Cardiac arrest is the medical term used when a heart ceases to function, often as the result of injury.
While Doctor Leonard McCoy was trying to treat his wounds after an assassination attempt, Klingon Chancellor Gorkon went into cardiac arrest and died. (Star Trek VI: The Undiscovered Country)
During surgery by Doctor Toby Russell and Dr. Beverly Crusher to replace his crushed spinal cord, Lt. Worf went into cardiac arrest, and was clinically dead for some time, before some backup in his Klingon anatomy restarted his heart. (TNG: "Ethics")
In 2369, Captain Jean-Luc Picard was shot in the chest, which caused his artificial heart to stop working. He was later revived in Sickbay. (TNG: "Tapestry")
In 2372, Ensign Samantha Wildman's new-born baby died due to cardiac arrest when insufficient power was avaliable to drive the incubator she was placed in after birth.(VOY: "Deadlock")