“The Catholic Church claimed its symbol of the Sacred Heart began with a vision of Saint Margaret Marie Alacoque late in the seventeenth century, depicted by her as a heart surrounded by thorns. The symbol was, however, a great deal older than that. It appeared in an alchemical text published before Saint Margaret Marie was born. It appeared in a number of stained glass windows and cloister decorations several centuries earlier. And the symbol of the heart as a stand-in for the soul was a common place of Christian iconography. The tympanum of Bourges Cathedral showed the vessel of the soul weighed in the balances after death, bearing a striking resemblance to the ancient Egyptian ab or “heart-soul” that was to be weighed in the balances by the Goddess Maat, Mother of Truth.
The ab was that one of the Egyptian’s seven souls that was supposed to come directly from the mother’s heart, in the form of the holy lunar blood that descended into her womb to take the shape of her child. The hieroglyphic sign for this eminently matriarchal idea was a dancing figure, representing the inner dance of life perceived in the heartbeat. As long as the dance continued, life went on. Osiris in his death phase was called Still-Heart because he no longer danced.
The idea of a heartbeart-dance at the core of all living things was vividly presented in Oriental symbolism by the perpetual Dance of Shiva (see Dance), taking place in the “center of the universe” which is also the human heart.”
-Heart, The Woman’s Dictionary of Symbols and Sacred Objects.