Cardiac arrest refers to the loss of heart function. The heart’s main function is to pump blood towards the arteries so that they transport oxygen and other nutrients to the tissues. The main cause for cardiac arrest is heart attack. There are other extracardiac causes that may lead to cardiac arrest such as hypoxia when drowning or hypovolemic shock when hemorrhaging.

The most frequent body mechanism during cardiac arrest—after having a heart attack—is a serious arrhythmia called ventricular fibrillation. This arrhythmia might occur as a consequence of a sudden lack of oxygen caused by the obstruction of a coronary artery. Ventricular fibrillation causes chaos in the heart’s electrical activity which becomes mechanically inefficient and, as a consequence, the heart pumps little or no blood.

Warning Signs


When experiencing cardiac arrest, the person collapses, loses consciousness, suddenly loses all responsiveness, doesn’t breathe normally and shows no sign of heart rate.

What To Do?

Brain death or clinical death start around 4 to 6 minutes after cardiac arrest. Therefore, upon warning signs and if a person collapses, the first thing you should do is call the local emergency number—911 in some countries— and if you received proper training, give the person Cardiopulmonary Resuscitation (CPR). It is estimated that every minute the affected person spends without CPR, they lose a 10% chance of surviving and after 5 minutes, chances decrease considerably. CPR can mean the difference between a person’s life and death. This is why it is highly advisable to take a basic CPR course; there are some courses specially designed for beginners (non-medical staff) and specialized hospital staff.