New Vernakalant for Acute Afib conversion-Will quick trigger fingers for CARDIOVERSION increase stroke ?

Dr Melissa Walton-Shirley


April 14, 2009

Funny how a development so significant could be no more than a blip on the screen  on occasion.  Perhaps I  missed the entire Vernakalant development story because I read about the compound RSD1235 and thought "good luck making it past our FDA and to the US market".  I either missed the story all together or firmly tucked it into the "yeah right" portion of my brain.  I've had to do a little homework because this hopeful replacement for electrical cardioversion is already available outside the US, a sure sign that it will likely make its appearance in local ER's and ICU's fairly soon .  The greatest indicator of its pending arrival is Merck's 60 million dollar installment , a move that is likely based on something a bit more promising than a mere crapshoot.   

In considering how to fit this medication into my daily routine,  my initial impression is that  there will NOT be many indications for it.  Maybe those folks that come into ICU's post op with documented sinus rhythm who have witnessed new  onset of atrial fib would be a good first place to start.  I'd be very comfortable using it there. The idea of going to the bedside, giving a bolus or two of a drug that will convert 50% of patients to sinus in 15 minutes is a  lovely thought and less of a hassle than having to hold the  hands of nervous patients and family members who can't stand the thought of someone being gently electrocuted for sinus rhythm's sake. 

However, I worry that  Vernakalant will be inappropriately utilzed in ERs en masse to facilitate quick patient exits. The temptation will be great to just whip it out willy nilly in this economic environment where "drive through" everything is appealing.   In patients with high CHADS scores, they very well could be discharged without Coumadin and return in a few days with a devastating acute middle cerebral artery occlusion.  Since so many patients are mistaken with regard to the duration of their atrial fibrillation, I'd be very mistrustful of the perception of timing of onset of palpitory awareness.  As a cardiologist, I'd want an echo first.  I'd like to see their last EKG.  In some, I'd want a TEE pre-bolus and if you are going to sedate a patient for a TEE, why not just sedate them a little more and cardiovert them while their enjoying a little extra anesthesia?

This medication also has a strange side effect profile.  We'll have to tell them that 30% of patients have an odd change in taste perception,(but that could work for us.......i.e. instruction to the patient: "you'll think it's a hot fudge sundae but really it's lettuce"?)  11% will experience some form of paresthesias (will I worry they are Tia's?) and 16% will need to keep a box of tissue handy because they have an increase in "sneezing"(no honey, it's not the new cat, it's your cardioversion medication).  Others have transient but what appears to be relatively benign dips in blood pressure.( So do folks with cardizem IV, not usually a big deal).   

So until this medication reaches the US and is put into use, it will be difficult to predict the degree of implementation.  Will it go the way of IV dofetilide or will it become as common as IV cardizem?  Probably the best use of this medication will be a pairing with a heparin drip and p.o. Coumadin with a few days in the hospital post conversion, just to be on the safe side with discharge only after a therapeutic INR is achieved. 

I'm sure we'll figure it out, but if we don't figure it out well, quick trigger fingers for cardioversion in  hopes of a rapid ER discharge order could spell an increase in stroke incidence.  With all the information that cardiologists usually gather before we undertake a cardioversion, I don't think the problems will occur in the "IN- patient" population.  I think it's the "OUT -patients"  who have something to fear and unfortunately, I think it's more than "fear, itself". 

 Fortunately, we may have data that keep us from having to re-invent the wheel, after all, it's already being utilized in other parts of the world.  However, before we start to utilize it ourselves, we need to think about it a bit.......I mean REALLY think about it.




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