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Quasi‑septal heart murmur - Causes, Treatment & When to See a Doctor

📅 Updated: June 2026 ⏱️ 6 min read ✅ Medically reviewed

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Quasi‑Septal Heart Murmur – Causes, Symptoms, Diagnosis & Treatment

Quasi‑Septal Heart Murmur

What is Quasi‑septal heart murmur?

A quasi‑septal heart murmur is a type of innocent (non‑pathologic) or functional murmur that is heard over the left sternal border, close to the region where the interventricular septum lies. The term “quasi‑septal” describes the acoustic location rather than a specific disease; it signifies that the sound originates near the septum but does not necessarily indicate structural damage.

Most often, these murmurs are soft, systolic, and low‑pitch. They are frequently detected incidentally during routine physical examinations or school‑based screenings. While many are benign, they can sometimes be the first clue to underlying cardiac abnormalities that require further evaluation.

Sources: Mayo Clinic, American Heart Association, National Institutes of Health (NIH).

Common Causes

Quasi‑septal murmurs can arise from a variety of physiologic or pathologic conditions. Below are the most frequently encountered causes (listed alphabetically):

  • Physiologic flow murmurs – increased blood flow across a normal valve during childhood, pregnancy, fever, or exercise.
  • Ventricular septal defect (VSD) – a small hole in the septum that creates a left‑to‑right shunt, producing a harsh systolic murmur.
  • Atrial septal defect (ASD) – especially the secundum type; blood shunts from left to right, causing a systolic ejection murmur heard near the septum.
  • Hypertrophic cardiomyopathy (HCM) – asymmetric septal hypertrophy leads to dynamic obstruction and a crescendo‑decrescendo systolic murmur.
  • Pulmonary stenosis – narrowing of the pulmonary valve creates a harsh systolic murmur that may radiate to the left sternal border.
  • Aortic stenosis (early‑onset) – in rare pediatric cases or young adults with bicuspid aortic valves, a murmur can be heard near the septum.
  • Increased cardiac output states – anemia, hyperthyroidism, or physiologic tachycardia can amplify normal flow sounds.
  • Congenital malformations of the great vessels – e.g., coarctation of the aorta, which may alter flow patterns.
  • Endocarditis (early stage) – vegetations can create turbulent flow that mimics a septal murmur.
  • Acute rheumatic fever – inflammation of the mitral valve can generate murmurs near the left sternal border.

Associated Symptoms

Because many quasi‑septal murmurs are innocent, they often occur without any other symptoms. When the murmur is a marker of an underlying cardiac problem, patients may report the following:

  • Shortness of breath, especially on exertion
  • Chest discomfort or tightness
  • Palpitations or irregular heartbeats
  • Fatigue or decreased exercise tolerance
  • Syncope (fainting) or near‑syncope
  • Swelling of the ankles or abdomen (signs of heart failure)
  • Frequent respiratory infections in children (possible VSD/ASD)
  • Growth delay in infants with significant left‑to‑right shunts

When to See a Doctor

Even if the murmur feels “harmless,” certain clues suggest that prompt evaluation is needed:

  • The murmur is loud, harsh, or changes with position.
  • It is accompanied by any of the symptoms listed above.
  • There is a family history of congenital heart disease, cardiomyopathy, or sudden cardiac death.
  • The child has poor weight gain, frequent respiratory infections, or failure to thrive.
  • During pregnancy, a new murmur appears and is associated with dyspnea or edema.

If any of these apply, schedule an appointment with a primary‑care physician or pediatrician. Early detection of structural heart disease improves long‑term outcomes.

Diagnosis

Evaluation of a quasi‑septal murmur follows a stepwise approach, beginning with a detailed history and physical exam and progressing to imaging and functional studies when needed.

1. Clinical History & Physical Examination

  • Ask about onset, duration, exercise tolerance, and associated symptoms.
  • Review family and perinatal history.
  • Listen with a stethoscope at multiple sites (aortic, pulmonic, tricuspid, and mitral areas) and in different positions (lying, sitting, standing, Valsalva).

2. Electrocardiogram (ECG)

Detects conduction abnormalities, chamber enlargement, or signs of hypertrophy that may point to HCM, VSD, or other structural issues.

3. Chest X‑ray

Looks for cardiac enlargement, pulmonary vascular congestion, or bony abnormalities that could affect heart sounds.

4. Echocardiography (Transthoracic Echo – TTE)

The gold‑standard imaging test. It provides real‑time visualization of valve function, septal integrity, chamber size, and flow gradients. Color‑Doppler can determine the direction and size of any shunt.

5. Cardiac Magnetic Resonance Imaging (CMR)

Reserved for complex cases (e.g., HCM with ambiguous echo findings) to evaluate myocardial thickness, fibrosis, or atypical anatomy.

6. Additional Tests (if indicated)

  • Exercise stress test – assesses murmur intensity change with exertion.
  • Cardiac catheterization – invasive measurement of pressures and shunt quantification when non‑invasive data are inconclusive.
  • Blood tests – complete blood count (to rule out anemia), thyroid panel (hyperthyroidism), or inflammatory markers (for endocarditis).

Treatment Options

Treatment depends on the underlying cause. Below is a summary of common scenarios.

Innocent (Physiologic) Murmurs

  • Reassurance and routine follow‑up; no medication required.
  • Educate patient/family about signs that warrant re‑evaluation.

Small Ventricular or Atrial Septal Defects

  • Observation – many small defects close spontaneously in childhood.
  • Prophylactic antibiotics before certain dental procedures (per American Heart Association guidelines) if the defect is moderate‑to‑large.

Significant Septal Defects

  • Transcatheter device closure – minimally invasive and preferred for many secundum ASDs and perimembranous VSDs.
  • Surgical repair – indicated for large defects, associated valve disease, or when anatomy is unsuitable for devices.

Hypertrophic Cardiomyopathy

  • Beta‑blockers or non‑dihydropyridine calcium channel blockers to reduce outflow obstruction.
  • Disopyramide (in selected patients) as an additional agent.
  • Septal myectomy or alcohol septal ablation for refractory symptoms.
  • Implantable cardioverter‑defibrillator (ICD) for patients at high risk of sudden cardiac death.

Valvular Stenosis (Pulmonary or Aortic)

  • Balloon valvuloplasty – first‑line for many pediatric pulmonary stenoses.
  • Valve replacement or repair – indicated for severe aortic stenosis or when balloon dilation fails.

Increased Cardiac Output States

  • Treat underlying cause: iron supplementation for anemia, antithyroid medication for hyperthyroidism, or infection control for fever.
  • Limit intense physical exertion until the primary condition is resolved.

Endocarditis or Rheumatic Fever

  • Targeted antibiotic therapy (often intravenous) for endocarditis.
  • Penicillin or other disease‑specific regimens for rheumatic fever, plus anti‑inflammatory agents.

Prevention Tips

While many murmur‑producing conditions cannot be completely prevented, several strategies can lower the risk or mitigate severity:

  • Maintain optimal iron levels – regular screening for anemia, especially in menstruating women and children.
  • Control thyroid function – periodic thyroid tests for family history of hyperthyroidism.
  • Vaccinations – stay up‑to‑date with influenza, pneumococcal, and COVID‑19 vaccines to reduce febrile illnesses that can accentuate flow murmurs.
  • Healthy lifestyle – balanced diet, regular moderate exercise, and avoidance of tobacco reduce cardiovascular strain.
  • Prompt treatment of infections – early antibiotics for streptococcal throat infections prevent rheumatic fever.
  • Pregnancy care – prenatal visits with cardiac assessment if a murmur appears or worsens.
  • Family screening – if a close relative has congenital heart disease, consider early echocardiography for children.
  • Educate children and teens about reporting chest pain, palpitations, or fainting episodes.

Emergency Warning Signs

If you or a loved one experiences any of the following, seek emergency medical care (call 911 or go to the nearest emergency department):

  • Sudden, severe chest pain or pressure that radiates to the arm, jaw, or back.
  • New or worsening shortness of breath at rest.
  • Fainting, loss of consciousness, or near‑syncope, especially during or after exertion.
  • Rapid, irregular heartbeat that feels “fluttering” or “racing.”
  • Swelling of the legs, abdomen, or face accompanied by a feeling of tightness in the chest.
  • High‑fever with chills, night sweats, or a new heart murmur suggestive of endocarditis.
  • Sudden weakness or numbness on one side of the body (possible embolic event from a heart defect).

Timely medical attention can be lifesaving, particularly when a murmur reflects a serious structural heart problem.

**References**

⚠️ Medical Disclaimer

Important: The information provided on this page is for general informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.

If you think you may have a medical emergency, call your doctor, go to the emergency department, or call 911 immediately.

📚 Medical References