At McGill University, scientists have grown a beating miniature heart from the blood of a patient with dilated cardiomyopathy — a disease that quietly enlarges and weakens the heart until transplant becomes the only remaining option. By reprogramming those blood cells into heart muscle tissue and organizing them on a microchip, the researchers have created something rare: a living mirror of one person's illness, small enough to hold yet faithful enough to reveal the disease's deepest signatures. It is a moment in which medicine's oldest ambition — to understand suffering from the inside — find