Delayed cardiac dysrhythmias after fingolimod administration.

A 51-year-old woman with relapsing-remitting multiple sclerosis was initiated on fingolimod. She developed a Mobitz Type I (Wenckebach)second-degree atrioventricular (AV) heart block during the initial 6-hour monitoring. She was transferred to the emergency department for further monitoring, where she went into a junctional tachycardia then went back into a Mobitz Type I AV block. The patient was symptomatic with a heart rate nadir of 38 beats per minute and treated with atropine. Junctional tachycardia has not been previously reported with fingolimod use. Patients may require extended cardiac monitoring after fingolimod administration.