"Heartlines" is a song recorded by New Zealand music duo Broods from their second studio album, Conscious (2016).

Its accompanying music video, directed by Dano Cerny, stars New Zealand actress Rose McIver and Australian actor Oliver Ackland; it received media attention for its incorporation of bio-interactive Microsoft Band technology in collaboration with Microsoft.

"Heartlines" was written by Georgia and Caleb Nott, who comprise Broods, as well as Lorde (credited under her birth name Ella Yelich-O'Connor) and Joel Little, who was responsible for production.

[1] Broods released an acoustic version of the track,[2] and three remixes produced by Cheat Codes,[3] Mount,[4] and Race Banyon.

[9] Georgia explained that the song was inspired by Caleb's undetermined relationship with a woman who lived "on the other side of the world".

[6] Stroud from the publication called it an "unimpeachable synthpop anthem", further commenting that the duo "continue to showcase this deft sense of sonic craftsmanship.

cited "Heartlines" as a "pleasing moment" in the record, stating that it "smoothly [executes] an ambiguous neither-major-nor-minor sentiment".

[7] Pryor Stroud of PopMatters characterized her vocals as a "weapon of pure emotional power and kinetic force".

[20] The accompanying music video for "Heartlines" was directed by Dano Cerny and was produced in partnership with Microsoft; it premiered on Broods' YouTube channel on 27 June 2016.

[22] New Zealand actress Rose McIver and Australian actor Oliver Ackland star in the video as each other's love interests.

[24] He revealed that the filming process was a challenge for production crew who had to "stay within range of Georgia's wrist" while also being "careful not to step into the frame".