Heart health · Resting 12-lead ECG
Private ECG (Electrocardiography)
A quick, non-invasive recording of your heart’s electrical activity to assess heart rate, rhythm and conduction, with private access in Central London and St Albans.
- No GP referral required
- Non-invasive test
- London & St Albans
- Resting electrical heart assessment
About the test
What is an electrocardiogram?
An electrocardiogram, usually called an ECG or EKG, records the electrical activity generated by the heart as it beats. Small adhesive electrodes are placed on the chest and limbs and connected to an ECG machine, which displays the electrical signal as a series of waveforms.
A resting ECG can provide useful information about heart rate, rhythm and electrical conduction. It may show changes associated with arrhythmias, conduction disturbances, chamber enlargement and other cardiac abnormalities.
Understanding the tracing
The main components of an ECG waveform
The live PrivateSono page describes the P wave, QRS complex and T wave as key components of the cardiac electrical cycle.
Atrial electrical activation
The P wave represents atrial depolarisation — the electrical activation that precedes contraction of the atria.
Ventricular activation
The QRS complex represents ventricular depolarisation — the electrical activation associated with ventricular contraction.
Ventricular recovery
The T wave represents ventricular repolarisation, when the ventricles electrically recover after activation.
What the ECG can assess
Electrical heart information from a resting ECG
The tracing is interpreted in context with your symptoms, medical history and any other tests.
Heart rate
Shows whether the heart rate is slow, normal or fast at the time of the recording.
Heart rhythm
Can identify rhythm abnormalities that are present during the test, including atrial fibrillation and other arrhythmias.
Conduction
Can show electrical conduction delays or blocks, including atrioventricular or bundle-branch abnormalities.
Ischaemic-type changes
Some ECG changes may raise concern for myocardial ischaemia or previous myocardial injury, but a normal ECG cannot exclude coronary disease.
Chamber strain patterns
Some waveform patterns may suggest atrial or ventricular enlargement or hypertrophy and can prompt further assessment.
Baseline comparison
A resting ECG can provide a useful baseline for future comparison, particularly when symptoms or cardiac risk factors are being assessed.
When an ECG may be useful
Symptoms and reasons for testing
A resting ECG is often used as an initial heart rhythm test when symptoms or risk factors suggest that electrical cardiac assessment may be helpful.
- Palpitations or awareness of an irregular heartbeat
- Dizziness, light-headedness or episodes of near-fainting
- Unexplained fast or slow pulse
- Chest symptoms requiring non-emergency cardiac assessment
- Shortness of breath where a heart rhythm problem is being considered
- Hypertension or cardiovascular risk assessment
- Pre-treatment or medication monitoring when an ECG is clinically indicated
- Baseline cardiac assessment before further heart testing
New or severe chest pain, especially with breathlessness, sweating, collapse, fainting or pain spreading to the arm, back, neck or jaw, requires urgent medical assessment. Call emergency services or attend emergency care as appropriate.
Important limitations
What a resting ECG cannot rule out
A single resting ECG is a snapshot of electrical activity at one point in time.
Intermittent arrhythmias
An intermittent rhythm problem may not be present during a short resting ECG. Ambulatory ECG or Holter monitoring may be needed.
Structural heart disease
An ECG does not directly show valve disease, chamber dimensions or cardiac pumping function. Echocardiography is used for structural assessment.
Coronary artery disease
A normal resting ECG cannot reliably exclude coronary artery disease. Further assessment may include clinical review, exercise testing, CT coronary angiography or other testing when appropriate.
Preparing for the test
Simple preparation for your resting ECG
No special fasting or complex preparation is normally required.
Wear accessible clothing
The chest, wrists and ankles may need to be accessible for electrode placement. A gown or privacy measures can be used where appropriate.
Avoid oily chest creams
Oily lotions can make electrode adhesion more difficult. If possible, avoid applying heavy creams to the chest immediately before the appointment.
Bring your medication list
Some medicines can influence heart rate, rhythm or conduction. Bring an up-to-date list if relevant.
Bring previous ECGs
If you have an older ECG or cardiology report, bring it for comparison where clinically useful.
Your appointment
What happens during a resting ECG?
- 1
Clinical information
Your reason for testing, symptoms, relevant medical history and medication are confirmed.
- 2
Electrode placement
Small adhesive electrodes are placed on the chest and limbs in standard positions. Skin preparation may be needed to improve signal quality.
- 3
Resting recording
You lie still while the ECG machine records the heart’s electrical activity. The machine does not send electricity into your body.
- 4
Interpretation and next steps
The ECG is reviewed within the clinic’s clinical pathway. If further assessment is indicated, this may include cardiology consultation, echocardiography, ambulatory monitoring or other investigations.
Book online
Book your Private ECG
Use the heart-service booking selector below to choose the appropriate ECG or heart-health option, clinic, date and appointment time.
Secure online booking
Book your scan
Choose a time that suits you — we search every eligible specialist and confirm your appointment instantly.
- 1Appointment
- 2Your details
- 3Payment
- 4Confirmed
Available times
Choosing a specialist re-draws the calendar to show only their available dates.
Your appointment
- Scan type
- Branch
- Date of scan
- Specialist
- Scan Time
- Price
Your details
All fields are required unless marked optional.
Appointment available
Secure payment
Use the secure Stripe tabs below to select Card, Google Pay, Apple Pay or Klarna when available.
Payment methods shown depend on your device and the options enabled in Semble Pay. Card details are handled securely by Stripe and are not stored by this website.
Booking confirmed
Clinic locations
Private ECG in Central London and St Albans
Choose your preferred clinic through the booking selector.
Central London
27 Welbeck Street
London, W1G 8EN — Marylebone / Harley Street medical district.
View location →Good to know
Private ECG FAQs
Common questions about resting electrocardiography and the next steps after an ECG.
Still unsure? Call 020 7101 3377What is an ECG?
An ECG, or electrocardiogram, is a non-invasive test that records the electrical activity of your heart using adhesive electrodes placed on the chest and limbs.
How much is the PrivateSono ECG?
The live PrivateSono ECG page currently lists the standalone ECG at £119. Confirm the final fee in the booking selector before payment.
What can the ECG assess?
A resting ECG can provide information about heart rate, rhythm, electrical conduction and certain waveform abnormalities. It must be interpreted alongside your symptoms and medical history.
Can it detect atrial fibrillation?
Yes, if atrial fibrillation is present during the recording, a resting ECG can usually identify the characteristic rhythm. Intermittent episodes may require longer ambulatory monitoring.
Can a normal ECG rule out heart disease?
No. A normal ECG does not exclude all heart conditions, intermittent rhythm problems or coronary artery disease.
Does an ECG show the heart valves?
No. Valve structure and heart pumping function are assessed with an echocardiogram rather than an ECG.
Do I need a GP referral?
No. Private self-referral is accepted for this service.
Do I need to fast?
No routine fasting is normally needed for a resting ECG.
Does the ECG hurt?
No. The machine records electrical signals and does not deliver electricity to your heart. Removing adhesive electrodes may cause minor temporary skin discomfort.
How should I dress?
Wear comfortable clothing that allows access to the chest, wrists and ankles. Privacy and dignity measures can be used throughout the examination.
What if I have a pacemaker?
Tell the clinician if you have a pacemaker, implanted defibrillator or other cardiac device, and bring any relevant device or cardiology information.
Can the ECG detect a previous heart attack?
Some ECG patterns may suggest previous myocardial injury, but ECG findings are not always definitive and additional clinical assessment or imaging may be required.
What happens if the ECG is abnormal?
Depending on the abnormality and your symptoms, the next step may include GP or cardiology review, echocardiography, ambulatory ECG monitoring, blood tests or other cardiac investigations.
When should chest pain be treated as an emergency?
New or severe chest pain, especially with shortness of breath, sweating, fainting, collapse or pain spreading to the arm, back, neck or jaw, needs urgent emergency assessment rather than a routine ECG booking.
Where can I have the ECG?
PrivateSono has clinics at 27 Welbeck Street in Central London and 54–56 Victoria Street in St Albans. Select the available location in the booking system.
Private heart testing
Ready to book your ECG?
Use the heart-service booking selector to choose your clinic and appointment.