Atrial Fibrillation in a Young Healthy Adult: A Case Report From Anaphylaxis to Arrhythmia

Atrial fibrillation (AF) is rare in young adults without underlying cardiac pathology. We present a 33-year-old previously healthy male who developed new-onset AF with rapid ventricular response (RVR) after receiving epinephrine for a bee sting-associated allergic reaction. The arrhythmia occurred within five minutes of intramuscular epinephrine administration and resolved following rate control with intravenous diltiazem. Cardiac workup, including echocardiography and thyroid function tests, was unremarkable. He remained in sinus rhythm during telemetry monitoring and was discharged with outpatient follow-up. This case highlights the potential for transient AF in the setting of allergic reactions and raises diagnostic and therapeutic questions regarding the role of venom-induced autonomic effects versus sympathomimetic drug administration.