Circadian rhythm of heart rate variability is reversibly abolished in ischemic stroke.

Abstract

Background and Purpose Acute brain infarction significantly decreases heart rate variability as a result of cardiovascular autonomic dysregulation. However, information regarding circadian rhythms of heart rate and heart rate variability is limited. Methods In this prospective study, we analyzed 24-hour circadian rhythm of heart rate and the time and frequency domain measures of heart rate variability in 24 patients with hemispheric brain infarction, 8 patients with medullary brainstem infarction, and 32 age- and sex-matched healthy control subjects. ECG data were obtained from the patients in the acute phase and at 6 months after the infarction. Results In the acute phase of stroke, all the components of heart rate variability, ie, standard deviation of RR intervals, total power, high-frequency power, low-frequency power, and very-low-frequency power, were similar at night (from midnight to 6 am) and during the day (from 9 am to 9 pm), indicating that the circadian oscillation of heart rate variability h...