Here are some sources that you might find interesting:

Callahan, Annice. Karl Rahner's Spirituality of the Pierced Heart: Toward a Reinterpretation of Devotion to the Sacred Heart (Lanham, Md.: University Press of America, 1985. Out of print.)

Callahan, Annice, ed. Spiritualities of the Heart: Approaches to Personal Wholeness in the Christian Tradition. NY: Paulist, 1990. Out of print.

Cuskelly, E.J., ed. With a Human Heart. Kensington, Australia: Chevalier Press, 1981. On loan through Annice Callahan, RSCJ, via acallahan@rscj.org

Haughton, Rosemary, et al. A New Heart for a New World: An Exploration of the Desires of God's Heart. Homebush, New South Whales, Australia: St. Paul Publications, 1986. On loan through Annice Callahan, RSCJ, via acallahan@rscj.org

Haring, Bernard. Heart of Jesus: Symbol of Redeeming Love. Liguori, Missouri: Liguori Pub., 1983. On loan through Annice Callahan, RSCJ, via acallahan@rscj.org

Nouwen, Henri. Heart Speaks to Heart. Notre Dame: Ave Maria Press, 1988.

Wright, Wendy. Sacred Heart: Gateway to God. Maryknoll, New York: Orbis Books, 2001.