Chemical Cardioversion Success Rates for AFL/AFib

Pharmacologic Conversion – Non-Critically Ill Patients

Agent (route)	Atrial Flutter Conversion Rate	Atrial Fibrillation Conversion Rate	Pros / Cons & Key Contra-indications
Ibutilide (IV)	70 – 90 %	30 – 50 %	Pros: very rapid (≈30 min). Cons/CI: torsades (~4 %); continuous ECG; avoid if QT > 440 ms or severe hypokalaemia.
Flecainide (PO/IV)	≈ 34 %	60 – 70 %	Pros: “pill-in-the-pocket”. Cons/CI: QRS widening; risk of 1:1 flutter (co-give AV-nodal blocker); avoid if QRS > 120 ms or ≥2° AV-block.
Propafenone (PO/IV)	~ 33 %	60 – 70 %	Pros: rapid; mild β-block action. Cons/CI: metallic taste, bronchospasm; avoid in severe asthma, marked bradycardia, major hepatic impairment.
Vernakalant (IV)	≤ 10 % (not recommended)	50 – 70 %	Pros: atrial-selective; very fast. Cons/CI: dysgeusia, hypotension; avoid if SBP < 100 mm Hg, recent MI < 30 d, or severe aortic stenosis.
Amiodarone (IV/PO)	25 – 30 %	60 – 70 %	Pros: wide safety margin. Cons/CI: slower action; IV hypotension; long-term thyroid/lung/liver toxicity; avoid with severe iodine allergy.
Dofetilide (PO)	60 – 70 %	20 – 30 %	Pros: oral start; predictable kinetics. Cons/CI: telemetry admission; torsades risk; CI if CrCl < 20 mL/min or baseline QT > 440 ms.

Pharmacologic Conversion – Critically Ill / ICU Patients

Agent (route)	Atrial Flutter Conversion Rate	Atrial Fibrillation Conversion Rate	Pros / Cons & Key Contra-indications
Ibutilide (IV)	≈ 78 % (≤1 h)	≈ 80 % (≤1 h)	Pros: quickest; works in septic/ventilated pts. Cons/CI: torsades (~4 %); correct Mg⁺⁺/K⁺; avoid if QTc > 440 ms or recent class Ia/III drug.
Procainamide (IV)	≈ 70 % (≤12 h)	≈ 70 % (≤12 h)	Pros: efficacy similar to amiodarone; less hypotension than feared. Cons/CI: BP drop; QRS/QT widening; stop if SBP < 80 mm Hg, QRS > 160 ms, QTc > 500 ms.
Amiodarone (IV)	30 – 60 % (24 h)	60 – 80 % (24 h)	Pros: safe in low-EF or vasopressor pts; prevents relapse if continued. Cons/CI: slower; solvent hypotension; central line for ≥2 g; CI with high-grade AV-block or severe iodine allergy.
Vernakalant (IV)	— (not effective)	≈ 53 % (≤6 h, post-cardiac-surgery)	Pros: atrial-selective; rapid. Cons/CI: transient hypotension (34 %); use only if SBP ≥ 100 mm Hg, QTc < 440 ms; avoid recent MI < 30 d or severe AS.
Sotalol (IV loading)	~ 50 % (limited data)	65 – 70 %	Pros: β-block plus class III (rate + rhythm). Cons/CI: torsades risk (QT monitoring); negative inotrope—avoid if shock; CI if CrCl < 40 mL/min, QTc > 450 ms, HR < 50 bpm.