Successful Reversion of Refractory Supraventricular Tachycardia With Neostigmine During Emergent Endoscopic Retrograde Cholangiopancreatography: A Case Report.

We describe a 69-year-old man in septic shock undergoing an emergent endoscopic retrograde cholangiopancreatography (ERCP) whose narrow-complex supraventricular tachycardia (SVT, 180-200 bpm) persisted despite synchronized cardioversion, vagal maneuvers, adenosine, esmolol, and amiodarone. Changing vasopressors from norepinephrine to phenylephrine and angiotensin II aided in rate control. Noting transient reversion during maneuvers provoking vagal stimulation, when SVT reoccurred we titrated intravenous neostigmine in 0.5 to 1.0 mg increments (3.5 mg total), achieving a stable sinus rhythm at 80 bpm without adverse effects. This case illustrates neostigmine's value as an off-label vagomimetic rescue when guideline-directed therapies fail, and vagal stimulation appears beneficial. .