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Atrial Fibrillation

 

Atrial Fibrillation

The most common cardiac arrhythmia, atrial fibrillation, occurs when the normal electrical impulses that are generated by the SA node are overwhelmed by disorganized electrical impulses in the atria.

Atrial Fibrillation EKG Tracing

These disorganized impulses cause the muscles of the upper chambers of the heart to quiver (fibrillate) and this leads to the conduction of irregular impulses to the ventricles.

For ACLS, atrial fibrillation becomes a problem when the fibrillation produces a rapid heart rate which reduces cardiac output and causes symptoms or an unstable condition.

When atrial fibrillation occurs with a (RVR) rapid ventricular rate (rate > 100 beats/min), this is called a tachyarrhythmia. This tachyarrhythmia may or may not produce symptoms. Significant symptoms that occur are due to a reduction in cardiac output.

The following is a list of the most common symptoms.

  • palpitations or chest discomfort
  • shortness of air and possibly respiratory distress
  • hypotension, light-headedness and possibly loss of consciousness
  • peripheral edema, jugular vein distention, and possibly pulmonary edema

For the purpose of ACLS, it is important to be able to recognize atrial fibrillation when the patient is symptomatic. On an ECG monitor, there are two major characteristics that will help you identify atrial fibrillation.

  1. No p-waves before the QRS on the ECG. This is because there are no coordinated atrial contractions.
  2. The heart rate will be irregular. Irregular impulses that the ventricles are receiving cause the irregular heart rate.

When the heart rate is extremely rapid, it may be difficult to determine if the rate is irregular, and the absence of p-waves will be the best indicator of atrial fibrillation.

ACLS Treatments:

For the purposes of ACLS atrial fibrillation is treated when the arrhythmia/tachyarrhythmia produces hemodynamic instability and serious signs and symptoms.

For the patient with unstable tachycardia due to a tachyarrhythmia, immediate cardioversion is recommended. Drugs are not used to manage unstable tachycardia.

Cardioversion of stable atrial fibrillation should be performed with caution if the arrhythmia is more than 48 hours old and no anticoagulant therapy has been initiated due to the risk of emboli that can cause MI and stroke.

Below is a short video which will help you quickly identify atrial fibrillation on a monitor.
Please allow several seconds for the video to load.

  66 Responses to “Atrial Fibrillation”

  1. This site is brilliant. How, though, to treat symptomatic bradycardia with afib? Atropine and pacing?

    • It depends if the atrial fibrillation is new onset. If it is new onset then it should be taken care of after the patient is stabilized and the cause of the bradycardia dealt with. Treat the patients slow rate first. Pacing would probably be the easiest intervention that would stabilize the patient. ECG and cardiac enzymes should be checked to r/o myocardial infarction.

      Kind regards,
      Jeff

  2. Hello Jeff,

    I had a question about a fib. Suppose a patient has new onset a fib. and unstable with SBP of 80. and they have clear sepsis with lactate of 4. Would you cardiovert or give fluids first ?

    • I would give fluids first. It is very likely that the hypotension is related to sepsis rather than the atrial fibrillation. You can give 500-1000 ml of fluid fairly rapidly to determine if the patient will stabilize.

      Also, if the duration of being in atrial fibrillation is not known, then a TEE (Trans-esophageal Echocardiogram) would need to be performed to rule out thrombosis prior to any thought of cardioversion.

      Kind regards,
      Jeff

  3. Hi,

    The video and your website are great. About shocks,how much do you use in acute A fib? 120 J? What do you give for sedation? Do you use any benzodiazepines?

    Thanks in advance,

    • Acute unstable a-fib would present as a narrow irregular tachycardia. This is treated with a starting dose of 120-200 J synchronized cardioversion. You would use some form of sedation.

      Kind regards,
      Jeff

  4. I do appreciate your training that mentions a big caution in cardioversion in atrial fib & atrial flutter for those patients that have presumably who have been living with their symptoms for awhile (over 48 hrs) knowingly or unknowingly, WITHOUT the benefit of anticoagulation or TEEs to verify thrombus formation or not. Your information suggests holding off on cardioversion until heparin IV drip or other effective anti-coagulant treatment for potential thrombus has occurred.

    I have searched the AHA manual ( 2011 printing) and do not see any training on this. Please correct me if I’m missing some important information. But I would like to be prepared for the expectation in real life for this “red-flag” or at least be prepared if it is a current AHA training point or not.- maybe to see in a test question or scenario?

    • The information that was discussed about TEE to rule out thrombus is a little beyond the scope of basic ACLS, and it is why you did not find in in the ACLS provider manual. The treatment of afib or aflutter that has gone untreated beyond 48 hours (or unknown) will probably not come up ACLS class or in testing.
      Also, the only place where this is discussed on the site is in the comments. This is because the question has been brought up several times by other students on the site.
      It is highly unlikely that you will discuss this in ACLS Class, but it is a very important bit of information to retain.

      Kind regards,
      Jeff

  5. Very helpful site for me as a PCP.Thanks.Mani.

  6. Imagine a patient brought to ER with SBP <90, sweating and chest pain and ECG shows Atrial fibrillation. TEE is performed and Shows thrombus. What should be our line of treatment? Should we go for cardioversion or should we initiate anticoagulation before cardioversion?
    Regards
    Jalal

    • You would not want to use cardioversion with this patient at this time. The patient would probably be placed on some type of anticoagulant and given something to decrease the heart rate and possibly something to improve blood pressure.
      This patient would need to be medically managed until the patient could be seen by a cardiologist.

      Kind regards,
      Jeff

  7. Cardioversion begins at what level?

    • For the patient who has atrial fibrillation, the indication for cardioversion would be if the patient is hemodynamically unstable. Some things to look for would be SBP< 90mmhg, altered mental status, and chest pain.
      Also, with atrial fibrillation a TEE (Transesophageal Echocardiogram) should be performed prior to cardioversion if the pt. has not had anticoagulant therapy. This would ensure that the patient did not have any type of thrombus that could worsen the patient’s condition if cardioversion is performed.

      Kind regards,
      Jeff

  8. this site is save me from alot of missing during my lecture,,,, thank you alot

  9. what is the drug of choice for AF ? Here our cardiologists use Amiodarone regularly. Do we have to treart rate & rhythm seperately in AF ?.

    • I would not say that there is one drug of choice for atrial fibrillation.
      In the critical care setting when atrial fibrillation is accompanied with a rapid ventricular rate amiodarone is used. Quite frequently, I have seen cardizem or some other calcium channel blocker used to slow the heart rate.

      Kind regards,
      Jeff

  10. Hi Jeff, I must say that I do love this site, it is helping me tremendously in preparing for ACLS coming up in the next 8 days.
    What are some of the beta blockers that are used in the stable tachyarrhythmias?

  11. I think having a strip on top of all of the arrhythmia pages would be helpful. When I want to go back and forth between arrythmia’s to compare and figure out the difference in appearance I find it frustrating that I have to play the video for atrial fib to see a strip. Also if the videos had the capability to back up so you don’t have to replay the whole video when you don’t understand one little section that would be awesome. I seem to be having trouble recognizing atrial fib. Any hints? This site is great and has been extremely helpful. Thank you

    • There is as image up on this page now. Thanks for pointing this out. Remember this for a-fib: Irregular rate and no P-waves. If you see an irregular heart rate and no p-waves, there is a high likelihood that you are dealing atrial fibrillation.
      Kind regards,
      Jeff

  12. Why choose Verapamil ?
    It depends if you are planning a rate control (option ) or rhythm control (not a good option) strategy.
    Beta blockers are however considered to be superior as far as the negative chronotropic effect is concerned.
    However, be careful if you are dealing with AF with pre-excitation i.e. WPW as using BB and Verapamil may be catastrophic,

  13. Your site and WONDERFUL FORMAT has SAVED ME from the American Heart ACLS book!
    T H A N K Y O U!

  14. What are your thoughts on administering Verapamil in the pre hospital setting of AF?

    • I can’t really comment on it, because I haven’t used it in the pre-hospital
      setting. I performed a cursory literature search and could not find any
      studies comparing verapamil with say amiodarone or synchronized
      Cardioversion. I will look around a bit more and see what I can find.

      Kind regards,
      Chris

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