Stump the Experts – EP Lab Digest

My “Stump the Experts” column is up at EP Lab Digest. The Case of the Tachy Trucker can be found HERE.

If you think you know the answers to the questions in Part I and Part II, please email your guesses to the Managing Editor Jodie Elrod.

Good luck!


  • Christopher says:

    Are there larger images? Killin' my eyes with the little PNG's 🙂

  • Tom B says:

    Sorry, guys! I know the resolution could be better, but you'll have to make your guess based on the ECGs provided. Come on, fellas! You're the special forces of ECG Geekery! :)Tom

  • Brian T says:

    Here are my thoughts:This guy recently wore a holter monitor and was given a clean bill of health. This makes the rhythm in question unlikely to be sinus with BBB because the BBB would have been seen before. So I am asking myself what else would cause abberantly conducted supraventricular depolarizations. A preexcitation syndrome could do this; namely WPW or LGL. A rate this high (250) definentely is consistent with this too, especially if the underlying rhythm is AF. Although the rhythm appears regular, it is simply too fast to determine regularity (i.e we can't exclude AF from the dx). Once the rhythm converts to an apparent sinus rhythm, we see no delta wave or QRS widening, but we do see a very short PRI. This is consistent with LGL. I don't know however whether or not an LGL mediated tachycardia (such as AF) would appear wide. The second 12 lead however does not appear to be a sinus rhythm. It looks like AF with PVC's. If the intial rhythm was AF with aberancy, I'm not sure why it would slow down though. On the other side of things…. The inital rhythm appear VERY wide (favoring VT) and demonstrates V lead concordance (favoring VT). Aditionally, the 12 lead after auto-conversion is riddled with ectopy, which makes me think his heart is very irratable (and therefore prone to having runs of VT). I don't know…..sorry if this is disorganized and non-sensicle. Thank the sweet lord for Amiodarone.

  • Tom B says:

    Brian T – I can't say anything that would give away the answer, but I will say that AF/WPW (atrial fibrillation with an accessory pathway) tends to be very fast and very irregular, and can be wide or narrow or both.Usually when AF is too fast to pick up on irregularity, it's because the limiting factor is the refractoriness of the AV node. That's not the limiting factor when there's an accessory pathway.With an irregular or polymorphic rhythm, when the rate is very fast (approaching 250) or the shortest R-R interval is 6 small blocks or less, then you should suspect AF/WPW and treat (or not treat) accordingly! Tom

  • medic1488 says:

    So my guess on this would tend to be an AVNRT that just happens to be a bit faster than normal. He did this while fueling up. So what else do truck drivers do at this time? Eat and drink. And what is he drinking? Coffee, red bull, etc…. It appears to me that post conversion to be a buch of PACs (from the best I can tell with the quality of picture) So my thought is that this truck driver stops for fuel, has a red bull or something similar, starts throwing PACs which throw him into a AVNRT. When hes on the holter monitor he probably is living a bit different lifestyle (ie: stays off the road) so they dont catch anything on the monitor.Just my thoughts.

  • Tom B says:

    medic1488 – I love the rationale for your hypothesis! :)Tom

  • medic1488 says:

    Keep in mind it is just that, a hypothesis. I widsh a bigger image could be viewed off that site. I have hemmed and hawed over what I think some aspects could be. One thing that I think I might see is a shortened PR interval but no delta waves (from what I can see). Maybe an underlying LGL which would also make him prone to tachydysrhythmias.

  • Tom B says:

    medic1488 – I sincerely meant that I loved the rationale for your hypothesis! Of course I understand it's just a hypothesis. But I hadn't considered those points. I thought it was interesting.Tom

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