Synchronized cardioversion |


  1. judith mahood says

    For cases where electrical shock is needed, if the patient is unstable, and you can see a QRS-t complex use (LOW ENERGY) synchronized cardioversion. If the patient is pulseless, or if the patient is unstable and the defibrillator will not synchronize, use (HIGH ENERGY) unsynchronized cardioversion (defibrillation).

    Shouldn’t it read “if the patient is stable , and you can see a QRS-t complex use (low energy)

    • Jeff with admin. says

      No it should not read that. For the stable patient synchronized cardioversion is not

      Synchronized cardioversion is indicated for the unstable patient who has unstable tachycardia with a pulse.

      Kind regards,

  2. Don Marr says

    How long do I wait in between increasing amplitude shocks during cardioversion? Is it 2 minutes like defibrillation?

    • Jeff with admin. says

      When cardioverting, there should be an increase in the amplitude of the charge with each successive shock. If cardioversion fails after the first attempt then increase the shock dose in a stepwise fashion.

      When cardioverting. The wait time between shocks is minimal. If cardioversion fails then an additional shock at a higher shock dose should be provided without delay.

      Kind regards,

    • Jeff with admin. says

      It is well established with in the literature that pulseless ventricular tachycardia has a high conversion rate when defibrillation is used. This is why it continues to be included with the left branch of the cardiac arrest algorithm and is treated with high energy unsynchronize shocks.

      Cardioversion is the preferred treatment for monomorphic ventricular tachycardia with a pulse because when defibrillation is used there is a higher likelihood that the patient may be converted into ventricular fibrillation.

      The preferred treatment for polymorphic ventricular tachycardia with a pulse is defibrillation. This is because it is unlikely that the defibrillator will synchronize with a ventricular tachycardia that is polymorphic in nature.

      Kind regards,

    • Jeff with admin. says

      Polymorphic ventricular tachycardia will most likely require defibrillation since it will not be possible to sync the rhythm with the defibrillator.

      Kind regards, Jeff

  3. Greg says

    First…. great site… I’m very impressed and can’t imagine how it could be any better.
    I have an interesting question that may not have an answer. Several years ago I was teaching our hospital our defibrillator machine during our annual review. I had the big idea that I would shock myself with our biphasic defibrillator at its lowest setting, 2 joules, to get a sense as to what we do when we shock someone. The jolt took my breath away and I remember crumpling to the floor probably more out of nerves than anything else.

    When I looked up joules, I got some formula that made no sense to this layman. Is there anyway to describe how impactful defibrillating at 100 joules compared to 200 joules is to the human body? How about pacing at 50 or 100 milliamperes?

    I think this is one of those questions that we never think to ask but is very important if you’re about to be on the receiving end.


    • Jeff with admin. says

      As little as 10 Joules is used for the conversion of atrial fibrillation.

      The dose of 2 Joules if given unsynchronized could’ve definitely thrown you into ventricular fibrillation.

      The reason why it took your breath away was because your heart probably stopped beating for a second or two.

      Electricity no matter the dose when given through a biphasic defibrillator travels directly through the heart.

      Cardiac pacing with milliamperes is a minuscule dose compared to 2 Joules.
      It would be like comparing 1 mg of epinephrine with 1 microgram.

      The equations to understand the difference between Joules and amperes is over my head, but the way that the electricity goes into the body is different.

      I’m glad you’re OK. That probably could have killed you if it would’ve been delivered at exactly the right time. Hopefully, if it through you into VF somebody else would’ve seen that and counter shocked you with 200 J.

      Kind regards,

  4. Annemarie says

    I have my advanced life support course coming up and I have found this very useful. I now feel more prepared. Thank you so much.

    • Jeff with admin. says

      If the patient is pulseless you should begin CPR immediately, have someone get an AED or defibrillator and follow the cardiac arrest algorithm.

      A patient that is pulseless will never have normal respirations. You might see kussmaul respirations which are sporadic breathes that can occur during cardiac arrest, but you’ll never see normal respirations.

      Kind regards,

    • Medgirl says

      If the patient is unconscious, and pulseless, the patient is not breathing. You should begin CPR immediately.

  5. sanam gul says

    i want to b part of ur conversation n these answers that u people gave all are very usefull for me in my studies…thanks to all of u

  6. Chintha Samarawickrema says

    Very good explanation of Synchronized & Unsynchronized Cardioversion! For a long time I had a hard time understanding them properly. Thank you very much, Jeff!

  7. Aurora says

    Dear sir,
    I just want to ask what will happen if 1 mg of Epinephrine bolus is given to patient with a rhythm of bradycardia?
    Another thing,if the rhythm is vfib and synchronized shock is given will the shock be effective? Waiting for your reply

    • Jeff with admin. says

      If epinephrine is given to the patient with bradycardia, this will likely increase the heart rate.
      A defibrillator cannot synchronize the ventricular fibrillation. An Unsynchronized shock would need to be given.

      Kind regards,

  8. Mary Rickard says

    Jeff, I always worry when it’s time to renew. This time I feel way more prepared. Great learning tool. I will definitely recommend it to others.

  9. Dr Satish. N v says

    In narrow complex tachycardia. B p not recordable. Breathless. Needs sedation before cardioversion?
    Shall I use synchronized cardioversion?

      • Brendan` says

        Narrow complex tachycardia with no pulse would be a PEA. I don’t think you would do an unsynchronized defibrillation of that. You should probably be doing CPR, epinephrine IV, and a fluid bolus…

        If the patient is awake in a narrow complex tachycardia, but has an unreadable blood pressure, I don’t think they get the benefit of sedation before synchronized cardioversion. Just a sympathetic, “this is going to hurt, but it is all we can do to try and slow your heart down”.

      • Jeff with admin. says

        Yes Brendan, you are correct. I was mistaken when I answered this question this would be considered PEA. The interventions that you listed are correct.
        Thanks so much for the feedback and correction. I do appreciate it.

        Kind regards,


      yes ,synchronized cardioversion is used in all atrial tachy cardia,despite patient is haemodynimacally compromised

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