View source for Atrial fibrillation with RVR

==Background==
{{Afib background}}

==Clinical Features==
*[[Palpitations]]
*[[Shortness of breath]]
*Dyspnea on exersion
*[[Chest pain]]
*Consider [[WPW]] if:
**Wide QRS
**Rate approaching 300 bpm

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

==Evaluation==
[[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.]]
===Workup===
*[[ECG]]
*Labs
**CBC
**Chem 10
**Consider coags, especially if on anticoagulation
**Consider LFTs
**Consider [[BNP]] if heart failure unclear
**Consider thyroid function tests
**[[Troponin]] if patient has chest pain
*[[Chest XR]]
*Consider [[Ultrasound:_Cardiac|Cardiac Echo]] - if signs of new/worsening heart failure

===Diagnosis===
[[File:RapidAFib150.jpg|thumb|Atrial fibrillation at approximately 150 beats per minute]]
*Based on [[ECG]]

==Management==
===Unstable===
*[[Synchronized cardioversion]] (100-200J)
**Atrial fibrillation - start at 200 J
**Atrial flutter - start at 50 J
**If you have time sedate with etomidate or ketamine before defibrillation 
***Dose (Etomidate): Start with 0.1mg/kg IV; repeat if needed
***Dose (Ketamine): Start with 0.5mg/kg IV; repeat if needed
*Indications: ischemic chest pain, SBP < 90, acute pulmonary edema, altered mental status
*Consider cardiostable sedation such as 5mg [[etomidate]]
**+/- subdissociative pain dosage [[ketamine]] at 15mg
*If shock does not work:
**Verify not preexcitation ([[WPW]])
**Increase diastolic BP to perfuse the heart
***
***Push-dose [[phenylephrine]]
****Will maintain BP when give rate-control meds
****50-200mcg q2-5min with goal MAP 70-75
***Can also do [[phenylephrine]] as a drip or [[norepinephrine]] drip
**After MAP is better then try to rate control with one of the following
***[[Amiodarone]] 150mg over 10min (preferably through central venous access) for up to 6 doses OR
***[[esmolol]] drip (easy to turn off) OR 
***[[diltiazem]] infusion 2.5mg/min until HR <100 or max 50mg
**[[Magnesium]]
***Be careful since can worsen vasodilation for these hypotensive patients
***2 g over 1-5 min, repeat if no response after 15 min, then consider 1-2 g/h for 4 hrs if response<ref>Kwok MH et al. Use of intravenous magnesium to treat acute onset atrial fibrillation: a meta‐analysis. Heart. 2007 Nov; 93(11): 1433–1440.</ref>
***Significantly less effective than [[amiodarone]] or [[calcium-channel blockers]]
***Ensure baseline magnesium level
***Check magnesium q2hrs if infusing

===Stable and Symptomatic===
'''Make sure you are not slowing down a normal physiologic response (e.g. fever, hypoxia, shock, etc.)'''
*Goal <110bpm
**RACE-II trial demonstrated that lenient control (goal HR < 110bpm) was noninferior to strict control (HR < 80 bpm) in preventing the primary outcome<ref>Van Gelder IC et al. Lenient versus strict rate control in patients with atrial fibrillation. N Engl J Med. 2010 Apr 15;362(15):1363-73. [http://www.nejm.org/doi/full/10.1056/NEJMoa1001337 full text]</ref>

===Stable and Asymptomatic===
If mild or no symptoms and pulse only mildly elevated (<110bpm) ok to manage with PO meds

===[[Cardioversion]]===
*Consider for:<ref>[[EBQ:Ottawa_Aggressive_ED_Cardioversion_Protocol|Ottowa Aggressive Protocol]]</ref>
**Symptoms <48hr
**New diagnosis
**No history of similar episodes
**No LV dysfunction
**No mitral valve disease
**No prior thromboembolic event
**Already Anticoagulated
*If cardioversion is considered, pretreatment with rate or rhythm control medications can reduce effectiveness<ref>Blecher GE, et al. Use of rate control medication before cardioversion of recent-onset atrial fibrillation or flutter in the emergency department is associated with reduced success rates. CJEM. 2012;14(3):169-177.</ref>
**90% effective, 60% effective with pretreatment

====Anticoagulation Prior to Cardioversion====
{{Anticoagulation prior to cardioversion}}

===Medication Choices===
{| class="wikitable"
| align="center" style="background:#f0f0f0;"|'''Medication'''
| align="center" style="background:#f0f0f0;"|'''Dose'''
| align="center" style="background:#f0f0f0;"|'''Comments'''
| align="center" style="background:#f0f0f0;"|'''Contraindications'''
|-
!colspan="6" style="background-color: #f0f0f0;font-size:110%"|'''[[Calcium-Channel Blockers]]'''
|-
| [[Diltiazem]]||
*Bolus 0.25mg/kg (average adult dose 20mg) over 2 min  
*If, after 15min 1st dose is tolerated but inadequate re-bolus 0.35mg/kg  
*If patient responds start infusion at 5-15mg/hr or give PO [[diltiazem]] 60mg QID
||
*Preferred in patients with chronic lung such as [[Asthma]] and [[COPD]]<ref>Short PM, Lipworth SI, Elder DH, Schembri S, Lipworth BJ. Effect of β-blockers in treatment of chronic obstructive pulmonary disease: a retrospective cohort study. BMJ. 2011 May 10;342:d2549</ref>
||
*Decompensated heart failure 
*Preexcitation (especially in pediatrics) 
*Significant hypotension
|-
!colspan="6" style="background-color: #f0f0f0;font-size:110%"|'''[[Beta-Blockers]]'''
|-
| [[Metoprolol]]||
*Bolus 2.5-5mg IVP over 2min q5min up to 3 doses  
*If patient responds orally load with 25-50mg. The initial oral dose may be estimated based on the IV dose required, based on a 1:2.5 conversion from IV to PO
||
*Particularly useful when A-fib associated with exercise, after acute [[MI]], or with [[thyrotoxicosis]]
*Long-term β-blocker improves patient survival (CCB may worsen outcomes), thus starting a β-blocker upon discharge, strongly consider using the agent for rate control also.<ref>Effect of metoprolol CR/XL in chronic heart failure: Metoprolol CR/XL Randomised Intervention Trial in Congestive Heart Failure (MERIT-HF). Lancet. 1999 Jun 12;353(9169):2001-7Effect of verapamil on mortality and major events after acute myocardial infarction (the Danish Verapamil Infarction Trial II–DAVIT II). Am J Cardiol. 1990 Oct 1;66(10):779-85</ref>
||
*[[COPD]]
*[[Asthma]]  
*[[Decompensated heart failure]]  
*[[Hypotension]]
|-
| [[Esmolol]]||
*Bolus 0.5mg/kg over one minute, followed by 50 µg/kg/min  
*If, after 4min response is inadequate, re-bolus followed by infusion of 100 µg/kg/min  
*If, after 4min response is still inadequate, try final bolus followed by infusion of 150 µg/kg/min  
*If necessary, infusion can be increased to maximum of 200 µg/kg/min after another four minutes
||
*Use if unsure whether patient will tolerate a β-blocker since the duration of action is only 10 minutes
||
|-
!colspan="6" style="background-color: #f0f0f0;font-size:110%"|'''Other'''
|-
| [[Digoxin]]||
*0.25mg IV q2hr up to 1.5mg, then 0.125-0.25mg PO or IV QD  
*Adjust dose in presence of renal failure, amiodarone, etc
||
*Consider as initial therapy for patients with LV dysfunction who:  
**Do not achieve rate control targets on β-blockers alone  
**Cannot tolerate addition of or increased doses of β-blocker due to decompensated [[CHF]]  
**Would have [[digoxin]] added anyway to improve [[CHF]] symptoms independent of A-fib  
*Consider as initial therapy in patients with severe hypotension  
*Consider as 2nd agent in patients in whom IV BB or IV CCB has failed to control their rate  
*May take up to 6-8 hours to work
||
|-
| [[Amiodarone]]||
*Load 3-7mg/kg IV over 30 min
*then, 1200mg over 24hr via continuous infusion or in divided oral doses<ref>Khan IA et al. Amiodarone for pharmacological cardioversion of recent-onset atrial fibrillation. Int J Cardiol. 2003 Jun;89(2-3):239-48.</ref>
||
*Consider for patients with decompensated heart failure or those with accessory pathways  
*2nd-line agent for chronic rate control when [[beta-blockers]] and [[calcium-channel blockers]], alone, combined, or when used with [[digoxin]], are ineffective
||
|-
| [[Magnesium sulfate]]||
*4.5 IV over 30 min<ref>Bouida W et al. Low-dose Magnesium Sulfate Versus High Dose in the Early Management of Rapid Atrial Fibrillation: Randomized Controlled Double-blind Study (LOMAGHI Study). Acad Emerg Med 2018 Feb;26(2):183-191.</ref>
||
*IV MgSO4 appears to have a synergistic effect when combined with other AV nodal blockers resulting in improved rate control.
*Given in conjunction with [[beta-blockers]] and [[calcium-channel blockers]].
||
|}

===Evidence of preexcitation===
*Defined as:
**Slurred upstroke of QRS complex
**Wide QRS complex >120 msec
**Short PR interval <120msec
*Management: '''Avoid AV nodal agents'''
*Unstable:
**[[Synchronized cardioversion]] (120-200 joules for biphasic waveforms, 200 joules for monophasic waveforms)
*Stable <ref> Page RL et al. 2015 ACC/AHA/HRS Guideline for the Management of Adult Patients With Supraventricular Tachycardia: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Circulation. 2016;133(14) </ref>:
**[[Procainamide]] (17 mg/kg loading dose at 20 to 50 mg/minutes or 100mg every 5 minutes, maintenance infusion 1 to 4 mg/minute) <ref> Neumar RW, Otto CW, Link MS, et al, "Part 8: Adult Advanced Cardiovascular Life Support:2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care," Circulation, 2010, 122:729-67. </ref>
**[[Ibutilide]] (1mg over 10 minutes, repeat 10 minute infusion can be given)<ref>Dr. Smith's EKG Blog What to do when Atrial Fib with RVR will not Electrically Cardiovert. And how do you measure the QT in Atrial Fib? http://hqmeded-ecg.blogspot.com/2021/02/what-to-do-when-atrial-fib-with-rvr.html</ref>
**Avoid [[amiodarone]], does not slow accessory pathway and has beta blocking properties, may increase conduction via accessory pathway
**[[Cardioversion]], consider sedation prior
**Avoid AV nodal blocking agents ([[diltiazem]], [[metoprolol]]) as can lead to [[ventricular fibrillation]]/tachycardia
**Try to avoid [[cardioversion]] without adequate anticoagulation

==Disposition==
*Admit patients who were unstable
*Stable and asymptomatic patients can typically be discharged, once controlled
*Other patients to be determined on a case-by-case basis

==See Also==
*[[Atrial Fibrillation (Main)]]
*[[EBQ:Ottawa_Aggressive_ED_Cardioversion_Protocol|Ottawa Aggressive Cardioversion Protocol]]

==External Links==
*[http://www.aliem.com/beta-blockers-vs-calcium-channel-blockers-atrial-fibrillation-rate-control-thinking-beyond-ed/ ALiEM - BB vs CCB]
*[http://emcrit.org/podcasts/crashing-a-fib/ Crashing Afib - EMCrit]
*Diltiazem load: [[:File:dilt-load.pdf]]<ref>http://ehced.org/wp-content/site/Drips/dilt-load.pdf</ref>
*[http://www.emdocs.net/unstable-atrial-fibrillation-a-guide-to-management/ Unstable Atrial Fibrillation: A Guide to Management from emDocs]

==References==
<references/>

[[Category:Cardiology]]