ELI5: Explain Like I'm 5

Cardiac action potential

Cardiac action potential is like a light switch. When the switch is flipped on, electricity goes through and a door opens. In your heart, the electricity is special chemicals that help it beat. The special chemicals flow from one part of the heart muscle to the other. This makes the heart muscle squeeze and push out blood to the rest of your body. The whole process happens in a few milliseconds, and without it, your heart wouldn't beat.