SF Watch is an occasional series in which I note occurrences of reality imitating art in Science Fiction books I've read. Spoiler Alert!
In Arthur C. Clarke's 1979 novel The Fountains of Paradise, the protagonist Vannevar Morgan has a heart condition. He wears a coronary alarm, or CORA, that will warn him (and the medical services) when a heart attack is imminent. Unfortunately, he's building something that takes him out of the reach of the emergency services...
Heart Watch offer a handheld device that can transfer EKG data over the phone to a specialist. The idea is that you use it at the first signs of discomfort, and the specialist then decides if you need to get to a hospital. A kind of medium-tech version of CORA, then.