Resident Author: Madeline Brockberg, MD

Faculty Editor: Steven Mcguire, DO

An 86 year old male with a complicated past cardiac and GI history rolls into the resuscitation bay. He has a known history of afib on apixaban, prior esophageal cancer s/p esophagectomy and multiple significant GI bleeds of unknown origin. He is sitting on the stretcher with a bag of coffee ground emesis in his lap and actively vomiting dark red blood. Quickly, 2 large bore IVs are established, 40 mg IV pantoprazole is given, GI is stat paged and unmatched blood is on its way. As you are resuscitating the patient and discussing the need for airway management, the nurse points out a wide complex tachycardia on the monitor.

An EKG shows persistent monomorphic ventricular tachycardia. BP is 110/80 and now the patient has stopped vomiting. He is sitting up and talking to you with a seemingly normal mental status and denying chest pain or shortness of breath.

The first critical decision point is stable vs unstable. This patient has a high likelihood of decompensation but currently has an appropriate blood pressure (greater than 90/60) and adequate perfusion evidenced by a normal mental status and denial of chest pain and shortness of breath. So, for now he can be considered stable (1).

After that decision, there is the more complicated decision of what agent to reach for to terminate the ventricular tachycardia. The available choices are amiodarone, procainamide, lidocaine and adenosine. This review will discuss the benefits of procainamide over amiodarone and how to dose both in the Emergency Department.

Amiodarone is a popular choice for an antiarrhythmic that acts on sodium channels, beta adrenergic receptors, potassium channels and calcium channels (it is a class I, II, III and IV drug) to varying degrees. Despite its popularity, it carries a Class IIb recommendation from the AHA (1). Procainamide is a Class Ia antiarrhythmic agent that carries a Class IIa recommendation from the AHA (1). It is an older drug but it has been directly compared to Amiodarone in a head to head trial with favorable results (2).

Given the AHA recommendation and available evidence, I use it as a first line agent for termination of stable ventricular tachycardia.

The PROCAMIO trial was a multicenter, randomized and prospective trial that compared IV procainamide vs IV amiodarone for stable ventricular tachycardia (2). The doses used were:

  • IV procainamide 10mg/kg over 20 min
  • IV amiodarone 5mg/kg over 20 min

It spanned six years and was a relatively small clinical study (74 patients recruited). 

Outcome Procainamide Amiodarone OR 95% CI (p-value)
Major Cardiac Adverse Events 9% 41% 0.1 0.03-0.6 (0.006)
V-tach termination (within 40 minutes) 67% 38% 3.3 1.2-9.3 (0.026)
Adverse Events Within 24 Hours 18% 31% 0.49 0.15-1.61 (0.017)

It is worth noting that this trial was done in Europe and the dosing was slightly different that what you may be familiar with in the US. A more common dose at our Trauma Center in Boston is to give procainamide at 17 mg/kg with a max rate of 50 mg/min or to give 100 mg IV over 2 minutes every 5 minutes until you convert the rhythm. Amiodarone can be administered by a loading dose of 150 mg IV over 10 minutes, followed by an infusion.  

The most common adverse event with both drugs was hypotension (2). When this happens, you should be ready to cardiovert, so pad placement prior to drug administration is critical. In the above patient, we were able to convert the patient to normal sinus rhythm with 17 mg/kg of procainamide. The patient was intubated post conversion for emergent EGD and despite the love for it in our department, ketamine was carefully avoided given the sympathomimetic surge associated with its use as an induction agent.

The head-to-head trial is the best evidence available for procainamide over amiodarone. However, prior to this study, there were several retrospective case series that indicated similar results and prior studies that demonstrated the efficacy of procainamide over lidocaine (3, 4, 5).  So, even though your pharmacist may have to run out of the resus bay to grab this “very old drug”, consider it for your next stable patient with ventricular tachycardia.

References:

  1. Neumar RW, Otto CW, Link MS, et al. Part 8: adult advanced cardiovascular life support: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation 2010;122(Suppl 3): S729–67.
  2. Ortiz M et al. Randomized Comparison of Intravenous Procainamide vs. Intravenous Amiodarone for the Acute Treatment of Tolerated Wide QRS Tachycardia: the PROCAMIO Study. Eur Heart J 2016. PMID: 27354046
  3. Marill KA, et al. Amiodarone is poorly effective for the acute termination of ventricular tachycardia. Ann Emerg Med. 2006 Mar;47(3):217-24.
  4. Desouza IS, et al. Antidysrhythmic drug therapy for the termination of stable, monomorphic ventricular tachycardia: a systematic review.Emerg Med J. 2013;0:1-7.
  5. K Komura S, Chinushi M, Furushima H, et al. Efficacy of procainamide and lidocaine in terminating sustained monomorphic ventricular tachycardia. Circ J May 2010;74:864–9.