Question: What's the Difference Between Ventricular Fibrillation and Cardiac Arrest?
Answer: Cardiac arrest is the term that describes when a heart stops pumping blood around. When a victim's heart stops pumping blood and he or she stops breathing (which usually happens within a few seconds of the heart stopping), the victim is considered clinically dead. If the victim's heart doesn't start again or CPR isn't started within 4 minutes of cardiac arrest, brain damage is almost guaranteed.
Ventricular fibrillation is a form of heart rhythm disturbance that causes cardiac arrest. During ventricular fibrillation, the heart stops beating normally and simply begins quivering. No blood is pushed through because there is no squeezing action.
Believe it or not, if you have to go into cardiac arrest, ventricular fibrillation is the best case scenario. Ventricular fibrillation responds very well to electric shock, which stops the quivering and lets the heart's normal electrical activity start over. That's why we call those shock boxes defibrillators.
Ventricular fibrillation causes cardiac arrest, but not all cardiac arrest is caused by ventricular fibrillation.
Herlitz, J., et al."Characteristics of cardiac arrest and resuscitation by age group: an analysis from the Swedish Cardiac Arrest Registry." American journal of emergency medicine. Nov 2005