April 16, 2014

Atrial flutter, fibrillation and ablation

Everything you wanted to know about atrial fibrillation and flutter…and then some more!

Flutter

Consult with electrophysiologist Randy Jones MD

Is there a limit to the number of cardioversions a patient can have in a year?

  • No limit
  • If a patient comes into the ED for frequent cardioversion, treatment strategy needs to be changed.
  • Ablation, increased dose of medication or new medication
  • Goal is have the patient be able to tolerate the condition. No matter the treatment, it should be considered a chronic condition like hypertension. It can be managend and controlled, but it is a lifelong companion

What is the clinical difference between a-fib and a- flutter? 

  • If it looks like a mix of fib and flutter, it’s probably just a-fib. Delete the term fib-flutter from your EKG lexicon.
  • Classic/ typical flutter –EKG down going saw tooth pattern in II, III and AVF & up going in V1. An electric circuit going around the tricuspid valve counter-clockwise.
  • Interrupting the circuit will terminate the rhythm. That’s why it doesn’t take so muchenergy to cardiovert.
  • It is a defined track.
  • If any point of the track is interrupted, the dysrhythmia ends. Compare to a-fib, which involves  a larger area of  atrium and thus takes more energy to convert

Why you should be nervous about sending an atrial flutter patient home

  • Be aware if you slow the atrial rate you may raise the ventricular rate, by allowing the av node to conduct 1:1
  • A concern in sending someone home with a flutter is that the rate may become very variable (i.e. while lying down they may be in a 4:1 conduction though while standing may go to 2:1.
  • Ablation is an effective tx for a –flutter
  • Recurrence rate almost 100% without ablation

Treatment of Atrial Fibrillation (outside of rate control)

Cardioversion

  • Electricity
  • Chemical:  Procainamide: 1 gm in 250cc D5w over 1 hour-discussed in previous episode-52% conversion

Pill in a Pocket

  • American guidelines of tx of atrial fibrillation August 2006, endorsed the pill in pocket approach.
  • Dosage is 200 mg of flecainide or 450 mg of propafenone (for people weighing 70 kg (155 lbs) or less) or 300 mg of flecainide or 600 mg of propafenone for people weighing more than 70 kg.
  • First time should be done in the a monitored setting

Ablation

  • Candidates: younger, normal sized atrium, not in long term/chronic afib
  • Desire to discontinue use of warfarin not a reason for ablation. Ablation does not decrease stroke risk. Pts will still need anticoagulation. Desired outcome from ablation is to improve symptoms and quality of life
  • Warfarin treatment after an ablation procedure typically 2-3 months, though this can be looked at individually
  • *IF a patient is high risk for thromboembolic event, will place pt on warfarin indefinitely, even if in NSR

How do you decide if a patient needs anticoagulation?

In the United States

Recent European guidelines use the CHADS-VASc score, which favors oral anticoagulants. Anyone over a score 2 oral anticoagulant, 1=ASA or oral anticoagulant and 0 was basically nonexistent

Dabigatran: Alternative to Warfarin

  • Dabigatran (Pradaxa) is an anticoagulant from the class of the direct thrombin inhibitors. An alternative to warfarin, it does not require frequent blood tests for international normalized ratio (INR) monitoring while offering similar results in terms of efficacy.
  • The U.S. Food and Drug Administration (FDA) approved dabigatran on October 19, 2010, for prevention of stroke in patients with non-valvular atrial fibrillation. Click here to read the RE-LY trial that compared Dagibatran and warfarin.
  • No direct reversal agent, factor VII  may be effective (in theory).
  • Dosing 150mg BID
  • Be aware -Although no way to monitor if anticoagulation is adequate, physicians may have to take the patients “word” on the fact that have been compliant with BID dosing.

Further Reading:

Written Summary:  Justin Arambasick MD  Akron General  Medical Center

Related posts:

About Rob Orman

Deceptively tall.
Podcaster to the stars, father of many, lover of few

Comments

  1. Hey Rob and Justin --

    Great summary — and perfect timing! I just added the CHA2DS2 to MDCalc, as well as the HAS-BLED bleeding risk score.

  2. You and Weingart need to join forces and take over the world. Great stuff!! Thank you very much for all your hard work

  3. Nice show notes Justin!
    C

  4. Sounds like there is a Ed cardioversion protocol in your ED for A. Fib -- are you able to share it?

    • Ian, the original algorithm flowchart has been lost in the sands of time. For patients presenting with A fib less than 48 hours duration, I am following a modified version of the Ottawa A Fib Protocol. If a patient presents having just eaten, I’ll offer procainamide (1g over 1 hour). If they are still in a fib, they’ll get DC cardioversion. If the patient presents with an empty stomach and is game to go straight to the shock, I’ll skip the procainamide.
      Here is a link to the Ottawa protocol.

  5. Rob, are any of the failed cardioversion strips Randy mentioned available? I think they would be an excellent resource for highlighting potential pitfalls to students.

  6. What is the role of amiodarone in patients with afib? From my readings, mixed evidence for cardioversion. However what about use of amiodarone before electric cardioversion, in preventing recurrence of afib and increasing your chances of sustaining sinus rhythm? Drug of choice for patient with afib and HF?

  7. Hey Rob, I’m a frustrated electrophysiologist who wished he was an intesivist trapped in a body of a FP resident….You, Scott W, Jeff Guy, Amil, Smith, Newman, Shrievs, et al make this not only interesting but fun!!!
    Question. Dr. Jones talked about afib/flutter being not being a likely entity. I was so fascinated by this that I did some research on it. It turns out that there are articles disagree with this:
    1) http://content.onlinejacc.org/cgi/content/full/43/11/2063
    2) http://cardiovascres.oxfordjournals.org/content/54/2/217.full?ijkey=04664e3cda295594d4e7e87e6e00c26cabb2a0b6&keytype2=tf_ipsecsha

    There are about a half dozen more I’ve read…
    What gives? Did I just misunderstand? Help out a dumb FP resident!

    • Rob Orman says:

      Simon-

      Many patients with A flutter also have underlying A fib, although usually they don’t have the same rhythm disturbance simultaneously. There was a pilot study last year looking at cardioverting a flutter using very low energy (under 50 J). The study found that with low energy, patients with acute flutter more often that not went into fib and not sinus rhythm. Fib and flutter are strange bedfellows and their cohabitation makes ablation for flutter complicated because, even though the fib may be cured, there may still be fib to deal with.

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  1. [...] Budgie Smuggler” Orman is back with a vengeance with this month’s podcast featuring Flutter, Fib, and the mystery of ablation. Each podcast is now provided with a great set of show notes.  EMCritWeingart delivers part 2  of [...]

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