EKG – 5 – Supraventricular Tachycardia

A 47 yr old woman, h/o HTN and Diabetes type II, presents to Mirebalais complaining of 1 month of dull epigastric pain.

Vitals on presentation:  BP 95/72, FC 180, FR 28, O2 sat 97% on Room Air

WHAT DOES HER EKG SHOW?  And what’s your next step in management of this patient’s condition?
EKG of the week #5


AXIS:  normal (I+, II +, aVF+)
RATE: around 180 bpm
RHYTHM:  Regular with no obvious P waves
INTERVAL:  borderline wide (around 120ms – 3 small boxes, each small box is .04s) with morphology of INCOMPLETE LEFT BUNDLE BRANCH BLOCK, or a large rS in V1 and large R in V6, the “appearance of left bundle morphology” without widened QRS
ST SEGMENTS: unremarkable

Initially upon receiving this patient, there was a question among the ER staff as to whether or not p waves were present.  I will tell you that even if it was a sinus rhythm, you will usually not be able to see p waves with a rate of 180, it is simply too fast and p waves can be hidden among the t waves.  180bpm per minute would be quite fast for a sinus rhythm for someone in their late 40s,  but certainly it is not impossible, so how then can we determine whether the rhythm is sinus or not?

If it is sinus rhythm, there should some variation, meaning when you watch her heart rate on a monitor, you would expect that it would go back and forth between the high 170s and low 180s.  However when we put her on a monitor, her heart rate stayed exactly 180 for at least 5 minutes, and did not change with fluids.  This highly suggests a cardiac arrythmia rather than fast sinus rhythm.

MANAGEMENT:  Patient was given 6mg and then 12mg adenosine and converted to the following sinus rhythm

EKG of the week #5 - 2

Giving adenosine:  Adenosine is an AV nodal blocking agent with a half life of less than 10 seconds meaning it is rapidly metabolized in the blood and therefore when administering it, you must try to get it to the heart as quick as possible (before it is metabolized).  This is typically achieved by rapidly bolusing adenosine followed immediately by a rapid flush.  We set up our ports in the following way:

Please note a more proximal vein (i.e. antecubital vein) would have been an even better choice!


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