The Eucharist is truly the "Heart" of the Mass. When we receive Communion we are receiving the Heart of Jesus. A number of Eucharistic miracles have pointed to this fact over the years. Here is a link that speaks about one of these miracles - Modern Day Miracle of the Eucharist. As in Lanciano where the host was tested and found to contain heart tissue so, too, in this more recent Eucharistic miracle the host that was studied was found to contain this same tissue.
We've all heard the phrase, "You are what you eat" but I'd like to point you toward another great article on the Eucharist called Christ's Unfathomable Love. This takes "You are what you eat" to a whole new level!
Thank you, Lord, for the gift of the Eucharist. That you share with us your own Divine Heart is indeed...unfathomable.