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    Atrial Fibrillation

    Cardiovascular, Critical Care / Resuscitation

    Last Updated Dec 06, 2018
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    Context

    • Atrial fibrillation and flutter (AFF) are two of the most common dysrhythmias encountered in the emergency department.
    • While conventional guidelines are helpful, they are often drawn from the cardiology literature, and may not always be applicable in emergency patient presentations.
    • Unless the patient has an acute-ST-elevation myocardial infarction, management can be similar in urban and rural settings.

    Unstable due to AFF

    • This is very rare.
    • If the patient has obvious signs of shock, ST-segment elevation, or acute pulmonary edema, immediate sedation (preferably ketamine) and electrical conversion is recommended.
    • All such patients should be admitted.

    AFF WITH an acute underlying medical condition

    • If a patient has AFF and an acute illness such as sepsis or heart failure, treatment should be directed at the underlying cause.
    • It is critical to identify these patients. Almost all of them will arrive by ambulance, OR have a chief complaint of dyspnea, chest pain, or weakness, OR have a CHADS-VASC score > 2.
    • In such cases, aggressive rate or rhythm control will more often lead to adverse events, rather than AFF control.
    • Patients with kidney disease (eGFR < 59) have a 15% additional risk of an adverse event if managed with rate or rhythm control.
    • All such patients should be admitted to hospital. Continue treating the underlying illness as appropriate.

    High Risk for a Stroke

    • If the AFF onset is greater than 48 hours, OR if the patient has a CHADS2 score > 1, OR if there has been a stroke within 6 months, OR if the patient has a mechanical valve or rheumatic heart disease, then rate control (see below) should be initiated with a goal of < 100 beats per minute.
    • If symptoms cannot be controlled, patients should be admitted.
    • If patients can be discharged, they require oral anticoagulation for at least 4 weeks and should have internal medicine or cardiology follow-up within that time for new-onset AFF, or primary care follow-up for recurrent AFF. (See below for anticoagulation guidelines.)

    Low Risk for a Stroke

    • If the AFF onset is less than 48 hours (12 hours for CHADS2 > 1) OR there has been therapeutic anticoagulation for at least 3 weeks, then rhythm control (conversion by drugs or electricity) is recommended.
    • Electrical-then-chemical and chemical-then-electrical approaches are both safe (low rate of adverse events) and effective (close to 100% will convert) but an electrical approach has a lower length of stay.
    • If neither approach works, attempt rate control. If symptoms cannot be controlled, patients should be admitted.
    • If patients can be discharged the CCS guidelines recommend 4 weeks of anticoagulation for all patients. CAEP recommends that physicians hold an informed discussion with all patients regarding risks and benefits of anticoagulation.

    Rate Control

    • Use metoprolol 2.5 – 5 mg iv q15 min up to 3 doses, then discharge on metoprolol 25 mg po twice daily.
    • If metoprolol is contra-indicated, use diltiazem 0.25 mg/kg IV over 10 minutes; then q15-20 min at 0.35 mg/kg up to 3 doses, and then discharge on 30 – 60 mg po 4 times per day.

    Anticoagulation

    Should be dictated by balancing stroke risk (CHADS-65) and bleeding risk (HAS-BLED) and with an informed patient discussion. (Consult the Thrombosis Canada App for more detailed information)

    • CHADS-65
      • If a patient has any of the following: heart failure, hypertension, diabetes, prior stroke, or is greater than 65, they are considered high-risk and warrant anticoagulation. Recent CCS guidelines emphasize that all AFF patients who convert to normal sinus require anticoagulation, but this is disputed by CAEP recommendations.
    • HAS-BLED score(major bleeding risk)
      • 1 point each for hypertension; abnormal  kidney (cr > 200 umol / L / dialysis / transplant) or  liver function; (cirrhosis or ALT / AST / AP >3x normal) prior stroke; prior major bleeding; unstable international normalized ratio,;(INR time in therapeutic range < 60%) drugs (NSAIDs, clopidogrel) or alcohol use (> 8 drinks per week)  Greater than 2 points indicates high risk of bleeding.

    Follow-Up

    • Patients with new-onset AFF should be seen by a cardiologist, preferably within a month.
    • Patients should also be seen by a family physician, ideally within a week.

    Quality Of Evidence?

    Justification

    ED care: Has been derived from a number of retrospective ED-based studies.

    Low

    Anticoagulation: Has been validated in large prospective trials in numerous settings.

    High

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