Rolf et al. Paroxysmal atrial fibrillation after initiation of fingolimod for multiple sclerosis treatment
42 year old male had PAF on initiation, resolution on withdrawal of, recurrence on reinitiation and reresolution permanently on discontinuation of fingolimod. Extensive cardiac testing was negative. This is different than the bradycardia that is known to occur with fingolimod which requires initiation with cardiac monitoring.
Authors note that fingolimod is an agonist of S1P-R1,2,3 in cardiovascuklar system. In atrial myocytes, binding of the receptors causes activation of the potassium channels leading to an inward K current and decreased firing rate. Therefore drug causes bradycardia or AV conduction blockade. There is in animal models, S1P induced reperfusion tachyarrythmias.