Another great morning report today about a classic cardiac condition that we are all going to encounter at some point in our careers…stable SVT. The patient in question was a 39 year old female who complained of acute onset painless palpitations.
In stable narrow complex SVT, first try vagal maneuvers, then adenosine. There are further treatments that are outside the scope of this post.
- Non Pharmacologic therapy – AKA vagal maneuvers
- Carotid massage (eval for carotid bruit first, beware dislodging clot and causing stroke in older patients, don’t massage both sides at once ;))
- Ice pack to face
- Valsalva Maneuver – Click here to learn the best way to ensure adequate valsalva
- Pharmacologic Therapy – Adenosine
- The standard adenosine dosing is 6mg followed by 12mg if no response to initial dose
- Adenosine may not be effective if it is administered incorrectly:
- Did you use a large bore IV?
- Did the medication flow backwards through the IV tubing?
- Consider 3 way stopcock
- Consider manually kinking line distal to administration to prevent back flow
- Did you flush the medication with a normal saline filled syringe
- Is the patient’s arm bent so as to obstruct venous return? consider making the patient keep their arm straight and elevated over their head to maximize venous return
- Remember this is a push dose drug and should be administered rapidly through the IV
Many medications can inhibit or augment the effects of adenosine, a list of which is below
- Adenosine Inhibitors: you may consider using higher doses of adenosine in patients who use the following:
- Adenosine augmentors: you may consider using smaller doses of adenosine in patients who use the following:
- Calcium Channel Blockers
- Central IV access
Video’s for your enjoyment
References and suggested further reading
- ER, season 4, episode 15
- Rosens chapter 77, Dysrythmias
Max and Steve