Use of of Antiarrhytmics in the ICU for Atrial Fibrillation : Sepsis and Septic Shock

Preferred Caution / Consider Avoid (or avoid in shock)

Drug	Typical ICU Dose	Onset	Hemodynamically Unstable Role	Hemodynamically Stable Role	Contraindications (major)	Sepsis / ICU Notes
Propafenone (Class IC)	IV: 2 mg/kg over 10–20 min (max ~150 mg) (IV availability varies) PO (pill-in-the-pocket): 600 mg once (only for truly stable, preserved LV function)	Minutes–hours (IV); hours (PO)	Caution Consider only if EF normal, no structural heart disease, ischemia excluded, and BP supported; avoid otherwise.	Preferred (select) Rapid rhythm conversion if no structural heart disease, EF normal, and sepsis physiology allows.	Structural heart disease, LV dysfunction, recent MI, significant conduction disease w/o pacer	In septic shock with preserved LV, shown to convert faster and with fewer recurrences than amiodarone; niche use only.
Ibutilide (Class III)	>60 kg: 1 mg IV over 10 min ≤60 kg: 0.01 mg/kg IV over 10 min May repeat once after 10 min if no conversion	~20–30 min	Caution Cardioversion first; consider if CV fails/unavailable and QTc acceptable.	Preferred Very effective for recent-onset AF/AFL; continuous ECG monitoring required.	Baseline QTc > 440–450 ms, history of torsades, severe LV dysfunction, recent MI	High torsades risk in sepsis; correct K > 4.0 and Mg > 2.0 before dosing; monitor ≥ 4 h post-dose.
Amiodarone (Class III)	Load: 150 mg IV over 10 min (may repeat) Infusion: 1 mg/min x 6 h → 0.5 mg/min x 18 h Oral: 200–400 mg daily	~1–2 h for rate; slower for conversion	Preferred Useful when hypotensive or after failed cardioversion; watch for bradycardia/hypotension.	Caution Versatile when others fail/contraindicated; slower conversion than ibutilide.	Severe bradycardia, high-grade AV block w/o pacer, true iodine allergy	Common in ICU; observational data suggest β-blockers may have mortality benefit for rate control when BP tolerates.
Esmolol (β1-blocker)	500–1000 mcg/kg IV bolus → 50–200 mcg/kg/min infusion (titrate)	Minutes	Avoid in shock May worsen hypotension; consider only if BP supported and need tight rate control.	Preferred Rate control with outcome benefits in sepsis if BP tolerates; rapid titration.	Bradycardia, hypotension, severe bronchospasm, acute decomp HF	Very short half-life allows fine control; reassess frequently as sepsis evolves.
Landiolol (β1-blocker)	Start 1 mcg/kg/min → titrate to HR goal (often up to ~10 mcg/kg/min)	Minutes	Caution Less hypotension than esmolol, but still use carefully in unstable shock.	Preferred Rapid HR control with minimal BP drop; availability varies by region.	Similar to esmolol (bradycardia, hypotension, bronchospasm, acute decomp HF)	Good option in septic AF with borderline BP when available.
Digoxin (cardiac glycoside)	IV load total 8–12 mcg/kg: give 50% initially, then 25% q6h x 2 doses Adjust for renal function; monitor levels and conduction.	Hours	Caution / Adjunct Useful for rate control in LV dysfunction with hypotension; not a converter.	Adjunct Slower rate control; combine with other agents as needed.	2nd/3rd-degree AV block w/o pacer, WPW with AF, digoxin toxicity	Less effective in high sympathetic tone early in sepsis; minimal BP effect makes it attractive in hypotension.
Diltiazem (Cardizem, non-DHP CCB)	IV bolus: 0.25 mg/kg over 2 min → may repeat in 15 min at 0.35 mg/kg Maintenance: 5–15 mg/h infusion	Minutes	Avoid in shock Can worsen hypotension; avoid in severe LV dysfunction.	Preferred Effective rate control in stable patients with preserved BP.	Severe LV dysfunction (EF < 40%), hypotension, WPW with AF, bradycardia, AV block	Rapid rate control in stable AF; hypotension frequently limits use in septic ICU patients.
Verapamil (non-DHP CCB)	IV bolus: 2.5–5 mg over 2 min; may repeat 5–10 mg after 15–30 min Maintenance: 5–10 mg/h infusion	Minutes	Avoid in shock Negative inotropy/vasodilation may worsen hemodynamics.	Caution Can control rate in stable AF, but more hypotension risk than diltiazem.	Severe LV dysfunction, hypotension, WPW with AF, bradycardia, AV block	Less favored in septic AF due to hypotension risk; avoid in severe LV dysfunction.

Practical pearls: Treat sepsis source, correct hypoxia/acidosis, and replete electrolytes (target K > 4.0, Mg > 2.0) before pharmacologic conversion. In true hemodynamic instability, electrical cardioversion remains first-line; drugs here are adjuncts or alternatives when CV fails or is not feasible.