Sudden cardiac arrest (SCA) occurs when the heart stops beating suddenly and without warning. It is different than a heart attack, which is caused by blocked blood flow to a part of the heart. During a heart attack, the heart keeps beating.
What causes cardiac arrest?
In most people, ventricular fibrillation (v-fib) causes cardiac arrest. In v-fib, the lower chambers of the heart don’t beat normally and pump very little or no blood to the rest of the body. V-fib is a type of arrhythmia.
Sudden cardiac arrest can also occur if the heart’s electrical signal slows or stops or if the heart muscle doesn’t respond to the electrical signals that trigger a heartbeat.
Risk factors for sudden cardiac arrest include coronary artery disease, inherited disorders, or structural issues with the heart muscle. However, sudden cardiac arrest can occur in otherwise healthy people.
Symptoms of cardiac arrest
The first sign of sudden cardiac arrest is usually fainting (syncope). Prior to losing consciousness, you may also feel:
After losing consciousness, the heart will stop beating. Once that happens, blood stops flowing to the brain and other vital organs, which can cause death in minutes. Automated external defibrillators (AEDs) can be used by bystanders to save the life of a person having SCA.
How is cardiac arrest diagnosed?
Sudden cardiac arrest is usually diagnosed after it happens by ruling out other causes of fainting. Several tests can detect factors that put you at risk for cardiac arrest:
- Blood tests
- Cardiac catheterization
- Cardiac MRI
- Electrocardiogram (EKG)
- Electrophysiology study
- Multiple gated acquisition (MUGA) test
How is cardiac arrest treated?
Sudden cardiac arrest is a medical emergency that must be treated immediately with a defibrillator. This device shocks the heart and can restore a normal rhythm. As time passes, the chances of a defibrillator restoring normal sinus rhythm rapidly decrease.
You’ll need to be hospitalized following cardiac arrest. Your doctors will try to determine what caused the cardiac arrest and begin treatment to prevent another episode. You will need to see a cardiologist that specializes in problems with the heart’s electrical system. They are called electrophysiologists.
An implantable cardioverter defibrillator (ICD) can be placed to terminate v-fib in the future.