L has just thought of a cunning plan to prevent himself being killed by a Death note:
He straps a device to his heart that directly links to an equivalent device strapped to Watari's (his butler) heart. If either heart stops beating (or the device is removed), then the other self-detonates and kills the other person. Which thus renders the Death note essentially useless against either of them, given the following rule:
Even though only one name is written in the Death Note, if it influences and causes other humans that are not written in it to die, the victim’s cause of death will be a heart attack ~ Rule XXVI - II linked death note rules wiki
Is this possible, or would L just die from a heart attack anyway?