View source for Atrial fibrillation (main)

==Background==
[[File:RiskFactors.jpg|thumb|Non-modifiable risk factors (top left box) and modifiable risk factors (bottom left box) for atrial fibrillation. The main sequelae of atrial fibrillation are in the right box.]]
*Chronic and paroxysmal a-fib are associated with thrombus formation

{{Afib background}}

==Clinical Features==
===History===
*Asymptomatic - 44%
*[[Palpitations]] - 32%
*[[Dyspnea]] - 10%
*[[Stroke]] - 2%
*Also can present with [[congestive heart failure]]/acute pulmonary edema

===Physical===
*Irregularly irregular heart rate

==Differential Diagnosis==
{{Tachycardia (narrow) DDX}}
{{Tachycardia (wide) DDX}}
{{Palpitations DDX}}

==Evaluation==
[[File:Afib.jpg|thumb|Atrial fibrillation at approximately 150 beats per minute]]
[[File:ECG Atrial Fibrillation.jpg|thumb|A 12-lead ECG showing atrial fibrillation at approximately 132 beats per minute.]]
===ED Work-Up===
*[[ECG]]<ref>2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation: Executive Summary. J Am Coll Cardiol. 2014;64(21):2246-2280.  doi:10.1016/j.jacc.2014.03.021</ref>
*Eval for [[ACS]] only in:
**Patient with ECG changes suggestive of ischemia, [[hypotension]], [[angina]]
**A fib is rarely only manifestation of ACS, although RVR and hypotension can provoke demand ischemia
*Acute lab studies for all patients:
**CBC
**Chem-10
**Coagulation studies (for patients requiring anticoagulation)
*Additional labs (consider based on clinical scenario):
**TSH & free T4 (Afib increased in sublinical [[hyperthyroidism]])
**BNP
**D-dimer
**Troponin
**Magnesium level
**[[Digoxin]] level (if appropriate)
*Imaging
**CXR (if concern for heart failure or infection)
**Chest/Abdominal CT (if concern for sepsis)

===Diagnosis===
[[File:Afib ecg.jpg|thumb|ECG of atrial fibrillation (top) and normal sinus rhythm (bottom). The purple arrow indicates a P wave, which is lost in atrial fibrillation.]]
''Based on one of three ECG patterns:''
#Typical
#*Irregularly, irregular R waves
#*QRS rate 140-160/min
#Large fibrillatory waves
#*May look like flutter waves
#**Unlike a-flutter, the fibrillatory waves are irregular 
#Slow, regular A-fib
#*Due to complete AV block with escape rhythm 
*Ischemic changes?
*Rate > 250? (think preexcitation)

==Management==
''See [[atrial fibrillation with RVR]] for emergent treatment''
===Rate vs. Rhythm Control===
*Rhythm control (i.e. [[synchronized cardioversion]])
**Consider in the emergency department for:<ref>EBQ:Ottawa Aggressive ED Cardioversion Protocol</ref>
***Unstable (due to rhythm)
***Younger patients (<65 years old) with new or paroxysmal episode (<48 hours)<ref>Atrial Fibrillation: Would You Prefer a Pill or 150 Joules? Ann Emerg Med. 2015;66:655-657.</ref>
**Procedural anticoagulation status
***If <48 hours of symptoms, do not need to anticoagulate prior to rhythm control (may perform in ED)<ref>EBQ:48hr Cardioversion for Afib]]</ref>
***If >48 hours of symptoms, need have rhythm control as out patient referral (if stable)
**Method: [[Procedural sedation]] and analgesia (e.g. [[fentanyl]] and [[propofol]]). Apply pads in anterior to posterior position. Synchronized electrical cardioversion starting at 150 to 200 J.
*Rate control for all others or cardioversion failure
**General principal - IV medications for immediate rate control followed by PO medications for sustained rate control
**[[Beta-blocker]] 
***Metoprolol 5 mg IV q 5 min (max 3 doses) followed by 25-100 mg PO
**[[Calcium channel blocker]]
***Diltiazem 0.25 mg/kg to 0.35 mg/kg IV (20 mg typical starting dose), can follow with 25 mg IV as second dose if needed
***Followed by PO dose 60-120 mg 
***If unable to get sustained response with IV push, consider diltiazem gtt
**[[Digoxin]]
***Indicated if patient hypotensive and cannot get AV nodal blockade or if patient has advanced heart failure
***Typical digitizing dose 500 mcg then 250 mcg q4hx 2 for total dose of 1000 mcg
***Requires renal dosing if patient has impaired renal function
**[[Amiodarone]]
***Indicated if patient has hypotension or advanced heart failure, usually second line after digoxin
***Typical dosing 150 mg IV x 10 min then 1 mg/min x 6 hours then 0.5 mg/minx 18 hours
***Amiodarone can convert patient to sinus rhythm.  Consider simultaneously starting empiric anticoagulation if high thromboembolism risk, see below
**[[Procainamide]]
***Indicated: Hemodynamically stable with systolic Blood Pressure >100 mmHg, less than 48 hrs onset, Normal Serum Potassium and Serum Magnesium
***Ottawa protocol Method: Procainamide 1 g IV over 60 minutes. Monitor with frequent Blood Pressures, and hold Procainamide if systolic Blood Pressure <100 mmHg. Monitor telemetry for Arrhythmia, QTc Prolongation, QRS Widening and for successful cardioversion.

{{Anticoagulation in atrial fibrillation}}

====CHADS2-VAsc Score====
{| class="wikitable"
| align="center" style="background:#f0f0f0;"|'''Risk Factor'''
| align="center" style="background:#f0f0f0;"|'''Points'''
|-
| [[CHF]]||1
|-
| [[hypertension]]||1
|-
| [[DM]]||1
|-
| Previous [[stroke]]/[[TIA]]||2
|-
| Vascular disease (e.g. IHD, PVD)||1
|-
| Female sex||1
|-
!colspan="6" | Age
|-
| ≥ 75 years old||2
|-
| 65 to 74 years old||1
|}

*Score 0: consider no treatment or [[ASA]]
*Score 1: consider [[warfarin]] or [[ASA]] 
*Score 2-6: consider [[warfarin]] (INR goal = 2-3)
*All patients with significant valvular disease should be on anticoagulation

====HAS-BLED<ref>Pisters R, Lane DA, Nieuwlaat R, et al. A novel user-friendly score (HAS-BLED) to assess 1-year risk of major bleeding in patients with atrial fibrillation: the Euro Heart Survey. Chest 2010; 138:1093.</ref>====
''Used to assess 1 yr risk of bleeding on OAC medications''
{| {{table}}
| align="center" style="background:#f0f0f0;"|'''Risk Factor'''
| align="center" style="background:#f0f0f0;"|'''Point'''
|-
| Hypertension||1
|-
| Abnormal renal and/or hepatic function||1 point each
|-
| Stroke||1
|-
| Bleeding tendency/predisposition||1
|-
| Labile INR on warfarin||1
|-
| Elderly (age >65 years)||1
|-
| Drugs (aspirin or NSAIDs) and/or alcohol||1 point each
|-
|}
*Score 1: 1.0 bleeds per 100 patient-years
*Score 2: 1.9 bleeds per 100 patient-years
*Score 3: 3.7 bleeds per 100 patient-years
*Score 4: 8.7 bleeds per 100 patient-years
*Score 5-9: Insufficient Data

==Disposition==
''Similar outcomes for Canadian vs. American strategies, despite lower admission rates in Canada<ref>Rising KL. Home is Where the Heart Is. Annals of Emergency Medicine. 2013;62(6):578-579</ref>''
===Canadian===
*"Limit hospital admission to highly symptomatic patients in whom adequate rate control cannot be achieved"<ref>Stiell, et al. Atrial Fibrilation Guidelines. Canadian Cardiovascular Society Atrial Fibrillation Guidelines 2010: management of recent-onset atrial fibrilation and flutter in the emergency department. Can J Cardiolol. 2011;27:38-46</ref>

===American===
Indications for hospitalization:
*Patient with acute heart failure or hypotension after rhythm or rate control
*AF secondary to hypertension, infection, COPD exacerbation, PE, ACS/MI 
*Age > 60 (high risk of thromboembolism, more likely to have comorbidities)
*Initiation of heparin or other anticoagulant
*If considering ablation of accessory pathway in patient with AF
*Symptomatic recurrence in the ED
*Hemodynamic instability

Indications for discharge (low-risk patients):
Discharge with urgent cardiology follow up
*<60 years old
*No significant comorbid disease
*No clinical suspicion for [[PE]] or MI
*Conversion in ED or rate control

==Complications==
*Hemodynamic compromise
**A-fib lowers CO by 20-30%
**Impaired coronary blood flow 
*Arrhythmogenesis
*Arterial thromboembolism

==See Also==
*[[Atrial fibrillation with RVR]]
*[[ACLS (Main)]]
*[[In-Training Exam Review]]

==References==
<references/>
[[Category:Cardiology]]