flatliner

plural flatliners

1. fishingAn angler who uses a flatline.
2. rareA patient with no heartbeat.

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

   1996, Bill Butterworth, Butterworth gets his life together, page 144

   2 more examples

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

   1998, George Mckinney, Cross the Line

   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.

   2011, Laurence Street, Introduction to Biomedical Engineering Technology, page 125