Lacosamide-Induced Complete Heart Block in a Healthy Young Female.

New-onset complete heart block (CHB) occurring in a healthy young female is a relatively rare finding. We report a case of a 33-year-old female who was incidentally found to have CHB after presenting with a left tibial shaft fracture after a fall. Despite a past medical history of epilepsy, the maintenance of a long, seizure-free period coupled with the absence of neuromuscular weakness prompted a thorough investigation, and the etiology of the CHB was ultimately determined to be lacosamide (LCM), the antiseizure medication. The discontinuation of LCM resulted in spontaneous conversion to sinus rhythm, and an outpatient follow-up 4 weeks after discharge revealed no further episodes of falls, heart block, or other symptoms. We believe this is a rare presentation of LCM-induced CHB in an otherwise healthy young female.