Should we cardiovert acute Atrial Fibrillation in the ED?

Is it safe to cardiovert a hemodynamically stable patient with recent onset atrial fibrillation? The evidence says yes, but not everyone is a believer…

I’ve talked quite a bit about atrial fibrillation on ERCast, and the topic that generates the most emails, by a wide margin, is cardioverting the hemodynamically stable patient with recent onset atrial fibrillation or flutter (RAFF). Recent onset is defined by dysrhythmia onset within 48 hours of presentation. Forty eight hours is considered the time window for safe (minimal thromboembolic risk) RAFF cardioversion.

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Why would we even consider cardioverting a RAFF patient in the ED?

The palpitations, shortness of breath, dizziness, and weakness caused by RAFF were the reason they came to see you.  Having done hundreds of ED RAFF cardioversions, I can tell you, that when patients get  out of RAFF, they feel much better. Leaving a RAFF patient in a fib presents an extra level of complexity. What is your plan for discharge if you are going to leave the RAFF patient in atrial fibrillation? Most of the time, it involves anticoagulating and referring them to cardiology for cardioversion at a later date. Is that really a better option? If it were a matter of patient safety, i.e. performing delayed cardioversion with full anticoagulation is safer than ED RAFF cardioversion, then there would be no discussion-we would err on the side of patient safety. But there is no evidence that delayed cardioversion with full anticoagulation and echocardiogram to rule out clot in the atrium is any safer than cardioverting RAFF patients in the ED.

Do you have to go straight to cardioversion?

There are several options for the hemodynamically stable RAFF patient in the ED.

Option one: Have the patient come back tomorrow so they can be rechecked within 48 hours of symptom onset, since that is the known window of safety for cardioversion without anticoagulation. Fifty percent of RAFF patients will convert spontaneously within 24 hours and there is no rule that says cardioversion has to happen this minute. I instruct patients to not eat after midnight (so they can have an empty stomach for procedural sedation-not that there’s evidence to support this, but I’d rather have a patient with an empty stomach than one with a belly full of Egg Mcmuffins and Vegemite), come back in the morning and, if they’re still in a fib, proceed with cardioversion. If there is rapid ventricular response associated with the RAFF, I will IV rate control in the ED and give an oral rate control agent (usually diltiazem) prior to discharge.

Option two:  Cardiovert right now- either chemically with procainamide or straight to electricity. I’d say about 80% of the time, the experienced a-fibbers want to go straight to electricity and not mess around. They also don’t want to have to come back for a recheck. The new onset a fib patients will opt for the ‘come back the next day ad recheck’ option more often than a patient with previous episodes, but even the majority of first timers go for cardioversion during the current ED visit. I like the Ottawa Aggressive Protocol for managing RAFF and will offer 1g IV procainamide over 1 hour as an initial step, especially if the patient is hesitant to proceed with sedation and electricity.

Option 3: Do no ED cardioversion at all. Anticoagulate (or start on a daily aspirin if a low CHADS score and no plan for future cardioversion) and refer the patient to cardiology. You can also start your patient on LMWH and set them up for an urgent TEE to look for atrial clots. Some hospitals do not have ready access to transesophogeal echocardiogram (TEE) and, in this case, the patient will get a few weeks of anticoagulation before cardioversion.

There is an option 4, which doesn’t get the bold highlight, and that is to rate control, give a dose of low molecular weight heparin, and admit all RAFF patients to the telemetry unit. This is still done in many hospitals in the United States, but I’m not sure why.

Let’s address the elephant in the room…

Is it safe to cardiovert RAFF patients?

How do you really KNOW there is no clot in the atrium? How do you know you aren’t going to stun the atrium, make some sort of thrombogenic medium and cause a stroke in a few days? Is there a way to know this without doing a TEE? A study in Heart 2011 suggested that N-terminal pro-brain natriuretic peptide (NTproBNP) level can help to tell if patients have been in afib for a short or long period of  time and whether or not there is a clot in the atrium. This was a small study and may ultimately allow us to do cardioversions in patients who aren’t sure of how long they’ve been in afib, but there’s not enough evidence to support it NTroBNP in clinical practice. Use of D-dimer to detect atrial clot has been tried with varying success but the evidence isn’t convincing. But why even worry about biomarkers? If the patient knows exactly when their symptoms started and they present within 48 hours of onset, do we need to go through any extra steps beyond an H and P and having a conversation?

Let’s take a look at a December 2011 Annals of Emergency Medicine article titled: Is discharge to home after emergency department cardioversion safe for the treatment of recent onset atrial fibrillation? This was a “Best Available Evidence” review that looked 5 papers addressing the safety of ED cardioversion.

The authors’s synopsis of the 5 reviewed papers was that most of the complications related to cardioversion come from procedural sedation. When I am having a PARQ (Procedures, Alternatives, Risks and Questions) conversation with the patient, one of the main things I focus on is how we are going to do the sedation, the potential risks and what we will do to mitigate those risks.

As far as complications from cardioversion itself, in the five studies reviewed, there were some chest wall burns and 2 episodes of ventricular tachycardia. One v-tach converted spontaneously and 1 was successfully shocked. Sometimes, in the back of our minds, we worry that we are going to cause a more serious arrhythmia if we shock a patient with a-fib. There have been a few reported cases of ventricular tachycardia but it is extremely rare, and the two in this paper were short lived.

Our main worry is that we are going to cause a stroke

Combining the outcome data of the 5 studies in this ‘best available evidence’ paper, there were zero reported post cardioversion thromboembolic events after ED discharge with follow up periods ranging from 7 to 30 days.  Zero is pretty impressive, and when we’re talking about something like stroke, zero risk is about where we want to be. But like most things in medicine and life, there is no ‘all or nothing’ and the risk cannot really be zero.

The first study that directly looked at the risk of stroke and conversion to sinus rhythm in the setting of RAFF was from Annals of Internal Medicine 1997 titled Risk for Clinical Thromboembolism Associated with Conversion to Sinus Rhythm in Patients with Atrial Fibrillation Lasting Less Than 48 hours. Three hundred fifty seven hospitalized patients converted to sinus rhythm within 48 hours of a fib onset. Some converted spontaneously and some were cardioverted. Out of those 357, there were three thromboembolic events shortly after conversion from fib to sinus. All three of these patients were in their 80s and all three converted spontaneously.

Should we give a dose of LMWH before ED cardioversion?

There are several theories addressing why atrial fibrillation causes clots to form in the atrium. One is that prolonged fibrillation causes stagnation of blood and subsequent clot formation. Another is that conversion from fib to sinus, either spontaneously or via cardioversion, depresses left atrial function which leads to clotting. We worry about both of these when considering cardioversion of ED RAFF patients. Regarding theory two, clot formation as a result of cardioversion, wouldn’t it make sense to give some anticoagulation like LMWH at the time of cardioversion to decrease the risk of clot formation? In the 1997 Annals of Internal Medicine study mentioned above, no difference in thromboembolic stroke risk was seen between patients who did and did not receive acute anticoagulation with either warfarin or heparin. Take that with a grain of salt because this study was not powered to define/detect a small difference in benefit from anticoagulation in RAFF. The 1997 Annals study showed a 0.8% rate of thromboembolism and most others report a 0.0% rate. A clinical trial designed to detect a decrease in thromboembolic risk would need  thousands of patients with treatment and non treatment arms to see if there’s any benefit giving anticoagulation for RAFF cardioversion. At that point, when you are giving thousands of patients acute anticoagulation to try and prevent a rare event, you’re likely to see more harm from the treatment itself than benefit in preventing strokes. Some, such as the American College of Chest Physicians, recommend considering acute heparin for high risk patients getting cardioversion, but even they recognize that there’s no evidence to support this approach.

ED discharge

When discharging a patient with new onset atrial fibrillation after a successful cardioversion, there are a few key points I put into the conversation.

“Atrial fibrillation is usually not a one time occurrence and will invariably recur. The next time it happens, you don’t need to come immediately to the ED if you aren’t having chest pain, SOB, feeling dizzy, etc. Give it some time if you can tolerate the symptoms. Most episodes are short lived and, for the longer ones, there is a 48 hour window in which we can cardiovert.”

“You need to establish care with a cardiologist to get an echocardiogram and discuss long term a fib management.”

If this is a patient with new onset a fib or one who is not on an anti-platelet agent or anticoagulant, I will also calculate the patient’s CHADS VASC score on MDcalc and give them a printout showing their future stroke risk. Many of these folks are not even taking aspirin – I at least start them on that. Should you start oral anticoagulants in the ED? I personally don’t but have them follow up with cardiology or their primary provider ASAP. The decision of whether or not to start anticoagulation is a huge conversation. One of my partners feels differently. He starts patients on anticoagulation right there in the ED if patients are high risk. But this, my friends, is a talk for another day.

Additional Resources

2012 World Journal of Cardiology review on Atrial Fibrillation Risk Stratification 

2012 Emerg Med J study on electricity vs propafenone for RAFF cardioversion

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    1. Rob Orman

      Todd- Thanks for posting the link to your research group’s Annals Emerg Med paper. It’s amazing how little we know about something so common. True/focused outcome data in our patient population and RAFF patient’s in general has been sparse. Regarding your last comment that you cardiovert without reservations, there seems to be a divide in decision making between the US and Canada. From the informal surveys I’ve done, ED rhythm control for RAFF is the common practice in Canada, but much less so in the US. I think the evidence far favors ED cardioversion than admission/sending home in a-fib.

      The article by Belcher, et al in May 2012 CJEM suggested that rate control prior to attempted cardioversion decreases the success rate. It certainly flies in the face of what we used to think- that pretreatment with rate control increased successful conversion to sinus. Since reading the article, I have stopped giving rate control to minimally symptomatic/hemodynamically stable RAFF patients that I plan on cardioverting (either chemically or with electricity).

  1. Andy Buck

    Great, concise post that covers all the relevant variables. I like to do as you say: rate control prn, discharge and re-present fasted the next day, or DCR on the spot if symptomatic, frequent flyer or at risk of going over 48-hrs if discharged. But I’ve been skeptical for a while about the timing of onset of symptoms matching the timing of onset of AF, and the patient-reported timing scares me a bit. ie How do we know that when the patient “feels like they’re in AF” is actually when the AF started? Will we ever be able to clarify this without a bunch of AF outpatients wearing continuous monitoring? Somewhat reassuring that the post reversion stroke risk is actually so low.

    1. Rob Orman

      In the past few years, I think ED cardioversion of RAFF has become more common. That being said, there are still many shops where RAFF patients are admitted on LMWH and diltiazem drips -not only a waste of money, but, in my opinion, places the patient at higher risk of complications than those that are feared from ED cardioverion. So the short answer to your question is yes.

  2. Elisha T

    Great podcast as usual, Rob.
    One strategy that you’ve mentioned a few times is sending a patient home in A-Fib if present less than 48h and bringing back next day for rhythm check +/- cardioversion if still needed. I have to admit I’ve never seen this done here in Canada… maybe it’s a culture thing.
    My argument for CV of patients in the 48h window at first visit is that the studies show that the longer AF persists, the harder it is to convert (although generally it is thought that within the first 7 days has the highest success). Not sure if there is an appreciable difference when it comes down to hours (ie 6 hrs vs 40 hrs) but I generally go for cardioversion on first visit if <48hr. That's just my 2 cents.

    1. Rob Orman

      Elisha, I’d say that a fib patient’s opt for a recheck within 48 hours about 5% of the time. Of those who have been cardioverted before, I’ve had one patient decline cardioversion on the index visit and come back the day. What I’ve presented is my method, by no means the only one. My preference is to cardiovert ASAP; to your point, afib begets afib. Thanks for your comments!

  3. ekgpress

    FIRST -- Absolutely EXCELLENT podcast Rob. Truly impressive how you objectively present the data -- and how you offer a number of valid approaches to the problem. Clearly NO ONE SIZE FITS ALL …

    That said -- the subject is far from simple. I agree that the approach to recent onset AFib in the ED has evolved. There is more than one solution and treatment needs to be individualized.

    ITEM #1 -- I question whether the term “RAFF” = Recent-Onset AFib (or AFlutter) is optimal. There are TWO issues that I believe GREATLY influence many facets of one’s approach: i) NOAFF (New-Onset AFib/Flutter); vs ii) RRAFF (Recent Recurrence of AFib/AFlutter). Reasons why this difference is important are several. The BEST chance (by far) to get a patient out of AFib and maintain sinus rhythm is with the 1st episode. Atrial remodeling (both electrical and physiologic) begins very soon after AFib onset -- so the sooner sinus rhythm is restored, the better (although slight delay of days or a week or two or three probably doesn’t matter that much; longer delays do matter).

    ITEM #2 -- Recurrence of AFib is frequent -- MUCH MORE SO than the < 20% figure I believe you cited in your talk. Just because one "can" cardiovert a patient in the ED does NOT necessarily mean one "should" cardiovert that patient -- especially IF AFib is likely to recur in that patient …. VERY different for the 1st episode -- when you're really trying to cardiovert with more realistic hope of maintaining sinus rhythm.

    ITEM #3 -- The definitions of the various conditions referred to in this podcast blur to me. Are we including under "RAFF" all recent AFib (both new-onset and recurrent)? RAFF with rapid ventricular response or otherwise highly symptomatic patient? RAFF with controlled ventricular response and heart awareness, but not overly symptomatic patient? Patients with "lone AFib" and nothing else? vs patients with lots of underlying cardiac problems and high intrinsic risk of stroke? Patients with potentially "fixable" precipitants of this AFib episode (ie, heart failure, poor oxygenation from pulmonary disease) -- in which case the AFib (and many of the symptoms) may resolve (or greatly improve) simply by treating the underlying condition? Decision of whether or not to attempt ED cardioversion in my opinion should depend on which of the above factors are operative …

    ITEM #4 -- It is important to be aware of Holter studies documenting ~ 90% of all paroxysmal AFib episodes are asymptomatic. This point is also an important one to keep in mind when trying to ascertain if "new-onset" AFib truly occurred the moment the patient thinks (rather than in- and out- AFib over a much longer period of time).

    ITEM #5 -- I like Rob's approach of informed decision-making with the patient. Especially for the adequately anticoagulated patient with recurrent AFib who is "back in it again" and who SPECIFICALLY requests to "get me out of this rhythm as fast as you can" -- I do agree that ED cardioversion is a highly viable option for this select group of patients IF this is what the patient wants.

    ITEM #6 -- For other patients (which should be the majority) -- One needs to ask if "benefit" from immediate ED cardioversion outweighs "potential to harm" by doing so. As Rob indicates -- there IS risk with the sedation process -- there are other side effects (skin burns, VT) -- and just because the small series of studies that have been done didn't have patients who developed stroke doesn't mean that isn't a possibility. That said -- the GOOD news from the studies you cite is that stroke risk seems low for true "new-onset" AFib in patients without lots of other stroke-predisposing factors. But IF cardioversion is not benign -- and at least 50% (or more) of patients will be in sinus rhythm if you do nothing over the next 24 hours -- What is the rush to cardiovert if the patient is not overly symptomatic and there is potential for harm from the treatment?

    ITEM #7 -- There IS medicolegal liability if nonemergent ED cardioversion does result in a stroke. I don't know that you can call ED cardioversion "the standard of care" at this point (the EP cardiologist I just informally consulted thinks no). It's one thing if emergency cardioversion for a crashing patient in AFib needs to be done that instant. It's quite another if there is no emergency situation -- the patient is not anticoagulated -- and as per the above, "duration" of AFib is not always as easily determined as one may think … Transthoracic Echo (even if you could get this quickly) in no way excludes atrial clot (because it doesn't adequately view the left atrial appendage). TEE is needed to exclude clot -- and that's not a stat ED procedure for nonemergent cardioversion.

    ITEM #8 -- Who will follow these patients? You mention having the patient come back to the ED in 24 hours to see if they then want to be cardioverted? Where does the patient go for the next visit after that? The premise of return at 24 hours is based on the "48 hour rule" -- but to be aware that there really is NOT data documenting "no stroke risk" for AFib <48 hours (we surmise and it is logical that stroke is less likely due to less time for stasis, therefore less chance of clot formation -- but that's a guesstimate at best). And -- given that 90% of paroxysmal AFib episodes are asymptomatic -- we often really just don't know when AFib really began (gotta acknowledge that …. ). Important to establish who will be following these patients as soon as this can be done. I don't know that it is best practice for whoever is working the next day's shift to be the one to check on the patient.

    ITEM #9 -- AFlutter is different. It's less stable initially -- though when chronic (established) -- it is almost always now "curable" with ablation. AFlutter patients ought to be referred to EP folks for consideration for cure of their arrhythmia.

    ITEM #10 -- Many chronic AFib patients may now also be curable by ablation. More likely if the patient has PAF (paroxysmal AFib) -- but other even chronic AFib patients may also at times be successfully ablated. Important to know when to refer.

    BOTTOM LINE: The issue is not whether ED physicians "can" cardiovert AFib in the ED -- but rather SHOULD they be doing this? (except under special circumstances when there is true need for emergency cardioversion -- such as crashing patient with new fast AFib or WPW with very fast AFib). I think it reasonable for ED physicians to cardiovert selected chronic AFib patients with a certain number of recurrences IF such patients are adequately anticoagulated and specifically requesting electrical cardioversion because they are "in it again" and are miserable. But more than 50% of patients with recent AFib will be in sinus rhythm again within 24 hours even if you do nothing (more if you are able to "fix" a precipitating factor) -- and although most patients do well, cardioversion in the ED is not completely benign.

  4. ekgpress

    P.S. I fully expect spears, darts and poison arrows to be sent my way by some for my above commentary ….. Have mercy -- but also please contemplate the above points. Then throw the poison darts at me if you wish …

    P.P.S. The one thing I think we can ALL agree on is that Rob Orman does a SENSATIONAL job with ERCast.


    Thanks for Dr.Rob for raising the issue of Afib cardioversion. Thanks again to “ekgpress” for his great comments.. I think the issue of cardioversion will be digestible if we use it for younger age group with chads of zero…
    ** as “ekgpress” says 90% of Afib patients are asymptomatic of their arrhymias on holter, May I ask about their age group.. I assume the older the patient, the lesser the perception of Afib !!

    ** Now if the Issue is all about stroke risk after cardioversion.. still I observe all of those patients with recent onset AF (new or recurrent) are being managed with Amiodarone infusion by our cardiologists.. So, the risk of stroke is there !! and as I know risk of stroke is equal after restoration of sinus rhythm whether electrical or chemical cardioversion was selected ..

    ** Last point, the main and most important point to be emphasized here is which patient can be safely cardioverted?? of course the older & comorbid the patient is, the higher the risk of stroke. I prefer to chose those young patient (20s or 30s) whom chads score is zero to cardiovert in ER if I’m comfortable with the patient’s history of Afib.. on the other hand, I will rate control those who are older and less reliable in their history.. It might be similar to evolving practice of lumbar puncture without Head CT as practice is changing over time..

    again.. thanks for warm discussion.. I really like this topic and your comments

  6. Hassan Ali Almaateeq

    in the past, No one accept to do LP before head CT to avoid the risk of herniation if space occupying lesion was not suspected. With time, the risk of herniation was found to be very small in selected population whom meningitis is being suspected. Those with no Focal neurological deficit, normal level of consciousness, no seizure, immuncompetent can undergo LP safely without Head CT… Will Afib cardioversion follow the same route ?!

  7. Movinmeat

    I was initially going to say that I can’t believe that we are still having this conversation, but on reflection I am not surprised at all. Over the last 15 years there’s been a remarkable evolution of the management of AF through the ED. I’m old enough to remember when an afibber was the best case of the shift because it was an easy admit. Start heparin, start a dilt ggt, and up they went to card tele, where they became SEP. (Somebody Else’s Problem) Then we spent a few years fucking around with chemical cardioversions, including a mercifully brief and painful flirtation with ibutilide. Now, maybe for the last seven years, we’ve been primarily cardioverting all appropriate a fib cases, and it’s a thing of beauty.

    Bear in mind here that the disease we are talking about is generally paroxysmal AFib. I don’t know why the academics ALWAYS need to invent a new acronym to justify getting a grant, but we all know that this is what we are talking about treating. PAF is fixable (when it’s not, as noted, self-limited). Bill the Boozehound is probably staying in AF, as is Terry Thyrotoxicosis, as is, um, Myrtle Mitralstenosis, no matter what you do. That’s not the patient population we’re arguing over. But your healthy patient with sudden onset but persistent AF, these are the people who we are itching to DO SOMETHING about, because we can (see: hammer, nail).

    EKGpress makes great points, and his final question is a good one: we can, should we?

    (Obligatory echolalia regarding individualized decision-making, involving patients in informed decision-making, etc)

    I say, resoundingly, YES.

    1. We know cardioversion is safe. First degree burns (oh no! The skin is red!) is not a meaningful risk. Strokes simply are not happening. If there were a case of a low-risk patient with a CVA after cardioversion it would be published in the literature as a landmark case report, yet nobody has managed to spot this particular unicorn. And if you as an ED physician can’t safely sedate someone for this simplest of procedures, then you shouldn’t be allowed out of the house unsupervised.

    2. It inarguably benefits the patient. Remember: PAF is a benign and often self-limited disease. People are not dying of this. The outcome to measure is not quality-adjusted life weeks, as Billy Mallon colorfully ranted. The sole morbidity is that people in AF, even rate controlled, feel like crap. And you can quickly and safely make them feel better. Many would have gotten better anyway, to be sure. Think of this like a supercharged amoxicillin for strep throat. You are not saving lives, but you are relieving suffering for a significant subset of patients, and that is worth something. (Yes, yes, I know, antibiotics for strep… Don’t even start) There is also the mostly-theoretical but probably real fact that there may be some small subset of patients who would have been in permanent AF but for your intervention, but that is a small and secondary reason for early cardioversion.


    4. When managing a busy and high acuity ER, immediate DC cardioversion is the most efficient way to deal with this particular condition. I have a responsibility to all the other patients I am caring for as well as those in the waiting room. A quick assessment, some labs, get RT, and BANG. Patient goes home. (Usually with very high satisfaction scores, but that’s another issue.) No point spending hours dicking around with procainamide or diltiazem, no need to bring them back for a second visit, certainly no need to waste an inpatient bed. Ten minutes, and you’re done, the patient is happy, they feel better, and you have an empty ED bed for the next patient. If you feel like being a hero, send them home on low dose metoprolol to make it less likely they’ll be one of the few who have to come back again. But I have limited resources, as does my ER, and time is the most precious of those. This is simply the best stewardship of the resources we have.

    5. By far the most important reason: it makes you look like a goddamn superhero. As Greg Henry likes to say, Medicine is theater for ugly people. Well, my colleagues, this is your moment in the spotlight. Nothing you do will have the dramatic effect that a semi-elective cardioversion of AFib does. You stride in, like a god, and push that button, and ZAP, unleash the lightning. The patient, who will be getting a very large bill regardless of what you do, will feel like they certainly got value for their healthcare dollar! Contrast that with the “come back tomorrow” patient who got a similar multi-thousand dollar bill even though (say it with me here) “the doctor didn’t DO anything.”

    So, this is why I primarily cardiovert all our PAF patients. I hope you found it useful.

    You’re welcome.

  8. Gabe Rose

    Rob, thank you for re-addressing Afib in this light -- the literature is well summarized and you make excellent anecdotal guidelines!

    I also want to thank some of your responders for sprucing up the post and making it even more deliciously entertaining.

    In our previous conversation, we mainly discussed CV of an unstable a fibber whereas the stable RAFF patient is really the topic here. On the matter of the stable RAFF I have to agree with you Rob. When CV vs rate control vs wait and see are all on the table I like the David Newan approach of a good PARQ discussion that leaves ultimate clinical decision making in the patient’s lap (sort of). Yet, when the pressure is low, the patient altered, the troponins up, or the sats down I’d still show ’em a pair. Of paddles that is!

    1. ekgpress

      NICE Comment Gabe! Agreement is universal that the truly unstable patient with RAFF needs paddles. But most new AFib patients are not truly unstable because of the new AFib -- in which case ‘automatic paddles’ without pause for judgement and individualized joint decision-making is not the way to go. A good PARQ discussion with consideration of relevant factors for the case-at-hand is reasonable middle-ground.

  9. Katrin Hruska

    Our protocols for A-fib is one of the few things that haven’t changed since I was in med school. We use po, or if necessary, iv metoprolol for rate control and send the patient home, if they present during the first 24 hours. Since we don’t do any procedural sedantion, (we only have access to diazepam) in the ED, the patient will come back fasting for an ecg check and possibly cardioversion the next day, preferably straight to cardiology, but in some hospitals they have to be admitted through the ED. Patients with recurrent episodes often show up fasting on day two.

  10. ekgpress

    Just came across this 2011 Annals of Emergency Medicine Journal Club article by Sachs & Schriger entitled, “To Shock or Not to Shock: That is the Question; Is there an Answer?”. For ANYONE who has participated above who TRULY wants to understand the issues and “state-of-the-art” -- this is SUPERB reading. Be aware -- it takes a moment to read this and digest its contents -- but it is well worth the effort! Download of the PDF at:

  11. Rick Abbott

    And, here’s the patient’s perspective:
    Yes, indeed I did feel poorly (2.5 hr bike ride home took 4 hours).
    Yes, indeed I knew exactly when I went into AF.
    I continued to feel poorly (I was busy, worked a couple of shifts -- thinking seriously of having one of my ED techs just cardiovert me cold turkey during the shift -- while in AF).
    Working those shifts was truly a bad idea -- I should have just had the cardioversion done within 24 hr of going into AF.
    There is no question whatsoever, that as the patient I preferred the electrical cardioversion to screwing around for hours with drugs with all their side effects.
    I now know that I really like propofol. Really nice, pleasant brief nap. I could’ve gone back to work in an hour or two.

    So, if I ever do this again, just zap me.

  12. Mr.T. (@NaeemTo)

    I have a question for all you hyper-intelligent people. I recently had a man in his 70s present with new onset AF for a few hours. Previously well though 6 weeks earlier he had an attack of vertigo and ataxia while travelling in SE Asia. They found a Cerebellar CVA after doing an MRI though Echo and Carotid Dupplex was normal and he was in Sinus Rhythm.

    No I’ve heard discussions informing me me that Cryptogenic stroke is commoner than we think and the majority of these cases have PAF if long-term cardiac monitoring is performed.

    Now should I have Cardioverted this gentleman. No one has mentioned the optimal management for this sort of a patient. Personally I just rate controlled and anticoagulated him with LMWH and referred him for early Cardiology FU as an outpatient.

    What do the illuminati think I should have done?

    1. Rob Orman

      I would manage this patient exactly as you describe. The confounding factor of the recent stroke bumps this up a level of complexity as well as risk that this episode of AF was not an isolated incident.

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  16. Jim

    Thromboembolic Complications After Cardioversion of Acute Atrial Fibrillation : The FinCV (Finnish CardioVersion) Study. Airaksinen et al, Journal of the American College of Cardiology
    Volume 62, Issue 13, 24 September 2013, Pages 1187–1192
    A total of 7,660 cardioversions were performed in 3,143 consecutive patients with atrial fibrillation lasting <48 h in 3 hospitals. For this analysis, embolic complications were evaluated during the 30 days after 5,116 successful cardioversions in 2,481 patients with neither oral anticoagulation nor peri-procedural heparin therapy.
    There were 38 (0.7%; 95% confidence interval [CI]: 0.5% to 1.0%) definite thromboembolic events (31 strokes) within 30 days (median 2 days, mean 4.6 days) after cardioversion. In addition, 4 patients suffered transient ischemic attack after cardioversion. Age (odds ratio [OR]: 1.05; 95% CI: 1.02 to 1.08), female sex (OR: 2.1; 95% CI: 1.1 to 4.0), heart failure (OR: 2.9; 95% CI: 1.1 to 7.2), and diabetes (OR: 2.3; 95% CI: 1.1 to 4.9) were the independent predictors of definite embolic events. Classification tree analysis showed that the highest risk of thromboembolism (9.8%) was observed among patients with heart failure and diabetes, whereas patients with no heart failure and age <60 years had the lowest risk of thromboembolism (0.2%).
    Conclusions: The incidence of post-cardioversion thromboembolic complications is high in certain subgroups of patients when no anticoagulation is used after cardioversion of acute atrial fibrillation.

    Time to Cardioversion for Acute Atrial Fibrillation and Thromboembolic Complications. Nuotio et al, JAMA. 2014;312(6):647-649.
    Time to cardioversion was determined as the difference between the beginning of arrhythmic symptoms to the exact time of cardioversion. If the duration of arrhythmia was uncertain, the cardioversion was excluded.
    Procedures were divided into groups according to the time to cardioversion: less than 12 hours (group 1), 12 hours to less than 24 hours (group 2), and 24 hours to less than 48 hours (group 3).
    We found that a delay to cardioversion of 12 hours or longer from symptom onset was associated with a greater risk of thromboembolic complications (1.1%). When the duration of AF was less than 12 hours, the risk of thromboembolism was low (0.3%) without anticoagulation.
    A multivariate regression analysis revealed that cardioversion after 12 hours of symptom onset increased the risk of embolic complications more than threefold. The small number of events led to wide confidence intervals, but the p values reached statistical significance.
    In multivariable logistic regression analysis, time to cardioversion longer than 12 hours was an independent predictor for thromboembolic complications (odds ratio of 4.0 [95% CI, 1.7-9.1] between groups 2 and 1 [P = .001]; odds ratio of 3.3 [95% CI, 1.3-8.9] between groups 3 and 1 [P = .02]).

  17. Jeff

    The risk of stroke with electrical cardio-version seems to be well studied and well supported, particularly when outside the 48 hour window. However, i have yet to find any data that supports there being an increased risk of stroke with chemical cardioversion with rhythm controlling agents like amiodarone (seems to be the only antiarrhythmic used these days), particularly in the acute care setting such as the ED. Studies such as the AFFIRM trial seem to suggest no difference in stroke risk when comparing rate control to rhythm control strategies. But despite this, it seems that most practitioners still believe there is a “theoretical risk” of “throwing a clot” when patients flip back in to sinus rythm after being started on amiodarone if they haven’t been anti-coagulated prior. Is this risk only theoretical?

Awesome article, I know - please share your erudite thoughts...