Heart murmurs explained: Should you worry if your doctor hears one?

By Sina Hartung, MMSC-BMI, Harvard Medical SchoolReviewed by Eureka Health Medical Group
Published: July 9, 2025Updated: July 9, 2025

Key Takeaways

A heart murmur is a whooshing or swishing sound that a clinician hears with a stethoscope when blood flows turbulently through or near your heart. Many murmurs are harmless “innocent” sounds, especially in children and pregnant people, but others signal valve disease, congenital defects, or heart failure that need prompt evaluation with an echocardiogram. The key is defining the cause, severity, and whether the murmur reflects damage that requires treatment.

What exactly is a heart murmur and why does it occur?

A heart murmur is not a disease—it is an acoustic clue. Turbulent blood flow through normal or abnormal structures creates extra sounds between the normal lub-dub beats. Identifying the timing (systolic, diastolic, continuous) and pitch helps doctors decide if the murmur is harmless or worrisome.

  • Turbulence creates the soundWhen blood accelerates through a narrowed (stenotic) valve or leans back through a leaky (regurgitant) valve, it sets up vibrations doctors hear as a murmur.
  • Innocent murmurs dominate in childhoodUp to 50 % of healthy school-age children have vibratory murmurs that disappear by adolescence without any heart disease.
  • Pregnancy often causes new benign murmursIn the third trimester blood volume rises by roughly 40 %, speeding flow through the heart and creating a temporary systolic murmur that fades after delivery.
  • Pathologic murmurs reflect structural problemsA harsh diastolic murmur almost always indicates valve disease such as aortic regurgitation and warrants echocardiography.
  • Innocent murmurs are still heard in one in ten adultsPopulation studies show roughly 10 % of otherwise healthy adults have a benign “flow” murmur despite normal cardiac anatomy. (HarvardHealth)
  • Fever, anemia or heavy exercise can trigger transient flow murmursAnything that accelerates blood through the heart—including high temperature, low hemoglobin, or strenuous physical activity—may temporarily produce an innocent whooshing sound. (MayoClinic)

Which heart murmurs are red-flag signs that need urgent care?

Certain murmur features strongly predict underlying heart disease and should trigger prompt imaging or referral to a cardiologist. Waiting can allow valve damage to progress or heart failure to set in.

  • Diastolic or continuous murmurAny murmur heard between beats (diastolic) or throughout the cycle often signals serious valve pathology and merits echocardiography within days.
  • Grade 3 or louder intensityMurmurs graded 3/6 or higher on physical exam double the likelihood of significant structural heart disease.
  • Murmur with symptomsIf the noise comes with chest pain, shortness of breath, fainting, or blue lips, call 911—these can indicate critical aortic stenosis or congenital defects.
  • Change in an old murmurA previously stable murmur that has become louder or changed in timing may mean valve infection (endocarditis) or worsening regurgitation.
  • Holosystolic murmur nearly always indicates structural diseaseAny pansystolic sound that fills all of systole is considered abnormal and should trigger cardiology referral because it often reflects ventricular septal defect or severe mitral/tricuspid regurgitation. (AAFP)
  • Murmur that grows louder when the patient stands up is a warning signA murmur that increases in intensity with standing or Valsalva manoeuvre raises suspicion for hypertrophic cardiomyopathy or other pathologic lesions and warrants urgent echocardiography. (AAFP)

What can you do day-to-day if your murmur is classified as benign?

Innocent or mild murmurs usually require no procedures, but healthy habits and periodic reevaluation keep your heart protected over time.

  • Schedule a re-check every 1–2 yearsEven harmless murmurs deserve a follow-up auscultation to confirm they have not evolved.
  • Keep blood pressure below 120/80 mm HgHigh pressure accelerates valve wear; home cuffs and smartphone reminders help reduce risk.
  • Maintain oral hygieneGum infection can seed the bloodstream and infect abnormal valves; twice-daily brushing and dentist visits every six months cut endocarditis incidence by 50 %.
  • Exercise but know your limitsAdults with innocent murmurs can follow standard aerobic guidelines (150 minutes weekly) unless a doctor says otherwise.
  • Monitor new symptomsRecord episodes of breathlessness or palpitations in a diary; trend data helps clinicians decide on earlier imaging.
  • Adopt a heart-healthy diet and stay smoke-freeKaiser Permanente recommends benign-murmur patients avoid tobacco, emphasize fruits, vegetables, whole grains, fish or lean meats, and low-fat dairy to keep the entire cardiovascular system resilient. (KP)
  • Address reversible factors that can amplify the soundMayo Clinic notes that fever, anemia or hyperthyroidism can temporarily create or intensify an innocent murmur; treating these underlying issues often makes the extra sound disappear. (Mayo)

Which tests and treatments might your doctor discuss for a pathologic murmur?

When a murmur raises concern, targeted diagnostics pinpoint cause and severity so treatments—from medication to surgery—can be timed correctly.

  • Transthoracic echocardiogram is first-lineNon-invasive ultrasound maps valve motion and pressure gradients; it detects 90 % of clinically significant lesions.
  • Electrocardiogram screens for rhythm impactLeaky or tight valves may stretch chambers and cause atrial fibrillation, visible as irregular baseline waves.
  • Blood tests look for infection or strainElevated C-reactive protein may point to endocarditis, while a BNP higher than 100 pg/mL suggests heart failure.
  • Medications treat consequences, not the soundBeta-blockers slow heart rate in mitral valve prolapse; diuretics ease lung congestion from severe regurgitation.
  • Valve repair or replacement restores flowTranscatheter aortic valve replacement (TAVR) now treats high-risk patients with severe aortic stenosis and carries a 30-day mortality under 3 %.
  • Cardiac catheterization confirms valve severity when imaging is unclearIf transthoracic echo leaves unanswered questions, threading a catheter into the heart directly measures pressure gradients and can allow balloon valvotomy or stent placement in the same session. (MayoClinic)
  • Chest X-ray flags cardiac enlargement or pulmonary congestion that warrant expedited echoPlain radiography can reveal an enlarged heart silhouette or fluid in the lungs, helping clinicians triage murmurs that may reflect advanced valve disease. (Hopkins)

Frequently Asked Questions

This content is for informational purposes only and is not intended as medical advice. Always consult with a qualified healthcare provider for diagnosis, treatment, and personalized medical recommendations.

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