Mobitz type I and II atrioventricular blocks during fingolimod therapy

We investigated patients who showed a second-degree atrioventricular block (S-AVB) after the first fingolimod administration. We observed six patients with S-AVB, three Mobitz type I, and three type II. Monitoring continued on the second day for all patients. Three patients showed persistence of the S-AVB, with resolution on the second or third day. One patient had a persistent S-AVB up to the fourth day when fingolimod was discontinued. We conclude that Mobitz type II S-AVB is possible during fingolimod therapy. Patients with S-AVB could be monitored until resolution of the S-AVBs, as these may persist several days after the first fingolimod administration.