The word(s) "heart" appears 213 time(s) in 195 verse(s) in Quran in Abdullah Yusuf Ali translation.

(161) While the Unbelievers got up in their hearts heat and cant - the heat and cant of ignorance,- Allah sent down His Tranquillity to his Messenger and to the Believers, and made them stick close to the command of self-restraint; and well were they entitled to it and worthy of it. And Allah has full knowledge of all things.

(162) Those that lower their voices in the presence of Allah's Messenger,- their hearts has Allah tested for piety: for them is Forgiveness and a great Reward.

(163) And know that among you is Allah's Messenger: were he, in many matters, to follow your (wishes), ye would certainly fall into misfortune: But Allah has endeared the Faith to you, and has made it beautiful in your hearts, and He has made hateful to you Unbelief, wickedness, and rebellion: such indeed are those who walk in righteousness;-

(164) The desert Arabs say, "We believe." Say, "Ye have no faith; but ye (only) say, 'We have submitted our wills to Allah,' For not yet has Faith entered your hearts. But if ye obey Allah and His Messenger, He will not belittle aught of your deeds: for Allah is Oft-Forgiving, Most Merciful."

(165) "Who feared (Allah) Most Gracious Unseen, and brought a heart turned in devotion (to Him):

(166) Verily in this is a Message for any that has a heart and understanding or who gives ear and earnestly witnesses (the truth).

(167) The (Prophet's) (mind and) heart in no way falsified that which he saw.

(168) Gives a little, then hardens (his heart)?

(169) He merges Night into Day, and He merges Day into Night; and He has full knowledge of the secrets of (all) hearts.

(170) Has not the Time arrived for the Believers that their hearts in all humility should engage in the remembrance of Allah and of the Truth which has been revealed (to them), and that they should not become like those to whom was given Revelation aforetime, but long ages passed over them and their hearts grew hard? For many among them are rebellious transgressors.