What is the emergency management and ICU prescription for atrial fibrillation?

Emergency and ICU Prescription for Atrial Fibrillation

Immediate Assessment and Stabilization

For hemodynamically unstable patients with atrial fibrillation (hypotension, acute heart failure, ongoing chest pain, or shock), perform immediate electrical cardioversion without delay. 1

Hemodynamic Status Evaluation

• Assess blood pressure, mental status, signs of heart failure (pulmonary edema, elevated JVP), and evidence of end-organ hypoperfusion 2, 3
• Obtain 12-lead ECG to confirm AF, assess ventricular rate, and identify pre-excitation (WPW syndrome) 4, 2
• Check for reversible precipitants: sepsis, acute coronary syndrome, pulmonary embolism, thyrotoxicosis, electrolyte abnormalities, or acute alcohol intoxication 1, 2, 3

Rate Control Strategy (Hemodynamically Stable Patients)

For Preserved Left Ventricular Function (LVEF >40%)

Administer IV beta-blockers (metoprolol 2.5-5 mg IV over 2 minutes, repeat every 5-10 minutes up to 15 mg) or diltiazem (0.25 mg/kg IV bolus over 2 minutes, followed by 0.35 mg/kg if needed, then infusion 5-15 mg/hour) as first-line agents. 1, 4

Target heart rate: <110 bpm at rest (lenient control) initially, with stricter control (<80 bpm) only if symptoms persist. 1

Prescription Example for Preserved LVEF:

• Injection Metoprolol 5 mg IV slowly over 2 minutes, may repeat every 5 minutes up to 3 doses (total 15 mg) 1
• OR Injection Diltiazem 20 mg (0.25 mg/kg) IV over 2 minutes, may give second dose of 25 mg (0.35 mg/kg) after 15 minutes if needed 1
• Followed by Diltiazem infusion 5-15 mg/hour IV to maintain rate control 1

For Reduced Left Ventricular Function (LVEF ≤40%) or Decompensated Heart Failure

Use IV beta-blockers cautiously or IV digoxin (loading dose 0.25 mg IV, then 0.25 mg IV every 6 hours for 2 doses, followed by 0.125-0.25 mg IV/PO daily) as first-line agents. 1, 4

IV amiodarone (150 mg IV over 10 minutes, then 1 mg/min for 6 hours, then 0.5 mg/min for 18 hours) may be considered for rate control when other measures fail or are contraindicated. 1

Prescription Example for Reduced LVEF:

• Injection Digoxin 0.25 mg IV slowly, repeat 0.25 mg IV after 6 hours, then 0.125-0.25 mg IV/PO once daily 1, 5
• OR Injection Amiodarone 150 mg IV over 10 minutes, followed by infusion 1 mg/min for 6 hours, then 0.5 mg/min for 18 hours 1
• Avoid calcium channel blockers (diltiazem/verapamil) in decompensated heart failure 1

Anticoagulation (Critical Priority)

Initiate therapeutic anticoagulation immediately with IV unfractionated heparin (80 units/kg bolus, then 18 units/kg/hour infusion, target aPTT 1.5-2 times control) or subcutaneous low molecular weight heparin (enoxaparin 1 mg/kg twice daily) unless contraindicated. 1, 3, 6

Anticoagulation Prescription:

• Injection Heparin 5000 units IV bolus (or 80 units/kg), followed by continuous infusion at 1000-1200 units/hour (or 18 units/kg/hour), adjust to maintain aPTT 1.5-2 times control 1
• OR Injection Enoxaparin 1 mg/kg subcutaneous every 12 hours 3, 6

For AF duration >48 hours or unknown duration, continue anticoagulation for minimum 3 weeks before cardioversion and 4 weeks after. 1, 4

Rhythm Control (Cardioversion) - Only if Appropriate

Electrical Cardioversion

Perform immediate synchronized DC cardioversion (biphasic 120-200 joules) for hemodynamically unstable patients regardless of AF duration. 1

For stable patients, cardioversion is appropriate only if AF duration is clearly <48 hours, or patient has been therapeutically anticoagulated for ≥3 weeks, or transesophageal echo excludes left atrial thrombus. 1, 4, 6

Pharmacological Cardioversion (Stable Patients, AF <48 hours)

• Injection Amiodarone 150 mg IV over 10 minutes, may repeat 150 mg if needed, followed by maintenance infusion 1
• Avoid Class IC agents (flecainide, propafenone) in setting of acute MI, structural heart disease, or ischemic heart disease 1, 3

Special Situations

Wolff-Parkinson-White (WPW) Syndrome with Pre-excited AF

NEVER use AV nodal blocking agents (beta-blockers, calcium channel blockers, digoxin, adenosine) in pre-excited AF as they may precipitate ventricular fibrillation. 1

Perform immediate electrical cardioversion if hemodynamically unstable. 1

If stable, use IV procainamide (15 mg/kg IV over 30-60 minutes) or IV ibutilide. 1

Acute Coronary Syndrome with AF

Use IV beta-blockers as first-line unless contraindicated (severe LV dysfunction, cardiogenic shock, bronchospasm). 1

If beta-blockers contraindicated, use IV digoxin or IV amiodarone for rate control. 1, 3

Perform immediate cardioversion if hemodynamic instability or intractable ischemia present. 1, 3

Thyrotoxicosis with AF

Administer beta-blockers (propranolol 1 mg IV every 5 minutes up to 5 mg, or metoprolol) as first-line for rate control. 1

If beta-blockers contraindicated, use diltiazem or verapamil. 1

Complete ICU Prescription Template

For Hemodynamically Stable AF with Preserved LVEF:

1. Injection Metoprolol 5 mg IV slowly over 2 minutes, may repeat every 5 minutes (maximum 15 mg total) 1
2. Injection Heparin 5000 units IV bolus, then continuous infusion 1000-1200 units/hour, adjust to aPTT 1.5-2 times control 1
3. Monitor: Continuous cardiac monitoring, vital signs every 15 minutes initially, target HR <110 bpm 1
4. Tablet Metoprolol 25-50 mg PO twice daily for maintenance (once rate controlled) 1, 4

For Hemodynamically Stable AF with Reduced LVEF (≤40%):

1. Injection Digoxin 0.25 mg IV slowly, repeat 0.25 mg after 6 hours, then 0.125 mg IV/PO daily 1, 5
2. Injection Amiodarone 150 mg IV over 10 minutes if digoxin insufficient, followed by 1 mg/min infusion for 6 hours, then 0.5 mg/min 1
3. Injection Heparin 5000 units IV bolus, then continuous infusion 1000-1200 units/hour 1
4. Monitor: Continuous cardiac monitoring, avoid calcium channel blockers 1

For Hemodynamically Unstable AF:

1. Immediate synchronized DC cardioversion: 120-200 joules biphasic 1
2. Injection Heparin 5000 units IV bolus concurrently, then continuous infusion 1
3. Post-cardioversion: Continue anticoagulation minimum 4 weeks 1, 4

Critical Pitfalls to Avoid

• Never use digoxin as sole agent for rate control in paroxysmal AF—it is ineffective 1, 4
• Never use AV nodal blockers (beta-blockers, calcium channel blockers, digoxin, adenosine) in pre-excited AF/WPW syndrome 1
• Never use Class IC antiarrhythmics (flecainide, propafenone) in acute MI or structural heart disease 1, 3
• Never attempt cardioversion without anticoagulation if AF duration >48 hours or unknown, unless patient is hemodynamically unstable 1, 4
• Never use calcium channel blockers in decompensated heart failure or LVEF ≤40% 1
• Never discontinue anticoagulation prematurely after cardioversion—continue minimum 4 weeks and long-term based on stroke risk 1, 4

Monitoring Requirements

• Continuous cardiac telemetry monitoring 2, 3
• Vital signs every 15 minutes during acute rate control, then hourly once stable 2
• Serial ECGs to assess rate control and rhythm 4, 2
• Daily aPTT monitoring for heparin (target 1.5-2 times control) 1
• Renal function and electrolytes (especially potassium and magnesium) daily 1, 2