Key Points

• 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.
• SCA usually causes death if it's not treated within minutes.
• SCA usually occurs when the heart develops an arrhythmia (irregular heartbeat) that causes the heart to stop pumping blood to the body.
• SCA is not the same as a heart attack. During a heart attack, the heart usually doesn't stop beating. SCA, however, can happen after or during recovery from a heart attack.
• Most cases of SCA are due to an arrhythmia called ventricular fibrillation. Other electrical problems in the heart also can cause SCA. Several factors can cause the electrical problems that lead to SCA. These factors include coronary artery disease (CAD), severe physical stress, inherited disorders, and structural changes in the heart.
• SCA occurs most often in people in their mid-thirties to mid-forties. It affects men twice as often as women. The major risk factor for SCA is undiagnosed CAD.
• Usually, the first sign of SCA is loss of consciousness (fainting). At the same time, no heartbeat (or pulse) can be felt. Some people may have a racing heartbeat, dizziness, lightheadedness, chest pain, shortness of breath, nausea (feeling sick to the stomach), or vomiting before SCA.
• SCA often happens without warning. It requires immediate emergency treatment. Doctors rarely have a chance to diagnose SCA with medical tests as its happening. Instead, SCA usually is diagnosed after it happens. Doctors do this by ruling out other causes of a person's sudden collapse.
• SCA requires immediate treatment with a defibrillator. This device sends an electric shock to the heart. The shock may restore a normal rhythm to a heart that's stopped beating. To work well, defibrillation much be done within minutes of SCA.
• 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.
• If you survive SCA, you usually will be admitted to a hospital for observation and treatment. Your medical team will try to find out what caused your SCA. If you're diagnosed with CAD, 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 SCA get a device called an implantable cardioverter defibrillator (ICD) to prevent a repeat SCA. 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.
• Talk to your doctor about ways to prevent death due to SCA. Medical devices, medicines, and lifestyle changes can lower your risk for SCA. What steps you should take depend on if you've already had SCA, if you've never had SCA but are at high risk for the condition, or if you've never had SCA and have no known risk factors for the condition.