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Monday’s medical myth: flatlining patients can be shocked back to life

Beep….beep……….beep……….beeeeeeeeeeeeeeeeeeeeeeeeep. “We’re losing him. Out of my way, nurse!” The quick-thinking young doctor charges the defibrillator paddles and places them on the chest of the lifeless…

Like much of what we see on TV, this one’s a myth. Image from shutterstock.com

Beep….beep……….beep……….beeeeeeeeeeeeeeeeeeeeeeeeep.

“We’re losing him. Out of my way, nurse!”

The quick-thinking young doctor charges the defibrillator paddles and places them on the chest of the lifeless patient, whose cardiac monitor is showing a straight green line. The patient gets a huge dose of electricity; his back arches and his limp body lifts up off the bed with the shock.

Seconds pass, then the familiar, comforting waveform appears on the monitor. The patient begins to stir, and is soon sitting up enjoying the healing properties of hospital sandwiches and a cup of tea.

You’ve probably seen this flatlining scene a million times on TV and films. Heck, they even named a Kevin Bacon film after it! It’s thrilling, compelling – and completely wrong.

To understand why this myth is so egregious, we need a quick background briefing on cardiac arrest.

The heart’s electrical system controls the organ’s ability to pump blood to the rest of the body. If the flow of this electricity becomes disorganised or the heart muscle stops responding normally, the regular pumping action is lost. Blood stops flowing and the body tissues have to cope with the sudden lack of oxygen supply. This is known as cardiac arrest.

We can see the various electrical wave patterns of the heart in cardiac arrest using an electrocardiogram or ECG. There are four main rhythms you might see during a cardiac arrest:

  1. Pulseless ventricular tachycardia (VT) is a very rapid and inefficient heart rhythm. The heart is beating so quickly that it can’t fill properly between beats. Circulation therefore drops rapidly to dangerously low levels.

    VT is a rapid rhythm which doesn’t allow the heart to fill. ECGPedia.org

  2. Ventricular fibrillation (VF) is basically chaotic, unco-ordinated contractions of the heart muscle. Picture a heart quivering like a bowl of meaty jelly, unable to summon a proper contraction to send the blood on its way.

    VF is perhaps the most ‘survivable’ cardiac arrest cause ECGPedia.org

  3. Pulseless electrical activity (PEA) is where the heart rhythm appears normal on the ECG but the electrical activity is not producing any movement of the heart muscle. The lights are on, physiologically speaking, but nobody is home.

    A normal-looking ECG trace can belie a life-threatening condition in PEA acls-algorithms.com

  4. Asystole (aka flatline) is the complete absence of any detectable electrical activity of the heart muscle. It appears as a flat line on the monitors. Clearly this is the worst type of cardiac arrest and there’s little chance of coming back from it.

    A period of asystole follows some more normal beats Wikipedia.com

These four ECG findings are classified into “shockable” and “non-shockable” rhythms, depending on whether they respond to the electrical current of the defibrillator.

Pulseless ventricular tachycardia and ventricular fibrillation (1 and 2) are shockable, largely because they tend to be caused by the electrical activity of the heart being thrown out of whack, and not by the heart muscle itself being badly damaged.

Hitting the heart muscle with a big dose of electrical energy acts a bit like hitting Ctrl-Alt-Delete on your computer (or Alt-Command-Esc for the Mac users). A single shock will cause nearly half of cases to revert to a more normal rhythm with restoration of circulation if given within a few minutes of onset.

Pulseless electrical activity and asystole or flatlining (3 and 4), in contrast, are non-shockable, so they don’t respond to defibrillation. These rhythms indicate that the heart muscle itself is dysfunctional; it has stopped listening to the orders to contract. The causes are hard to reverse and survival rates are very low.

If you’ve flatlined, a shock is the last thing you need. Image from shutterstock.com

The treatment of choice for asystole is to continue CPR (cardiopulmonary resuscitation) and give a whacking great dose of adrenaline. In fact, if you stop CPR to give an inappropriate shock, the patient’s outlook is even more dire.

But unlike the famous overdose scene in Pulp Fiction might suggest, there seems to be no survival advantage and quite considerable extra risk of giving it directly into the heart. (I’m also ignoring the fact that adrenaline would be useless for a heroin overdose.)

So next time you see that ominous flat line appearing on the monitor, and hear the heroic physician shout “clear” while busting out the paddles, you can join the exasperated ranks of those in the know, and try not to let reality ruin this most dramatic of TV tropes for you.

This is the 100th medical myth and the last in the series. Click here to see the other myths we’ve busted over the past two years.

Join the conversation

21 Comments sorted by

  1. David Thompson

    Science Communications at Hawkesbury Institute for the Environment (UWS) at University of Western Sydney

    I've enjoyed this series. Innumerable arguments were deftly 'won' by judicious direction to this learned column series. :)

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    1. Michael Vagg

      Clinical Senior Lecturer at Deakin University School of Medicine & Pain Specialist at Barwon Health

      In reply to David Thompson

      Thanks David! This series has been squarely aimed at the office watercooler, and it's been our pleasure to have brought some hard evidence to these sorts of casual discussions, and allow TC devotees to come out on top!

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  2. Mat Hardy

    Lecturer in Middle East Studies at Deakin University

    I recall years ago seeing that someone had done a study (I think published in the NEJM) where they had compared the incidence and outcomes of defrib in popular medical shows of the time (Like ER) with the clinical realities. The major findings were that defrib occurred at a rate in the shows that was far beyond what it did in reality, that multiple treatments of defrib were the norm (generally 3+ repetitions) and, most importantly, that the overwhelming outcomes for patients on TV revived in this way was a complete return to normal body function. ie. no brain damage from lack of oxygen, further heart issues, etc etc. The point being that, like the CSI Factor in the legal system, families of patients were developing unrealistic expectations of what was possible for their relative.

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    1. Sue Ieraci

      Public hospital clinician

      In reply to Mat Hardy

      You're right, Mat - several studies have shown this. A paper in Resuscitation 2009 also reported:

      "Survival (or not) to discharge was rarely shown. The average age of patients was 36 years and contrary to reality there was not an age related difference in likely success of CPR in patients less than 65 compared with those 65 and over (p=0.72). The most common cause of cardiac arrest was trauma with only a minor proportion of arrests due to cardio-respiratory causes such as myocardial infarction."

      This effect has had consequences for both paramedics on-scene and Emergency Department staff, when families expect that a "zap" will revive anyone.

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    2. Michael Tam

      Conjoint Senior Lecturer, and Staff Specialist in General Practice at UNSW Australia

      In reply to Mat Hardy

      I think it was with CPR:
      dx.doi.org/10.1056/NEJM199606133342406

      Cheers.

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    3. Michael Vagg

      Clinical Senior Lecturer at Deakin University School of Medicine & Pain Specialist at Barwon Health

      In reply to Mat Hardy

      When I was a junior hospital doc, one of my registrars broke her ankle while running to an arrest call. She was reproached widely for trying too hard to get to what was likely to be a futile intervention! In 2 years as a resident I think I saw 3 or 4 successful in-hospital arrests vs 30 or 40 unsuccessful ones.

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    4. Michael Tam

      Conjoint Senior Lecturer, and Staff Specialist in General Practice at UNSW Australia

      In reply to Mat Hardy

      I have a similar experience. Of all the in-hospital arrests I've attended as a junior hospital doctor, only a handful were "successful" insofar that the patient survived the resuscitation process. I can't actually clearly remember a single occasion where the patient survived to be discharged from hospital.

      That being said, I do have a few patients in general practice who while in hospital after a heart attack, were successfully defibrillated from VT/VF arrests.

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    5. Mat Hardy

      Lecturer in Middle East Studies at Deakin University

      In reply to Mat Hardy

      You're dead right. That was the paper. I'm astounded to see that it was 17 years ago. Makes me (1) feel old and (2) wonder why the hell I have hung on to that bit of info (albeit confusing CPR with defrib) considering I have no professional connection with medicine. The brain is a funny thing.

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  3. Kate Rowan-Robinson
    Kate Rowan-Robinson is a Friend of The Conversation.

    Registered Nurse/Sexology Student

    Ah, my all-time pet peeve busted.

    Very appropriate for the 100th medical myth.

    Thanks for a great series :)

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  4. Tracy Heiss

    logged in via Facebook

    How disappointing! It's been mostly this series that has kept me coming back. And every single time I've been enticed by other great reads, and have learnt so much by default! Thank you very much indeed. May I ask why it is the last?

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    1. Fron Jackson-Webb

      Section Editor at The Conversation

      In reply to Tracy Heiss

      Hi Tracy,

      I'm glad you enjoyed the series. The 100th myth seemed like a good place to finish the series, as we covered most of the key medical myths over the past two years. In saying that, we'll continue to bring you more as they emerge, it just won't be weekly.

      Cheers,
      Fron

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  5. Craig Somerton

    IT Professional

    Thank you Michael. Your weekly mythbusting articles have been relevant, informative, educational and above all - entertaining.

    Please don't stop now, there are still plenty of myths that need exposing.

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  6. Mike Stasse

    retired energy consultant

    Michael obviously needs a Linux computer..................................... they almost never flatline!

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  7. Margo Saunders

    Public Health Policy Researcher

    However... there is also this: "A Melbourne hospital is trialling a new procedure that it says can save the lives of heart attack victims who have been clinically dead for up to an hour. The Alfred Hospital is using portable CPR and heart-lung machines to continue chest compressions, while rapidly cooling the patient's body to prevent brain damage. Senior intensive care physician Professor Stephen Bernard says the trial is doubling the length of time in which paramedics and doctors can continue resuscitation efforts."
    [http://www.abc.net.au/news/2013-05-14/new-procedure-prolongs-lives-of-heart-attack-victims/4687680]

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  8. Rubens Camejo

    logged in via Facebook

    Darn!

    You've just ruined many a good movie I've watched....Double darn!

    Anyone need an unused set of paddles I had put away for a rainy day?

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  9. Mark Amey

    logged in via Facebook

    My other pet hates are patients speaking whilst intubated and ventilated, or, worse, patients being ventilated via nasal canulae. I'm slightly less annoyed by the doctor, or nurse, who perform and IV injection with a big needle, whilst the patient has a running IV in the other arm.

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    1. Sue Ieraci

      Public hospital clinician

      In reply to Mark Amey

      My pet hate is the ventilated patient who appears to be in a single room of an ordinary ward - not even in ICU.

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    2. Mark Amey

      logged in via Facebook

      In reply to Mark Amey

      ...and not a doctor, nurse, or any other staff member in sight, and the female patients mange to wear lipstick, eyeliner, etc!

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  10. Simon hauser

    Medical Specialist

    In summary: You can't flog a dead horse

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