The word(s) "heart" appears 169 time(s) in 159 verse(s) in Quran in Muhammad Pickthal translation.

(121) And they say: Our hearts are protected from that unto which thou (O Muhammad) callest us, and in our ears there is a deafness, and between us and thee there is a veil. Act, then. Lo! we also shall be acting.

(122) Man tireth not of praying for good, and if ill toucheth him, then he is disheartened, desperate.

(123) Or say they: He hath invented a lie concerning Allah? If Allah willed, He could have sealed thy heart (against them). And Allah will wipe out the lie and will vindicate the truth by His words. Lo! He is Aware of what is hidden in the breasts (of men).

(124) If He will He calmeth the wind so that they keep still upon its surface - Lo! herein verily are signs for every steadfast grateful (heart). -

(125) And verily whoso is patient and forgiveth - lo! that, verily, is (of) the steadfast heart of things.

(126) Hast thou seen him who maketh his desire his god, and Allah sendeth him astray purposely, and sealeth up his hearing and his heart, and setteth on his sight a covering? Then who will lead him after Allah (hath condemned him)? Will ye not then heed?

(127) And verily We had empowered them with that wherewith We have not empowered you, and had assigned them ears and eyes and hearts; but their ears and eyes and hearts availed them naught since they denied the revelations of Allah; and what they used to mock befell them.

(128) Then have patience (O Muhammad) even as the stout of heart among the messengers (of old) had patience, and seek not to hasten on (the doom) for them. On the day when they see that which they are promised (it will seem to them) as though they had tarried but an hour of daylight. A clear message. Shall any be destroyed save evil-living folk?

(129) Among them are some who give ear unto thee (Muhammad) till, when they go forth from thy presence they say unto those who have been given knowledge: What was that he said just now? Those are they whose hearts Allah hath sealed, and they follow their own lusts.

(130) And those who believe say: If only a surah were revealed! But when a decisive surah is revealed and war is mentioned therein, thou seest those in whose hearts is a disease looking at thee with the look of men fainting unto death. Therefor woe unto them!