The word(s) "heart" appears 171 time(s) in 159 verse(s) in Quran in Muhammad Habib Shakir translation.

(61) And Ibrahim asking forgiveness for his sire was only owing to a promise which he had made to him; but when it became clear to him that he was an enemy of Allah, he declared himself to be clear of him; most surely Ibrahim was very tender-hearted forbearing.

(62) Certainly Allah has turned (mercifully) to the Prophet and those who fled (their homes) and the helpers who followed him in the hour of straitness after the hearts of a part of them were about to deviate, then He turned to them (mercifully); surely to them He is Compassionate, Merciful.

(63) And as for those in whose hearts is a disease, it adds uncleanness to their uncleanness and they die while they are unbelievers.

(64) And whenever a chapter is revealed, they cast glances at one another: Does any one see you? Then they turn away: Allah has turned away their hearts because they are a people who do not understand.

(65) Then did We raise up after him apostles to their people, so they came to them with clear arguments, but they would not believe in what they had rejected before; thus it is that We set seals upon the hearts of those who exceed the limits.

(66) And Musa said: Our Lord! surely Thou hast given to Firon and his chiefs finery and riches in this world's life, to this end, our Lord, that they lead (people) astray from Thy way: Our Lord! destroy their riches and harden their hearts so that they believe not until they see the painful punishment.

(67) Most surely Ibrahim was forbearing, tender-hearted, oft-returning (to Allah):

(68) And all we relate to you of the accounts of the apostles is to strengthen your heart therewith; and in this has come to you the truth and an admonition, and a reminder to the believers.

(69) They said: If he steal, a brother of his did indeed steal before; but Yusuf kept it secret in his heart and did not disclose it to them. He said: You are in an evil condition and Allah knows best what you state.

(70) Those who believe and whose hearts are set at rest by the remembrance of Allah; now surely by Allah's remembrance are the hearts set at rest.