a heartbeat away
heartbeat (away) from being (something)
In a position to move into a position immediately upon the absence of one's superior or predecessor (often assumed to mean from death). The position of vice president may not seem important, but whoever it is will be a heartbeat away from being president, so we should take that into account when voting.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
a ˈheartbeat away (from something)very close to something: The offices are a heartbeat away from Singapore’s business centre. ♢ With all her musical talent, it seems that success is just a heartbeat away.
Farlex Partner Idioms Dictionary © Farlex 2017