EKG Challenge #5

What is the diagnosis?

This is a narrow complex regular tachycardia. The differential diagnosis includes - sinus tachycardia, atrial flutter, paroxysmal supraventricular tachycardia PSVT which includes AVNRT - AV nodal reentrant tachycardia and AVRT  (Atrioventricular Reciprocating Tachycardia), atrial tachycardia, irregular narrow complex tachycardias would include MAT (Multifocal Atrial Tachycardia) and Atrial Fibrillation.

The most commonly seen etiology is PSVT. There do not appear to be P waves. However it is difficult to definitively rule out the other etiologies. One must always consider Atrial Flutter with 2:1 block when the HR is around 150. Best lead to see P wave activity is V1 (here red arrows show some blips which may be buried Ps)

Is there a role for adenosine?

Adenosine will frequently terminate a PSVT and unmask underlying atrial flutter so can often be diagnostic

Name an initial non-pharmacologic intervention

Vagal maneuvers. Consider using a 10 cc syringe and asking the patient to blow the plunger out ( Lin ALiEM 2012 ). Additionally there may be improved success with vagal maneuvers using postural modification as described in the REVERT Trial ( Wiki EM Summary )

Take Home Points

1. Always consider Atrial Flutter with 2:1 conduction if the HR is around 150s
2. Adenosine can be therapeutic (terminating PSVT) and and diagnostic (unmasking P waves)
3. Consider postural modification to vagal maneuvers

Resources:
Lin,Michelle (2012,June26) https://www.aliem.com/2012/06/tricks-of-trade-valsalva-maneuver-by/
Brady WJ, Laughrey TS, Ghaemmaghami CA. Cardiac Rhythm Disturbances. In: Tintinalli JE, Stapcyznski JS, Ma OJ, Yealy DM, Meckler CD, Cline DM, editors. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. 8th ed. McGraw-Hill; 2011.
Appelboam A. et al. Postural modification to the standard Valsalva manoeuvre for emergency treatment of supraventricular tachycardias (REVERT): a
randomised controlled trial. Lancet 2015 Oct 31;386(10005):1747-53