Cardiac arrest and heart attack are two conditions used interchangeably by most people; however, there is a distinct difference between the two. A heart attack is a circulation problem that occurs when oxygen-rich blood is blocked in the arteries from reaching the heart; a person experiencing a heart attack is usually conscious. A cardiac arrest is an electrical problem that occurs when the heart stops beating correctly, and there is no detectable pulse; a person experiencing a cardiac arrest will quickly stop breathing normally.

What Causes a Heart Attack?

A heart attack could be caused by fatty deposits building up in the coronary arteries. Plaque can break away, with a blood clot forming around it, interrupting the usual flow around the body and stopping blood from reaching the heart.     

While not as common, a severe spasm of the coronary artery may temporarily pinch it shut and cut off blood flow. If left untreated, the heart muscle will become damaged and can start to die, leading to a cardiac arrest.

What Causes Cardiac Arrest?

Cardiac arrest is caused by an electrical malfunction in the heart. It suddenly stops pumping oxygenated blood around the body, to the brain and vital organs. Causes of this include:

  • Ventricular fibrillation (VF) – The most common cause of cardiac arrest. This is an example of a dangerous heart rhythm, when the heart quivers or “fibrillates” instead of pumping.
  • Cardiomyopathies (disease of the heart muscle) and inherited heart conditions, which include defects present from birth.
  • Heart valve disease – when one or more of the heart valves don’t work properly.
  • Severe or untreated myocarditis – inflammation of the heart muscle.

Other causes of cardiac arrest include:

  • Heart attack – often caused by coronary heart disease
  • Severe loss of blood, or other bodily fluids
  • Hypoxia – a severe lack of oxygen
  • Electrocution
  • Drug overdose
  • Hypothermia – low core body temperature
  • Abnormal pH, potassium or blood glucose levels

Recognition and First Aid for a Heart Attack

A person having a heart attack is usually conscious and may present with the following signs and symptoms:

  • Feel a crushing pain in their chest. This could spread to their jaw and down one or both arms.
  • Breathlessness, or gasping for breath.
  • Sweating profusely.
  • Have indigestion-type pain.
  • Collapse without warning.
  • Feel dizzy.
  • Have pale skin, with blue lips.
  • Have a rapid, weak or irregular pulse.
  • Have a feeling of impending doom.

The required first aid:

  • Call Emergency Medical Services immediately and follow the dispatchers’ instructions.
  • Help the patient into a comfortable position – likely sitting on the floor with knees bent and their head and shoulders supported.
  • If aspirin is available, provide this for the patient (unless they are under 16 or allergic).
  • Ask the patient if he/she has angina medication, and assist the patient to take it if so.
  • Keep monitoring their condition using the Cycle of Care and be prepared to deliver CPR if the patient becomes unresponsive.

Recognition and First Aid for Cardiac Arrest

If a victim is in cardiac arrest, they may not experience symptoms beforehand, will collapse suddenly and will present with the following signs and symptoms:

  • Unconscious.
  • Unresponsive.
  • Not breathing normally, or at all.

The required first aid:

  • Call Emergency Medical Services immediately and follow the dispatchers’ instructions.
  • Give immediate CPR and use a defibrillator (AED) to assist in shocking the heart back into a normal rhythm.

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