Sinus Node

A circadian clock in the sinus node mediates day-night rhythms in Hcn4 and heart rate

Heart rate exhibits diurnal variation with slower rhythms during sleep. While neural factors were assumed responsible, this study tested whether intrinsic pacemaking contributes. The day-night difference in the average heart rate of mice was …

A circadian clock in the sinus node mediates day-night rhythms in Hcn4 and heart rate

BACKGROUND. Heart rate follows a diurnal variation, and slow heart rhythms occur primarily at night. OBJECTIVE. The lower heart rate during sleep is assumed to be neural in origin, but here we tested whether a day-night difference in intrinsic …