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  Southern Technical Aquatic Resource & Rescue

Heart Attack verses Sudden Cardiac Arrest
A "Heart Attack", or what is known to the medical profession as a Myocardial Infarction (MI) and Sudden Cardiac Arrest (SCA) are not the same thing, but in fact are completely different from each other - like that of apples and oranges. Sure they both grow from trees and are fruits but they still are different. So what are the differences?

Heart Attack:
This is caused by a circulation problem within the heart when one or more of the small arteries delivering blood to the heart are blocked. This blockage keeps oxygen that is in the blood from reaching the heart muscle, which causes the heart muscle to become damaged. A simple way to understand this is look at it as a "plumbing problem" within the heart itself.

This damage to the heart can lead to other problems like the hearts electrical system malfunctioning. When the heart electrical system begins to malfunction it can create some dangerous rhythms that can eventually lead to Sudden Cardiac Arrest.

Sudden Cardiac Arrest:

Compared to a heart attack, sudden cardiac arrest is caused by the "electrical problem" that was created by the "plumbing problem", whereby an produces an abnormal heart rhythm that does not allow blood to flow correctly throughout the body. 

The abnormal heart rhythms, in medical term arrhythmias, that may occur during sudden cardiac arrest (SCA) are:

  • Ventricular Fibrillation (VF) - the heart quivers all over all instead of beating
  • Ventricular Tachycardia (VT) - the bottom of the heart beats too fast which does not allow for the blood to be pumped out of it
  • Asystole - the absence of any movement within the heart (stops all together)
  • Pulseless Electrical Activity (PEA) - the heart produces some electrical activity trying to cause the heart to beat but the heart muscle                will not contract or beat

In the event of Sudden Cardiac Arrest, time is critical. For every minute defibrillation is delayed, the victim's chance of survival decreases by nearly 10%. After 10 minutes, typically Sudden Cardiac Arrest survival rates could potentially drop to extremely low numbers without any bystander CPR and/or an Automated External Defibrillator (AED). 

Manual CPR was developed to keep oxygen moving to the brain of a person whose heart has stopped beating. The idea is that by physically pushing on the chest approximately 2 inches, the heart will be forced to move oxygen and blood to the brain. This along with an AED can increase survival rates from Sudden Cardiac Arrest to nearly 75% by delivering a life-saving shock within the first 6 minutes.