ACLS Rhythm Interpretation

ACLS EKG Rhythms and Interpretation

Each Icon below will take you to a page for the Respective ACLS EKG. These pages cover all of the basic ACLS EKG’s from Ventricular Fibrillation to Complete Heart Block. After each article is a short video that simulates the ACLS EKG on a defibrillator monitor.

Pulseless Rhythms

Pulseless Ventricular TachycardiaVentricular FibrillationPulseless Electrical ActivityAsystole






  1. espinoza.p4013 says

    Dear Jeff:

    You did an excellent job on your website! It served as the perfect refresher for me . I only reviewed for 2 days and got all 50 (scored 100/A+) written questions correct plus rocked my megacode.


  2. calannon says

    THANK YOU FOR THIS SITE JEFF!! I just completed ACLS for the first time and passed with flying colors! I had none of the prerequisite knowledge and learned it all from this fantastic site! I had it on my iPhone so it was convenient to study from while I was on vacation or stuck in traffic!
    My ACLS instructor was especially impressed with my Megacode responses. The sample quizzes and Megacodes from you saved me for sure -you made learning FUN!
    I’ve recommended you to all my co-workers regardless of whether they’re taking ACLS for the first time or just re-certifying.
    Thanks again!

  3. julezzz26 says

    Just passed my acls recertification after using your site. Thank you so much for your incredible site. I never would have passed without it! A million thanks!

  4. says

    I am scheduled to take an American Heart Association ACLS Class to get my AHA ACLS back on April 9th, and 10th. Does anyone have advice so I can successfully get through, and pass the Class, and quickly move forward to AHA PALS, and Advanced Trauma Life Support ATLS ????

    Preparing for the Paramedic Program BYUi .

    Thank you

    Paul E. Morris
    Volunteer MCI Medical Assistant, EMT
    Medical Reserve Corps
    Washington State

    • says

      This site will thoroughly prepare you for AHA ACLS certification and you should have plenty of time to prepare if you start now. After you finish with ACLS, I think it would be wise to complete advanced trauma life support and then move on to PALS.

      Kind regards,

  5. Kwang Lim says

    Hi Jeff, Wow ! There are tons of info ! I am so excited.!
    About 3rd degree block EKG, it is a hard strips to recognized quickly.
    Although, it is a completely disorganized PQRS, actually some video shows more # of QRS, than some others ( type 2) . Are those QRS perfusion? I see the imminent danger. Can you kindly
    explain about the physiological aspect ? Also 3rd degree block has to have certain # of QRS ?
    ex. less than 40, 30, 20 / min. etc. Thank you so…. much.

    • says

      Physiologically speaking, the atrium and the ventricle are not coordinated at all. The atria are doing their own thing and the ventricles are doing their own thing. Electrical impulses are not being delivered from the atrium to the ventricles. There is no specific number of QRS complexes or p-waves. There is simply no coordinated effort between the upper and lower parts of the heart.

      Kind regards,

  6. says

    this is one of the most simplest explanation i’ve seen on this topic. i just finished my ACLS and now undergoing EMT training and i just want to let you know it really really helps. thanks.

  7. says

    I hope this information will help me. As a healthcare professional, it has always been a problem when it comes to analizing cardac rhythms. this materials is well symplified.
    thank you for providing such great material free of charge.

  8. Kimmie1 says

    Jeff, do you have an instructional or tutorial regarding how to use a monitor….or suggestions on any I could look up? I know this may sound dumb, but not all people work with one on a regular basis. I appreciate any feedback on this. Also, thank you for this wonderful site, as it is helping me very much to understand some concepts I’ve had problems with. Thanks!

    • says

      At this time, I do not have any tutorials for using a monitor/defibrillator. This YouTube video is a very good overview of the use of a monitor/defibrillator.
      There are a number of different varieties of monitor/defibrillators available, and each one may have a few minor different features. The best way to learn about these machines is to put your hands on them and play with them. If you have one available, I would encourage to mess around with it once or twice a month to stay familiar with its features.
      Kind regards,

    • says

      There is no place on the site that specifically covers PVC. A PVC is a premature ventricular contraction. The PVC is caused when the ventricle is irritated and fires without an electrical current coming from the atria to the ventricles.
      This is why PVCs always have a wide QRS complex. The electrical impulse is generated in the ventricles, unlike a normal impulse which is initially generated in the atria and travels from the atria to the ventricles.

      Kind regards,

      • says

        Hi Jeff,

        I have been a nurse for a while now and worked in various ER’s for nearly 2 decades. I really wanted to say the modern approach to ACLS as a team is way better than the earlier years…… For those that could use some help with rhythm interpretation there is a book titled, “Rapid Interpretation of EKG’s” , by Dr. Dale Dubin. It can be found virtually anywhere and was very helpful for me to understand what I’m seeing on that cardiac monitor and why. He is very simple in his teaching approach in the book. It will cover everything including 12 lead interpretation. I have surely recommended it to new nurses prior to their initial ACLS. Now, 20 years later, it’s still a great resource. Hope this can help some.

  9. says

    I am so glad that there is a site dedicated for these rhythms and ACLS that is so well organized, well researched and so easy to understand. I would like to stress on the last point because tI have never been able to understand these from anywhere…and now finally I do!!! I am taking Step 2 CK next month and thanks to Jeff , I finally can go confident on these emergency medicine questions. Thank you so much Jeff !!!

  10. VEDA says

    Thank you for a very informative lesson. I benefited from the live examples and simple, clear commentaries which makes it easier to remember. Great job!

  11. Armymom2x says

    Thank you Jeff for this wonderful review! I passed my ACLS my first time! I come back frequently as a refresher! I have passed this site along to my coworkers who will be also taking ACLS for the first time!

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