What is a Sudden Cardiac Arrest?


Sudden Cardiac Arrest (SCA) is a condition in which the heart stops beating suddenly and unexpectedly due to a malfunction in the heart’s electrical system.  The malfunction that causes SCA is a life-threatening abnormal rhythm; an arrhythmia.  The most common arrhythmia is Ventricular Fibrillation (VF).

When in VF, the heart’s rhythm is so chaotic (called “fibrillating”) that the heart merely quivers and is unable to pump blood to the body and brain.  Once a heart has entered VF, an SCA may occur. During SCA a victim first loses his or her pulse, then consciousness and finally the ability to breathe.  All of this can happen quickly – in fact, in a matter of seconds…

What are the Facts about Sudden Cardiac Arrest?

  • It strikes without warning taking the lives of 250 people a day in the UK
  • Less than 5% of its victims in the UK survive
  • It kills more people than lung or breast cancer
  • It can happen to anyone, even young athletes
  • Defibrillation is the only treatment
  • Defibrillation within three minutes increases the chance of survival to over 70%
  • What is a Public Access Defibrillator (PAD)?

  • A Public Access Defibrillator (PAD) is an emergency life-saving device for use in the event of Sudden Cardiac Arrest.  It is a portable appliance that analyses the heart rhythm and, if needed, administers an electrical charge to the heart in order to establish a regular heartbeat in the event of a Cardiac Arrest.Only within the first few minutes following a Cardiac Arrest will a victim be in a ‘shockable rhythm’, and therefore rapid defibrillation is vital.  Placing PADs in the community can dramatically reduce the time from collapse to defibrillation and can greatly improve survival rates.
  • How does a PAD work?

    When turned on, the PAD will instruct the users to connect the pads to a patient’s bare chest.  The pads enable the Defibrillator to examine the patient’s heart and determine if the patient is in a viable, shockable rhythm.  If the device determines that a shock is required, it will charge up in preparation to deliver a shock.  The PAD is very safe as it will only deliver a charge when it determines a shockable rhythm is present.  For more information click here.

    When charged, the device instructs the user to ensure no-one is touching the victim and then to press a button to deliver the shock.  In the case of a fully automatic PAD the unit will advise the user that it will deliver the shock without further intervention.  After the shock is delivered, the device will instruct the user to commence/continue CPR (Cardio Pulmonary Resuscitation) for a period, after which it will analyse the patient’s heart rhythm once again, advising whether a further shock or more CPR is needed.

    A PAD has an internal memory, which stores the ECG of the patient along with details of the time the unit was activated and the number and strength of any shocks delivered.  All this memorised data can be either downloaded to a computer or printed out, so that it can be analysed by appropriate medical personnel.

    Who can use an PAD?

    Using a PAD is as simple as 1…2…3

  • It is the view of the Resuscitation Council (UK) that the use of an PAD is NOT to be restricted to trained personnel.  However chances of survival increase if the person has had some training in its use.  For this reason, it is recommended to run public awareness sessions and training when placing a PAD in the community.  PADs have visual prompts and voice prompts which guide the resuscitator through the process of defibrillation.  The device is failsafe and will not administer a shock unless a particular heartbeat is detected.

Can a Defibrillator be misused

A defibrillator will never administer a shock to a patient that does not require it, however it will still guide you through all the steps which may still be necessary.