Sudden cardiac arrest (SCA) is an abrupt loss of pulse and consciousness caused by an unexpected failure in the heart's ability to effectively pump blood to the brain and around the body. It is usually caused by life-threatening arrhythmias, which are abnormalities in the heart's electrical system.
The sudden cardiac arrest victim first loses his or her pulse, then consciousness, and finally the ability to breathe. All of this happens quickly - within a few seconds.
Without immediate treatment, 90-95 per cent of SCA victims will die. The only definitive treatment for SCA is defibrillation - an electric current that "shocks" the heart so that a normal rhythm may resume.
Sudden cardiac arrest (SCA) is often confused with a heart attack. A prior heart attack increases one's risk for SCA, but SCA is quite different from a heart attack.
Both disorders stem from problems with the heart but each with distinct risk factors, treatment options, and outcomes.
• A heart attack is caused by a circulation or plumbing problem of the heart, when one (or more) of the arteries delivering blood to the heart is blocked. Oxygen in the blood cannot reach the heart muscle, and the heart muscle becomes damaged.
• Often a victim of a Heart Attack will remain conscious and will experience warning pains and symptoms.
• A heart attack can be treated with clot busting drugs and/or surgery.
• Some people will suffer a mild heart attack and never know.
• This damage to the heart muscle can lead to disturbances of the heart's electrical system. Such a malfunction of the heart's electrical system may cause dangerously fast heart rhythms that can lead to SCA.
• In contrast to a heart attack, sudden cardiac arrest (SCA) is usually caused by an electrical problem in the heart.
• SCA occurs when the heart's lower chambers (ventricles) suddenly develop a rapid, irregular rhythm (ventricular fibrillation) causing the ventricles to quiver rather than contract.
• The chaotic quivering motion of the ventricles renders the heart an ineffective pump that can no longer supply the body and brain with oxygen.
• A SCA victim will always die unless the heart is defibrillated quickly.
Around 140,000 people die from sudden cardiac arrest each year in the UK. It is the world’s biggest killer and can happen to anyone at anytime.
SCA can happen to anyone but someone is at higher risk if:
• They have previously suffered a heart attack or heart disease
• Have a family history of heart problems
• Have unknown heart problems
• Are a victim of asphyxiation (drowning, choking etc)
• Are a victim of electrocution
• Have an impact or trauma to the chest
Survival rates of a SCA victim drop by over 10% for every minute without defibrillation. After 10 minutes, the chances of survival are extremely small. With an AED on site, if defibrillation can take place within 3 minutes, the average chances of survival are 70% compared to 5% if a treatment is delayed until the emergency services arrive.
On the adult chain of survival sudden cardiac arrest is identified as an early priority.
Effective CPR will delay cell death but at no point will it get the heart beating regularly again, the ONLY effective treatment is defibrillation.