Atrial Fibrillation
Cardiovascular, Critical Care / Resuscitation
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?
High
We are highly confident that the true effect lies close to that of the estimate of the effect. There is a wide range of studies included in the analyses with no major limitations, there is little variation between studies, and the summary estimate has a narrow confidence interval.
Moderate
We consider that the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. There are only a few studies and some have limitations but not major flaws, there are some variations between studies, or the confidence interval of the summary estimate is wide.
Low
When the true effect may be substantially different from the estimate of the effect. The studies have major flaws, there is important variations between studies, of the confidence interval of the summary estimate is very wide.
Justification
ED care: Has been derived from a number of retrospective ED-based studies.
Anticoagulation: Has been validated in large prospective trials in numerous settings.
Related Information
OTHER RELEVANT INFORMATION
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Consult the Thrombosis Canada App for more detailed information
Reference List
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Thrombosis Canada Risk Calculators. Accessed April 25 2017.
Context
Relevant Resources
RELEVANT RESEARCH IN BC
Cardiovascular EmergenciesRESOURCE AUTHOR(S)
DISCLAIMER
The purpose of this document is to provide health care professionals with key facts and recommendations for the diagnosis and treatment of patients in the emergency department. This summary was produced by Emergency Care BC (formerly the BC Emergency Medicine Network) and uses the best available knowledge at the time of publication. However, healthcare professionals should continue to use their own judgment and take into consideration context, resources and other relevant factors. Emergency Care BC is not liable for any damages, claims, liabilities, costs or obligations arising from the use of this document including loss or damages arising from any claims made by a third party. Emergency Care BC also assumes no responsibility or liability for changes made to this document without its consent.
Last Updated Nov 01, 2019
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