Central Autonomic Dysfunction Delays Recovery of Fingolimod Induced Heart Rate Slowing

Background In multiple sclerosis (MS) patients, Fingolimod may induce prolonged heart-rate slowing which might be caused by MS-related central autonomic lesions. Objectives To evaluate whether MS-patients with prolonged heart-rate slowing (> six hours) upon Fingolimod show cardiovascular-autonomic dysfunction before Fingolimod-initiation. Methods Before Fingolimod-initiation, we recorded electrocardiographic RR-intervals (RRIs) and blood-pressure (BP) at rest, upon standing-up, during metronomic deep-breathing, Valsalva-maneuver, and "sustained-handgrip-exercise" in 21 patients with relapsing-remitting MS, and 20 healthy persons. We calculated sympathetic and parasympathetic cardiovascular parameters, including low-(LF) and high-frequency (HF) powers of RRI-and BP-oscillations, RRI-RMSSDs, RRI-and BP-changes during handgrip-exercise, parasympathetic heart-rate-slowing in relation to BP-overshoot after Valsalva-strain-release. We compared values of healthy persons and patients with and without prolonged heart-rate slowing after Fingolimod-initiation (ANOVA; significance: p<0.05). Results Upon Fingolimod-initiation, 7/21 patients had prolonged HR-slowing. Before Fingolimod, these patients had higher resting BP and higher BP increase during handgrip-exercise than had the other participants (p<0.05). They did not reduce parasympathetic HR-parameters upon standing-up. After Valsalva-strain-release, their parasympathetic HR-slowing in response to BP-overshoot was four times higher than in the other participants (p<0.05). Conclusions The autonomic cardiovascular dysfunction in MS-patients with delayed HR-re-acceleration upon Fingolimod-initiation suggests that MS-related central autonomic lesions compromise HR-re-acceleration upon Fingolimod.