Management of Atrial Fibrillation with Rapid Ventricular Response (HR 200)
For AF with RVR and a heart rate of 200 bpm, immediately assess hemodynamic stability: if the patient is unstable (hypotensive, chest pain, altered mental status, pulmonary edema), perform urgent electrical cardioversion; if stable, use IV beta-blockers or non-dihydropyridine calcium channel blockers (diltiazem) as first-line rate control, reserving IV amiodarone for patients with heart failure, hypotension, or when first-line agents fail or are contraindicated. 1, 2
Immediate Assessment
Check for hemodynamic instability including severe hypotension, ongoing chest pain/ischemia, altered mental status, or acute pulmonary edema—any of these mandate immediate electrical cardioversion rather than pharmacologic rate control 3, 1
Obtain a 12-lead ECG to confirm AF diagnosis, measure ventricular rate, and critically identify pre-excitation patterns (delta waves suggesting Wolff-Parkinson-White syndrome), as this completely changes management 1
Assess for underlying precipitants including acute MI, pulmonary embolism, thyrotoxicosis, sepsis, or electrolyte abnormalities that require simultaneous treatment 4
Rate Control Strategy Based on Cardiac Function
For Preserved Ejection Fraction (Stable Patients)
First-line agents are IV beta-blockers (metoprolol, esmolol) or IV diltiazem, which are Class IIa, Level of Evidence A recommendations for acute rate control in most patients with AF-RVR 3, 1
IV diltiazem or esmolol offer rapid onset (within minutes), making them ideal for emergency rate control in hemodynamically stable patients 5
Target heart rate should be <100 bpm at rest, with adequate control during moderate exertion to 90-115 bpm 6, 5
For Heart Failure or Reduced Ejection Fraction
IV amiodarone or digoxin are recommended as first-line agents when heart failure or reduced ejection fraction is present, as beta-blockers and calcium channel blockers can worsen hemodynamic compromise 3, 1
IV amiodarone is specifically indicated (Class I, Level B) for acute rate control in patients with AF and heart failure who do not have an accessory pathway 3, 2
Avoid non-dihydropyridine calcium channel blockers in decompensated heart failure as they may exacerbate hemodynamic compromise (Class III recommendation) 3
For Hypotensive Patients
IV amiodarone is the preferred agent when hypotension is present, as standard AV nodal blockers are contraindicated in this setting 2
Administer amiodarone as 150 mg IV over 10 minutes (loading dose), followed by 1 mg/min for 6 hours, then 0.5 mg/min maintenance infusion—not as a single bolus 2, 7
Monitor closely for worsening hypotension during amiodarone infusion (occurs in 16% of patients); if it develops, slow the infusion rate and consider vasopressors, inotropes, or volume expansion 7
When Amiodarone is Appropriate
IV amiodarone is useful when other measures are unsuccessful or contraindicated (Class IIa, Level C), making it a second-line agent for rate control in most scenarios 3, 1
Consider amiodarone when beta-blockers and calcium channel blockers have failed to achieve adequate rate control in stable patients 3
Be aware that amiodarone may convert AF to sinus rhythm (rhythm control effect), which carries thromboembolic risk if AF duration >48 hours without anticoagulation 3
Critical Contraindications and Pitfalls
Pre-Excitation Syndromes (Wolff-Parkinson-White)
Never use AV nodal blocking agents (beta-blockers, calcium channel blockers, digoxin, amiodarone) in pre-excited AF, as they can paradoxically accelerate ventricular response and precipitate ventricular fibrillation (Class III recommendation) 3, 1
For hemodynamically stable pre-excited AF, use IV procainamide or ibutilide to restore sinus rhythm 1
For hemodynamically unstable pre-excited AF with very rapid rates, immediate electrical cardioversion is mandatory to prevent ventricular fibrillation 1
Other Important Warnings
Amiodarone can cause bradycardia (4.9% of patients) and AV block; slow or discontinue infusion if this occurs, and have temporary pacing available 7
Amiodarone prolongs QTc and can cause torsades de pointes (<2% incidence); monitor QTc during infusion and correct electrolyte abnormalities (hypokalemia, hypomagnesemia) before administration 7
Do not use digoxin as sole agent for rate control in active patients or those with paroxysmal AF (Class III recommendation) 3, 1
Anticoagulation Considerations
Assess stroke risk using CHA₂DS₂-VASc score; anticoagulation is recommended for scores ≥2 1
For AF duration >48 hours or unknown duration, do not perform elective cardioversion (electrical or pharmacologic with amiodarone) without either 3-4 weeks of anticoagulation or transesophageal echocardiography to exclude left atrial thrombus 3, 1
Emergent cardioversion for hemodynamic instability should not be delayed for anticoagulation, but initiate anticoagulation immediately after 1
Amiodarone-Specific Monitoring
Monitor liver enzymes as acute hepatocellular necrosis can occur with IV amiodarone, though baseline elevations are common and not a contraindication 7
Watch for progressive hepatic injury and consider reducing infusion rate or discontinuing if this develops 7
FDA approval for IV amiodarone is specifically for ventricular arrhythmias (VF/VT), not AF, though it is widely used off-label for AF rate control 7