53 Universal human experience has made the image of the heart something unique. Indeed, throughout history and in different parts of the world, it has become a symbol of personal intimacy, affection, emotional attachment and capacity for love. Transcending all scientific explanations, a hand placed on the heart of a friend expresses special affection: when two persons fall in love and draw close to one another, their hearts beat faster; when we are abandoned or deceived by someone we love, our hearts sink. So too, when we want to say something deeply personal, we often say that we are speaking “from the heart”. The language of poetry reflects the power of these experiences. In the course of history, the heart has taken on unique symbolic value that is more than merely conventional.
Source: Dilexit Nos (Vatican.va)