Atrial Fibrillation

Atrial Fibrillation is largely an outpatient disease, and most patients presenting to the ED with Afib, new onset or recurrent, can be discharged home after initiation of appropriate anticoagulation and reasonable rate control. However there are some reasons that a period of observation may be helpful.

  • Need for rate control when heart rates are elevated and not improving in ED.

  • Evaluation for early TEE and Cardioversion

  • Evaluation for CAD or structural heart disease prior to starting Flecanide

Inclusion Criteria

Prior to admission to ED Observation for Atrial Fibrillation all patients must have

    • ECG

    • CBC

    • BMP

    • Recent TFTs

    • Urine Pregnancy test in woman of child bearing age

    • Working IV line

    • Ability to consent or designated and documented medical proxy

Exclusions

  • New Onset Clinical Heart Failure. This patient should be admitted.

  • RVR with Hypotension (MAP < 65)

  • Concurrent Sepsis, Thyrotoxicosis, Alcohol Withdrawal, Pulmonary Embolism, Pregnancy

  • Patients with a high risk of bleeding AND a high risk of stroke as calculated by the CHA₂DS₂-VASc score. Consider discussing with cardiology for referral for left atrial appendage (watchman) device.

Anticoagulation

Most patients presenting with new onset Atrial Fibrillation should be anticoagulated to reduce the risk of stroke. Even if their CHA₂DS₂-VASc score is low, sinus rhythm is the ideal state for most patients and they will benefit from an outpatient cardioversion after their diagnosis. Even low stroke risk patients must be anticoagulated for at least 3 weeks before and 4 weeks after a cardioversion. For most patients a NOAC or DOAC medication is the preferred anticoagulation regimen. Exceptions are kidney failure, mechanical valve or patients with known mitral stenosis, who should be prescribed warfarin. The KP preferred NOAC is Dabigatran (Pradaxa). A bridge is not necessary in the absence of a known clot.


Electrical Cardioversion

Patients with new onset atrial fibrillation should be referred for an outpatient cardioversion after initiating anticoagulation. This can be arranged by calling the appropriate on call cardiologist. If a patient can confirm at least 21 days of uninterrupted anticoagulation prior to presenting, or if they can reliably confirm onset of atrial fibrillation (wearable heart monitoring device, highly symptomatic and known time of onset) less than 12hours prior to presentation then a sedation and cardioversion can be preformed in the main ED. For select patients in whom time of onset of symptoms or appropriate anticoagulation cannot be confirmed, and for whom discharge for an outpatient cardioversion is impractical, a Transesophageal Echocardiogram followed by cardioversion may be beneficial. These patients can be cared for in ED Observation while awaiting their procedure. For these patients, please discuss with the on-call cardiologist prior to admitting to ED obs. Remember to make them NPO at midnight prior to their procedure.


Chemical Cardioversion

Conversion to sinus rhythm with medications (amiodarone, ibutilide, flecanide etc) carries the same risk of stroke as electrical cardioversion. Thus the parameters for initiating chemical cardioversion regarding anticoagulation are the same as those for electrical cardioversion noted above. If a patient has a recent normal stress test, then Flecanide is usually the preferred medication as it has fewer side effects. Amiodarone can be very effective as well and can be used even in known CAD or structural heart disease, however, side effects can limit its tolerability. Please discuss with cardiology prior to initiating chemical cardioversion.


Rate Control for RVR

Most patients can tolerate mild tachycardia for quite some time, and can be discharged with oral rate control medications to follow up with cardiology if rates are reasonable (for me this is usually < 120 bpm). If a patient presents with atrial fibrillation with RVR and rate control cannot be achieved in a timely manner in the main ED after initial bolus doses, they can be cared for in ED Observation to get better rate control. Reasonable initial rate control regimens include

  • Diltiazem 30 mg PO Q6h, can increase to max dose of 90 mg Q6h

  • Metoprolol Tartate 25 mg PO Q6h can increase to 75 mg q6h


Rates < 110 should be considered "rate controlled". Once the minimum effective dose for rate control is found, a patient can be converted to long acting For example a patient who has a heart rate < 110 BMP on Diltiazem 60 mg PO Q6h can be discharged on Diltiazem ER 240 mg PO daily. Patients being discharged on Metoprolol are generally given the short acting "tartate" formulation twice daily and total daily dosing should be adjusted accordingly.


Discharge Criteria

A patient can be discharged from ED Observation once adequate rate control can be achieved (< 110 BPM) and an appropriate plan for anticoagulation and followup has been made, usually involving cardiology.


Admission to Hospital from ED Obs

If ventricular rates cannot be rate controlled within 24 hours in ED observation, please discuss with cardiology regarding need for admission and initiation of a titratable drip medication or in hospital cardioversion.