flatliner

noun

1. An angler who uses a flatline.
2. (rare)A patient with no heartbeat.

   “[…]unless my heart stops, okay? Nada — unless I'm a flatliner."”

   “In spite of his dramatic highs and the canyon lows, Kurt was a flatliner—a patient with no heartbeat.”

   “Though occasionally a “flatliner” can be revived with a defib, it is most commonly used to change the uncoordinated contractions of the heart (fibrillation) into a normal sinus rhythm—that is, to defibrillate the heart.”