When it comes to hearth health, a lot of attention is focused on heart attack symptoms and prevention. However, the American Heart Association reports that almost 300,000 people each year suffer sudden cardiac arrest (SCA) outside of hospitals. SCA is a dangerous condition in which electrical signals to the heart malfunction, causing the heart to beat in an atypical rhythm.

“A cardiac arrest is when the heart stops supplying blood to the rest of the body. Usually it’s due to an abnormal beating of the ventricle (the bottom part of the heart) that prevents normal blood flow,” explains Dr. Kimberly Perry, chief of emergency medicine at Christian Hospital and a board member for the American Heart Association Greater St. Louis Division.

Unlike the electrical disruption of SCA, a heart attack is characterized by one or more obstructed cardiac blood vessels, which prevent blood flow and endanger the heart muscle. Within as little as 90 minutes, heart muscle tissue can stop functioning due to lack of oxygenated blood. In some cases, a heart attack can lead to cardiac arrest, usually within the first 24 hours.

While it is most common for cardiac arrest to follow a heart attack, SCA can be caused by a variety of often-undiagnosed heart abnormalities. “Other causes of muscle cell damage, such as myocarditis or cardiomyopathy, valvular heart disease or congenital heart abnormalities, can cause sudden cardiac arrest. Electrical abnormalities of the heart also can cause sudden cardiac arrest, such as long QT syndrome or Brugada syndrome, often exacerbated by drug use or electrolyte disturbances,” says Dr. Stuart Higano, an interventional cardiologist, medical director of Heart LifeLine Alliance and director of the acute cardiac care team at Missouri Baptist Medical Center.

People who have SCA lose consciousness and stop breathing or breathe irregularly. Survival is unlikely unless cardiopulmonary resuscitation (CPR) is initiated quickly. “CPR is remarkably effective in saving the life of someone who has sudden cardiac arrest. However, CPR is only useful when coupled with early activation of the emergency medical system (calling 911) to provide a rapid defibrillation, or shock, to restore a normal rhythm,” Higano says.

CPR can maintain some blood circulation until the heart is shocked back into rhythm. The American Heart Association recommends that everyone become familiar with hands-only CPR, a method in which hard, fast chest compressions are administered until help arrives. The technique is simple and can be viewed in a one-minute AHA video tutorial on You Tube. Local CPR classes are available through the AHA and information is available at heart.org or by calling 692-5635.

Reducing the risk of SCA involves controlling many of the same risk factors that affect overall cardiovascular health. Smoking, high cholesterol, hypertension, physical inactivity, obesity and diabetes can contribute to increasing risk.