Warning Signs of a Cardiac Arrest: How to Recognise the Symptoms Before, During and After an Emergency
Every year, tens of thousands of people in the UK suffer an out-of-hospital cardiac arrest. Sadly, many of these emergencies happen with little warning, often at home, in the workplace, at school or in public places. Read on how to recognise a cardiac arrest
Although cardiac arrest is sudden, it isn’t always completely unexpected. Many people experience symptoms in the hours, days or even weeks leading up to the event. Recognising these warning signs and knowing how to respond quickly can make the difference between life and death.
For children, cardiac arrest is much less common, but it usually develops after a child becomes critically unwell. This means recognising deterioration early is just as important as knowing how to perform CPR.
In this guide, we’ll explain:
- The difference between a heart attack and a cardiac arrest
- Warning signs before a cardiac arrest
- Signs of cardiac arrest in adults
- The BBB Triangle for recognising deterioration in children
- What to do during a cardiac arrest
- What happens afterwards
- How training prepares you to respond with confidence
What Is a Cardiac Arrest?
A cardiac arrest occurs when the heart suddenly stops pumping blood effectively around the body. Without blood circulating, oxygen can no longer reach the brain and vital organs.
Within seconds, the person becomes unconscious.
Within minutes, permanent brain damage can begin.
Without immediate treatment, cardiac arrest is fatal.
Unlike a heart attack, where blood flow to part of the heart muscle is blocked, cardiac arrest is an electrical problem. The heart develops a dangerous rhythm or stops altogether, which prevents it from pumping blood.
This is why immediate CPR and early defibrillation are so important.
Heart Attack vs Cardiac Arrest – What’s the Difference?
Many people use the terms interchangeably, but they are not the same.
A heart attack happens when the blood supply to part of the heart muscle is blocked. The heart usually continues beating, and the person is often awake and able to communicate. Symptoms typically include chest pain, shortness of breath, sweating, nausea and pain radiating to the jaw, neck, back or arm.
A cardiac arrest, on the other hand, is when the heart suddenly stops pumping blood effectively. The person collapses, becomes unresponsive and is not breathing normally. This is an immediate life-threatening emergency requiring CPR and a defibrillator (AED) if available.
Importantly, a heart attack can sometimes trigger a cardiac arrest, which is why anyone with symptoms of a heart attack should receive urgent medical assessment.
Can You Spot the Warning Signs Before a Cardiac Arrest?
Many people are surprised to learn that cardiac arrest isn’t always completely unexpected.
Research has shown that a significant number of people experience warning signs beforehand.
These symptoms may occur:
- Several weeks beforehand
- A few days before
- A few hours before
- Immediately beforehand
Recognising these signs gives an opportunity to seek urgent medical help before the heart stops.
Common Warning Signs in Adults
Chest Pain or Pressure
This is the symptom most people recognise.
It may feel like:
- Tightness
- Pressure
- Crushing pain
- Heaviness
- Burning
Some people describe it as someone sitting on their chest.
The discomfort may come and go or remain constant.
Any persistent chest pain should be treated seriously.
Pain That Spreads
Pain doesn’t always stay in the chest.
It may spread to:
- Left arm
- Right arm
- Both arms
- Jaw
- Neck
- Back
- Shoulders
- Upper abdomen
Women, older adults and people with diabetes may experience less typical symptoms, making it especially important not to dismiss unexplained pain or discomfort.
Shortness of Breath
Difficulty breathing may occur:
- At rest
- During light activity
- Suddenly without explanation
Some people feel they cannot catch their breath or become unusually breathless while doing everyday activities.
Extreme Fatigue
Feeling unusually exhausted for no obvious reason can sometimes be an early warning sign.
This may develop over several days.
People often describe:
- Feeling drained
- Needing to rest more than usual
- Being unable to complete routine tasks
While fatigue has many causes, unexplained extreme tiredness alongside other symptoms should never be ignored.
Dizziness or Feeling Faint
Reduced blood flow caused by heart problems may lead to:
- Light-headedness
- Feeling faint
- Near collapse
- Loss of balance
These symptoms are especially concerning when accompanied by chest discomfort or breathlessness.
Cold Sweats
Sudden sweating without physical exertion can indicate the body is under significant stress.
The person may appear:
- Pale
- Cold
- Clammy
- Sweaty
Nausea or Vomiting
Some people, particularly women, experience nausea, indigestion or vomiting rather than classic chest pain.
Because these symptoms can mimic less serious conditions, they are sometimes overlooked.
Palpitations
Some people notice:
- Racing heartbeat
- Fluttering
- Skipped beats
- Irregular rhythm
Although many palpitations are harmless, persistent or sudden changes in heart rhythm accompanied by dizziness, chest pain or breathlessness require urgent medical attention.
When Should You Call 999?
Never ignore warning signs that could indicate a serious heart problem.
Call 999 immediately if someone experiences:
- Persistent chest pain
- Chest pain spreading to the arms, neck, jaw or back
- Sudden collapse
- Severe shortness of breath
- Loss of consciousness
- Symptoms of a heart attack
It is always safer to seek medical advice than to wait and hope symptoms improve.
Signs That Someone Is in Cardiac Arrest
Cardiac arrest is usually dramatic and unmistakable.
The person will typically:
- Collapse suddenly
- Become unconscious
- Not respond when spoken to
- Not respond to pain
- Not be breathing normally
- Only gasp occasionally (agonal breathing)
- Show no signs of life
Agonal gasps can easily be mistaken for breathing, but they are not effective breaths. If someone is unresponsive and only gasping, treat this as a cardiac arrest and begin CPR immediately.
Recognising Cardiac Arrest in Children
Cardiac arrest in children is rare compared with adults.
Unlike adults, where cardiac arrest is often caused by a heart problem, children usually suffer cardiac arrest because their breathing or circulation has progressively deteriorated.
This means recognising deterioration early is critical.
The sooner intervention occurs, the greater the chance of preventing a cardiac arrest altogether.
One useful way of assessing a seriously unwell child is by using the BBB Triangle.
The BBB Triangle
The BBB Triangle stands for:
- Breathing
- Brain
- Behaviour
These three areas provide a simple way to recognise when a child needs urgent medical attention.
Breathing
Always observe how a child is breathing.
Warning signs include:
- Very fast breathing
- Very slow breathing
- Noisy breathing
- Grunting
- Gasping
- Chest recession (the skin pulling in between or below the ribs)
- Blue lips or face
- Long pauses between breaths
Children often work much harder to breathe before they stop breathing altogether, so increased effort is a significant warning sign.
Brain
The brain is highly sensitive to a lack of oxygen.
Changes in alertness are often one of the earliest signs that a child is becoming critically ill.
Watch for:
- Reduced responsiveness
- Confusion
- Drowsiness
- Difficulty waking
- Limpness
- Seizures
- Collapse
- Loss of consciousness
If a child becomes difficult to wake or unusually sleepy, urgent medical assessment is required.
Behaviour
Parents and carers often notice changes in behaviour before any obvious physical symptoms.
These may include:
- Being unusually quiet
- Irritability
- Inconsolable crying
- Refusing food or drink
- Reduced interaction
- Not wanting to play
- Becoming floppy
- Pale or mottled skin
Trust your instincts. If a child is “not themselves”, it may be an early indication that they are becoming seriously unwell.
What To Do During a Cardiac Arrest
When someone suffers a cardiac arrest, every second counts.
Follow these steps:
- Ensure the scene is safe.
- Check if the person responds.
- Open the airway.
- Check for normal breathing for no more than 10 seconds.
- If they are not breathing normally, call 999 immediately or ask someone else to call.
- Send someone to retrieve the nearest Automated External Defibrillator (AED), if available.
- Begin high-quality CPR without delay.
- Turn on the AED as soon as it arrives and follow its spoken instructions.
- Continue CPR until the person shows signs of life, the ambulance crew takes over, or you are physically unable to continue.
Even if you are unsure whether it is a cardiac arrest, starting CPR is far better than doing nothing.
What Happens After the Emergency?
The emergency doesn’t end when the ambulance arrives.
If you’re in a workplace, school or community setting, there are important actions to take after the incident:
- Provide a clear handover to the ambulance crew.
- Record what happened, including times and actions taken.
- Replace used first aid supplies and AED pads.
- Check the AED is ready for future use.
- Report the incident according to organisational procedures.
- Offer emotional support to those involved, as witnessing a cardiac arrest can be traumatic.
- Conduct a debrief to identify any learning points and improve future emergency responses.
Taking these steps helps organisations remain prepared and supports everyone affected by the incident.
Why First Aid Training Matters
Knowing the signs of cardiac arrest is only the first step.
Without the confidence to act, valuable minutes can be lost.
Regular first aid training teaches people how to:
- Recognise life-threatening emergencies
- Call for help quickly
- Perform effective CPR
- Use an AED with confidence
- Recognise deteriorating children using the BBB Triangle
- Work calmly under pressure
- Support casualties until emergency services arrive
Skills can fade over time, so refresher training is just as important as initial certification.
Final Thoughts
Cardiac arrest can happen to anyone, anywhere and at any time. While it often strikes without warning, many people experience signs that something is wrong before they collapse. Learning to recognise those warning signs, acting quickly, and knowing what to do during and after the emergency can dramatically improve the chances of survival.
For adults, don’t ignore symptoms such as chest pain, unexplained breathlessness or sudden dizziness. For children, remember the BBB Triangle; Breathing, Brain and Behaviour—as a simple way to recognise serious deterioration before it becomes a cardiac arrest.
Knowledge saves lives, but confidence comes from training. Whether you’re a teacher, parent, workplace first aider or member of the public, learning these skills means you could make all the difference when every second counts.
Our current first aid courses;
Our Emergency and First Aid at Work courses are for those working in an office, factory, warehouse, manufacturing or on a building site. These courses will set you up to know exactly what to do in an emergency. Completing our courses will help you understand the hazards and risks in your workplace to therefore prevent accidents.
Apprentices, staff who are unlikely to be left alone with children, and lunchtime supervisors are all candidates for our Emergency Paediatric First Aid Training. Our one-day course includes roles and responsibilities of a first aider, first aid kits, accident reporting, reasons of a life-threatening condition, CPR, defibrillator, causes of unconsciousness and recovery position, choking, bleeding, burns, and minor injuries.
Our Paediatric First Aid Training 2-day course includes all elements of the one-day first course including; broken bones, spinal injuries, head injuries, slings, sprains and strains, diabetes, febrile convulsions, hypothermia, hyperthermia, epilepsy, poisons, eye injuries, allergies and anaphylaxis, and asthma.
This course is ideal for those working alone with children, whether you are a Teacher or Teaching Assistant working in the Early Years or a childminder. Our Paediatric courses are fully accredited. We have open courses running at our Brownhills Centre or we can come to your setting.
Additionally, if you prefer to have a short session with us and complete a bespoke parents/grandparents course; our Parent’s first aid course is for you. These start from 2 hours up to 4 hours. Can include any modules of your choice, but we will cover: reasons of life-threatening conditions, CPR, Defibrillator, unconsciousness, recovery, choking and gagging, burns, and minor illnesses, including dangers within the home.
Our courses provide you with the peace of mind that you’ll know what to do in the event of an emergency, such as illnesses like asthma. Furthermore, getting first aid training will give you the skill set of knowing exactly what to do if your child, friend, or work colleague suffers from an injury or life threatening condition. Never put yourself in a situation where you’re thinking, “How to recognise a cardiac arrest” Get First Aid Trained Today!
If you have any questions with this blog we are happy to help. How to recognise a cardiac arrest – if you want to know how, book onto an annual first aid course with us. Here is the link to our upcoming courses. https://www.hmbtrainingservices.co.uk/courses
For further enquiries, please call us on: 01543 453338 or email on info@hmbtrainingservices.co.uk
