The best replacement for defibrillator is cardioversion.

The best alternatives to defibrillator are rated as following:
★★★★★  cardioversion
★★★★★  pacemaker
★★★★  monophasic
★★★  cpr
★★★  defibrillator
★★  aed
★★  taser
★  defibulator
★  biphasic
  monophasic defibrillator
  pace maker

Your alternative for defibrillator is not listed? Suggest!
Speaking about defibrillator, one probably shouldn't forget about pacemaker.

Other search terms related to defibrillator and their ratings are:

★★★★★ pacemaker
★★★ pacer
★★ pacing
★★ cardiac monitor
external pacemaker
You have in mind a companion for defibrillator and it is not yet here? Propose!

Google Trends

Scale is based on the average worldwide traffic of defibrillator in all years. Click on graph for more.