This early afternoon show in the Pleasance Dome is one to get the blood pumping. Gavin Plimsole is an Arthur Dent-like character who has been told his heart fibrillations mean he’s susceptible to sudden cardiac death, a diagnosis which leaves him pondering another damaging blow to his heart – a painful recent break-up with the girl he loves. It gets him thinking. What do all our heartbeats mean? What use do we make of them? To help discuss the point, the audience have all been strapped up to heart monitors, so we can see the state of our hearts in real time projected upon Gavin’s shed.

Our heart monitors, nicely but somewhat arbitrarily used to select people for audience participation, are a nice touch. Get your heartrate up to 120 and you can decide what Gavin should do about his love’s new boyfriend. Cut it to 70 and decide whether he tells her he loves her. We’re also told that the marble run attached to the side of the shed is kickstarted every time our collective hearts beat 500 times (not strictly true or it would be an endless stream of marbles, but another inventive idea).

But though it gives the show a personal touch, it’s makes for a cluttered set and performance. Between Plimsole, his two helpers and all the props, there’s a lot going on, and it’s not all suitable for the space. The projection of our heart monitors is not on a flat surface making them hard to read, the marble run is prone to malfunction and there’s a lot going on with boxes and feet which isn’t visible from the back. And it’s not entirely clear what effect, if any, the choices of the audience are having on the story. At one point, after presenting audience members with three options to choose, Plimsoll cycles through them all. An atmospheric climax ends rather confusingly, and with a cryptic “ending 4” pinned to the shed door, which suggests we’ve managed to point him in some direction or other, but we’re not sure how. What significance the shed has beyond a useful prop is also unclear.

Admirably ambitious, and bound to get you thinking about your own heart health, both biologically and romantically, The Inevitable Heartbreak of Gavin Plimsole is full of ideas, but could dispense them with a steadier pulse.