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Sudden Cardiac Arrest

What is Sudden Cardiac Arrest?

Sudden cardiac arrest (SCA) occurs when the heart suddenly and unexpectedly stops beating, preventing blood flow to the brain and other vital organs. If not treated within minutes, SCA usually causes death. By contrast, a heart attack occurs when blood flow to the heart is blocked. SCA is an electrical problem; heart attack is a circulation problem.

Sudden Cardiac Arrest Causes and Risk Factors

SCA can occur following a heart attack, or during recovery from one. Although most heart attacks do not lead to SCA, heart attacks increase the risk for SCA.

Additional heart conditions that may disrupt the heart’s rhythm and cause SCA include:

  • Thickened heart muscle (cardiomyopathy)
  • Heart failure
  • Arrhythmias (particularly ventricular fibrillation)
  • Long Q-T syndrome (infrequent, hereditary disorder of the heart’s electrical system, usually affecting children or young adults)

Symptoms of Sudden Cardiac Arrest

SCA occurs suddenly and often without warning. When the heart stops beating, it ceases pumping blood to the brain, lungs and other organs. Seconds later, a person loses consciousness and has no pulse. Death occurs within minutes if the victim does not receive treatment.

Diagnosing Sudden Cardiac Arrest

SCA happens without warning and requires emergency treatment. Doctors rarely diagnose SCA with medical tests as it is occurring. Instead, SCA often is diagnosed after it happens, by ruling out other causes of a person's sudden collapse.

Treatments for Sudden Cardiac Arrest

SCA is reversible in most victims if treated within a few minutes. The American Heart Association recommends the following protocol:

  • Call 9-1-1 for emergency medical services.
  • Get an automated external defibrillator (AED), if one is available, and use it as soon as it arrives.
  • Begin cardiopulmonary resuscitation (CPR) immediately and continue until professional emergency medical services arrive.
  • If two people are available to help, one should begin CPR immediately while the other calls 9-1-1 and finds an AED.

Free BLS life support certification at work, church, or civic organizations helps increase the chance of SCA survival. Visit the American Heart Association for classes in your area.

Memorial Hermann’s team of world-class affiliated cardiologists work with SCA survivors to determine the cause of their SCA and to try to reduce the risk of recurrence.

FAQs about Sudden Cardiac Arrest

Can SCA be prevented?

If you’re at high risk for SCA, your physician may refer you to a cardiologist or an electrophysiologist (a cardiologist who specializes in problems with the heart’s electrical system), who will work with you to determine if you require treatment to prevent SCA. Your physician may prescribe certain diagnostic tests, including an electrocardiogram (EKG), an echocardiogram, a cardiac MRI, cardiac catheterization, an electrophysiology study or blood tests.

How common is SCA?

According to the American Heart Association, over 320,000 out-of-hospital cardiac arrests occur annually in the U.S., making SCA a leading cause of death.

I survived SCA. What’s next?

If you have survived SCA, you will likely be admitted to the hospital for ongoing care and treatment. If diagnosed with coronary heart disease, your cardiologist may prescribe procedures, such as an angioplasty or coronary artery bypass graft (CABG) surgery, to help restore blood flow through narrowed or blocked coronary arteries. SCA patients who have been diagnosed with a heart arrhythmia may be treated with an implantable cardioverter defibrillator (ICD) that uses electric pulses or shocks to help control dangerous arrhythmias.

Getting Started

At Memorial Hermann, affiliated physicians and surgeons perform more than 200,000 heart procedures annually. In fact, more than 50 percent of Houston’s heart care specialists are on active staff at Memorial Hermann hospitals.

As a result, our patients have access to the complete range of cardiac treatments, from interventional cardiology to electrophysiology.

To learn more about our diagnostic tests, cardiologists or treatment facilities, please use our contact form here. Schedule an appointment with a Memorial Hermann Cardiologist online or by calling (713) 222-2273.