Comparing 12-Leads: Common Error or Common Disease?

The following is a case report involves three ECG's recorded on three different patients on three different crews during the same week. Your mission, should you decide to accept it, is to determine what these three patients have in common and what action should be taken!

The first 12-Lead ECG is from an 88 year old male with chest pain:

The second 12-Lead ECG is from a 40 year old female with chest pain:

The third 12-Lead ECG is from a 58 year old male with dyspnea:

  • What is it about these three 12-Lead ECG's that is so striking?
  • What are your differential diagnoses for these three patients?
  • Are these three patients experiencing the same pathophysiology?
  • What are the potential causes of the patterns found on these three separate ECG's?


  • SAP says:

    Leads V4&6 are weird. In EGC1, you have abnormal progression of the precordiial QRSs, with a shorter and inverted complex in V4 and V6 than one would expect. In ECGs 2&3, these leads are of such low voltage you could be forgiven for thinking they showed asystole…

  • Lucas says:

    It kind of looks like they all have low amplitude comparatively low amplitude complexes in leads aVL, v4, and v6.

    Incorrect lead placement?

  • David Albert says:

    Leads V4 & V6 are identical and simply wrong in all 3 patients. Check the lead wires to see if the are shorted together (I suspect the same ECG machine was used in all 3 patients). Otherwise, it’s the unit with channels V4 & V6 are shorted internally. It may be the connector.

  • purujit says:

    hyperkalemia? peaked t waves in all the ecgs.

  • k.rae. says:

    PPM battery end of life.

  • Simon M says:

    I have to agree with David. Leads aVL, V4 and V6 are almost identical in each of the ECGs. Not an unlikely scenario that these were all recorded with the same ECG apparatus, thus showing the same lead shortage. Also noted the Z-axis is between ~5° anterior to 5° posterior on all three. Normal range is 20-40° posterior, so this could support any suspicion of lead-issues. The computerized interpretation also suggests possible old lateral infarct, maybe due to the t-wave inversion?

  • Rob says:

    If it's a technical problem then it seems like a machine problem not external wire issue or lead misplacement. What wire would have to be defective in order to affect only aVL and none of the other limb leads? They all appear normal and match up with each other. The same goes for lead misplacement, where would the leads have to be for all the limb leads to correlate appropriately while aVL is significantly different? I can't think of any way to reproduce these tracings by moving wires around or interfering with their conductivity. So if we are playing EKG equipment diagnostician then it's a central thing not peripheral.
    As for a patient issue as a cause…I can't think of anything here either. Any cause of severely low lateral limb voltage like an old MI or a large mass would affect I and V5 as well, but they are appropriate voltage and morphology compared to the other leads. Can't really think of anything that would cause low voltage in aVL, V4 and V6 only, and happens three times in a week. 

  • Dustin says:

    Poor lead placement or monitor problem….

  • Code5 says:

    I agree with most of the coments here that the morphology is definitly scued! I would first make sure my lead palcement is correct before proceeding any further, loss of 'R' wave progression needs to be validated first.

  • Lance says:

    This has to be a monitor problem.  3 Different patients with 3 different crews, reduces this to the common factor between them, the equipment.  I've been finding that recently, the new cables by viso control have had some serious issues, especially if the crews don't wrap them properly.  They degrade rapidly and they fail commonly and more troubling, inconsistantly.  They'll be fine for the morning check, and then on your 3rd chest pain of the day, good-bye 12 lead capability…

1 Trackback

Leave a Reply

Your email address will not be published. Required fields are marked *