Cardiac Arrest

Cardiac arrest happens when your heart abruptly stops pumping blood to the rest of the body due to a problem with electrical signals in the heart. When this occurs, the brain is starved of oxygen, causing a loss of consciousness and the ability to breathe. Cardiac arrest is a medical emergency, and without immediate treatment, is fatal.

CausesThe most common cause of cardiac arrest is a dangerous abnormal heart rhythm called ventricular fibrillation – when the electrical activity of your heart becomes so chaotic that the heart stops pumping and quivers or 'fibrillates' instead.

Other heart-related causes of cardiac arrest:

  • coronary heart disease
  • heart attack
  • cardiomyopathy and some inherited heart conditions
  • congenital heart disease
  • heart valve disease
  • acute myocarditis
  • heart conduction disorders that make you more likely to experience abnormal heart rhythms, such as Long QT syndrome

Other causes of cardiac arrest:

  • electrocution
  • drug overdose
  • severe hemorrhage
  • drowning

SymptomsIn most cases, there are no symptoms preceding cardiac arrest. Without immediate treatment, it will be fatal. Someone experiencing cardiac arrest:

  • Won’t be conscious
  • Won’t be responsive
  • Won’t be breathing, or breathing normally

TreatmentVentricular fibrillation is treated by giving an electrical shock through the chest wall using a defibrillator. This can be done by a member of the public, emergency services, or at a hospital.

Immediate CPR will keep oxygen circulating around the body until a defibrillator can be used and/or until the emergency services arrive.

Cardiac Arrest vs a Heart AttackA common misconception is that cardiac arrest and heart attacks are the same thing. This is not the case. So, what’s the difference between cardiac arrest and a heart attack?

In short, cardiac arrest is an electrical problem, whereas a heart attack is a circulation problem.

Cardiac Arrestoccurs when the heart suddenly stops beating due to a problem with electrical signals to the heart muscle.


Heart Attack happens when the blood supplying the heart muscle is cut off due to a blood clot in one of the heart’s arteries.

Heart attacks cause chest pain, and though symptoms can be less severe than with cardiac arrest, permanent damage to the heart can occur. During a heart attack, the heart is still sending blood to the body and you will be conscious and breathing.