Authors: Vidovich C et al.
Source: A & A Practice. November 2025. Volume 19(11):e02090. DOI: 10.1213/XAA.0000000000002090
Summary:
This case report describes the successful termination of refractory supraventricular tachycardia (SVT) using intravenous neostigmine in a critically ill patient undergoing emergent endoscopic retrograde cholangiopancreatography (ERCP). A 69-year-old man with septic shock from obstructive cholangitis developed unstable narrow-complex SVT (180–200 bpm) shortly after induction of general anesthesia. The arrhythmia proved resistant to standard guideline-directed therapies, including synchronized cardioversion, vagal maneuvers, adenosine, esmolol, magnesium, and escalating doses of amiodarone.
Hemodynamic management was optimized by discontinuing norepinephrine and substituting phenylephrine and angiotensin II, which modestly improved rate control. During the procedure, transient reversion to sinus rhythm was repeatedly observed with gastric insufflation, suggesting a vagally mediated mechanism. Based on this observation, the anesthesia team elected to carefully titrate neostigmine—an acetylcholinesterase inhibitor with vagomimetic properties—administered in incremental doses of 0.5 to 1.0 mg (3.5 mg total) under full monitoring with pacing pads in place.
Neostigmine resulted in stable conversion to sinus rhythm at approximately 80 bpm without adverse effects such as bradycardia, heart block, or hypotension. The patient remained hemodynamically stable for the remainder of the prolonged procedure, allowing definitive biliary source control via percutaneous intervention. Postoperatively, the patient maintained sinus rhythm in the ICU, with the authors emphasizing that sustained improvement was most likely driven by sepsis source control rather than lingering pharmacologic effects.
The discussion places this case in historical context, noting neostigmine’s former use for SVT in the 1940s and its subsequent abandonment due to reports of severe bradyarrhythmias. Although omitted from modern SVT guidelines, the authors argue that neostigmine may have a niche role as a rescue therapy in highly selected, refractory cases—particularly when clear evidence suggests vagal responsiveness. They stress that neostigmine should only be considered in fully monitored environments with immediate access to anticholinergics and pacing, and only after standard therapies have failed.
What You Should Know:
• Neostigmine has potent vagomimetic effects and was historically used to treat SVT.
• In rare, refractory cases, enhancement of vagal tone may terminate SVT when guideline-directed therapies fail.
• Careful dosing, close monitoring, and immediate availability of atropine and pacing are essential.
• Observed physiologic responses (eg, arrhythmia improvement with vagal stimulation) can guide unconventional rescue strategies.
Key Points:
• This case demonstrates successful use of neostigmine for refractory SVT during general anesthesia.
• SVT termination appeared vagally mediated, supported by transient responses to gastric insufflation.
• Incremental dosing avoided serious muscarinic complications.
• Neostigmine remains off-label and should be reserved for exceptional circumstances in expert hands.
Thank you to A & A Practice for publishing this instructive case, which highlights thoughtful physiologic reasoning and disciplined escalation when managing life-threatening, refractory arrhythmias in the operating room.