Heart Rate Variability in Patients with Spontaneous Intracerebral Hemorrhage and its Relationship with Clinical Outcomes

Background Although abnormal heart rate variability (HRV) is frequently observed in patients with spontaneous intracerebral hemorrhage (ICH), its time course and presentation of different indices remain unclear, and few studies have focused on its association with clinical outcomes. Methods We prospectively recruited consecutive patients with spontaneous ICH between June 2014 and June 2021. HRV was evaluated twice during hospitalization (within 7 days and 10–14 days after stroke). Time and frequency domain indices were calculated. A modified Rankin Scale score ≥ 3 at 3 months was defined as a poor outcome. Results Finally, 122 patients with ICH and 122 age- and sex-matched volunteers were included. Compared with controls, time domain and absolute frequency domain HRV parameters (total power, low frequency [LF], and high frequency [HF]) in the ICH group were significantly decreased within 7 days and 10–14 days. For relative values, normalized LF (LF%) and LF/HF were significantly higher, whereas normalized HF (HF%) was significantly lower, in the patient group than in the control group. Furthermore, LF% and HF% measured at 10–14 days were independently associated with 3-month outcomes. Conclusions HRV values were impaired significantly within 14 days after ICH. Furthermore, HRV indices measured 10–14 days after ICH were independently associated with 3-month outcomes.