77 year old female: Unresponsive – Discussion

This is the discussion for 77 year old female: Unresponsive, if you have not read the case report we recommend you start there!

First, a hat tip to our readers who were unafraid to tackle this challenging scenario. Second, we were very impressed to see a number of readers correctly identify this challenging rhythm!

When we left off our crew was attending to an altered 77 year old female they picked up at a local skilled nursing facility. The patient's presentation seemed fairly routine for an Altered Mental Status rule-out.

However, once she was placed on the monitor her status became less clear:

We'll See What Shakes Out - Rhythm Strip

Given the fast rate and possibility for SVT, atrial fibrillation, or even ventricular tachycardia the crew needed more information.

When faced with an uncertain rhythm strip it is best to acquire more leads, and a 12-Lead is a wonderful way to do so:

We'll See What Shakes Out - 12-Lead

So what are we looking at?

  • Many readers pointed out the irregularly irregular tachycardia present in just about every lead.
  • Some readers pointed out the regular rhythm present in lead III.
  • Other readers noted the 3-Lead and 12-Lead were full of artifact.
  • Some readers gave up with cries of, "Treat the Patient! Not the Monitor!"

Ok, I can read the comments; tell me what it is!

The answer is easiest to see in the initial rhythm strip. A closer inspection reveals that when you try to line up Leads II and III, they do not even march out!

We'll See What Shakes Out - Rhythm Strip Marked Up

If we were to display a tracing of the pulse oximetry waveform, it would likely be more evident that only Lead III is providing a useful display.

So why did our patient's pulses not match with her cardiac rhythm?

And why did our patient have an irregular tachycardic rhythm in every lead but Lead III?

Both prehospital and hospital providers who routinely acquire electrocardiograms are familiar with artifact obscuring rhythm and 12-Lead interpretation. Common causes of artifact on the ECG include power line intereference, patient movement, and baseline wander. Lesser known causes of artifact on the ECG include cable failure, neurostimulators, lead placement over arterial pulse points, and electrode manipulation.

Cardiac monitors are designed with electrical filters which screen out intereference which is of a frequency that exists outside the range of physiologic parameters. Unfortunately, if the frequency of an artifact occurs at a near-physiologic rate it will be up to the provider interpreting the ECG to mentally "screen out" the interference.

In this case our patient has advanced Parkinson's disease, which is a degenerative neurological disorder affecting the central nervous system. The most visible symptom of this disease is the motor dysfunction and the characteristic tremors it produces in the periphery. As with any patient motion, it can cause artifact on the surface ECG.

If we take a closer look at Leads II and III we can see that the Parkinsonian Tremors present produced artifact at a rate of 250-300 and looked surprisingly like Atrial Fibrillation with WPW!

We'll See What Shakes Out - Lead II and Lead III

There have been multiple case reports of Parkinsonian Tremors mimicing ventricular tachycardia, ventricular fibrillation, atrial flutter, and supraventricular tachycardia. In one case, a comatose ventilated patient inappropriately received defibrillation for what appeared to be ventricular tachycardia!

When evaluating a patient with tremors it is best to place the leads in the Mason-Likar configuration, i.e. the limb leads are placed on the chest and abdomen. However, sometimes even that will not help and a switch to an anterior-posterior configuration (roughly approximating the pads position, or V4-RA and V8-LL) may be your only option to record a semi-clean tracing.

Remember, as prehospital providers it is important that we be able to explain our findings on the ECG because it may have a large impact on the patient's inhospital care.


Our crew was perplexed as to the discrepancy between the patient's pulse rate and that the rhythms in Leads II and III seemed, "out of sync". They contacted medical control for guidance and were advised to transport to the closest facility and to withold rate control while the patient's blood pressure was adequate.

Narcan was administered due to a persistently low SpO2 and pinpoint pupils. The remainder of the transport was unremarkable and the patient's vital signs remained relatively unchanged. A palpable pulse of 70 was weakly present at the radials while a monitored heart rate of 250-280 was given.

Upon arrival at the receiving facility the patient was noted to have converted to a normal sinus rhythm, with an RBBB and ocasional PVC's. However, during the course of her ED stay she had another "bout of tachycardia" on the monitor and was sent to the floor for observation. It is the opinion of this author that the patient's recurrent tachycardia was merely artifact, likely similar to that seen in her prehospital ECG's.

We hope you enjoyed this case as much as we did!


  • Flash Larry says:

    I came to this case late, too late to comment elsewhere. Excellent case, however. It demonstrates quite nicely why our first dictum is "do no harm." For my purposes, I was initially reading this as SVT with WPW (because my wife has it), BUT the pulse and the BP mitigated against it. Therefore, in reading the initial case (just before I read this "answer") I decided not to treat for SVT. Even it it were an SVT, this is a complex case and if the patient is holding an adequate BP, and with a close response to the hospital, I assume the first dictum, "do no harm" and concern myself with the fact that if I were to do anything like administer adenosine, there might be unpredictable, untoward effects.
    I did note the possible CNS depression early, and that was my first thought as to what was happening to this patient even before seeing the initial ECG. I'm curious as to what the hospital found with respect to this when they drew labs, and what they concluded. I concur with the judicious administration of narcan in this case to see what the response would be, since there are few untoward effects from narcan.
    This is an interesting case where, if there were no ECG available, the treatment would have been closer to appropriate than it might have been with the ECG. It would have been based on the patient's appearance and vital signs rather than the machinery.

  • doobis says:

    It is always nice to learn some new things; I had not noticed that the leads in II & III did not match up.  Something I will look at closer in the future.  I wonder if placing the defib pads on the PT and switching over to "Paddles" mode, similar to what was mentioned in this discussion, would have revealed the true nature of the rhythm prior to giving any cardioversion, another "safety check".  I also imagine that most medics would see the PT shaking in the field and take a closer look at the PT and how their EKG presented.

  • Flash Larry,

    It is my understanding that narcan did not improve the patient's clinical status.

  • doobis,

    I think a lot of providers have a false sense of urgency during most ECG interpretation in the field, especially if it "looks bad". These are precisely the ECG's where we should stop and take at least a minute to ensure we know what we're looking at.

    Thank you for your feedback!

  • kyle says:

    I suppose I would have overreacted.   The unresponsive nature and the pinpoint pupils (if not reactive to narcan) and the repeated nature of the uresponsive episodes…. would have had me thinking tumor near the pons, and transporting for fear of the off chance of an anurism or bleed in that area.

  • arnel says:

    Very nice case Christopher. Is there an explanation why lead III is a bit "stable"  in the background of artifacts?

  • Mike Sherriff says:

    I think there is another VERY, VERY important teaching point. 
    IF this case was Atrial Fib (which it is not), it would have to be considered A-Fib with WPW/accessory pathyway.  If you saw strips like this, and it wasn't artifact, you would need to think A-Fib with WPW.  Not A-Fib with aberancy, or A-Fib with RVR–think A-Fib with WPW.
    If you are treating A-Fib with WPW: you need to use ELECTRICITY!!!!! Maybe procainamide if you have it.  But really, get all the usual meds (adenosine, lidocaine, amiodarone, diltiazem, etc) out of your treatment plan.  They may not just hurt, but actually kill the pt. Not later at the hospital or next week, but right now, in front of you!
    Electricty is the safest option in A-Fib with WPW.  (But this is not A-Fib with WPW, but if it were it could look pretty similar)

  • kerrysivula says:

    i was always to treat the patient and not the montor. montor can mess up

  • smlvl says:

    That was a wonderful explanation of the ECG presentation and I'll certainly be taking the troubleshooting lead placements to heart!
    But I am still curious about one thing; did they ever figure out what was causing the AMS?

  • James D says:

    It would seem that the bullet comment in the article — "Some readers gave up with cries of, "Treat the Patient! Not the Monitor!" — was a little premature, especially when my treatment regimen was correct. I didn't consider it giving up, just the prudent thing to do.

  • Kevin says:

    This was clearly rate related, the rate was too fast for the pulse ox. If this guy was at 250-280, and unconscious, he should have immediately been cardioverted..

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