Technically, the shock delivered during defib is called conversion. It pauses the incorrect electrical activity to give the heart a chance to restart with a normal rhythm with a pulse. You're 100% dead wrong on restarting the heart from flat line (asystole). Source - I've done it A LOT. https://theconversation.com/mondays-medical-myth-flatlining-patients-can-be-shocked-back-to-life-13662

Technically, the shock delivered during defib is called conversion. It pauses the pulseless electrical activity to give the heart a chance to restart with a normal rhythm with a pulse. You're 100% dead wrong on restarting the heart from flat line (asystole). Source - I've done it A LOT. https://theconversation.com/mondays-medical-myth-flatlining-patients-can-be-shocked-back-to-life-13662