A-Fib w RVR


Atrial Fibrillation
Atrial Flutter
Categories of Atrial Fibrillation
Category Comments
New-onset -
Paroxysmal Short bursts of sudden onset
Spontaneous cardioversion within 7 d, typically within 24 h
Persistent Lasts for more than 7 d
Requires either pharmacologic or electrical conversion
Permanent Continuous either due to prolonged symptoms or refractory to cardioversion

A-Fib  Algorithm
Unstable Stable
- Chest Pain
- SOB
- Hypoten..
- Confusion

< 48 hr

> 48 hr
 



Synch. Cardiov.


Rate Control
PLUS
Fully Anti-Coagulate
(LMWH 1mg/kg, Heparin protocol)


 
CAD    β-blocker

COPD   CCB

•Acute CHF Exac
 
    Amiodarone
  or

  digoxin
BP
 
•EF <40%


Synch. Cardiov.


(
Anti-coagulate x 3 wks)
Calculate
CHA2DS2-VASc Score
Score Risk Anticoag Tx
0 low No antithrombotic therapy (or Aspirin)
1 Mod Oral anticoagulant (or Aspirin)
>2 High Oral anticoagulant


Look for Etiology
 

Obtain good Hx, CBC, CMP, CE & EKG, Pulse Ox, Cardiac monitor, TSH, UDS, CXR, 2D Echo (r/o valve disorder), ?TEE (if suspect thrombus in ventrical), Drug Levels, D-Dimer?/CTA (R/O PE)
 


Cardiovert (elective)
 
Amiodarone
ibutilide
Procainamide
Flecainide
Propafenon

Overview

Etiology

  • CAD/Acute MI
  • Valve Disorder
  • HTN
  • Electrolyte derangements
  • Thyrotoxicosis
  • Rheumatic heart disease
  • Digoxin toxicity
  • COPD
  • Pericarditis
  • PE, hypoxia
  • WPW

History

  • Chest pain & hx of coronary dz
    • Suggests ischemic origin
  • Fevers, malaise
    • Possible sepsis
  • N/V & diarrhea
    • Acute volume shifts
  • Thyroid dz
  • Medications
  • Ingestions
    • EtOH
    • Drug use
  • Have pt try to identify time of Sx onset
  • Symptoms variable, may be vague
    • Range from asymptomatic to shock
    • Palpitations, fatigue, dizziness, syncope
    • Angina, CHF
    • May present w/ CVA
       

Physical exam

  • Focus first on vitals
    • Immediate intervention if unstable
  • Cardiovascular exam is next
    • Irregularly irregular rhythm
      • Random AV conduction
    • No S4: no atrial activity
    • Pulse deficit sign
    • Absence of JVP a-wave
    • Any murmurs
    • Signs of CHF
      • S3 gallop
      • JVD
      • Pedal edema
      • Rales
  • Neurological exam
    • R/O thrombotic complications
       

Diagnosis

  • Labs/Tests
    • CBC, CMP
    • Ca, Mg: r/o abnl
    • Cardiac enzymes (Troponin)
    • Tox screen: r/o ingestions if indicated
    • TSH
    • Digoxin level: if indicated
    • ECG: (compare w/previous tracings if available)
      • Identify ischemic changes
      • Identify rate/rhythm
      • Determine QRS duration
      • Look for aberrancy
    • Usual findings
      • Continuous baseline fibrillatory activity
        • May be fine or coarse
      • P-waves absent
      • Small, irregular fibrillation waves at baseline
        • Best seen in V1-V3, AVF
    • No PR interval
    • Variable, irregular ventricular response
      • Usual rate 160-180
    • QRS usually normal unless aberrancy (Ashman's)
    • ENSURE NO DELTA WAVES
      • Need to r/o WPW
      • Use of AV nodal blocking drugs highly discouraged (eg, adenosine, CCBs, digoxin, beta blockers)
        • Can cause rapid ventricular rate, Vfib, sudden cardiac death
  • Imaging
    • CXR: r/o underlying conditions:
      • Pericarditis
      • Mitral stenosis
    • ECHO to r/o underlying conditions
      • Thrombus
      • Valvular vegetation/dysfxn
      • If cardiac dysrhythmia is suspected (history, physical exam and ECG lack diagnostic accuracy)
        • Consider prolonged ECG monitoring and echocardiography
 

Treatment

  1. ABCs, IV, O2, monitor
  2. CAUTION!!! IF NORMAL/BRADYCARDIC RATE
    • May not be etiology of Sx
    • Look for underlying cause
      • AV nodal dz
      • Sick sinus syndrome
      • Digitalis toxicity (regular vent rate)
Treatment Comment
Anticoagulation: required for 3 weeks before cardioversion.
If Hemodynamically unstable/life-threatening complications
  • Synchronized Cardioversion (regardless of duration) if:
    • MI
    • Pulmonary edema
    • Hypotension
    • Decompensated heart failure
    • WPW w/ RVR
       
  • May try
    • Amiodarone 150mg IV over 10 min
      OR
    • Cardizem 2.5 mg/min till rate or MAX: 50 mg NO BOLUS in crashing pt.
      (How To Mix?)
Sedate if time allows.
Etomidate 7mg
+
Ketamine 10 mg

 

Consider phenylephrine (PUSH DOSE) to increase BP

First-line pharmacotherapy (If Stable)
Calcium channel blockers  
Diltiazem
Initial Dose: 10–20 mg (0.25 mg/kg) IV, over 2 min
Second Dose: (in 20 min): 15-25 mg IV (0.35 mg/kg) if no effect w/ first dose.
Drip: 5–15 mg/h (start at 5 mg/h, titrate 5mg/r q15mib to max 15mg/ht).

 

Alt: 2.5 mg/min till rate controlled or Max: 50mg (How To Mix?)
NOTE: No Bolus in crashing pt.

May administer a second dose of diltiazem, 25 mg (0.35 mg/kg) IV in 15 min, if needed.
Contraindications to diltiazem use:
Hypotension
Bradycardia
Wide QRS Complex
Severe congestive heart failure.
Ventricular tachyarrhythmia.
COPD.

or

ß-Blockers  
Metoprolol, 5 mg IV every 5 min up to 15 mg.  
or
Esmolol, 500 mcg/kg IV bolus, over 60 s, followed by an infusion starting at 50 mcg/kg/min. May repeat esmolol bolus, 500 mcg/kg, if inadequate response after 2–5 min.
Increase infusion rate in increments of 50 mcg/kg/min after each bolus.
Maximal recommended infusion rate is 300 mcg/kg.
or
Propranolol, 0.1 mg/kg divided in 3 doses, over 2 min, IV, slowly over 60 s. May repeat once.
Contraindications to ß-blocker use:
Ventricular tachyarrhythmia.
Hypotension.
Severe congestive heart failure.
History of severe COPD, asthma.
Second-line pharmacotherapy  (HYPOTENSIVE Pt)
Amiodarone
  • Loading dose: 150 mg IV over 10 min., then 1 mg/min x 6 hrs, then 0.5 mg/min x 18 hrs, then 400 mg PO BID x 10 days (total : 10g loading dose)
  • Maintenance Dose: 200mg PO qd, OR minimal possible dose.
  • Infusion: 1mg/min for 6hr, then 0.5 mg/min.
  • Life-long treatment on lowest dose till pt. develop adverse effects if started secondary to CABG, could be off in 6-8 weeks

 

For pt with EF < 40%
Contraindication:
 - Pt w/Iodine or shellfish allergy
 - Pregnancy
Adverse Effects:
 -Hepatotoxicity
 -Hypo or hyperthyroid
 -Pancreatitis
 -Pulm. Toxicity
 -ARDS (IV use)
 -Hypotension (IV use)  
 - Blur-grey skin (long-term use)
Digoxin 0.5 mg IV bolus, then 0.25mg IV in 4 hours, then 0.25 mg IV in 4 more hours if needed.
Max:
1 mg in 24 hours.
Maintenance:
0.25 mg (125-375 mcg) qd, titrate to effect. (takes about 4-6 hours to work, be patient)
For pt with EF < 40%
OR
BP plus A-Fib
If accessory pathway is present, AVOID ß-blockers and calcium channel blockers.  
Procainamide, 17 mg/kg IV over 30 min up to 50 mg/kg or 50% widening of QRS complex.  
Ibutilide, 0.01 mg/kg (0.01 mg/kg) IV - up to 1 mg, over 10 min.  
 
Conversion to Sinus Rhythm
  1. Control rate first
     
  2. If A-Fib < 48 hrs, may consider conversion to sinus rhythm
    • Anticoagulation
      • Anticoagulation BEFORE cardioversion may be unnecessary
      • If elect to anticoagulate, start IV Heparin
      • Target INR to an aPTT of 45-60 sec, check aPTT q6hrs & titrate according to institutional nomogram until therapeutic
    • Electrical conversion
      • Synchronized Cardioversion
      • Continue anticoagulation x 4 wks after cardioversion
        • Myocardial "stunning" may lead to thrombus
           
    • Chemical conversion
      • Class I antiarrhythmics
        • Procainamide: 10-18 mg/kg bolus IV
          • Give at 50 mg/min rate
          • Follow w/1-4 mg/min infusion
        • Quinidine sulfate: 200 to 300 mg PO initially, THEN
          • 200 to 300 mg every hr
          • Until conversion, SE, or total dose of 1000 mg
        • Flecainide: 300 mg PO single dose
          • Avoid if structural heart dz
        • Propafenone: 450-600 mg PO single dose
          • Avoid if structural heart dz
      • Class III antiarrhythmics
        • Amiodarone: 5 mg/kg IV over 10-15 min
        • Ibutilide: 0.015 to 0.02 mg/kg IV over 10 min
          • Conversion usually w/in 20 min
        • Dofetilide: 500 µg q12hrs
          • Renal failure: decr dose
      • If needed, can add calcium channel blocker before type IA agent
        • Lowers ventricular rate to <120 bpm
        • Attenuates vagolytic tachycardia
        • Verapamil: 5-10 mg IV OR 40-80 mg PO
        • Diltiazem: 20-25 mg IV OR 60-120 mg PO

         

  3. If AFib > 48 hrs
    • Anticoagulation for 3 - 4 wks before conversion
      OR
    • TEE to exclude atrial clot
    • Higher CHADS2 scores assoc w/incr risk of atrial clot
    • Start IV Heparin
      • Goal: aPTT of 45-60 sec, check aPTT q6hrs & titrate according to institutional nomogram until therapeutic
    • Start warfarin or Dabigatran at same time for long term anticoagulation
      • Both similar overall bleeding risk but warfarin assoc w/more ICH vs Dabigatran assoc w/more GI bleeding (mostly lower)
    • Dabigatran is a direct thrombin inhibitor similar in mechanism of action to argatroban
      • Has fewer drug & food interactions (although fatty foods delay absorption while PPI's decr absorption)
      • Does not need PT/INR monitoring & frequent dose adjustments that are required w/warfarin
      • Goal INR of Warfarin 2-3
      • No set starting dose for Coumadin, several different algorithms proposed but no set dosing
        • www.warfarindosing.org is a non-profit warfarin dosing online calculator that uses several different EBM tools for initial dosing
      • Dabigatran: more GI distress which in 1 study led to stopping use (about 10% of pts)
      • Dabigatran degrades d/t hydrolysis when exposed to environment, therefore, tell pts when prescribing they MUST keep in the bottle and NOT place in pill boxes
      • Dosing of Dabigatran:
        • CrCl >50 ml/min: 150 mg PO BID
        • CrCl 30-50 ml/min: 75 mg PO BID
        • CrCl <30 ml/min: Contraindicated, do not prescribe
           

Disposition

  1. Admit
    • Pts hemodynamically unstable, poor rate control, risk of embolism
    • Pts considered for early cardioversion
    • New onlset A-Fib (for further evaluation i.e, 2D Echo, lab work etc)
  2. Cardio consult
  3. Discharge
    • Ottawa Aggressive Protocol for recent onset a-fib or flutter described by Stiell et al
      • Includes IV chemical cardioversion, electrical cardioversion if necessary, and discharge home from ED
    • Pts w/o significant sx, hemodynamic compromise, embolism risk
      • Low risk of CVA, death or embolism within 30 days of discharge
    • Ensure follow up care
      • CHADS2: determine low vs high risk of stroke
      • Identify need for outpatient anticoagulation
         
    • Long term care may include radiofrequency ablation or medications

CHA2DS2-VASc Score

CHA2DS2-VASc Score

  Condition Points
C Congestive heart failure (or Left ventricular systolic dysfunction) 1
H Hypertension: blood pressure consistently above 140/90 mmHg (or treated hypertension on medication) 1
A2 Age ≥75 years 2
D Diabetes Mellitus 1
S2 Prior Stroke or TIA or 
thromboembolism
2
V Vascular disease (e.g. peripheral artery disease, myocardial infarction, aortic plaque) 1
A Age 65 - 74 years 1
Sc Sex category (i.e. female gender) 1

 
Score Risk

Anticoag Tx

Consideration

0 low No antithrombotic therapy (or Aspirin) No therapy if < 60yr & no structural heart dz  -OR-  Aspirin 81 - 325 mg daily
1 Mod Oral anticoagulant
(or Aspirin)
Oral anticoagulant: Either new oral anticoagulant drug e.g. dabigatran or well controlled warfarin at INR 2.0-3.0
-OR-
Aspirin 81 - 325 mg daily, depending on factors such as patient preference
>2 High Oral anticoagulant Oral anticoagulant, using either a new oral anticoagulant drug (e.g. [Xarelto 20mg po qd] or [Pradaxa 150 mg po bid]) or well controlled warfarin at  INR 2.0-3.0
 

Admission Order: A-Fib

1. Admit to: to telemetry

2. Diagnosis: A-Fib

3. Condition:

4. Vital Signs: q1h, Call MD if BP > 160/90, < 90/60; Apical pulse > 130 or < 50; R > 25, <10; T > 38.5 C

5. Activity: Bedrest with bathroom privileges.

6. Nursing: Routine.

7. Diet: Heart Healthy, low fat, low cholesterol.

8. IV Fluids: D5W at TKO.

9. Special Medications:
 

- If Hemodynamically UNstable:

- DC Cardiovert (synchronized) under short-acting general anesthesia.

- Uniphasic Synchronized: 100J, 200 j, 300J, 360J,  MAX: 400 j

- Biphasic Synchronized: 50J (A-Flutter Only), 100J, 200J, 300J.




- If Hemodynamically Stable:

- Oxygen 2L/min NC to keep Sat > 92%
 

- Rate Control:

Diltiazem, 15–20 mg (0.25 mg/kg) IV, over 2 min, followed by a continuous infusion at 4–20 mg/h (start at 5 mg/h)

-- OR
--

Metoprolol, 5 mg IV every 5 min up to 15 mg.

-- OR
--  

 Amiodarone
 

Loading dose
: 150 mg IV over 10 min., then 1 mg/min x 6 hrs, then 0.5 mg/min x 18 hrs, then 400 mg PO BID x 10 days (total : 10g loading dose)
Maintenance Dose
: 200mg PO qd, OR minimal possible dose.
Infusion
: 1mg/min for 6hr, then 0.5 mg/min.
Life-long treatment
on lowest dose till pt. develop adverse effects if started secondary to CABG, could be off in 6-8 weeks

-- OR --

Digoxin 0.5 mg IV bolus, then 0.25mg IV in 4 hours, then 0.25 mg IV in 4 more hours if needed.
Max:
1 mg in 24 hours.
Maintenance:
0.25 mg (125-375 mcg) qd, titrate to effect. (takes about 4-6 hours to work, be patient)
-

   - Anticoagulation:

- Heparin per protocol
  OR

- LMWH 1 mg/kg SQ q12h

   - Calculate Chad-Vas Score
         - Warfarin 5mg 1 po qd

 


10. Symptomatic Medications:

  - Acetaminophen (Tylenol) 325-650 mg PO q4-6h prn headache.
  - Zolpidem (Ambien) 5-10 mg qhs prn insomnia.
  - Docusate sodium (Colace) 100-200 mg PO qhs.
  - Zofran 4 mg IV q4h prn n/v.
 
- Famotidine (Pepcid) 20 mg IV/PO q12h  OR  Lansoprazole (Prevacid) 30 mg qd.

 

11. Extras: Portable CXR, ECG, echocardiogram, TEE

12. Labs: CBC, CMP, Serial Cardiac Enzymes, PT/INR, urine drug screen, UA with micro. TSH, free T3/T4, 24h urine for metanephrine. Plasma catecholamines, high sesitivity CRP.