Heart of David

1 Kings 11:4
As Solomon grew old, his wives turned his heart after other gods, and his heart was not fully devoted to the LORD his God, as the heart of David his father had been.

This verse may well be in the running for most occurrences of heart.
It partly moderates the previous verse and my questions about it: when Solomon grew old his wives turned his heart. It didn't happen immediately. The years of compromise finally exacted a price. His love for foreign women turned gradually to love for their dreadful gods.
Several of these are named in the following verses: Ashtoreth, Chemosh, the horrible Molech. But there were more, too many to name! If we haven't forgotten Molech and Ashtoreth, thankfully some of those pagan gods have faded from memory.
I think the last part of the verse says as much about David as about Solomon. David's heart was always devoted to the true God. He didn't always do right, and his old age wasn't a very pretty picture. But his heart never turned to other gods. It was fully devoted to Yahweh.
God, as I get older, keep my heart fully devoted to you. Keep my affections in healthy areas, so that my heart will not stray.