AI can predict if you'll die soon – but we've no idea how it works

Artificial intelligence can predict a person's chances of dying within a year by looking at heart test results – even when they look normal to doctors. How it does so is a mystery. Brandon Fornwalt at healthcare provider Geisinger in Pennsylvania, US and colleagues tasked an AI with examining 1.77 million electrocardiogram (ECG) results from nearly 400,000 people to predict who was at a higher risk of dying within the next year. An ECG records the electrical activity of the heart. The team trained two versions of the AI: in one, the algorithm was only given the raw ECG data, which measures voltage over time.