What is a Sudden Cardiac Arrest (SCA)?
SCA is a condition whereby 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, or 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 around the body and brain. Once a heart has entered VF, sudden cardiac arrest may occur. A victim in SCA first loses his or her pulse, then consciousness, and finally the ability to breathe. All of this can happen in a matter of seconds.
SCA is not the same as a heart attack, although a person suffering a heart attack has an increased risk of SCA.
A heart attack can be thought of as a problem with the plumbing of the heart, a SCA is a problem with the electrical system of the heart.
What are the symptoms of sudden cardiac arrest?
- Unresponsiveness
- Loss of consciousness
- Lack of pulse
- Cessation of breathing
- Ventricular Tachycardia
- Ventricular Fibrillation
How is sudden cardiac arrest treated?
Defibrillation and CPR
When someone is in cardiac arrest, defibrillation (the administration of an electric shock) is the only way to re-establish the heart’s natural rhythm.
Cardiopulmonary Resuscitation (CPR) will not restart a heart in cardiac arrest. CPR is a temporary measure used to continue a minimal supply of oxygen to the brain and vital organs.
When responding to a patient in cardiac arrest, the best approach is to combine CPR efforts with defibrillation. Often people think that CPR alone is enough to treat sudden cardiac arrest, but in fact CPR has a 5% success rate compared with a 50% success rate when coupled with an AED.
CPR alone = 5% success rate
CPR + AED = 50% success rate
Further information on AED usage and CPR guidelines are available from the Resuscitation Council (UK) www.resus.org.uk
The Chain of Survival
SCA survival depends on a series of critical actions. If one of these critical interventions is neglected or delayed, survival is unlikely. In 1990 the American Heart Association (AHA) developed the Chain of Survival, now recognised worldwide as the optimum response to SCA.
The Chain of Survival addresses the fact that most SCAs occur outside of a hospital setting. Death can occur within minutes, so in order to be effective the steps in the Chain must be followed promptly. Quick action by the first person on-scene can truly make a difference in saving a life.
The chain of survival protocol represents the sequence of four events that must be followed in the first vital minutes after collapse:
- Early Access to emergency care by dialling 999 immediately
- Early CPR should be started and continued until the arrival of emergency services
- Early Defibrillation should be administered with an AED as quickly as possible
- Early Advanced Care can be administered by emergency services personnel
A series of related and connected events, the Chain of Survival defines the roles of bystanders, dispatchers, first responders, emergency service personnel, paramedics, doctors and nurses, coordinated as a team to help save lives.
Strengthening each link in the chain helps to prevent sudden cardiac arrest from becoming sudden cardiac death.
Click here to see our Sudden Cardiac Arrest booklet
Have you ever suffered a cardiac arrest?
Arrhythmia Alliance invites you to share your story to help raise awareness of sudden cardiac arrest and the importance of automated external defibrillators (AEDs) as life-saving equipment.
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