Eli5: Why cant we resuscitate people with enough electric shocks?


Like say someone is perfectly healthy but their heart stops and they don’t get to the hospital in time. Why is it impossible to “turn them back on” through electricity? Especially since we figure the brain is just electrical impulses. Why can’t we jolt it back?

In: Biology

this is the misunderstanding with “the paddles” or as its called the defibrillators : they dont Restart a stopped heart, their job is ot shock the Heart muscle that is “spasming” back into a regular beat.

it does nothing for a stopped Heat: that requires CPR and chemical Aid and has to be performed quickly enough as so that the brain isn’t oxygen deprived for too long.

The brain is sending electrochemichal signals in a very complicated way. Different in every single nerve.

And even if we could replace the brain completely then it couldn’t restart after certain things happened. After the death it doesn’t take long for chemical processes to degrade our body because the byproducts of our metabolism aren’t transported away anymore. So unless you died literally a minute ago there is no chance to undo all the damage

A defibrillator (the shock thing) doesn’t restart a heart. It actually does the opposite. It stops it. Your heart regulates it’s own rhythm. If the heart goes into certain abnormal rhythms (like fibrillation, where it’s not beating properly), the defibrillator basically shocks it to make it stop, hoping that it’ll switch itself back on again with a normal (sinus) rhythm. If the heart isn’t doing anything (flatline) then the shock won’t help because it’s already off.

This is the reason why defibs are really dangerous. If someone’s heart isn’t in an abnormal rhythm and they get a shock, it might stop their heart and there’s no guarantee that it’ll start up again.

But to answer your question, shocks don’t start the heart. That’s why chest compressions are so important. They keep blood pumping in the hopes that the heart will start again. Otherwise, the brain will begin to get damaged from a lack of oxygen.

The brain is very sensitive to low oxygen because it’s very energy intensive. As little as 5 min without sufficient oxygen will lead to brain cells dying. That’s why you’ll see doctors jump straight into Chest compression and CPR, it’s done so that before medical help or support arrives, the brain doesn’t lose enough oxygen or it will die and you’ll have a vegetable.

Also, as u/A_Garbage_Truck also mentioned, paddles just correct the rhythm in your heart. It doesn’t exactly start it once it’s stopped. It synchronizes the heart’s beat so the contractions can happen more properly fixing blood supply to the body.

You might as well ask why burning someone with a fire or blasting them with UV doesnt bring them back. That’s not how the body works. If you shoot electricity through them you’re just cooking the corpse like you’re making panko from bread.

Like many ER docs would say “you can’t shock a stone heart”
If the heart has arrested – with no shockable rhythm, no amount of electricity can bring it back to life. However, effective CPR might give it a chance to maintain circulation while we look for reversible causes.