October is National Sudden Cardiac Arrest Awareness Month, dedicated to educating patients and the public about what sudden cardiac arrest is and how to respond to a cardiac arrest.
Sudden cardiac arrest is when the heart suddenly stops beating, resulting in no blood flow to the brain and other vital organs. Approximately 300,000 out-of-hospital cardiac arrests occur each year in the United States, with a median reported survival-to-hospital-discharge rate of 8%.
What causes sudden cardiac death?
All known heart diseases can lead to cardiac arrest and sudden cardiac death. Most of the cardiac arrests that lead to sudden death occur when the electrical impulses in the diseased heart become rapid (ventricular tachycardia) or chaotic (ventricular fibrillation) or both. This irregular heart rhythm (arrhythmia) causes the heart to suddenly stop beating. Some cardiac arrests are due to extreme slowing of the heart which is called bradycardia. .
In 90 percent of adult victims of sudden cardiac death, two or more major coronary arteries are narrowed by fatty buildups. Scarring from a prior heart attack is found in two-thirds of victims. When sudden death occurs in young adults, other heart abnormalities are more likely causes. Adrenaline released during intense physical or athletic activity often acts as a trigger for sudden death when these abnormalities are present. Under certain conditions, various heart medications and other drugs — as well as illegal drug abuse — can lead to abnormal heart rhythms that cause sudden death.
The term “massive heart attack” is often wrongly used in the media to describe sudden death. The term “heart attack” refers to death of heart muscle tissue due to the loss of blood supply, not necessarily resulting in a cardiac arrest or the death of the heart attack victim. A heart attack may cause cardiac arrest and sudden cardiac death, but the terms aren’t synonymous.
Rapidly implementing the “chain of survival” model can help increase the chances of survival from sudden cardiac arrest. The steps in the chain include activation of emergency medical services by calling 9-1-1, starting cardiopulmonary resuscitation (CPR), using an automated external defibrillator (AED), and acquiring appropriate care. This year marks the 50th anniversary of CPR; updated CPR guidelines will be released later this year by the American Heart Association (AHA).
