Case 0002 – Speeding on speed….

30 yo man with a past history of IVDU, infective endocarditis with mitral vegetations / scarring and “adult-onset ADHD”. Several recent admissions for SVT.  Presents to ED after consuming a handful of “LSD” in combination with his prescribed dexamphetamines.  Looking unwell, a bit angry, sweaty, pale, dilated pupils and a ventricular rate of 249!!  Normotensive, though drowsy and incomprehensible…

Clearly as a narrow-complex tachyarrythmia – likely SVT, possible short PR /pre-excitation on previous ECGs.  How to proceed?

When I was a Med student the teaching was, try vagal manouvres (occasional success) then hit them with adenosine via  big IV in the antecubital fossa.  But a lot of Cardiologists like to use verapamil, often as a prn outpatient med for recurrent cases.  So what is better – ADENOSINE vs CCBs?

Check out this recent work on the topic, via EM Updates

My reading of this small study is that IV verapamil 20 mg over 20 minutes is good, has a better reversion rate than adenosine but might cause a bit more hypotension.  Would like to see a bigger study but looks OK from a safety point of view.  Also – less reliance on getting a big fat IV in the ACF and the patient doesn’t get the thrill of “impending doom”, ?exacerbation of airways disease?  Of course te best course of action is to avoid taking the juice in the first place!  Gotta say, I am a bit innocent but surely it just ‘aint worth it?  Let me know…


  1. You can find instructions and the drip sheet for how to do this in this post on the crashing atrial fib patient.

    • Hi Scott
      Thanks for he links. For SVT I have been drawing up 20 mg verapamil in 20 ml syringe – I ask the nurse to push 2mls every 2 – 3 minutes.
      On average a good response by about the 10 – 15 mg mark. Often co-load with Mg++

      • like it! do you pretreat with calcium?

        • Have not done so yet – but it makes sense.
          Kinda odd giving Ca++, then loading with a Ca-channel blocker 😉
          But I guess they achieve different things – stabilise the action potential and slow the AV conduction.
          This will confuse even the most enthusiastic medical student – but a good demnstration of cardiac physiology!

  2. Hey casey,
    were discussing similar case this week. Cardiologist prefered the verapamil provided well monitored (has had to give some fluids ect for BP but not often) but he felt that if you know and use adenosine regularly its not bad for you to continue with this.
    So theres my (stolen) pragmatic kiwi response.

  3. Mike Sherriff says

    I would say Adenosine if I had to choose. Due to the previous short-PR/pre-excitation you have to consider WPW/accesory pathway. Adenosine will break orthodromic or antidromic AVRT and is not contraindicated in WPW (except AFib with WPW). CCB’s will likely break either, but if for some reason he deteriorates into A-Fib with WPW, you could have a problem due to the increased duration of effect of CCB versus adenosine.

  4. My 20c.
    Simple SVT, had it before, you know the ones – give verapamil. Get away from the impending doom of adenosine and get familiar with verapamil.
    Nope don’t pretreat with calcium 3/166 hypotension.

    This case – heart and head like benzos in amphetamine toxicity. Id be giving some iv midaz and DCCV / adenosine.

  5. Particularly in this case I would worry about accessory pathway induction cuz of WPW so perhaps adeno would be a better option

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