There are certain devices that do do that, but it's not a defibrillator. A defibrillator will stop/prevent an arrhythmia by stopping the heart, and letting it restart on its own (hoping that it goes to a normal rhythm), and delivering further shocks if it gets back into one.
The device you're looking for to help a heart beat again would be a pacer, or a pacemaker, which will shock the heart to force it to pump, and restore rhythm that way. They're commonly used for conditions like heart failure, if the heartbeat generation systems/internal pacemaker can't generate a heartbeat quickly enough to sustain life.