Blackout / first seizure assessment
An assessment to work out why someone blacked out or had a first suspected seizure, and whether it is the heart, a faint, epilepsy or something else.
✓ Medically reviewed by a GMC-registered consultant · last reviewed September 2026 · next review September 2027 · how we review
In short
- A blackout has many causes — faint, heart rhythm problem, seizure and others — and the assessment is mainly about telling them apart from the story and an ECG.
- A single blackout is not the same as epilepsy, and normal tests do not always give a firm answer.
- You must stop driving until you are assessed; the DVLA (or the DVA in Northern Ireland) sets time limits depending on the likely cause.
- The most important job is to spot a dangerous heart cause and to avoid wrongly labelling a faint as a seizure.
A plain-English summary. The detail — including risks and recovery — is below.
At a glance
A general guide. Your specialist will give you advice for your situation.
Helps identify a dangerous heart cause that needs urgent treatment
Treating an assessment as a way to confirm epilepsy from a single event — one blackout is not enough to diagnose epilepsy.
The clinician takes the history, examines you and usually does an ECG. Some findings, such as an obviously abnormal ECG, prompt action straight away.
A clear explanation of the likely cause, or an honest plan to find it, in writing.
The clinician takes the history, examines you and usually does an ECG. Some findings, such as an obviously...
You are told the likely cause or the plan to find it, given driving and safety advice, and told what to do if it...
Further tests such as heart monitoring, an echocardiogram, EEG or MRI may be arranged, with results following...
Results are reviewed and a clearer diagnosis or plan is given. If the cause is still unclear, longer monitoring or...
What is a blackout / first seizure assessment?
A blackout is a brief loss of consciousness — passing out. There are many causes, and telling them apart matters because the treatment is very different. Common causes include a simple faint (a drop in blood pressure), a heart rhythm problem, an epileptic seizure, low blood sugar, or a non-epileptic attack.
This assessment is the careful work a clinician does to find the likely cause. It is built mainly on the story of what happened — what you were doing, any warning, what a witness saw, how you recovered — supported by an examination and tests such as a heart tracing (ECG).
The assessment is a way of gathering information. A single blackout is not the same as epilepsy, and most people who faint do not have epilepsy. The aim is to spot the few people with a dangerous heart cause, decide whether epilepsy is likely, and avoid labelling someone with epilepsy when it is really a faint.
It cannot always give a definite answer after one event, and sometimes the safest plan is further monitoring rather than a firm diagnosis.
Types, options & approaches
There may be different ways to do this. The right approach depends on the clinical question and your circumstances.
Options at a glance
These are the main approaches described in this guide. The right option depends on the diagnosis, your goals and what your clinician thinks is safe.
History and witness account
The most important part. The clinician asks exactly what happened before, during and after, and seeks an account from anyone who saw it — this often points to the cause more...
12-lead ECG (heart tracing)
A quick, usually not painful recording of the heart's rhythm. NICE recommends an ECG for everyone after a blackout, because it can pick up rhythm problems that need urgent...
Tests for a heart cause
If a cardiac cause is suspected, you may have heart monitoring over hours to weeks, an echocardiogram (heart ultrasound) or other cardiology tests.
Tests for a seizure cause
If a seizure is likely, an EEG (brain electrical recording) and an MRI scan may be arranged. Neither, on its own, proves or rules out epilepsy.
Preparing for your test
- Write down exactly what happened: what you were doing, any warning signs, how long you were out, and how you felt afterwards.
- Bring an account, or a video if one exists, from anyone who witnessed the blackout — this is often the single most useful piece of information.
- List all your medicines and supplements, including anything that lowers blood pressure or could affect the heart.
- Note any family history of fainting, epilepsy, heart problems or sudden death at a young age.
- Mention whether it happened on standing, with pain or emotion, during exercise, or out of the blue, as this points to different causes.
- Tell the clinic if you drive, as you must stop driving until you have been assessed and meet the driving rules set by the DVLA (or the DVA if you live in Northern Ireland).
- Bring details of any previous ECGs, scans or hospital visits for similar episodes.
What happens
The clinician takes a careful history of the event and your background, then examines you, including your heart and blood pressure, sometimes lying and standing.
Most people have a 12-lead ECG, a quick heart tracing using sticky pads on the chest. If anything suggests a heart cause, you may be referred urgently for cardiology assessment, longer heart monitoring or a heart ultrasound.
If the picture suggests a seizure, you may be offered an EEG and an MRI scan of the brain. These help build the picture but do not give a yes-or-no answer on their own.
The clinician then explains the most likely cause, what it means for driving and safety, and whether you need treatment, further tests or simply reassurance. Sometimes the honest answer after one event is that more monitoring is needed before a firm diagnosis can be made.
Is this test right for me?
A good consultation should explore whether it's the right choice for you now — including reasons to wait or consider something else.
May not be suitable if…
- Treating an assessment as a way to confirm epilepsy from a single event — one blackout is not enough to diagnose epilepsy.
- Relying on an EEG or MRI to rule epilepsy in or out, as both can be normal in epilepsy and abnormal in people without it.
- Skipping the witness account or the ECG, both of which are central to a safe assessment.
- A routine clinic pathway when the history suggests a dangerous cardiac cause that needs urgent assessment.
Delay or rearrange if…
- There are red-flag features such as a blackout on exertion, on lying flat, or with chest pain, which need urgent rather than routine assessment.
- A key witness account or previous ECG is missing and would change the plan.
- You are acutely unwell, for example with ongoing chest pain, breathlessness or a head injury, which needs emergency care first.
- A possible reversible cause, such as a new medicine or low blood sugar, needs checking before extensive testing.
Alternatives to discuss
- Watchful waiting with safety advice after a clear single faint with normal examination and ECG.
- Longer heart rhythm monitoring rather than a one-off test if a cardiac cause is suspected but intermittent.
- Referral to cardiology rather than neurology if the picture points to the heart.
- Referral to a first seizure clinic rather than starting any treatment if a seizure is likely.
- Reviewing and adjusting medicines that may be causing faints, rather than further testing.
Before you decide
Use this as a shared-decision checklist. The aim is not just “can this be done?”, but whether it is right for you, now, with the risks and alternatives clearly understood.
What matters most to me?
Think about symptoms, daily life, work, caring responsibilities, sport, fertility, travel, appearance and anxiety — the right choice depends on your priorities, not just the medical facts.
What are all my options?
Ask about waiting, monitoring, medicines, rehabilitation, a smaller or larger procedure, a different test, NHS referral, or a second opinion where that would help.
What would make me pause?
Active infection, pregnancy, unstable medical problems, smoking, medicines that increase bleeding, poor support at home, or feeling pressured are all reasons to slow down and get tailored advice.
What happens if I do nothing today?
For some problems, waiting is safe; for others, delay can make treatment harder. A good consultation should explain the trade-off in plain English.
Benefits
- Helps identify a dangerous heart cause that needs urgent treatment
- Helps tell a simple faint apart from a seizure, avoiding a wrong epilepsy label
- Guides whether you need treatment, further tests, or just reassurance and advice
- Provides clear advice on driving and safety based on the likely cause
- Sets up the right follow-up if the cause is not clear after one visit
Risks & complications
- Not getting a definite answer after a single event, so further monitoring is needed
- Needing more than one test or appointment
- Temporary loss of driving while the cause is assessed
- Anxiety while waiting for results
- An incidental finding on a scan or heart test that needs further checks but may not be the cause
- A normal EEG or MRI that does not rule epilepsy in or out, leaving uncertainty
- A faint or seizure being mislabelled if the history or witness account is incomplete
- A serious cause, such as a dangerous heart rhythm, being missed if assessment is incomplete or driving advice is not followed
- A further blackout causing injury before the cause is found and treated
The biggest risk is a missed heart cause, which is why an ECG is recommended for everyone after a blackout and why certain ECG patterns mean urgent referral. The other key issue is being labelled with epilepsy after a single event when the cause is really a faint. Ask whether your blackout could be cardiac, what the ECG showed, and what should happen if it occurs again.
Published figures to discuss
This is an information-gathering assessment, so the key numbers are about how often a cause is found, how often tests are normal yet inconclusive, and how often a serious cause is present. These vary widely with age, symptoms and the population tested, so exact percentages are not reliable here and are deliberately not given.
| Figure | Reported range | How to interpret it | Source / confidence |
|---|---|---|---|
| Epileptic seizure versus faint | Often uncertain after one event | Eyewitness description, recovery time, tongue biting, triggers, ECG and neurological history are often more useful than any single test. | Guide sourcesClinical context |
| Cardiac cause of blackout | Uncommon but high priority | Blackout during exertion, while lying down, with palpitations/chest pain, or with family history of sudden death needs urgent cardiac review. | NICE CG109 — Transient loss of consciousness ('blackouts') in over 16snice.org.ukSource-linked context |
| Normal EEG or MRI after a true seizure | Recognised | Normal tests do not exclude epilepsy; diagnosis remains clinical and follow-up matters. | Guide sourcesClinical context |
| Driving and safety restrictions | Clinically important after a seizure or unexplained blackout | Patients should receive explicit driving advice (from the DVLA, or the DVA in Northern Ireland), as well as work and safety advice, while the cause is being investigated. | Guide sourcesClinical context |
These are literature figures, not a personalised prediction. Your own risks and likely benefits depend on your circumstances, your health, and how your care is carried out and followed up.
What happens afterwards
There is no physical recovery from the assessment itself. 'Afterwards' is mostly about getting the results, understanding the likely cause, following driving advice, and arranging any further tests or treatment.
- Waiting days or weeks for some test results
- Being asked to wear a heart monitor for a period
- Not having a firm answer after the first visit
- A period without driving while the cause is assessed
- Feeling shaken or anxious after an unexplained blackout
Aftercare
- Follow the driving advice you are given and tell the DVLA (or the DVA if you live in Northern Ireland) if required — do not drive until you are told it is safe.
- Keep a note of any further episodes, including what you were doing and any warning signs.
- Take any heart or other monitoring as arranged, and attend follow-up for results.
- If a faint is the likely cause, learn the warning signs and how to sit or lie down quickly.
- Avoid swimming alone, heights and other risky situations until the cause is known.
- Continue prescribed medicines unless told otherwise, and report any that may be lowering your blood pressure.
- Make sure someone close to you knows what to do if you black out again.
- Seek urgent help for the warning signs listed below.
- Detailed written account of the blackout
- Witness account or video if available
- List of all medicines and supplements
- Family history of heart problems or sudden death noted
- Previous ECGs or scans gathered
- Questions about driving written down
- Clinic contact details saved for results and advice
⚠ Get urgent help if…
- A blackout that happened during exercise or while lying down — this can suggest a heart cause and needs urgent assessment
- Blackout with chest pain, palpitations or breathlessness — seek urgent help
- A family history of sudden death at a young age combined with a blackout
- A blackout causing serious injury, or one in water
- A seizure lasting more than 5 minutes, repeated seizures, or not waking up properly afterwards — call 999
- Slurred speech, weakness, facial droop or a severe sudden headache — call 999
- Repeated blackouts before you have been assessed
Who to contact: your clinician, clinic or test provider first (keep their number to hand). For urgent advice when you can't reach them, call NHS 111. In an emergency, call 999.
General guidance — it doesn't replace the specific advice your specialist gives you.
Results & realistic expectations
A good result is a clear, well-explained likely cause, with a plan for treatment, further tests or reassurance, and sensible driving and safety advice. Sometimes the most honest result after one event is that no firm diagnosis can be made yet, and monitoring is the safest next step.
Normal tests are reassuring but do not always give a complete answer. A normal ECG does not rule out every heart problem, and a normal EEG or MRI does not rule epilepsy in or out. The assessment lowers the chance of a serious cause being missed, but it cannot promise that a blackout will never happen again.
How long the result stays useful depends on the cause. If a clear, treatable cause is found, the assessment may not need repeating. If the cause is uncertain, or if you have another blackout with new features, reassessment is sensible because the diagnosis and the driving advice can change.
Related tests, treatments or support
This assessment often brings together neurology and cardiology, because telling a seizure apart from a faint or heart rhythm problem is central. Blood tests, blood pressure checks, heart monitoring, an echocardiogram, an EEG and an MRI may be used in combination depending on the most likely cause.
Follow-up & long-term care
Follow-up depends on the findings. An abnormal ECG should lead to urgent cardiology review. If a seizure is likely, you should be seen by a specialist, ideally within two weeks of a first suspected seizure. If the cause is unclear, longer heart monitoring or further tests are arranged, with results explained and the driving advice updated.
Repeat, follow-on and what comes next
- A firm diagnosis often cannot be made after a single event, and longer monitoring may be needed.
- Normal tests do not exclude all causes, so reassessment may be needed if blackouts recur.
- An initial impression can change with a witness account, a video, or a recorded event during monitoring.
- Repeat testing is common when the first results are inconclusive.
Ask what happens if the result is unclear or needs repeating, and what is included if further tests or follow-up are needed.
What good aftercare looks like
- A clear explanation of the likely cause, or an honest plan to find it, in writing.
- Specific driving advice and a reminder of the duty to inform the DVLA (or the DVA in Northern Ireland) where relevant.
- A named contact and a defined route for results and for further blackouts.
- Urgent referral arranged if the ECG or history suggests a cardiac cause.
- A plan for follow-up and re-testing if the cause is not yet clear.
What affects the cost
Costs vary a great deal between people and providers, and we don't publish prices. What matters is understanding what drives the cost and making sure your quote is complete. The main things that affect it:
- Whether you need a single specialist opinion or ongoing follow-up
- How many tests are needed, such as ECG, heart monitoring, echocardiogram, EEG or MRI
- Whether tests are reported by a specialist and whether that is included
- Whether both neurology and cardiology input are required
- Repeat appointments if the cause is unclear after the first visit
- Letters or reports for work, driving or insurance
- The specialist's fee for the first appointment and for follow-ups
- The cost of each test, such as ECG, monitoring, echocardiogram, EEG or MRI
- Whether specialist reporting of tests is included
- What happens, and what it costs, if the result is inconclusive and more tests are needed
- Whether referral to a second specialty (for example cardiology) is included
- Whether letters for the DVLA (or the DVA in Northern Ireland), work or insurance are included
- How and when results are given, and how urgent findings are handled
On the NHS? Blackout and first seizure assessment is available on the NHS, often through dedicated first seizure or syncope clinics; private care is sometimes used for a quicker appointment, but the same tests and driving rules apply.
You're entitled to your total cost in writing — including reports, follow-up and what happens if the result is inconclusive — before you decide.
Consent traps and marketing red flags
These are not small details. They are often where patients lose choice, time to reflect, or realistic expectations.
Consent traps
- Not explaining that a single event may not give a definite answer.
- Not making clear the driving restrictions and the duty to inform the DVLA (or the DVA in Northern Ireland).
- Implying a normal EEG or ECG means nothing can be wrong.
- Labelling someone with epilepsy on weak evidence, with lasting effects on driving, work and insurance.
- Not explaining what happens, or who to contact, if a blackout recurs before follow-up.
Marketing red flags
- Offering a single 'definitive' test that promises to diagnose the cause of any blackout.
- Suggesting an EEG can confirm or exclude epilepsy on its own.
- Downplaying the need for an ECG and a heart assessment.
- Not mentioning driving restrictions.
- Pushing extensive private testing without first taking a proper history and witness account.
Choosing a specialist safely
- Check the specialist is on the GMC Specialist Register for this area.
- Make sure they work at a CQC-registered service, and look for membership of the relevant Royal College or professional body.
- You're entitled to time to consider and to have your questions answered before you agree — the specialist who looks after you should explain it, not a salesperson.
- Be wary of pressure: time-limited offers or deposits taken before you've had time to think are red flags, not bargains.
- You're entitled to your total cost in writing — including any follow-up — before you decide.
Questions to ask your medical professional
Take this to your consultation. A good specialist will welcome every one of these.
- Could my blackout have a heart cause, and what did the ECG show?
- Do you think this is a faint, a seizure, or something else, and how sure are you?
- What are the driving rules for me now, and do I need to tell the DVLA (or the DVA in Northern Ireland)?
- What further tests do I need, and what will each one change?
- What happens if the tests are normal but I black out again?
- What should I and the people around me do if it happens again?
- Are you on the GMC Specialist Register for this area, and which Royal College or professional body are you a member of?
- Will you be the specialist who carries out my test, and who looks after me afterwards?
- What are the risks for someone like me, and how often do your own patients have a problem or need it repeated or redone?
- What does a realistic result look like — and what can this test not achieve?
- What are my options, including waiting, doing nothing for now, or choosing a different approach?
- Can I have written information, results and aftercare instructions in a format I can use, including any accessibility or communication support I need?
- What is the total cost in writing, including any follow-ups, and how much time do I have to decide?
Frequently asked questions
Does a blackout mean I have epilepsy?
Why do I need an ECG if I think I just fainted?
Can I drive after a blackout?
What if the tests are normal?
How quickly should I be seen after a first seizure?
Can I have this assessment privately?
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How we made this page
Medically reviewed by a GMC-registered consultant. Written in plain English, checked against NHS, NICE, GMC and relevant Royal College / specialist-society guidance, and kept under review. No clinic paid to appear on this page, and we publish no pricing. This is general information to help you prepare — it is not a substitute for advice from your own clinician. How we review our guides →
Source hierarchy: UK regulator and NHS/NICE guidance first, then relevant Royal College or specialist-society guidance, then peer-reviewed evidence for procedure-specific figures where available.
Sources & standards: NICE CG109 — Transient loss of consciousness ('blackouts') in over 16s NHS — Fainting NICE NG217 — Diagnosis and assessment of epilepsy (first seizure) GOV.UK / DVLA — Fits, seizures or convulsions and driving GOV.UK / DVLA — Neurological disorders: assessing fitness to drive DVLA — Assessing fitness to drive (general information) DVA Northern Ireland — Telling DVA about a driver medical condition
Reviews reflect patients' experience of care, not clinical outcomes. For procedure volumes and outcome data see PHIN.
Last medically reviewed 2026-09-21. Spotted something wrong or out of date? Report an error in this guide.
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