"Beep... beep... beep...beep...
BEEEE EEEE EEEP!"Electrocardiograms are non-invasive devices that allow doctors to monitor a patient's heart rhythm, and are the best way for doctors to detect irregularities with the heart early enough to do something about them. Electrocardiograms are also Hollywood's favorite way of telling the audience that a hospital patient is in the process of dying. An injured or sickly character will go into the hospital, and while there will be hooked up to a machine that goes PING!. As long as the electrocardiogram machine is beeping, and as long as the line on the screen that indicates the character's heart is still beating is going up and down like a metronome, everything's fine. But then suddenly, the beeping becomes erratic and the lines on the screen will start jumping up and down until finally, the lines flatten out and the machine lets out one long sustained beep! The medical personnel scramble about, someone in the background is calling a Code Blue over the intercom, and inevitably a defibrillator will be wheeled in. Sometimes, the character will be revived and the beeping and regular jagged lines on the machine's screen restart. And sometimes not. The technical term for a "flatline" is asystole ("a-" for lacking, "systole" for the contraction cycle of a heartbeat). This event is not always the result of the character having a heart condition; asystole can be caused by lots of things, including profound hypoxia (lack of oxygen in the blood), poisonings and intoxications, and consequences of trauma (i.e. massive hemorrhage, tension pneumothorax - leaking air from a collapsed lung putting pressure on the heart, or cardiac tamponade - blood building up around the heart and squeezing it to death). However, the circumstances leading to asystole are always catastrophic in nature, such that even if you manage to re-establish a rhythm (itself usually a losing proposition), the patient's chances of actual recovery are abysmal. Regardless of what they were hospitalized for, thanks to The Law of Conservation of Detail, if a character is hooked up to a cardiac monitor, they will almost always flatline at some point. You definitely won't hear them if the character isn't going to die, because that beeping sound is just annoying. Additionally it will either be an instant thing from a regular heartbeat to a line, or a very sudden series of erratic bleeps suggesting the patient is having a heart-attack, often from stress, just before the flatline itself. If the scene is being played for comedy, the "flatline" may be the result of the patient playing with the monitor leads, getting up for a bathroom trip, a guest accidentally tripping over the monitor, or other such mundane causes. Rule of Perception says that a flatline on film is always... well, a flat line. However, in Real Life a recently asystolic patient would still show occasional waves on the screen, a condition also known as Pulseless Electrical Activity - the electrical signal to beat is being generated, but the heart muscle isn't responding anymore. The flatline may also wave in time with the 50Hz or 60Hz of mains power, especially if a mains filter is not used or is faulty. A sub-trope of He's Dead, Jim. See also Hell Is That Noise. For the Doctor Who episode, go here.
As a Death Trope, all Spoilers will be unmarked ahead. Beware.
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Anime and Manga
- In episode eleven of ef: A Tale of Melodies, Kuze's heart machine beeps and then the Heartwrenchingly sad ending theme plays. At the end his machine beeps again and he comes back to life.
- Code Geass: Euphemia.
- In Full Metal Panic!: The Second Raid, Gauron flatlines after Sousuke shoots him repeatedly. However, the beeping actually starts up again (which lead to many people believing that he had officially achieved immortality). Of course, the beeping turns out to be a bomb.
- In Death Note, Soichiro was lying in the hospital bed and his death was shown by the long beep.
- In Kill la Kill, we see this in a flashback with a baby Ryuuko during the time where her parents tried to infuse her with life-fibers Subverted in that she wasn't dead.
- Vampire Hunter D: Bloodlust. After Grove sacrifices himself to save Leila from a vampire the audience can hear the flatline sound from the medical equipment attached to him.
- In the Dragon Ball Z special "Episode of Bardock", Lord Chilled flatlined after barely escaping Bardock's wrath.
- Excel Saga: Hyatt is hooked up to one for an ACROSS staff-meeting, of all things. Naturally, she flatlines half-way through prompting Excel to engage in extremely spazzy CPR. Played for Laughs, naturally, as Hyatt dies all the time anyway, and she gets better as usual.
- During the climactic battle at the end of The Dark Knight Returns, just when Batman has Superman at his mercy, we see Batman's pulse, represented by a red line on panel. It spikes incredibly rapidly and then flatlines, indicating his self-induced and temporary heart attack. It resurges on panel during his "funeral", just in time for Clark Kent to hear it with his Super Senses.
- Gert's final page in Runaways shows her heartbeat interspersed between the panels. Then there's a shot of the fatal dagger penetrating her heart, overlapping the line going flat.
- In E.T. the Extra-Terrestrial, the fact that the life forces of ET and Elliot have been linked is indicated by electrocardiograms. As ET slowly dies, Elliot's own life signs get weaker and weaker. In the end, they both get better.
- In Sliding Doors, this occurs to Helen Quilley in one of the timelines as she dies in James' arms.
- Played for Laughs in Silent Movie.
- The Matrix
- 2001: A Space Odyssey
- The three Human Popsicle astronauts killed by HAL flatline. They don't get better. The computer display changes to "Life Processes Terminated."
- This also happened to Frank Poole, showing an entire battery of monitors slowly decaying to all flatline.
- Flatliners: As the title suggests, it happens many, many times.
- In Tank Girl, the head of Water and Power is indicated as dead by the flatlining of a display that showed pretty ocean waves becoming a placid surface of water. He actually survived ...sort of.
- In RoboCop 2. When Dr. Faxx shuts off Cain's life support system so his brain can be harvested.
- Used in the ending of Dr. Giggles. The surviving girl is hooked to an electrocardiogram, and we see her heart race increase as her love interest embraces her.
- Happens in Visiting Hours, when the psycho killerColt Hawker literally cuts an old woman's oxygen tube and watches her die. When a nurse gets on the scene, she finds a corpse and a heart monitor doing flatline.
- Aliens. Several Marines have their vital signs monitors flatline when they're killed by xenomorphs.
- Subverted in Apollo 13. The flight surgeon at the control room freaks out when the astronauts' monitors flatline, but they hear their voices through the radios fine, and the director assures him that the astronauts simply took their medical leads off. "A little medical mutiny" because they've been under a lot of stress and are tired of hearing the operators fuss about their heart rates.
- Subverted multiple times in Young Doctors in Love. The best one is when the heroine flatlines, Downer Ending music and credits start, then she wakes up and one of the doctors finds the monitor got unplugged.
- In Guardians of the Galaxy, the Downer Beginning has the hero's mother die in hospital on a flatline sound.
- Jurassic World: When the Asset Containment Unit gets wiped out trying to recapture the I. rex. As each operative dies, the people in the control room see their vitals flatline on a readout next to their name and ID photo.
- Resurrection features a heart monitor throughout the entire "near-death experience" scene, and yes it does flatline at one point.
- In Romy and Michele's High School Reunion, Michele's Dream Sequence ends 70 years in the future with Old!Romy flatlining as she gives Old!Michele the middle finger via video phone.
- Housepets The Series has a false alarm variety. Peanut was in a coma after fending off a mad dog to save his family. The doctors are alerted to a Code Blue in his room, and they rush in...to find Grape hugging a miraculously-awaken Peanut. She hugged him so passionately, she dislodged his ECG leads.
- The Moonstone Cup has Twilight's cardiac monitor do this. Because IT died, much to her chagrin ...
- Regret by Krazykatqueen has this with a dying Renko after Yukari (once Maribel Hearn) tells her she was sorry for her absence.
- In Kill la Kill AU, we have this with a mortally injured Ragyo, though we didn't really know if she died, as Amoridere wasn't sure what should come after that. It was later confirmed that she hadn't passed away.
- Pretty much every show set in a hospital has done this, if not hundreds of times, then at least dozens. Though the best ones usually avert Magical Defibrillator.
- ER, being set in an emergency room, might be the record-holder, because sometimes this occurs three or four times per episode.
- Done in a very odd way during the credits of the last St. Elsewhere episode. The MTM cat was shown lying still, flanked by a beeping heart monitor and IV bag. As the rather upbeat theme music ended, the monitor went to flatline instead of the kitty's traditional "Meow!" Yes, the autistic kid killed a kitty...
- Done repeatedly in Scrubs, of course.
- Ditto Emergency!, though they averted the Magical Defibrillator stuff.
- ER, being set in an emergency room, might be the record-holder, because sometimes this occurs three or four times per episode.
- Dallas: The seventh-season ending, where Bobby Ewing dies; this is not the "shower scene" cliffhanger that aired a year later, but the episode where Bobby was struck by a car and mortally injured. As usually seems to be the case for "he's gonna die" episodes, the entire cast gathers at the victim's bedside (in this case, Bobby's) as the soon-to-be-deceased mumbles a few last words to family and loved ones; in this case, Bobby's last muttered words are, "I love you" before the flatline. Unintentionally comes off as being Played for Laughs because of the cheesy setup, the lack of emotion shown by a fake teary-eyed Larry Hagman, and the foregone conclusion that Bobby was going to die (due to Patrick Duffy leaving the show due to conflicts with the show's producers and writers — until he got them resolved a year later ... ).
- Subverted in an episode of One Foot in the Grave. Margaret is hooked up to life support as Victor stays with her, holding her hand. The heart monitor does the standard "beep.. beep.. beep.. beep.. beeeeeeeeeeeeeeeep", and prompts a Really Dead Montage from Victor, and then a nurse wanders by, complains that the heart monitor had been faulty all week, bashes it, and apologises, as it starts beeping regularly again.
- Daphne's death in Heroes.
- Battlestar Galactica used this in the sickbay a few times. Probably the best example is when Caprica miscarries and the internal baby monitor flatlines.
- This happens in the final episode of the 3rd season of Charmed, All Hell Breaks Loose. Piper is shot and dies in the hospital. Later that episode, time is reset and Piper is alive again.
- When Yousuke dies in Maou.
- Dollhouse basically does this when Paul gets mindwiped:
- Computer monitor: SUBJECT: INACTIVEAlpha: Huh. When did you die?
- The Good Guys subverts this in the pilot episode. A plastic surgeon is operating on a criminal when a flatline occurs. The surgeon tells the guy's goons that it is probably just a loose wire but they do not believe him and pull out their guns. The doctor panics and the goons open fire, hit some oxygen bottles and blow themselves up. It really was just a loose wire.
- Subverted on on Chuck. In a season four episode, an attacker assaults someone who is gravely wounded in the hospital, and smiles when he sees the monitor flatline. Of course, the "victim" had merely unplugged his fingertip pulse-oximeter.
- Used for comedy in one episode of Home Improvement, Tim Allen takes applies 2 nodes to his chest, beep.....beep.....beep. He starts breathing heavily and tries again, beep..beep..beep..beep. He then puts the nodes on his head to which it flat-lines.
- Hospital scenes in Soap Operas seem fond of this trope. The setup is formulaic: The soon-to-be-departing cast member either is suffering from the final stages of an illness or is so severely hurt in an accident that the injuries cannot be healed and he/she is going to die, the character's family (or, especially if the character is a totally hot babe, just her boyfriend) gathers at bedside, the doomed character and several others share some tearful last words, and the flatline occurs, with rare attempts made by the doctors to resuscitate the character.
- Gentaro at the end of episode 31 of Kamen Rider Fourze. He wasn't hooked to any machine, but there was a line on the screen meant to invoke this.
- Mac Taylor on CSI NY. One of the doctors yells right out "He's flatlining!"
- Done for a little Comedic Sociopathy in Will & Grace. Rosario is in the hospital for tonsilitis, and Karen basically assumes she's faking for sympathy. Rosario flatlines, and Karen panics and spills her guts, saying she knew she was sick all along and just couldn't handle the idea of losing her. Rosario (who flatlined, remember) suddenly makes a snarky comment, them mentions that the reader came off her finger.
- Episode "Identified". After a UFO is shot down one of the aliens aboard it is captured. After he's exposed to the Earth's atmosphere he suffers from Rapid Aging. As the SHADO doctors try to save him a nurse watches a heart monitor. His heart beat continues for a few seconds and then flatlines.
- Episode "Computer Affair". Straker decides to use one of the "new anodynes" on a captured alien in the hope that it will act as a Truth Serum on him. Instead it makes his heart beat faster and then kills him, with a heart monitor showing the whole thing.
- In the Intelligence episode "Patient Zero", Gabriel fakes one while he and Riley investigate how an executed death row inmate could turn up as patient zero in a virus outbreak. Gabriel lies down on the death chamber gurney (no syringes) and has Riley activate the system, then hacks the EKG machine with his chip to produce a flatline result (partly as a prank, but also to demonstrate that the machine was tampered with).
- Tricorders on the various Star Trek will tend to make the noise if the person being scanned dies. It's rarely actually shown, though, just the reactions of the people that are around.
- The sickbay biobed monitor would usually set off an alarm if the readings of the patient in the bed went beyond the normal range of its species (which means a biobed monitor set for human readings would go nuts if Spock got on the bed without the monitor being reset for Vulcans). In the second pilot, however, when Gary Mitchell demonstrates his newfound powers by willing himself dead for a few seconds, the monitor bottoms out all of the readings and falls silent, only to resume normal readings when he revives himself.
- On one episode of Barney Miller, Dietrich is hooked up to a stress monitor and goes out on a call. Back at the station, the monitor starts going haywire, which alarms everyone, and then flatlines completely, making them assume the worst. Then Dietrich walks back in wearing department sweats—the disturbance was a woman attacking her husband with a fire hose, and in the "crossfire" the sensors shorted out.
- Mocked in the video for "Weird Al" Yankovic's "Like a Surgeon", where a patient has flatlined just as Al (dressed as a doctor) walks in. Al attempts to give the machine Percussive Maintenance, but then realizes that the machine isn't the problem. He promptly pounds the patient in the chest... and his heart starts beating regularly again. The song itself ends with a *beep* *beep* *beeeeeeeeeeeeeeee*
I can feel your heart beat/ For the very last time...
- A flatline sound begins a song by thrash metal band Toxik that is, appropriately enough, titled "Heart Attack".
- A beeping sound begins and ends the song "The End", which is the start of My Chemical Romance's The Black Parade album. The sound returns at the end of the song, which moves instantly into the beginning of "Dead", where the beeping hits the flatline tone.
- "My Child" by Disturbed ends with this sound, being that it's about the lead singer's miscarried baby. Yes, he really wanted to be a father.
- The music video for the Travis Tritt song "Tell Me I Was Dreaming" does this by showing the letters ASY (meaning asystole, naturally), instead of the straight line and long beep that normally happens (forward to 3:28 to see it).
- The opening of Nexus' Return from Flatliner features a Heartbeat Soundtrack followed by this.
- Xorcist's "Crack" opens with a flatlining EKG; by the dialogue (sampled from a 1980's anti-drug ad), a drug user apparently is having a Near-Death Experience after doing it the first time. "I didn't do that much stuff, it's only the first time! Oh God please, I wanna go back! "Oh please God, I wanna live!"
- The long, sustained G note during the song "My Iron Lung" by Radiohead sounds like a (take wild guess) a flat EKG. Considering the sardonic tone of the song, it's open to interpretation whether it means a person has died, or Radiohead is comparing their success as "dead"
- Experiment Four, Mr. 76ix's latest album, ends with this, and the last track is appropriately titled "Mors Janua Vitae".
- "Pink Cigarette" by Mr. Bungle has the sound of an EKG slowly enter the mix near the end of the song... It then flatlines, abruptly interrupting the music and lyrics mid-sentence. And all this happens when the narrator of the song starts counting down the hours "until you find me dead".
- Guns N' Roses has Coma, a song about a man on his death bed embracing his own death. It's interspersed with a beeping ECG in time with the percussion. Naturally, he flatlines at the point where he realises he's actually afraid of dying, as indicated by the long beeeeeeeeeeep and all the medics calling a Code Blue.
- In Rarity (a.k.a. Jeff Burgess)'s song Goodbye, the beeping comes in on the very last note, forming a harmony with the two vocalists. The vocals end just before it flatlines, leaving the long beep as the only thing you hear for the last ten seconds of the track. It's not entirely clear which vocalist's character has died.
- Tazz's entrance theme in WWE started with the sound of a heartbeat... which then fades into the beep of an ECG... which promptly flatlined.
- In one episode of The Very World of Milton Jones, Milton invents a checkout that can tell whether things are alive or dead. There follows a series of beeps (as he swipes items) followed by a long beep.
"I'm sorry, Ma'am, we've lost the broccoli."
- Parodied in The Complete History Of America Abridged, where the narration of The American Civil War has a beep between each of the slides (which get lost due to a stage mishap, forcing the actors to compensate). After the narration winds up with Abraham Lincoln getting shot by John Wilkes Booth and dying the morning after, there is a really long beep.
- This was used with Nanako in Persona 4, although she gets better... unless you decide to kill her would-be murderer.
- Combine soldiers in Half-Life 2 emit a long beep every time you kill one.
- It also occurs every time you die in Half-Life.
- The flatline for the players death seems to be the HEV suit's monitoring system while the combine soldiers seems more like radio feedback.
- The ancient PC game Weird Dreams used this trope. The premise of the game was that the weird scenarios were literally a dying dream. The player character was actually in Intensive Care. If the player lost the game, he died. Highlighted by a graphic of a heart monitor's beep stuttering while it briefly flatlined if the player lost a life. Lose the last life and it stayed flatlined.
- Part of the sound effects in the Dance Dance Revolution track "Healing Vision", the "plot" being that the person is having a near death experience. The flatline is much more obvious in "Healing Vision: Angelic Mix"; in that version, the EKG's even rhythm devolves into chaotic fibrillation for about three or four measures before flatlining. The arrow targets stop momentarily to highlight the steady sound, which persists through the rest of the song until the final two beats (inverting Last Note Nightmare nicely).
- In The Journeyman Project, a flatline tone is played upon Game Over.
- Syphon Filter 2, when Phagan is disconnected from life support.
- The introduction for Cyborg Justice has the flatline for the human pilot that dies, which is then replaced by a square wave.
- In Dead Space, this occurs when the wearer of a RIG dies, including NPCs as well as the player character.
- Used for player character death in Alien: Resurrection Licensed Game.
- In Illbleed, an electrocardiogram represents the player character's heartrate. Hit a scare trap and it goes up. If it gets too high, the character's heart explodes, and it flatlines. (It can also get too low if they bleed out, which also leads to death and a flatline.)
- Happens in the death sequence for Metroid Prime when the screen reads "LIFE SUPPORT SYSTEMS: OFFLINE" "GAME OVER".
- Also in Metroid Prime 2: Echoes during its death sequence. It beeps fast at the beginning, and flatlines when the screen reads "FAILURE. MISSION FAILURE" "GAME OVER".
- At the beginning of Fallout 3, Catherine, the player character's mother, has this when she goes into cardiac arrest after childbirth. Also heard when you find her skeleton during the Punga hallucination in Point Lookout.
- In Capcom vs. SNK 2: Mark of the Millennium, defeating one of the True Final Bosses (Shin Akuma or God/Ultimate Rugal) results in a visual of an EKG going flatline intersticed with the defeated boss's death scene.
- Since you spend most of the game going through a dying man's dreams, To the Moon has his electrocardiogram displayed on the top of the screen. His heart beat gets more and more frantic and erratic as the game goes on. Although you never see it, you eventually hear him "flatline" near the end of the game.
- In Live A Live, after Kirk's spacesuit has its life support system mysteriously switched off, he is brought in and taken to the sickbay, where he flatlines.
- Sunset Overdrive has this sound when the player character dies, preceded by a Critical Annoyance EKG beep.
- Used in Code Lyoko three separate times. The first episode to use this trope is "Killer Music" (Odd); the second, "Common Interest" (Aelita); and the third time "The Pretender" (Yumi).
- In the South Park episode "Stanley's Cup," Nelson, the little boy with cancer, ends up flatlining after Stanley's team lost the game.
- In "Cartmanland", a hospitalised Kyle flatlines from stress when he hears of Cartman's huge financial success on TV.
- Kenny flatlines at the end of "Chickenpox".
- The Simpsons:
- An April Fools prank leaves Homer in a coma. A teary-eyed Bart confesses that he pulled the prank, and as Homer's EKG beeps faster, the lines form the shape of Bart's head, just before he comes to and strangles Bart.
- This was also parodied in another episode with Bart talking to an injured Milhouse who is hooked up to an EKG. While Milhouse is still alive, the monitor flatlines.
Milhouse: Oh, it always does that. HUNGH! *hits monitor* *monitor starts again*
- Subverted In the Spongebob Squarepants episode "All that Glitters" SpongeBob is seen at the infirmary after he tries to replace his spatula with a high tech new one that deserts him:
SpongeBob: Spatula?? It can't be true. It's too late!! [sobs uncontrolably]Doctor: SpongeBob, I-I hate to tell you this..SpongeBob: I know. He's moved on to the big kitchen drawer in the sky. Hes gone!Doctor: Actually, it's not that. I didn't get the acting part.SpongeBob: [sobbing] I'm so sorry... [sobbing continues]Doctor: Oh, by the way, that's not your spatula. Your buddy's all patched up in the infirmary.
- [scene cuts to the spatula's hospital bed from the start of the episode, with the pulse meter slowing, then becomes a flat line]
- In Jackie Chan Adventures, Captain Black had been attacked by Valmont wielding the Dragon talisman. The end of the episode featured the long beep, only to reveal that Captain Black had just took off the sensors and tried to get out of the hospital.
- In the Invader Zim episode "Bad, Bad Rubber Piggy," Zim is keeping track of Dib's vital signs as he sends objects into the past to try and kill him — after sustaining multiple injuries, he finally flatlines after Zim replaces the paramedic's defilibrator with rubber pigs. Unfortunately for Zim, he gets better.
- Played for laughs (yes, this is possible with this trope) in Courage the Cowardly Dog. Courage has a heart attack during a Wild Take in one episode. When he's recovering in Dr. Vindaloo's office, he grabs the doctor and runs off. The leads on his EKG snap off and it goes to flatline.
- In an episode of King of the Hill, Hank's father Cotton is able to cause a flatline at will using a trick he learned in the military. He does this several times in the episode, so when he actually does die everyone's a little unsure.
- Ned's Newt, episode "Draw Your Own Concussion": An inversion of this occurs when the monitor flatlines after the doctors remove the ECG pads from Ned following their remark that he's cured.
- Subverted in Action League Now: "Danger for a Dignitary". After The Flesh accidentally gets an ambassador injured, Bill the Lab Guy is forced to do a delicate procedure to fix him:
Bill the Lab Guy: Nurse Thunder, I need more glue. (*flatline*) Oh no, I've lost him! I was afraid of this!Thunder Girl: Goody! Popcorn's done. (opens microwave; beep stops)
- In Hot Wheels Battle Force 5 Zoom flat-lines. Don't worry, he gets better.
- In Transformers: The Movie, Optimus Prime's vitals flatline towards the end of That Scene. Ouch.
- In Justice League when the League is trapped in Justice Lord!Batman's holding cells, the Flash starts moving so fast that his heartbeat moves too fast for the machines monitoring him to keep up, making it look like a flatline. This causes Lord!Batman to rush to the cell to check on him, at which point Flash drops the act and knocks Lord!Batman into the cell.
- In a rather serious episode of Adventure Time, this happens to Princess Bubblegum, but then she turns out alright.
- The first episode of Ultimate Spider-Man had Peter explaining to Aunt May that he's all right after his school was ambushed by the Frightful Four, but couldn't say the same for Harry, who wound up in the hospital. We cut to a heart monitor flatlining as if he had died, but it was just being switched off and wheeled out of his room by a nurse.
- Parodied in the Oggy and the Cockroaches episode "Face Off". While Jack is looking at Oggy's messed-up face, the monitor flatlines. However it starts beeping again until an Expy of Pac-Man eats the lines. This is followed by brief Pong gameplay. Apparently Joey was behind the monitor strangeness the whole time.
- Spoofed in Family Guy, where one of the inventions Peter patents when he takes over his father-in-law's company is the "African-American Heart Monitor". Instead of beeping, it plays a clip of a man saying "Yeah, yeah, yeah"; in place of the familiar flatline sound, the voice simply says "Aw, he dead."
- Unless it is a medical procedural like ER, the progression from a normal heartbeat—through various dysrhythmias and arrhythmias—to a flatline is usually depicted in fiction as unnaturally quick. Unless the patient suffered a catastrophic brain injury, decapitation, or a very high severing of the spinal cord, it usually takes several minutes for a patient to flatline as arrhythmias disrupt the flow of oxygenated blood to the brain. Except in rare cases, such as suppression by poisoning, extreme intoxication or extreme hypothermia, it is an extremely rare case that a patient who reaches asystole will be revived.
- Even in cases of extreme Central Nervous System trauma (brain injury, severed spinal cord, etc) the heart can continue to beat with a detectable rhythm for up to 30 minutes after brain death. In 1887 a sphygmograph (a crude early heart monitor that drew a pulse pattern onto carbon paper) was used to monitor the pulses of three hanged men. You can see the resulting traces here◊.
- A potentially catastrophic aversion to this is "pulseless electrical activity", or PEA. That's where the brain is sending the signals to the heart to establish heartbeat, but the heart isn't responding. So the monitor is beeping normally, while the patient looks dead as a doornail. This can happen with extreme physical restrictions to the heart muscle like pneumothorax or tamponade, or an extremely well-placed injury to the heart muscle that affects the nerves that transmit those signals.
- Usually averted with modern monitoring systems, which often use alternate alarm sounds to avoid scaring patients and their families, precisely because the single long tone is so distinctive. The downside is that all alarm conditions frequently get lumped into the same "panic alert" category. This frequently leads to several minutes explaining to a panicked patient and/or family that no, they aren't really dying, it's merely a false alarm or a temporary deviation from normal (patient moved in bed, fell asleep, dislodged a monitor lead, etc).
- The "played for comedy" flatline, as described in the introduction, is actually quite a common occurrence. The electrodes can easily slip off the skin, and since the regular beep volume is usually turned down low, nobody notices the irregular signal on the monitor until the flatline beep (or alternative alert) sounds. So there are many false alarms. It's not uncommon for an annoyed patient ostensibly hooked up to one of these to buzz for a nurse because the flatline tone is interfering with their sleep/TV show/whatever.