Important distinction: a heart attack is a blocked blood supply to heart muscle; cardiac arrest is when the heart stops pumping effectively. A heart attack can cause cardiac arrest, but they are not the same emergency. Early recognition, emergency activation, high-quality CPR and rapid defibrillation can preserve life.
Add a labelled image sequence showing responsiveness check, chest compressions, rescue breaths and AED use here.
Learning outcomes
- Differentiate heart attack, respiratory arrest and cardiac arrest.
- Recognise acute coronary syndrome and provide safe immediate first aid.
- Perform adult basic life support, including external cardiac massage, rescue breaths and AED integration.
- Explain hands-only CPR, conventional CPR and modifications for children, infants and special situations.
- Coordinate a resuscitation team while protecting the rescuer and documenting events.
1. Heart attack versus cardiac arrest
| Condition | What happens | Typical presentation | First-aid priority |
|---|---|---|---|
| Heart attack / acute coronary syndrome | Blood flow to a portion of heart muscle is reduced or blocked. | Central pressure or heaviness, pain to arm/jaw/back, sweating, nausea, breathlessness or unusual fatigue. The person is usually conscious. | Stop exertion, call emergency help, rest comfortably, monitor continuously and prepare for deterioration. |
| Cardiac arrest | The heart stops producing effective circulation. | Sudden collapse, unresponsiveness and absent or abnormal gasping. | Call for help/AED and start chest compressions immediately. |
| Respiratory arrest | Breathing stops while a pulse may initially remain. | Unresponsive, no normal breathing; pulse may be present in a trained healthcare assessment. | Open airway, provide rescue breaths and reassess; start CPR if pulse is absent or uncertain according to local protocol. |
2. First aid for suspected heart attack
- Stop activity and sit the person in a comfortable position, usually supported upright with knees relaxed.
- Call the local emergency service. Give the location, symptoms, age and whether the person is conscious and breathing.
- Loosen tight clothing, reassure and keep the person still. Do not allow them to walk or drive themselves.
- Ask about prescribed angina medicine and help them use it according to their prescription. Do not give someone else’s medicine.
- Follow local protocol or dispatcher advice about aspirin; check allergy, active bleeding, anticoagulants and other contraindications before any medication.
- Monitor responsiveness, breathing and skin colour. If the person becomes unresponsive and is not breathing normally, transition immediately to CPR.
Do not: dismiss indigestion-like symptoms, give food or drink, leave the person alone, encourage exertion or delay emergency transport while searching for a home remedy.
3. Recognising cardiac arrest
- The person does not respond to voice or gentle shoulder tap.
- There is no normal breathing, or only occasional agonal gasps.
- For a trained healthcare provider, no definite central pulse is felt within 10 seconds. Lay rescuers should not delay CPR by prolonged pulse checking.
- The skin may be pale or blue, and the person may have a brief seizure-like movement at collapse.
4. Adult basic life support sequence
- Scene safety: check electricity, traffic, violence, water and body-fluid risk.
- Response: shout and tap the shoulders. Ask someone to call emergency services and bring an AED.
- Airway and breathing: open the airway with head-tilt/chin-lift unless trauma requires a jaw thrust by a trained rescuer. Look for normal breathing for no more than 10 seconds.
- Start compressions: place the heel of one hand in the centre of the chest on the lower half of the sternum, second hand on top, fingers interlocked and arms straight.
- Rate and depth: compress at 100–120 per minute to approximately 5–6 cm in an average adult, allowing complete recoil and minimising pauses.
- Ventilation: if trained and willing, give 30 compressions followed by 2 breaths with a barrier device. Each breath lasts about one second and should visibly raise the chest.
- AED: switch it on, expose and dry the chest, attach pads as shown, stand clear during analysis and shock, then immediately resume compressions when instructed.
- Continue: rotate compressors about every two minutes if another trained rescuer is available. Continue until the person shows signs of life, trained help takes over, the scene becomes unsafe or you are physically unable to continue.
5. External cardiac massage: technique and quality
| Element | Correct technique | Common error |
|---|---|---|
| Position | Casualty supine on a firm surface when possible; kneel beside the chest. | Compressing on a soft bed without a safe alternative. |
| Hand placement | Centre of chest, lower half of sternum; fingers off the ribs. | Pressing over the xiphoid, ribs or upper abdomen. |
| Body mechanics | Shoulders over hands, elbows locked, use body weight vertically. | Bending elbows and tiring quickly. |
| Compression | 100–120/min, about 5–6 cm in adults, full recoil. | Shallow, slow, excessively deep or leaning between compressions. |
| Interruptions | Keep pauses as short as possible, including during AED analysis. | Stopping repeatedly to check a pulse or look for a response. |
6. Artificial respiration and rescue breaths
Artificial respiration means providing breaths when spontaneous breathing is absent or inadequate. A pocket mask or bag-valve-mask with appropriate training reduces exposure risk. For mouth-to-mouth ventilation, maintain an open airway, pinch the nose, seal the mouth and deliver two visible chest-raising breaths. If the chest does not rise, reopen the airway and look for obstruction; do not repeatedly force large breaths.
- Use compression-only CPR if untrained, unable or unwilling to provide breaths; continue until help or an AED arrives.
- For drowning, respiratory causes, children and infants, breaths are particularly important when the rescuer is trained and able.
- Use a barrier device where possible. Avoid mouth-to-mouth if the casualty is contaminated with a toxic substance or if it is unsafe.
- Do not ventilate too forcefully or rapidly; excessive ventilation increases stomach inflation and aspiration risk.
7. Special populations and situations
| Situation | Modification |
|---|---|
| Child or infant | Use the heel of one or two hands for a child and two fingers or two-thumb technique for an infant; compress about one-third of the chest depth and follow current local paediatric BLS training. |
| Pregnancy | Start CPR normally, activate advanced help early and follow trained guidance for manual uterine displacement in late pregnancy. |
| Trauma | Prioritise airway and CPR. Minimise spinal movement only when it does not delay ventilation or compressions. |
| Water rescue | Do not enter unsafe water. Once safely removed, begin assessment and CPR; use a defibrillator when the chest is dry. |
| Opioid overdose | Call emergency help, provide ventilation/CPR and administer naloxone if available and trained, without delaying compressions. |
8. Recovery after return of spontaneous circulation
If normal breathing and purposeful movement return, stop compressions, maintain the airway, place a breathing unconscious person in the recovery position unless trauma makes this unsafe, keep them warm and monitor continuously. Do not let them sit up suddenly, eat, drink or leave. Record the time of collapse, CPR cycles, shocks, medications and response for the receiving team.
9. Scenario
Scenario: A man collapses at a sports ground, does not respond and produces occasional gasps. Response: send someone for the AED and emergency service, place him on a firm surface, begin chest compressions immediately, use 30:2 CPR if trained and willing, follow AED prompts and minimise pauses. Gasping is not a reason to wait.
Exam points and revision questions
- Differentiate a heart attack from cardiac arrest.
- Demonstrate adult external cardiac massage and state the rate, depth and recoil requirements.
- Explain when compression-only CPR is appropriate.
- List four common causes of poor-quality CPR.
- Describe how an AED is integrated into resuscitation.