndrome, systolic murmur	Autosomal dominant (variable expression)
Hypertrophic Cardiomyopathy	Systolic murmur, dynamic with movement	Autosomal dominant
Bicuspid Aortic Valve	Ejection click and murmur	Familial, often autosomal dominant
Ventricular Septal Defect	Harsh holosystolic murmur	Multifactorial; sometimes familial

What to Look for if Genetically at Risk

Knowing your family’s heart history can help you recognize possible warning signs early. Inherited forms of heart valve and muscle diseases may predispose individuals to murmurs and other complications.

If you have a first-degree relative (parent or sibling) with a significant heart murmur, valve disease, or congenital heart defect, you should:

Share your family history with your healthcare provider.
Be vigilant for symptoms such as:

Shortness of breath, especially with exertion
Unexplained fatigue or weakness
Chest pain or palpitations
Fainting spells or dizziness
Swelling in the legs or abdomen
Sudden inability to exercise as before

Get periodic cardiac evaluations, especially during childhood or adolescence, and whenever new symptoms appear.

Risk Factors for Developing Heart Murmurs

Certain risk factors further increase the likelihood of having a heart murmur:

Family history of congenital heart disease or valve disorders
Uncontrolled maternal diabetes during pregnancy
Maternal infections such as rubella during pregnancy
Genetic syndromes (e.g., Marfan, Down syndrome)
Poorly managed infections (such as rheumatic fever from strep throat)

How Are Heart Murmurs Diagnosed?

If a murmur is detected during a physical exam, your healthcare provider may recommend further evaluation to determine if it’s innocent or pathological. Key steps in diagnosis may include:

Careful review of your family and medical history
Listening to the murmur’s timing, location, and character
Electrocardiogram (ECG) to check for electrical abnormalities
Echocardiogram—a detailed ultrasound of the heart structure and function
Other imaging (chest X-ray or MRI in select cases)

Pediatric murmurs often resolve with age, but persistent or abnormal murmurs in children or adults deserve careful investigation.

When Is Treatment Needed?

Treatment for a heart murmur depends on the underlying cause. Innocent murmurs require no intervention and typically resolve naturally. Treatment for abnormal murmurs can include:

Medications to manage symptoms such as high blood pressure or heart failure
Repair or replacement of faulty heart valves (surgical or catheter-based procedures)
Treatment of underlying infections (e.g., antibiotics for endocarditis)
Management of any associated medical conditions (anemia, thyroid disease)
Regular heart monitoring and specialist check-ups

For genetically determined conditions such as hypertrophic cardiomyopathy or severe congenital valve defects, regular follow-up and, sometimes, lifestyle adjustment may be recommended. Family screening may be suggested.

Living With a Heart Murmur: Prognosis and Outlook

The vast majority of innocent heart murmurs never cause health problems, and people enjoy normal, active lives without limitations. For abnormal (pathological) murmurs, prognosis is closely tied to the nature and severity of the underlying heart disease:

Congenital defects: Many can be corrected or managed, particularly when detected early.
Valve disease: With timely intervention, the outlook is often good.
Inherited cardiomyopathies: Regular surveillance and early treatment are crucial for optimal outcomes.

Genetic counseling may benefit families with a history of inherited heart disease, especially before pregnancy.

Frequently Asked Questions (FAQs)

Are heart murmurs themselves inherited?

No, the murmur itself is not inherited. Instead, the conditions causing abnormal murmurs (such as valve or septal defects) may have a genetic basis.

If my child has an innocent murmur, do I need to worry?

Most innocent murmurs in children are harmless, require no treatment, and usually resolve as the child grows. Consult your pediatrician for reassurance and further evaluation if you have concerns.

Can adults develop heart murmurs later in life?

Yes. Adults may develop murmurs due to age-related valve changes, high blood pressure, infections, or degenerative diseases. Not all adult murmurs are dangerous, but new symptoms should be evaluated.

How do I know if a murmur is serious?

The presence of symptoms (such as shortness of breath, chest pain, or fainting), family history of serious heart disease, or abnormal findings on heart imaging may signal a more serious problem. Always seek professional assessment.

What steps can I take if my family has a history of genetic heart conditions?

Discuss genetic screening options, maintain regular heart checkups, and share your family history with your healthcare provider. Early recognition and treatment improve long-term outcomes.

Key Takeaways

Heart murmurs are not diseases but signs of how blood flows through your heart. They may be innocent or linked to underlying heart problems.
Genetics, especially for certain congenital heart defects and valve disorders, can increase the risk of abnormal murmurs in families.
If you or a close family member have a history of heart murmurs or cardiac defects, inform your healthcare provider for tailored assessment and monitoring.
Most innocent murmurs require no treatment. Abnormal murmurs necessitate further investigation to determine the root cause and appropriate therapy.
Early detection and intervention, particularly in genetically influenced diseases, optimize prognosis and quality of life.

References

Author

medha deb

Medha Deb is an editor with a master's degree in Applied Linguistics from the University of Hyderabad. She believes that her qualification has helped her develop a deep understanding of language and its application in various contexts.

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