Heart in the Wrong Place

Anatomically, the human heart is located beneath the lower sternum, with only a very slight tilt to the left. In fiction, it's common to depict it as lying just under the left shoulder, level with the armpit, in a position where the left lung ought to be.

A case of Artistic License: Biology so commonplace as to constitute Reality Is Unrealistic. If a character's heart is in the wrong place because they've hidden it for safekeeping, that's a Soul Jar. If a character's heart is in a different place because they aren't human, it's Bizarre Alien Biology. This trope can overlap with CPR: Clean, Pretty, Reliable when nobody involved does the research beforehand.

A real-life inversion of Reality Is Unrealistic, or at least partially, in the case of situs inversus, although the heart in in pretty much the same place, the positions of the other asymmetric organs are reversed.

Film

 * In Terminator Salvation, when the T-800 visualizes Marcus's heart, it's too high and too far to the left.
 * In Pirates of the Caribbean: At World's End, when  reappears after becoming captain of the Flying Dutchman, the scar from impromptu heart surgery is visible high on the left side of the chest.
 * In Indiana Jones and the Temple of Doom, the villain snatches the heart from the left side of the sacrificial victim's chest. His attempt to do the same to Indy likewise uses this trope.
 * It's hinted, however, that is may be hypnotic imagery rather then the heart being literally ripped out.
 * Extremely common in vampire movies.
 * The movie Ninja Assassin featured multiple people with the medical condition Dextrocardia situs inversus, which occurs in approximately 1 in 12,000 people. In an inversion of both normal human anatomy and this trope, their hearts were tilted towards the right side of the chest.
 * Averted by Iron Man, whose heart-sustaining arc reactor is located in the center of his chest.
 * Not exactly averted in the movie, where the arc reactor is housed within a wide, wrist-deep hole exactly where his heart should be.
 * In Jennifer's Body, Jennifer places Jonas's hand above her left breast and asks him to feel her heart.

Literature

 * Discussed in Terry Pratchett's Monstrous Regiment when The Medic considers mercy-killing the team vampire before it goes mad with hunger.
 * Also used in Carpe Jugulum, when the Old Count turns out to have an anatomical chart showing where the heart is to help would-be heroes, otherwise he might end up leaky as a colander.
 * Discussed in Without Remorse by Tom Clancy. One of the reasons the police are sure that their killer is ex-military is because the death wounds are exactly where the heart should be and not where the average person thinks it is.
 * In Storm Front, the victims slain by the exploding-heart curse are described as having holes on the upper left side of their chests.

Live-Action TV

 * In "Dig That Cat, He's Real Gone", a Tales from the Crypt episode, a bear-shaped archery target has a valentine-shaped cutout on the left side of its chest.
 * On the makeup-F/X game show Face Off, a costume of a re-imagined, horror-themed Tin Woodsman featured a bare chest with a gaping hole where the character's heart is missing. Naturally, it's very high on the left side.
 * Averted early in Lost. The US Marshall that was on the plane was critically wounded in the crash, so Sawyer shoots him in the upper left part of his chest to put him out of his misery. Only for Jack to tell him that he missed the heart and hit his lung.

Tabletop Games

 * Among the many other failings of FATAL is the lungs on the critical hit chart; you're twice as likely to hit the right lung as the left lung (to make room for the heart, see?).
 * The "broken heart" piece in the game of Operation is positioned this way.

Real Life

 * The hand-on-heart gesture used in Real Life flag ceremonies actually places one's hand over one's left upper lung lobe.
 * Clothing intended for little girls sometimes incorporates a valentine-style heart symbol on the upper left of the chest.