Synchronous Heart Rate Reduction with Suppression-Burst Pattern in KCNT1-Related Developmental and Epileptic Encephalopathies.

Suppression burst (SB) is an electroencephalographic pattern observed in neonatal- and infantile-onset developmental and epileptic encephalopathies (DEEs), which are associated with a high mortality in early life. However, the relation of SB electroencephalogram (SB-EEG) with autonomic function requires clarification. We investigated the relationship between heart rate (HR) and phasic transition during SB-EEG in DEEs to explore the mechanism of early death. Seven patients (two with KCNT1-DEE) with neonatal- and infantile-onset DEE who presented with SB-EEG were retrospectively identified. Five-minute SB-EEGs were analyzed with simultaneous recording of electrocardiograms. Mean HR, suppression duration, and burst period were calculated by measuring RR intervals. Two patients with KCNT1-DEE exhibited synchronous HR fluctuations, with an HR decrease during suppression and an increase during burst. The HR decrease was larger (-6.1 and -7.7 %) and the median duration of suppression was longer (4.0 and 8.2 s) in patients with KCNT1-DEE than the other five (range: -2.9-0.9 % and 0.7-1.7 s, respectively). A strong negative correlation was confirmed between suppression duration and HR reduction rates in one patient with KCNT1-DEE. SB phases may influence HR regulation in patients with KCTN1-DEE.