Is there a slang word for "electronic cigarettes" (e-cigarettes)?

An electronic cigarette (e-cig or e-cigarette), personal vaporizer (PV) or electronic nicotine delivery system (ENDS) is a battery-powered vaporizer which simulates tobacco smoking by producing an aerosol[1] that resembles smoke. http://en.wikipedia.org/wiki/Electronic_cigarette

These e-cigarettes have been commercially available in some countries for a couple of years, the UK included.

Has any slang word already been coined for them? (e-smoke? e-fag? e-dugans?)

The noun vape for some of the electronic nicotine delivery devices seems to be coming into vogue. It appears to be short for vape pen, which in turn is short for vapor or vaporizing pen.

A common verb form is vaping.

A search for vape shows numerous usages.

SUPPLEMENT: As @JLG points out, vape now appears in the Oxford Dictionary Online, both in verb and noun forms.

I have seen them referred to as electrofags, as seen here:-

Electrofags – now more deadly than smoke.

It’s been some time since I mentioned Electrofags...

This is a natural derivation from the British slang fag:-

A cigarette: ‘she’s got a fag in her mouth, and she’s squinting her eyes against the smoke’ [Oxford Dictionaries]

but might not be suitable for American use, where fag has a different meaning.