To save one life is as if to save the world.

- The Talmud

Sudden Cardiac Arrest FAQs

What is sudden cardiac arrest?
Is SCA the same as a heart attack?
Who is at risk for SCA?
What is an ejection fraction?
What causes SCA in young people?
How can SCA be prevented?
How should SCA be treated?
What is an AED?
How does an AED work?
Who can use an AED?
Can I accidentally hurt the victim with an AED?
Can I hurt myself or others with an AED?
Can the AED be used safely if the victim is on a metal surface such as a bleacher or stretcher?
Are there special considerations when placing electrodes on a female victim?
What if the victim has a medication patch, such as nitroglycerin?
What if the victim has an implantable pacemaker or defibrillator?
Do AEDs alway help SCA victims?
What is the difference between AEDs and defibrillators commonly used on ambulances and in hospitals?
Where should AEDs be deployed?
Do I have to have a prescription to acquire an AED?
Do AEDs replace the use of CPR?
After resuscitation, will the victim be able to resume a normal life?
Can AEDs be used to treat children?
 

What is sudden cardiac arrest?
Sudden cardiac arrest (SCA) is a condition in which the heartbeat stops abruptly and unexpectedly. This usually is caused by ventricular fibrillation (VF), an abnormality in the heart's electrical system. When this happens, blood stops flowing to the brain the heart and the rest of the body, and the person collapses. In fact, the victim is clinically dead and will remain so unless someone helps immediately. A quick combination of CPR and defibrillation can restore life.

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Is SCA the same as a heart attack?
No. A heart attack is a condition in which a blood clot suddenly blocks a coronary artery, resulting in the death of the heart muscle supplied by that artery, unless the clot is opened within a few hours. Heart attack victims usually experience symptoms such as chest discomfort or pain and remain conscious. Most people who have a heart attack survive the event. Some will develop an SCA. Other people have an SCA independently from a heart attack and without warning signs. SCA results in death if it is not treated immediately. More...

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Who is at risk for SCA?
SCA often occurs in active people who seem to be healthy and have no known medical conditions. In these patients, SCA is the first indication of a heart condition. However, some people can be identified in advance as being at risk for SCA. Risk factors include:

  • Previous heart attack
  • Coronary artery disease (and risk factors for CAD including smoking, high blood pressure,
    diabetes, elevated LDL cholesterol, family history of heart disease, sedentary lifestyle)
  • Heart failure from other causes
  • Abnormal heart rate or rhythm (arrthythmia) of unknown cause
  • Episodes of fainting of unknown cause
  • Low ejection fraction (EF) (<35%).

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What is an ejection fraction?
The ejection fraction (EF) is a measurement of how much blood is pumped by the verntricles with each heart beat. A healthy heart pumps 55 percent or more of its blood with each beat.

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What causes SCA in young people?
There are three common causes. Long QT syndrome is an often unrecognized congenital condition that predisposes the child to an abnormality in the heart's electrical system, which can lead to SCA. This is a genetic disease that affects 1 in 7,000 young people. Episodes are most commonly triggered by physical exertion or emotional stress. Commotio cordis is an electrical disturbance cases by a blow to the chest. It occurs most often in baseball, but has been reported in other sports and situations in which there is a blow to the chest. Researchers at the U.S. Commotio Cordis Registry studied 124 cases and found the average age is 14. Only 18 victims (14%) survived; most who survived received prompt CPR and defibrillation. Hypertropic cardiomyopathy is a congenital heart muscle disease. The walls of the heart's left ventrical become abnormally thickened (hypertrophy). The structural abnormality can lead to obstruction of blood flow from the heart, causing loss of consciousness and irregular heartbeat, leading to SCA. About 1 in 500 to 1000 young people have this condition.

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How can SCA be prevented?
Living a healthy lifestyle--exercising regularly, eating healthy foods, maintaining a reasonable weight, and avoiding smoking--can help prevent SCA. Monitoring and controlling blood pressure, cholesterol levels and diabetes is also important. If abnormal heart rhythms or arrhythmias are detected, they can be treated through implantable cardioverter defibrillator (ICD) therapy, use of medications such as ACE inhibitors, beta blockers and calcium channel blockers, and catheter ablation.

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How should SCA be treated?
SCA is treatable most of the time, especially when it is due to an electrical abnormality called ventricular fibrillation (VF). Immediate treatment includes cardiopulmonary resuscitation (CPR) and use of defibrillators. This treatment must be provided within moments of collapse to be effective, preferably within three to five minutes. Even the fastest emergency medical services may not be able to reach a victim this quickly. That is why prompt action by bystanders is so critical and why it is so important that more laypersons learn CPR and how to use an automated external defibrillator (AED).

Subsequent care includes administration of medications and other advanced cardiac life support (ACLS) techniques by emergency medical personnel. In patients who have been successfully resuscitated but remain in a coma after cardiac arrest due to VF, mild hypothermia can improve the chances of survival with good brain function. SCA survivors should see heart specialists (cardiologists and electrophysiologists) for follow-up care.

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What is an AED?
An AED, or automated external defibrillator, is a device that automatically analyzes heart rhythms and advises the operator to deliver a shock if the heart is in a fatal heart rhythm. AEDs are safe and will not shock anyone who is not in a fatal heart rhythm. Non-medical personnel can use AEDs safely and effectively with minimal training.

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How does an AED work?
A computer inside the defibrillator analyzes the victim's heart rhythm. The device decides whether a shock is needed. Some devices shock the victim automatically if a shock is needed. Other devices require that the operator press a button to deliver the shock. The shock is delivered through pads stuck to the victim's bare chest. The shock stuns the heart, stopping abnormal heart activity, and allowing a normal heart rhythm to resume.

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Who can use an AED?
Modern AEDs are designed to be used by any motivated bystander, regardless of training. The devices are designed to advise the user about how to apply the device and whether or not to administer a shock. Some devices shock automatically if the victim has a fatal heart rhythm. Training is important, however, particularly since almost all victims also need CPR (cardiopulmonary resuscitation). Most of the time, the AED will advise the user to administer CPR, depending on the needs of the victim, and in these cases it is quite helpful to have CPR training. AEDs have been used successfully by police, firefighters, flight attendants, security guards and lay rescuers.

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Can I accidentally hurt the victim with an AED?
No. Most SCA victims will die if they are not treated immediately. Your actions can only help. AEDs are designed in such a way that they will only shock victims who need to be shocked.

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Can I hurt myself or others with an AED?
No, not if you use it properly. The electric shock is programmed to go from one pad to the other through the victim's chest. Basic precautions, such as not touching the victim during the shock, ensure the safety of rescuers and bystanders.

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Can the AED be used safely if the victim is on a metal surface such as a bleacher or stretcher?
Yes. AEDs can be used safely as long as the electrode pads do not come into contact with the metal surface.

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Are there special considerations when placing electrodes on a female victim?
If the victim is wearing a bra, remove it before placing electrodes.

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What if the victim has a medication patch, such as nitroglycerin?
Never place electrodes directly on top of medication patches. If the patch is in the way of the AED pads, remove it and wipe off the area with the victim's shirt. Then apply the pads to the clean, bare skin.

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What if the victim has an implantable pacemaker or defibrillator?
If the victim has a pacemaker or internal defibrillator with a battery pack (visible as a lump under the skin about two inches long), avoid placing pad directely on top of the implanted medical device.

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Do AEDs always help SCA victims?
No. AEDs are designed to treat victims in SCA with an irregular heart rhythm called ventricular fibrillation (VF). AEDs work best in these victims if they are used quickly and if the victim has received cardiopulmonary resuscitation (CPR). SCA victims who suffer from other irregular heart rhythms benefit from CPR, drug therapy and advanced treatments such as hypothermia.

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What is the difference between AEDs and defibrillators commonly used on ambulances and in hospitals?
Defibrillators sometimes used on ambulances and in hospitals, and often seen on TV, are manual defibrillators. They are larger than AEDs and are designed to be used by qualified medical personnel with special training. In contrast, AEDs are smaller and computerized so that virtually any operator can use the device and simply follow the audio and visual prompts. The decision to shock or not to shock is determined by the device, not the operator.

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Where should AEDs be deployed?
Logical locations for AED placement include police cars, airports, train and bus stations, highway rest stops, sports arenas, doctor and dentist offices, health clinics, fitness clubs, shopping malls, large grocery stores, theatres, workplaces, schools, churches and retirement communities. Increasingly, consumers are choosing to purchase AEDs for their homes and vehicles.

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Do I have to have a prescription to acquire an AED?
A prescription from a physician is required for purchasing most AED models. However, at least one model has been cleared by the Food and Drug dministration for use without a prescription and is available over the counter.

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Do AEDs replace the use of CPR?
No. CPR is still very important and high quality CPR can greatly improve the chances of survival.

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After resuscitation, will the victim be able to resume a normal life?
More than 80 percent of SCA victims who are discharged home from the hospital live at least one year. More than half live another five years after resuscitation. Most people who survive SCA can return to their previous level of functioning. All survivors need follow-up care with physicians who specialize in heart conditions (cardiologists and electrophysiologists.)

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