Conventional AI models in medicine are usually trained for a single, narrowly defined task, such as detecting a specific cardiac arrhythmia. So-called foundation models take a different approach: Much like a language model such as ChatGPT develops a comprehensive understanding of text, an ECG foundation model learns to "understand" the heart signal in all its diversity. It can then apply that knowledge to many medical questions—including those for which only limited specific training data is available. This is a decisive advantage, especially in medicine.