For generations, a heart attack has been seen as an irreversible decline. But a groundbreaking discovery by CUHK researchers may now be poised to change that. They have identified a hidden regenerative “switch” within the human immune system. Flipping it back on could reawaken the heart's dormant ability to heal itself—a power it once briefly held in infancy—turning a heart attack from a point of no return into a new beginning. This discovery doesn't just challenge a long-held medical belief; it opens an entirely new frontier in repairing damaged hearts.