Sudden Cardiac Arrest (SCA)

Sudden cardiac arrest is the abrupt loss of heart function, breathing and consciousness. The condition usually results from a problem with your heart’s electrical system, which disrupts your heart’s pumping action and stops blood flow to your body.

Sudden cardiac arrest isn’t the same as a heart attack, when blood flow to a part of the heart is blocked. However, a heart attack can sometimes trigger an electrical disturbance that leads to sudden cardiac arrest.

If not treated immediately, sudden cardiac arrest can lead to death. Survival is possible with fast, appropriate medical care. Cardiopulmonary resuscitation (CPR), using a defibrillator — or even just giving compressions to the chest — can improve the chances of survival until emergency workers arrive.


Signs of sudden cardiac arrest are immediate and drastic and include:

  • Sudden collapse
  • No pulse
  • No breathing
  • Loss of consciousness

Sometimes other signs and symptoms occur before sudden cardiac arrest. These might include:

  • Chest discomfort
  • Shortness of breath
  • Weakness
  • Fast-beating, fluttering or pounding heart (palpitations)

But sudden cardiac arrest often occurs with no warning.

When to see a doctor

Call 999 or 112 if you experience any of these signs and symptoms:

  • Chest pain or discomfort
  • Heart palpitations
  • Rapid or irregular heartbeats
  • Unexplained wheezing
  • Shortness of breath
  • Fainting or near fainting
  • Lightheadedness or dizziness

When the heart stops, the lack of oxygen-rich blood can cause death or permanent brain damage within minutes. Time is critical when you’re helping an unconscious person who isn’t breathing.

Recovery after a cardiac arrest

Immediate recovery

After a cardiac arrest, you’ll have been looked after in a coronary care or intensive care unit. You may have been put in an induced coma and kept asleep to allow your body to recover. 

Mid-term recovery

Doctors and cardiologists will want to work out what caused the cardiac arrest. They can then recommend medication and treatment, such as a pacemaker or implantable cardioverter defibrillator (ICD), to reduce the risk of it happening again. 

They may also refer you to cardiac rehabilitation to help rebuild your confidence, fitness and strength levels. Each programme is different, but it usually involves regular assessments such as checking your pulse and blood pressure, psychological support, health education talks and exercise sessions. 

Long-term recovery

It will take time to recover after a cardiac arrest, but your doctor will support you during this time. Talk to family and doctors about what will happen once you go home and practical matters, like driving and returning to work

Your doctor may suggest making lifestyle changes to reduce your risk of another cardiac arrest. This can include:

Because of a lack of oxygen to the brain during a cardiac arrest, you might experience long-term effects to your brain. These can include:

  • personality changes 
  • problems with memory
  • fatigue
  • dizziness or balance issues
  • aphasia/dysphasia (problems with speech and language)
  • myoclonus (involuntary movements)
  • permanent brain injury.

It’s normal to have no memory of a cardiac arrest. This can be alarming for you and your family members who may have seen it happening.

At MCP First Aid Training we provide a comprehensive range of training courses suitable for all ages.

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