Atrial Fibrillation with Rapid Ventricular Response

3 Comments

ablumenberg · April 21, 2016 at 12:45 am

Cardiovert with sedatives? Please explain!

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jshibata · April 22, 2016 at 5:39 pm
Yes always! A little sedation is great for pain, anxiety and from what i’ve read amnesia. If there is time to take 5 minutes to grab a sedative from the pixis, you should do it! And there usually is time.
I’ve mostly seen fentanyl and versed given, but in looking for evidence for the answer to your question, I found this great chart in Roberts and Hedges (1) which I’ll paste below that has all kinds of great options. I like the idea of using etomidate, but I’ve never seen this done.
Lobo et. al studied 100 patients given midazolam 7.5-20mg doses for DC and found that none of them remembered the event and would all have the procedure done again (2).
There’s a cochrane review of sedative agents for cardioversion which basically showed that there are many poor studies out there that compare different agents and find that most patients are adequately sedated with few adverse events with whatever agent was used (propofol, etomidate, midazolam, etc. etc.). The adverse events are the typical ones we expect when using these meds for conscious sedation. Most of this data is randomized, but not blinded (3).
My conclusion: Use what you like. We are emergency physicians who aren’t afraid to treat pain and anxiety because thankfully we are trained in basic anesthesia. That said… have fluids, a BVM and zofran ready.
Commonly Available Intravenous Medications Used for Sedation in Cardioversion:
DRUG DOSE COMMENTS
Midazolam 0.15 mg/kg Most commonly used
Induction occurs in about 2 min
Small drop in blood pressure
Flumazenil antagonist available
Methohexital 1 mg/kg Quicker onset than midazolam
Shorter duration than midazolam
Small drop in blood pressure
Rare complication of laryngospasm
Etomidate 0.15 mg/kg No drop in blood pressure
Painful IV infusion
Propofol 1.5 mg/kg Small drop in blood pressure
Painful IV infusion
Thiopental 3 mg/kg Painful IV infusion
Fentanyl 1.5 µg/kg An opiate
Added for more sedation
Can cause respiratory depression
Ketamine 1.5 mg/kg Will not cause hypotension
May be combined with reduced-dose propofol (0.5 mg/kg) or a full-dose benzodiazepine
1. Minczak, B. Defibrillation and Cardioversion. Roberts and Hedges’ Clinical Procedures in Emergency Medicine, Chapter 12, 228-247.e1.
2. Lobo et al. The use of conscious sedation in elective external direct current cardioversion: a single centre experience. BMJ Qual Improv Rep. 2015 May 12;4(1). pii: u208437.w3377. doi: 10.1136/bmjquality.u208437.w3377. eCollection 2015.
3. Lewis et al. Anaesthetic and sedative agents used for electrical cardioversion. Cochrane Database Syst Rev. 2015 Mar 22;3:CD010824. doi: 10.1002/14651858.CD010824.pub2.
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iandesouza · May 7, 2016 at 3:57 pm

Ha. Not many responses here. I guess most residents would answer, “Uh, I’d just ask my attending”. But, your attendings won’t be around to hold your hands forever.

The initial treatment should simply be a fluid bolus (1) with consideration of the presence of an underlying illness which should be treated. Although one may consider this an “unstable SVT” and choose cardioversion, guidelines (2) suggest that a tachydysrhythmia is unlikely to primarily cause hemodynamic instability when the rate < 150/min (“expert opinion”); it IS possible in those patients who have baseline systolic dysfunction. A bedside sonogram will allow an estimation of contractility, and if severely compromised, one can ready phenylephrine (push-dose and/or infusion) in anticipation of further hypotension during attempts at rate control. The decision to control the rhythm will then depend on the duration of the atrial fibrillation, but this is a different discussion…..

Rate-control may be best performed with calcium-channel antagonists. Studies (3, 4) have shown better efficacy when compared to beta-receptor antagonists, although the evidence is limited. Guidelines caution about the sequential administration of both calcium-channel and beta-receptor antagonists due to risk of complete AV block. This practice has not been directly studied. Ideally, one should choose one or the other, but if a crossover is to be attempted, I would suggest waiting for the first agent’s duration of effect to finish (and documenting such) prior giving the other.

1. Scheuermeyer FX, Pourvali R, Rowe BH, et al. Emergency Department Patients With Atrial Fibrillation or Flutter and an Acute Underlying Medical Illness May Not Benefit From Attempts to Control Rate or Rhythm. Ann Emerg Med. 2015;65(5):511-522 e512. DOI: 10.1016/j.annemergmed.2014.09.012

2. American Heart Association. Web-based Integrated Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care – Part 7: Adult Advanced Cardiovascular Life Support. ECCguidelines.heart.org

3. Martindale JL, deSouza IS, Silverberg M, et al. beta-Blockers versus calcium channel blockers for acute rate control of atrial fibrillation with rapid ventricular response: a systematic review. Eur J Emerg Med. 2015;22(3):150-154. DOI: 10.1097/MEJ.000000000000022

4. Fromm C, Suau SJ, Cohen V, et al. Diltiazem vs. Metoprolol in the Management of Atrial Fibrillation or Flutter with Rapid Ventricular Rate in the Emergency Department. J Emerg Med. 2015;49(2):175-182. DOI: 10.1016/j.jemermed.2015.01.014

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