Thursday, December 20, 2012

Tale of the Comeback Kid: Procainamide in the ED

It seems as though the traditional "go-to" management of atrial fibrillation in the setting of rapid ventricular response in the emergency department involves rate control and anticoagulation.

Can we break this tradition and consider alternative therapeutic management in certain subpopulations of patients with dysrhythmias?

Recently, there has been some discussion regarding the use of rhythm control for new-onset atrial fibrillation, particularly procainamide, which used to be used back in the day and has started to make a comeback.

You may ask why. Here's the story of the revived interest in the emergent use of procainamide in recent-onset atrial fibrillation as well as other dysrhythmias:

The Procainamide Comeback: Blasts from the Past and Hints for the Future
Indication
Recommendation
Proof
Conversion of recent-onset atrial fibrillation
Class Ia recommendation for our northern neighbors in Canada
·         One study demonstrated conversion rate of new-onset atrial fibrillation with the use of IV procainamide in nearly 52% of all patients.
·         Another study demonstrated 59.9% conversion rate in patients treated with IV procainamide using the Ottawa Protocol.
Wide-complex atrial fibrillation associated with Wolff-Parkinson-White (WPW) syndrome
Class I recommendation for management of atrial fibrillation in the setting of WPW as of 2011 ACCF/AHA/HRS guidelines
·         A review of various studies show amiodarone to not be the preferred treatment option for atrial fibrillation associated with WPW due to inducible proarrhythmias
·         Incidence was less with procainamide.
Stable monomorphic ventricular tachycardia
Class IIa recommendation (preferred over amiodarone [Class IIb]) based on 2010 AHA guidelines
·         One study demonstrated superiority of IV procainamide over IV lidocaine in terminating episodes of stable monomorphic ventricular tachycardia (79% versus 19%).

Interestingly enough, the Canadians seem to have a lot more to offer in terms of evidence surrounding the use of procainamide in the emergency department; perhaps we can adopt this practice more routinely when the situation arises.

To complete the preparation for the comeback of procainamide, let us now retrieve that vial sitting all the way in the back corner of the top shelf in your pharmacy and review the dosing just for kicks:

The loading dose of procainamide can be administered in a number of ways:
  • 20 to 50 mg/min IV OR 100 mg IV at a rate not exceeding 50 mg/min repeated every five minutes as needed to a total dose of 1 g
    • When a total of 500 mg has been given, one should wait ten minutes before continuing with administration to prevent profound hypotension.
  • Infusion of 17 mg/kg IV over one hour
    • In patients with renal dysfunction or congestive heart failure, loading dose should not exceed 12 mg/kg.
The maintenance dose of procainamide typically ranges between 1 and 4 mg/min administered via continuous IV infusion.

Procainamide is looking to redeem itself for use in the ED...are you up to the challenge?