Atrial fibrillation with RVR

Unstable (Cardioversion)

Indications

1. Ischemic CP
2. SBP < 90
3. Acute pulmonary edema
4. AMS

Above must be 2/2 RVR (i.e. if pulse is <130 look for other cause of above signs)

• Sedate: Versed / Ativan / Fentanyl
• Initial 100J monophasic or 50-70j biphasic synchronized cardioversion

Stable but Symptomatic (Rate Control)

• Goal < 110bpm1
• Be careful that you are not slowing down a normal physiologic response!
  • RVR in AF may be an appropriate response to fever, hypovolemia, hemorrhage, hypoxemia, withdrawal
• No evidence that pharmacological rate control has any adverse influence on LV dysfunction

Calcium-Channel Blockers

1. Preferred in pts with chronic lung disease or low EF
2. Contraindications
   1. Decompensated heart failure
   2. Preexcitation
   3. Significant hypotension

Diltiazem

1. Bolus 0.25 mg/kg (average adult dose 20mg) over 2 min
   1. If, after 15 minutes the first dose is tolerated but inadequate, re-bolus 0.35 mg/kg (average adult dose 25 mg)
   2. If pt responds to 1st or 2nd bolus start infusion at 5-15mg/hr
2. Takes 2-5 minutes to work, last 1-4 hours
3. 94% responive
4. If effective, can start PO dilt at 30mg QID

Beta-Blockers

• Particularly useful with a fib associated with exercise, after an acute MI, or with thyrotoxicosis
• Contraindicated in COPD, low EF CHF
• Metoprolol
  • 2.5-5mg IVP over 2min q5 min up to 3 doses
• Esmolol
  • Use if unsure whether pt will tolerate a BB (duration of action is only 10-20min)
  • Bolus 0.5 mg/kg over one minute, followed by 50 µg/kg/min
    • If, after 4 minutes response is inadequate, re-bolus followed by infusion of 100 µg/kg/min
    • If, after 4 minutes 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
• PO load with MTP 25-50mg following successful rate control with IV

Digoxin

• Consider as initial therapy for pts with LV dysfunction who:
  • Do not achieve rate control targets on beta blockers alone
  • Cannot tolerate addition of or increased doses of a beta blocker due to acute decompensated HF
  • Would have digoxin added anyway to improve CHF symptoms independent of AF
• Consider as initial therapy in pts with severe hypotension
• Consider as 2nd agent in pts in whom IV BB or IV CCB has failed to control their rate
• May take up to 6-8 hours to work
• Dosing
  • 0.25 mg IV q2hr up to 1.5 mg, then 0.125-0.25 mg PO or IV QD
  • Adjust dose in presence of renal failure, amiodarone, etc

Amiodarone

• Consider for use in pts with decompensated heart failure or those with accessory pathways
• 2nd-line agent for chronic rate control when BBs and CCBs, alone, combined, or when used with digoxin, are ineffective
• Load 5-7 mg/kg IV over 30 min; then 1200 mg over 24 h via continuous infusion or in divided oral doses

Stable and Asymptomatic

If mild or no symptoms and pulse only mildly elevated (<120bpm), ok to manage with PO meds

Evidence of preexcitation

• Initial therapy is aimed at reversion to sinus rhythm
  • Unstable -> urgent cardioversion
    • DC cardioversion
    • Pharmacologic cardioversion
      • Procainamide
        • 20-50 mg/min until arrhythmia is controlled, hypotension occurs, QRS complex widens by 50% of original width, or total of 17 mg/kg is given; followed by continuous infusion of 1-4 mg/min
  • Stable -> try to avoid cardioversion without adequate anticoagulation
  • Avoid AV nodal agents

See Also

Atrial Fibrillation (Gen)

Source

1/30/06 DONALDSON (adapted from Lampe), UpToDate, Niemann lecture

1RACE II study