Devotion to the Sacred Heart should bring us to a life of intimate union with Jesus who, we know, is truly present and living in the Eucharist. The two devotions - to the Sacred Heart and to the Eucharist - are closely connected. The Sacred Heart explains the mystery of the love of Jesus by which he becomes bread in order to nourish us with His substance, while in the Eucharist we have the real presence of the same Heart living in our midst. It is wonderful to contemplate this Heart of Jesus as the symbol of His infinite love, but it is even more wonderful to find Him always near us in the Sacrament of the altar. Jesus lives not only in heaven where His sacred humanity dwells in glory, but He lives also on earth wherever the Eucharist is reserved. In speaking of the Eucharist, Our Lord says to us: "Behold, I am with you all days, even to the consummation of the world" (Mt 28:20). In Holy Communion, then, this Heart beats within us, it touches our heart; through the love of this Heart, we are fed with His Flesh and with His Blood, so that we may abide in Him and He in us. "In the Eucharist," says Benedict XV, "this divine Heart governs us and loves us by living and abiding with us, so that we may live and abide in Him, because in this Sacrament.....He offers and gives Himself to us as victim, companion, viaticum and the pledge of future glory." Jesus said: "He that eateth My Flesh and drinketh my Blood abideth in Me and I in him" (Jn 6:57). The word "abideth" means that our union with the divinity of Christ does not cease after the sacred species are consumed. The three divine Persons dwell continually in souls in the state of grace; but there is also a certain enduring union with Jesus' sacred humanity, even when Christ is no longer substantially present in the one who has received Holy Communion, He is there by the influence of His operative presence and by the effusion of His grace. (Fragments from "The Sacred Heart and the Eucharist" - Ven Gabriel of St Mary Magdalene, OCD)
Encyclicals on the Holy Eucharist were written by Pope Leo XIII Mirae Caritatis and Pope Paul VI Mysterium Fidei
Homilies of Pope Benedict XVI on the solemnity of the Corpus Christ may be read HERE and HERE