Emergency Treatment
Sudden cardiac arrest (SCA) requires immediate treatment with a defibrillator. This device sends an electric shock to the heart. The electric shock may restore a normal rhythm to a heart that’s stopped beating.
To work well, defibrillation must be done within minutes of sudden cardiac arrest. With every minute that passes, the chances of surviving sudden cardiac arrest drop rapidly.
Police, emergency medical technicians, and other first responders usually are trained and equipped to use a defibrillator. Call 9–1–1 right away if someone has signs or symptoms of sudden cardiac arrest. The sooner help is called, the sooner potentially lifesaving treatment can be done.
Automated External Defibrillators
Automated external defibrillators (AEDs) are special defibrillators that untrained bystanders can use. These devices are becoming more available in public places like airports, office buildings, and shopping centers.
AEDs are programmed to give an electric shock if they detect a dangerous arrhythmia, such as ventricular fibrillation. This prevents giving a shock to someone who may have fainted but isn’t having sudden cardiac arrest.
Cardiopulmonary resuscitation (CPR) should be given to a person having sudden cardiac arrest until defibrillation can be done.
People who are at risk for sudden cardiac arrest may want to consider having an AED at home. Currently, one AED, the Phillips HeartStart Home Defibrillator, is sold over-the-counter for home use.
The benefits of home-use AEDs are still debated. Some people feel that placing these devices in homes will save many lives, because many sudden cardiac arrests occur at home.
Others note that no evidence supports the idea that home-use AEDs save more lives. These people fear that people who have AEDs in their homes will delay calling for help during an emergency. They’re also concerned that people who have home-use AEDs will not properly maintain the devices or forget where they are.
A large study on AEDs is currently under way. It may provide information on the pros and cons of having an AED in the home.
When considering a home-use AED, talk to your doctor. He or she can help you decide whether having an AED in your home will benefit you.
Treatment in a Hospital
If you survive sudden cardiac arrest, you usually will be admitted to a hospital for observation and treatment. In the hospital, your medical team will closely watch your heart. They may give you medicines to try to reduce the chance of another sudden cardiac arrest.
While in the hospital, your medical team will try to find out what caused your sudden cardiac arrest. If you’re diagnosed with coronary artery disease, you may have angioplasty or coronary artery bypass grafting. These procedures help restore blood flow through narrowed or blocked coronary arteries.
Often, people who have sudden cardiac arrest get a device called an implantable cardioverter defibrillator (ICD). This small device is surgically placed under the skin in your chest or abdomen. An ICD uses electric pulses or shocks to help control dangerous arrhythmias.
Sudden cardiac arrest (SCA) is a condition in which the heart suddenly and unexpectedly stops beating. When this happens, blood stops flowing to the brain and other vital organs.Sudden cardiac arrest usually causes death if it’s not treated within minutes.
Overview
To understand sudden cardiac arrest, it helps to understand how the heart works. The heart has an internal electrical system that controls the rate and rhythm of the heartbeat. Problems with the electrical system can cause abnormal heart rhythms called arrhythmias (ah-RITH-me-ahs).
There are many types of arrhythmias. During an arrhythmia, the heart can beat too fast, too slow, or with an irregular rhythm. Some arrhythmias can cause the heart to stop pumping blood to the body. These are the type of arrhythmias that cause sudden cardiac arrest.
Sudden cardiac arrest is not the same as a heart attack. A heart attack occurs when blood flow to part of the heart muscle is blocked. During a heart attack, the heart usually doesn’t suddenly stop beating. Sudden cardiac arrest, however, may happen after or during recovery from a heart attack.
People who have heart disease are at increased risk for sudden cardiac arrest. However, most sudden cardiac arrests happen in people who appear healthy and have no known heart disease or other risk factors for sudden cardiac arrest.
What Causes Sudden Cardiac Arrest?
Most cases of sudden cardiac arrest (SCA) are due to ventricular fibrillation v-fib). V-fib is a type of arrhythmia. In v-fib, the ventricles (the heart’s lower chambers) don’t beat normally. Instead, they quiver very rapidly and irregularly.
When this happens, the heart pumps little or no blood to the body. V-fib is fatal if not treated within a few minutes.
Other electrical problems in the heart also can cause sudden cardiac arrest. For example, sudden cardiac arrest can occur if the rate of the heart’s electrical signals becomes very slow and stops. Sudden cardiac arrest also can occur if the heart muscle doesn’t respond to the heart’s electrical signals.
Several factors can cause the electrical problems that lead to sudden cardiac arrest. These factors include:
Coronary artery disease (CAD), which reduces blood flow to the heart muscle
Severe physical stress, which raises the risk for abnormal electrical activity in the heart
Inherited disorders that disrupt the heart’s electrical activity
Structural changes in the heart that cause electrical signals to spread abnormally
Several research studies are under way to try to find the exact causes of sudden cardiac arrest and how to prevent them.
Coronary Artery Disease
CAD occurs when a fatty material called plaque (plak) builds up in the coronary arteries. These arteries supply your heart muscle with oxygen-rich blood.
Plaque narrows the arteries and reduces blood flow to your heart muscle. Eventually, an area of plaque can rupture, causing a blood clot to form on the surface of the plaque.
A blood clot can mostly or completely block the flow of oxygen-rich blood to the part of the heart muscle fed by the artery. This causes a heart attack.
During a heart attack, some heart cells die and are replaced by scar tissue. This damages the heart’s electrical system. The scar tissue may cause electrical signals to spread abnormally throughout the heart. These changes increase the risk for dangerous ventricular arrhythmias and sudden cardiac arrest.
CAD seems to be the cause of most cases of sudden cardiac arrest in adults. Many of these adults, however, have no signs or symptoms of CAD before having sudden cardiac arrest.
Physical Stress
Certain types of physical stress can cause the heart’s electrical system to fail. Examples include:
Intense physical activity. The hormone adrenaline is released during intense physical activity. This hormone can trigger sudden cardiac arrest in people who have other heart problems.
Very low blood levels of potassium or magnesium. These minerals play an important role in your heart’s electrical signaling.
Major blood loss.
Severe lack of oxygen.
Inherited Disorders
A tendency to have arrhythmias runs in some families. This tendency is inherited, which means it’s passed from parents to children. Members of these families may be at increased risk for sudden cardiac arrest.
An example of an inherited disorder that makes you more likely to have arrhythmias is long QT syndrome(LQTS). LQTS is a disorder of the heart’s electrical activity due to problems with tiny pores on the surface of heart muscle cells. LQTS can cause sudden, uncontrollable, dangerous heart rhythms.
People who inherit structural heart problems also may be at increased risk for sudden cardiac arrest. Many cases of sudden cardiac arrest in children are due to these problems.
Structural Changes in the Heart
Changes in the heart’s normal size or structure may affect its electrical system. Examples of such changes include an enlarged heart due to high blood pressure or advanced heart disease. Heart infections also may cause structural changes in the heart.
What Are the Signs and Symptoms of Sudden Cardiac Arrest?
Usually, the first sign of sudden cardiac arrest (SCA) is loss of consciousness (fainting). At the same time, no heartbeat (or pulse) can be felt.
Some people may have a racing heartbeat or feel dizzy or lightheaded just before they faint. Within an hour before sudden cardiac arrest, some people have chest pain, shortness of breath, nausea (feeling sick to the stomach), or vomiting.