The Ottawa Aggressive Protocol

26 Feb

Stiell IG, Clement CM, Perry JJ, Vaillancourt C, Symington C, Dickinson G, et al. Association of the Ottawa Aggressive Protocol with rapid discharge of emergency department patients with recent-onset atrial fibrillation or flutter. CJEM. 2010 May;12(3):181–191. PMID 20522282

There is big controversy over rate v rhythm in AF, and in ED management. I haven’t done this much, but the few times I have it’s been sedation and electricity. I’ve never used procainamide which perhaps reflects my ignorance rather than standard practice.

Anyhow. The big names in this are the Canadians and this is a study of it.


  • a chart review to document what they had been already doing for years in Ottawa Aggressive Protocol
  • as expected, procainamide followed by a shock if needed. Only in <48 hrs
  • two separate nurses abstracted charts, no detail on the methods (ie how they defined terms) here but most of it is pretty solid data
  • follow-up was loose (they just checked the record to see if anything bad happened) so it’s hard to know what happened after the visit but probably most were fine


  • 1000 pts, 600 of whom entered protocol. The ones who didn’t were because of >48 hr duration
  • 40% got some rate control (metoprolol or diltiazem) prior to procainamide
  • 35% needed DCC following failure of procainamide
  • 7% had a low BP briefly during the procainamide
  • 8% had a recurrence in a week needing management (not sure what this means…)


  • there is a smaller and similar chart review in AEM in 2007 PMID 18045891

I have little experience of this, and this is, of course, not meant to be evidence that it’s better than anything. But if you are going to do it then these are some of the numbers you might tell a patient.

8 Replies to “The Ottawa Aggressive Protocol

  1. One curious thing about this protocol is the use of Procainamide in patients with atrial flutter, which goes against the typical teaching that using an anti-arrhythmic prior to rate control in this setting can lead to an increased ventricular rate by converting 3:1 or 2:1 to 1:1 conduction.

    • I too have wondered about it…why procainamide if atrial flutter responds so well to 50J of cardioversion! The slowing of the macro-reentry to rates easily conducted by the AVN is bothersome.

      • Still waiting for an answer as to why procainamide in flutter. It’s beyond my knowledge i’m afraid… Either way it seems to have worked in the very few A Flutter pts in the study

  2. As a practical note I will mention that in much of Canada our standard of practice for initial management of selected patients with paroxsmal a-fib is sedation and cardioversion without any trial of anti-arrhythmic (ie. we often forego the procainamide) as part of their long term AF control strategy.

    We all recognize in this situation that cardioversion (with chemical or electricity) is for patient comfort mainly in this situation. A-fib remains a chronic condition, and decisions about anticoagulation for the paroxysmal a-fibber are best made without regard to the rhythm of the moment.

    This is a totally routine part of practice here in Canada. I will mention that the patient who is presenting frequently with a-fib should probably have their overall strategy reassessed, perhaps moving to rate control, prn propafenone, regular daily anti-arrhythmic therapy, or ablation. The majority of patients with a-flutter should have a review by an electrophysiologist for consideration of ablation, as a-flutter is a problematic rhythm, that is very amenable to ablation.

    So if someone is young, has a-fib less than 48 h, with clear onset, and feels lousy because of arrhythmia they will get some form of a trial of rhythm control.

    And finally the 8% recurrence rate is completely expected because these patients have paroxysmal afib. Cardioversion does not change this fact, it mearly makes them feel better.

    That’s my 2 cents (or should it be pence?)

  3. In Italy, as far as I know, when a patient with AF is suitable for pharmacologic cardioversion we use class 1C antiarrhythmic agent as propaphenon or flecainide with about 70% rate of success in gaining sinus rhythm.. No experience with procainamide. What do you do in Ireland?

    • Mostly I give them electricity. I’ve used flecanide just the once. I haven’t seen that many patients suitable for it to be honest. A lot are of unclear time of origin and get anticoagulation and follow up

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