I know defibrillators are used to help people experiencing cardiac arrest. But how exactly do electric shocks restore the normal rhythm? All bodily functions are depended on this one organ, so when this one little organ fails, what responds to the shocks to help bring the body back to life?
It’s astounding that this even happens at all in some cases.
In: Biology
Defibrillators do not help with cardiac arrest, that’s a myth from TV and movies. Defibrillation should only occur with certain irregular heartbeats that show up on an EKG. But if you’ve flatlined, a defibrillator isn’t going to do anything.
Your heart has its own electrical impulses and rhythm that cause normal heart contraction and a regular heartbeat. When this rhythm is out of whack and irregular, you can shock it back to normal. How exactly it works, we actually don’t know. It seems to just reset the heartbeat back to its normal rhythm. Sort of like turning off and turning on your computer when it’s not working right.
As for how they get your heart going again when it’s stopped. CPR will sort of mimic the effect of a heartbeat. A patient will also be given medications like epinephrine, which will help restart your heart if you’ve flatlined.
The heart isn’t like a battery. One misconception is that if your heart completely stops with no electrical activity (asystole) we can “jump start” the heart with a machine. That’s not the case. The heart muscle has an electrical pathway. If there’s an interruption like a heart attack, which makes the electrical activity have to find a new pathway it can cause dysrhythmia. This means the electricity kind of short circuits and doesn’t tell the heart muscle to contract properly. So the electrical shocks are to reset that pathway.
There are many causes that not only cause the heart to stop beating, but also cause it to contract in a completely disordered way.
If the heart stops beating, the defibrillation shock will not return the heart’s activity, therefore cardiac massage is the best option to force the heart to beat and deliver nutrients to essential organs, returning their functions (this includes the heart).
If the heart has completely disordered electrical activity that does not beat effectively, the shock will restart the electrical network, returning normal contraction.
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