Cardiacs are an English rock band formed in Kingston upon Thames by Tim Smith (guitar and lead vocals) and his brother Jim (bass, backing vocals) in 1977 under the name Cardiac Arrest. One of Britain's leading cult rock bands, Cardiacs' sound folded in genres including art rock, progressive rock, art punk, post-punk, jazz, psychedelia and heavy metal (as well as elements of circus, baroque pop, medieval music, nursery rhymes and sea shanties), all of which was topped by Smith's anarchic vocals and hard-to-decipher lyrics. The band's theatrical performance style often incorporated off-putting costumes and make-up, complete with on-stage confrontations. Their bizarre sound and image made them unpopular with the press, but they amassed a devoted following.

Tim Smith was the primary lyricist, noted for his complex and innovative compositional style. He and his brother were the only constant members in the band's regularly changing lineup. The band created their own indie label, the Alphabet Business Concern, in 1984 and found mainstream exposure with the single "Is This the Life?" from their debut album A Little Man and a House and the Whole World Window (1988). Their second album, On Land and in the Sea (1989), was followed by Heaven Born and Ever Bright (1992), which displayed a harder edged, metal-leaning sound retained in the subsequent albums Sing to God (1996) and Guns (1999). The final Cardiacs album, LSD, was left unfinished after Tim Smith was hospitalised with dystonia resulting from a cardiac arrest and stroke in 2008, which caused the band to go on hiatus indefinitely.

Smith's illness brought increased and belated critical recognition to Cardiacs, with several music outlets calling Sing to God a masterpiece. His death in 2020 saw a raft of tributes on social media. Many rock groups including Blur were influenced by Cardiacs' eclectic music, which appeared on streaming services in 2021. Alternately billed as "Cardiacs", "The Cardiacs", and "Cardiacs Family & Friends", Cardiacs members "past, present, and future" performed the music of Tim Smith at several sold-out gigs in 2024.