Precisely the same pages which have led Catholic artists(and theologians, for that matter) for generations to focus particularly on the Sacred Heart of Jesus.
The heart for the ancients was the home of the soul. And so for the early Church, the Sacred Heart of Jesus became a dramatic way of stressing both Christ's divinity and His humanity.
Of course, we moderns know better. Since the Enlightment, we've pulled hearts out and looked at them. And we didn't see any soul. So it must not be there. Today, we view the heart as a) a biological organ which pumps blood and b)a figurative symbol for the emotions which, we all know, are in fact caused by biochemical processes within the body on the brain.
Today, we are much more people of the mind, people of the brain. Undoubtedly, this leads many to view our art as (to use the word one Protestant recently used with me) "cheesy." Imagine, a representation of the Sacred Heart of Our Lord seen as "cheesy." The same heart Psalms 22 tells us has "become like wax, melting away" in His bosom. The same heart which rejoices when it proclaims in the same Psalm that our hearts may "be ever merry."(And, as I'm sure you recognize, this is the same psalm which was on Our Lord's lips while He suffered on the Cross.)
Take some time, doctor, and contemplate His Heart. You'll find it burns with the same love you see when you read the pages of the Gospels.