What is Sudden Cardiac Arrest?

Sudden Cardiac Arrest, or SCA, is the abrupt loss of heart function in a person who may or may not have been previously diagnosed with cardiovascular disease. The time and mode of the event are unexpected, and Sudden Cardiac Death (SCD) often results if not immediately treated by delivery of a therapeutic shock with a defibrillator. SCA occurs instantly or shortly after symptoms appear.  Each year, approximately 360,000 SCAs are reported to occur outside a Hospital or Medical Facility in the United States.

Is a Heart Attack the Same as Cardiac Arrest?

No.  The term “Heart Attack” is often mistakenly used to describe Sudden Cardiac Arrest, but they are very different.  While a Heart Attack may cause cardiac arrest and sudden death, Heart Attacks are caused by a blockage in a vessel that stops blood flow to a portion of the heart. A Heart Attack, or Myocardial Infarction (MI) refers to the death of the heart muscle tissue due to the loss of blood supply. It does not necessarily result in the death of the Heart Attack victim.

 Sudden Cardiac Arrest occurs when the heart’s electrical system malfunctions. SCA is caused by abnormal or irregular heart rhythms, also called “Arrhythmias.”  The most common arrhythmia in cardiac arrest is known as Ventricular Fibrillation. This is when the lower chambers of the heart (the ventricles) suddenly start beating fast and chaotically which makes it incapable of pumping blood. If the heart stops pumping blood, death can occur within a few short minutes. Cardiac Arrest may be reversed if an External Defibrillator is used to shock the heart and restore a normal heart rhythm within 3-4 minutes and/or Cardiopulmonary Resuscitation (CPR) is performed.