24 year old male: "Anxiety Attack" – Conclusion

This is the conclusion to our case 24 year old male: "Anxiety Attack". Be sure to read Part I before the conclusion!

When we left off, our providers were on scene with a young man, in custody, who was pale and had a radial pulse too fast to count. A narrow complex tachycardia was present on the monitor to which our patient helpfully pointed out, "it's SVT".

Let's find out if our patient is right!

Happens All the Time Man - Initial Rhythm Strip

The initial rhythm strip shows a regular, narrow complex tachycardia at approximately 200 bpm. Differentials include SVT (e.g. AV Nodal Reentrant Tachycardia and Orthodromic AV ReciprocatingTachycardia), atrial tachycardia, atrial flutter, and atrial fibrillation. However, given the rate, it would seem unlikely to be flutter, and given the near dead-on regularity it excludes atrial fibrillation.

Happens All the Time Man - Initial 12-Lead

The 12-Lead ECG confirms much of what we saw in the initial rhythm strip. We have a regular, narrow complex rhythm at 200 bpm. Retrograde P-waves are appreciable in leads II, III, aVF, and V1. These P-waves are often termed pseudo-S or pseudo-R' waves, and are most commonly seen in AVNRT. However, ST-elevation in aVR during SVT is a sign of orthodromic AVRT.

Regardless of mechanism, it is safe to say that our patient was right! He is currently experiencing SVT.

The treating paramedic also came to this conclusion and began treatment by lying the patient down and attempting vagal maneuvers. The patient was coached to bear down and then to blow through an empty 10 cc syringe, both without effect:

Happens All the Time Man - Vagal Attempt

An 18 gauge IV was established in the left antecubital fossa. 6 mg of adenosine was then administered rapid IV push followed by a 20 cc normal saline bolus flush. The following was captured:

Happens All the Time Man - Adenosine

This rhythm strip shows an interruption in the AV nodal reentry circuit with a conversion to a sinus tachycardia.

A repeat 12-Lead was obtained by the crew:

Happens All the Time Man - Post-conversion 12-Lead

The post-conversion 12-Lead shows a sinus rhythm without delta waves, epsilon waves, or acute ST/T-wave changes. The computerized interpretation notes a short PR interval of 98 ms, however, this author reads the PRi as normal at ~120ms. If an accessory pathway is present, conduction is concealed on the patient's baseline 12-Lead.

The patient was transported by the crew without incident and was lost to follow-up by EMS. However, this case shows that sometimes our patients will know exactly what is wrong, which underscores the importance of obtaining a good history.

  • What conditions could this patient have which caused his SVT?
  • What treatments may this patient receive if he continues to suffer from SVT?


  • Brian says:

    Why run a twelve lead when three congruent leads are showing svt? Hes going to get the adenocard either way because of his complaints and ekg findings. Just curious

  • renegade medic says:

    I also run 12-Leads on anyone experiencing any cardiac problem. I would assume that the crew was assessing for obvious signs as to the cause, such as an aberrant pathway or flutter waves/fibrillation. It is also extremely helpful for the recieving staff (assumably a cardiologist at the facility) to view EMS EKGs as this gives them an idea of what happpened when the event was occurring or had just occurred.

  • Floyd says:

    What other medications could be used if adenosine failed to convert? I have amiodarone and metoprolol.

  • Floyd says:

    Since you noted elevation in aVR and the possibility of orthodromic AVRT wouldnt procainamide be preferred?

  • Travis says:

    WOW all I got to say is some of yoy scare me an I hope yaw dont work EMS in greenville,pickens, andersona area of SC .. To the person that ask ”why even run a 12 lead” I sure hope your still in medic class cause 12 lead should be ran on any call cardiac in nature, an even on mva with significant trauma to chest an complains off chest pain..have seen AMI in the field without CP here lately so my thoughoots are if you gona put a pt on moniter than why not spend 60 to 90mon to do a 12lead…an about amio bein toxic then its prob cause you aint admin it right, a lot of people dont. It says clear as day that you Dilute it in 20cc normal saline, which combats the toxicology..an what bout d50 very necrotic stuff an awful on veins..an lidocain isnt much better than amio…. As far as this pt goes I woukd like to see a lewis lead ran on this pt

  • Nicky G says:

    I think the value of a 12 lead in these cases is that V1 and V2 can give a good view of P waves if not obvious in the limb leads.

  • Floyd says:

    12 Leads are prudent as long as the patient is stable enough to obtain one. Just like in cardiac arrest once the patient converts to a rhythm that will sustain life a 12 lead needs to be obtained.

  • Robert Fielding says:

    Travis: Did your paramedic class require basic English composition as a requirement? I hope you don’t speak the same way you spell…

    12 lead acquisition can give you a better understanding of the underlying rhythm. For example, retrograde p waves, st depression, and absence of p waves all give you confirmation of the rhythm. Some of these subtle features are not seen in every lead.

  • Christopher says:

    I would prefer metoprolol over amiodarone if 6/12/12 of adenosine fail to convert the rhythm. However, if they are in extremis, sedation and cardioversion is probably a better route.

  • Christopher says:

    A 12-Lead ECG gives you a better look at what is going on. A single 3-Lead only shows you part of the rhythm. VT can look narrow in some leads and wide in others, conversely, SVT can look wide in some leads and narrow in others.
    Rarely is a patient so unstable you cannot acquire a 12-Lead prior to your treatment.

  • zac says:

    it's common AVNRT – pseudo S waves in inferior Leads and pseudo R wave rsR in V1 a slow-fast reentry circuit – adenosine if stable    

  • Paul says:

    “an about amio bein toxic then its prob cause you aint admin it right, a lot of people dont. It says clear as day that you Dilute it in 20cc normal saline, which combats the toxicology”

    NO IT DOESN’T! You shouldn’t be a medic if you don’t know how toxic amiodarone is or how it works. And as for saying “then its prob cause you aint admin it right, a lot of people dont,” you aren’t administering it correctly at all! Amiodarone is not “diluted in 20cc’s of normal saline.” It is mixed in a 100cc bag of D5W/NS, and administered as an infusion over 10 minutes. You scare the hell out of me.

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