How are heart murmurs investigated in the UK? 

In the UK, heart murmurs are investigated through a multi-layered clinical pathway that begins with a physical examination (auscultation) using a stethoscope. For newborns, this occurs during the routine New-born Physical Examination (NIPE), while adults are often screened during GP check-ups. The primary diagnostic tools used by the NHS include pulse oximetry to check oxygen levels, an electrocardiogram (ECG) to monitor heart rhythm, and an echocardiogram, which is the ‘gold standard’ for identifying structural defects or valve issues. 

The investigation process is designed to differentiate between ‘innocent’ murmurs, which are common and harmless, and ‘pathological’ murmurs that indicate underlying heart conditions. Clinical guidelines from NICE and the British Heart Valve Society (BHVS) ensure that patients with symptomatic or complex murmurs are referred urgently to cardiology specialists for advanced imaging and management. 

What We will cover in this Article 

• The systematic screening process for heart murmurs in newborns. 

• How GPs and specialists investigate murmurs in adults. 

• The role of pulse oximetry and ECG in initial assessments. 

• Why the echocardiogram is the essential tool for definitive diagnosis. 

• Red flag symptoms that trigger urgent referral. 

• Specialist imaging tools including Cardiac MRI and CT. 

Investigation in Newborns and Children 

In the UK, the investigation of neonatal heart murmurs typically begins within 72 hours of birth as part of the Newborn Physical Examination (NIPE). Midwives and doctors listen for added sounds that may indicate the transition from fetal to newborn circulation. If a murmur is heard, the investigation prioritizes clinical stability and oxygenation. 

The investigation pathway for infants often includes: 

• Physical Assessment: Checking for femoral pulses (in the groin) to rule out narrowing of the aorta and looking for signs of cyanosis (blue-tinged skin). 

• Pulse Oximetry: Measuring oxygen saturation in the hand and foot. A difference of more than 3% or a saturation below 95% triggers an urgent cardiac review. 

• Review at 6 to 8 Weeks: Many murmurs are transient. If a baby is well, the GP will re-examine the heart at the 6 to 8 week check to see if the sound has disappeared. 

• Specialist Referral: If the murmur persists or is accompanied by ‘red flags’ such as poor feeding or breathlessness, the child is referred to a Paediatrician with Expertise in Cardiology (PEC) for an echocardiogram. 

How Heart Murmurs are Investigated in Adults 

For adults, heart murmurs are usually investigated when a clinician hears a sound during a routine examination or when a patient presents with symptoms like shortness of breath or chest pain. The NICE guidelines on ‘heart valve disease: referral’ (NG208) provide the framework for when a GP should order further tests or refer to a specialist. 

According to clinical standards, an adult with a murmur will typically undergo: 

• Characterisation: The clinician grades the murmur on a scale of 1 to 6 and determines its timing (systolic or diastolic) and its location on the chest. 

• Electrocardiogram (ECG): This test checks for electrical abnormalities, such as an enlarged heart or rhythm issues, which can be caused by long-term valve disease. 

• Referral Criteria: NICE recommends an urgent echocardiogram or specialist assessment within two to four weeks if the murmur is associated with heart failure symptoms (e.g., peripheral oedema) or if it is a loud systolic murmur with a reduced second heart sound. 

Diagnostic Tools and the ‘Gold Standard’ Echo 

The echocardiogram remains the most vital investigation for any heart murmur. It is a painless ultrasound scan that allows the cardiologist to see the heart’s valves in motion and measure the velocity of blood flow. This provides a definitive answer as to whether a murmur is innocent or caused by a structural problem like a leaky valve (regurgitation) or a narrow valve (stenosis). 

Investigation Tool	What it Measures	Importance in CHD/Murmurs
Pulse Oximetry	Blood oxygen levels	Essential for detecting ‘blue’ baby defects early.
ECG	Electrical heart rhythm	Identifies heart strain or enlarged chambers.
Echocardiogram (TTE)	Structural anatomy & flow	The ‘gold standard’ for diagnosing the cause of the murmur.
Chest X-ray	Heart size and lung fluid	Shows the secondary effects of heart defects on the lungs.
Cardiac MRI/CT	High-resolution 3D views	Used for complex surgical planning when ultrasound is limited.

Clinical research reinforces that early access to these tools is essential. According to the European Heart Journal, Guo, H., et al. (2025). ‘First trimester maternal infections and offspring congenital heart defects: a meta-analysis.’, environmental disruptions to heart development require precise imaging to manage the long-term health of the child. 

To Summarise 

Investigation of a heart murmur in the UK is a structured process that moves from a simple stethoscope check to advanced imaging like an echocardiogram. While many murmurs, especially in children, are innocent and require no treatment, clinical pathways ensure that symptomatic patients are identified and referred to specialists quickly. By combining physical exams with oxygen checks and heart scans, the NHS provides a robust safety net for detecting both congenital and acquired heart conditions. 

If you or your child experience a blue tinge to the lips, sudden difficulty breathing, or fainting during exercise, call 999 immediately. 

If you notice a sudden worsening of chest pain or an extremely rapid, irregular pulse, call 999 immediately. 

Authority Snapshot (E-E-A-T Block) 

This article was reviewed by Dr. Stefan Petrov, a UK-trained physician (MBBS) with postgraduate certifications in ACLS and BLS. Dr. Petrov has extensive experience in general medicine and emergency care, having performed clinical examinations and coordinated cardiac investigations in both hospital and primary care settings. His background in medical education ensures that this information on heart murmur investigation aligns with current NHS, NICE, and British Heart Valve Society (BHVS) standards.