When you are watching and listening to the personal stories, you may hear people mention some terms and abbreviations that you are not familiar with. The list below explains the some common ones:


An Out of Hospital Cardiac Arrest (OHCA) is a cardiac arrest that takes place outside a hospital. This can be in a public place, such as a shopping centre or in the street, or in a private place, such as the home.


Cardiopulmonary resuscitation (CPR) is an emergency procedure where someone presses up and down on the chest of a person who has had a cardiac arrest. If they are trained and confident in CPR, they may also give some rescue breaths via mouth-to-mouth resuscitation.


A defibrillator is a small device that gives an electric shock to the heart, through the chest wall, in order to re-start a heart that has stopped beating or that is beating abnormally. When this is done, it is called defibrillation.


An automated external defibrillator (AED) is a portable machine that can be used to defibrillate someone who is having a cardiac arrest.


A public access defibrillator (PAD) is an AED that is available in community settings to use when someone has a cardiac arrest. You can see them outside and inside many public buildings, for example, community halls, golf clubhouses and railway stations.

First Responder

A First Responder is someone who is trained in basic life support and the use of a defibrillator, who may be sent by the emergency services to attend a cardiac arrest. This could be, for example, paramedics, firefighters, Police Scotland staff or community first responders.


An implantable cardioverter defibrillator (ICD) is a small, battery-powered device that is placed under the skin of the chest or abdomen. It monitors the heart beat through thin wires attached to the heart. If the heart stops beating or beats abnormally, the ICD delivers an electric shock to the heart to get it beating normally again.

Intensive care unit (sometimes called an intensive therapy unit)

An intensive care unit (ITU) is a special hospital ward that provides intensive treatment and monitoring for people who are very ill. Many of the people in intensive care are on machines to help them breathe (ventilators).

Coronary care unit

A coronary care unit (CCU) is a hospital ward that specialises in the care of patients with heart problems who need continuous monitoring and treatment.

High dependency unit

A high dependency unit (HDU) is a ward where people can be cared for more extensively than in a normal ward. They are often located near intensive care units and patients who have been in intensive care often spend some time in HDU before going to a normal ward.

Induced coma

Some patients who survive a cardiac arrest are put into what is called an induced coma. This is where the person is given anaesthetic drugs, similar to those given when someone has an operation, to put them temporarily to sleep. This allows the body time to recover from the cardiac arrest. The person will be on a breathing machine (ventilator) to help them breathe.

Induced hypothermia

Induced hypothermia is called ‘cooling’. The person is cooled, using special blankets, to reduce the demands that their body is making on their brain. This is done where there is a risk that the person who had the cardiac arrest might suffer from damage to their brain, to give their body time to recover.


An electrocardiogram (ECG) is a non-invasive test, where electrode patches are attached to the skin to measure electrical impulses from the heart. An ECG can show disturbances in the electrical activity of the heart, which can be caused by abnormal heart rhythms and areas of injury.


An echocardiogram is usually called an Echo. A machine uses sound waves to produce images of the heart. Your doctor can use these images to examine the size and function of the heart and its motions as it beats. This test can help a doctor determine the cause of some heart problems.

The University of Edinburgh logo
CHSS logo
The Scottish Government logo