Atrial Fibrillation Pearls from Recent Lectures — Part II
Our recent guest speaker Wyatt Decker challenged us to examine the usual afib ED treatment in the US, which as Alan noted is: 1) Cardiovert if unstable 2) achieve rate control 3) give heparin and 4) admit.
Sure, there’s good reason for all we do. Besides the agents for rate control (see Part I) there’s good reason for anticoagulation. Risk of stroke in chronic afib is 5% a year, a 2-7 fold increase from baseline. 1 in 6 strokes are in AF patients and the use of anticoagulation is of proven benefit.
But what about the teaching (and 2001 AHA/ACC guidelines) that AF less than 48 hours is ok to convert back to sinus? There’s still concern for thrombus formation even in that short time, and cardioversion can lead to atrial stunning and embolic events after conversion.
AFFIRM showed for chronic AFib, rate control trends toward lower mortality and there’s similar risk of stroke in both groups. But for new onset afib, the jury is still out. Some converted patients (20-30%) will not have recurrence, and earlier return to normal sinus rhythm may improve chances of AF not recurring.
Ian Steill’s group in Ottawa (Stiell, A E M, 2007, 14:1158-1164) tackled both the common practice of rate control and admission – they set up a RCT with 1g procainamide over 60 minutes, followed by electricity if necessary (n=341). They saw 91% converted to NSR, with 94% were discharged home, and only 10% adverse events (transient hypotension). This aggressive protocol has caused some controversy – Mel Herbert talks about it more in a video lecture but notes that the folks who can go home after cardioversion are a lot like the folks who can go home after syncope — those with no comorbidities, no CHF, age under 60…
Decker’s data supports a less aggressive approach but one that may be palatable to more ED docs (Decker WW, Acad. Emerg. Med 2003; May 10(5)). His group first determined if the afib was less than 48 hrs old — if it was greater, patients got routine care. If less than 48 hours, pts were observed for 6 hours. If they reverted to NSR for 2 hours, they were discharged home. If still in afib, they were cardioverted and rhythm was checked in 2 hours. If it was NSR then, discharged home. If they were back in afib, they got heparin and were admitted.
They have good data that ED and hospital LOS is significantly less, and their 6-month outcome data on stroke or MI or death or even recurrent visit is good, but the sample size was too small to assess stroke risk.
Based on his data and experience, Decker gave some common sense warnings:
- Anticoagulation is still needed in AF of more than 48 hrs duration
- Early cardioversion (may be) desirable
- Patients who are converted to NSR in the ED may be candidates for outpatient evaluation
Posted
on Sunday, February 22nd, 2009 at 9:47 am by Nick. Filed under
Arrhythmias, Blog.
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