Would it be within reason to house-rule spells like shocking grasp, lightning bolt etc. or abilities like Elemental Fist (shock) to have the chance to defibrillate a person in conjunction with a heal skill check? Maybe set the DC as 10 + creatures hit die + creatures con mod? One might even take a penalty on the check in conjunction with the amount of 'damage' one deals. So a high level wizard might sacrifice his lightning bolt spell and cast it at a lower caster level to deal 5d6 shock to the corpse on the chance it might restart his heart, or he could use a shocking grasp, or a monk could use his elemental fist, and so on, and so on. This would kind of be a last ditch effort to save someone as unless one were highly trained in the heal skill, the DC could potentially be too high to have even a chance of success.
I would imagine this could accurately reflect paramedics and doctors. Based on the Pathfinder NPCs I've seen, most are only first or second level, and so they may have anywhere between a +5 to a +10 on the heal skill check using a defibrillator (mimicking a 1d6 shocking grasp) to restart a patients heart. Likewise, the DC for the check would be roughly 13, so there is a good chance the doctor fails, which reflects real life.
Well, if you want realism, that's not the way to go. There's no reason why these spells shouldn't be cooking people alive in a medical context and of course you can't just defibrillate people whenever they're dying, they're heart has to be misbehaving in a particular way.
All that said, if it's just meant to be there as a dramatic device or an odd little cool thing, I say go for it. Why the hell not?
non-sequiter, but this relates to the topic Whenever I play a paladin, my LoH is one of two things: a celebratory butt-pat, or a defib shock, complete with the character yelling "Clear!" when a party member goes down.
First off, I think you would be better off applying leeches to remove their bad blood in order to cure them.
Seriously, the sort of trauma from a sword/spell fight is not going to cause the heart to go into a state of fibrillation (where different parts of the heart are beating out of sync). Defibrillation shocks the heart, causing it to STOP beating (not start beating). This allows the heart to restart on its own, but in sync and allowing for a normal heartbeat. The cells of the heart are able to initiate a heartbeat on their own when they are healthy.
As an aside, essentially every TV show gets it wrong, when they have someone shocking someone and bringing them back to life. Now since this is fantasy, you could say it actually works (even though it wouldn't in real life). But then if it is fantasy, you could just as well use leeches to gain the same effect.