I Feel Much Better Now

Sometimes, when a person has a heart attack, that is to say the most important muscle in their body stops working and causes them to die, sometimes doctors will put electric paddles on the person's chest and shock them. And the heart starts beating again!

Why does that work?

That whole process seems very random and medieval.  Except for the electricity part. That doesn't seem medieval. The medieval defibrillator would probably seem even more random. It'd be two candles, smashed into a person's chest.

"CLEAR"!  Sssssssst!
OW!  What was that for?
"I was trying to start your heart."
That really hurt!
My nipples are blistered!
"Sorry,  let me put a couple of leeches on those burns..."

 The defibrillator just seems like a desperate guess.  Almost Frankenstein-esque.
"The Paddles, Egor!"
Yes, master!
KER-CHUNK
"He's Alive!  AlIIIIIIIVE!!"

I would have never thought that electrocuting something would make it work better.  Would you?
How can we get the dog to stop peeing in the house?
Well, lets attack these cables to his tail,
...and plug the other end into the wall.
Billy is struggling with Algebra.  He just can't seem to get it.
Jumper cables, please!
Here, Billy, bite down on this pencil...