"Agonizing Heart" (せつない心, Setsunai Kokoro) is an instrumental musical composition from the Japanese version of Yu-Gi-Oh! GX.
It is 1:20 long and has been released on the soundtrack Yu-Gi-Oh! Duel Monsters GX Sound Duel Vol II.
The composition is played in Yu-Gi-Oh! GX in:
- Yu-Gi-Oh! GX episode 6: "The Shadow Duelist, Part 2" when Jaden Yuki gives Alexis Rhodes a picture of Atticus Rhodes.
- Yu-Gi-Oh! GX episode 22: "The Duel Off, Part 2" when Jaden defeats Bastion Misawa and Gerard decides not to disclose story about the missing students.
- Yu-Gi-Oh! GX episode 26: "The School Duel, Part 2" when Chazz Princeton realizes what is the dueling about and decides to go back to Duel Academy.
- Yu-Gi-Oh! GX episode 41: "A Reason to Win" when Alexis recalls time of her childhood with Atticus.
- Yu-Gi-Oh! GX episode 44: "The Seventh Shadow Rider" when Jaden, Syrus and Chazz are talking about Lyman Banner at a campfire.
- Yu-Gi-Oh! GX episode 49: "Rise of the Sacred Beasts, Part 2" when Kagemaru stood up without using power of the Sacred Beasts.
- Yu-Gi-Oh! GX episode 64: "Camaraderie Contest" when Syrus states he believes Jaden will come back.
- Yu-Gi-Oh! GX episode 93: "Heart of Ice, Part 1" when Atticus recalls time of his childhood with Alexis.
- Yu-Gi-Oh! GX episode 161: "Shall We Duel? An Invitation to a Pair Duel" when Alexis is looking through pictures on her computer.
- Yu-Gi-Oh! GX episode 162: "Judai VS Asuka! A Set Card Full of Hidden Feelings"
- when Jaden and Alexis come round in the tag duel.
- when Alexis suppresses telling Jaden how she feels about him.
- Yu-Gi-Oh! GX episode 163: "A Challenge from Psycho Shocker" when Syrus Truesdale recalls Zane's graduation match against Jaden.
- Yu-Gi-Oh! GX episode 179: "Farewell, Judai! A Tearful Graduation Ceremony" during Alexis' graduation speech.
The composition is also played in Yu-Gi-Oh! 3D Bonds Beyond Time during the rooftop conversation.