Heart rate variability and delirium in acute non-cardioembolic stroke: a prospective, cross-sectional, cohort study

Abstract

Objectives Delirium is an acute fluctuating disorder of attention and awareness. It is associated with autonomic dysfunction and increased mortality. The primary endpoint of our study was to measure autonomic activity in acute stroke patients, by means of heart rate variability analysis, in order to identify autonomic modifications that can predispose to delirium. Methods Patients were consecutively enrolled from the stroke unit. Inclusion criteria were age ≥ 18 years and diagnosis of stroke with onset within the previous 72 h confirmed by neuroimaging. Exclusion criteria were atrial fibrillation, congestive heart failure, and conditions requiring intensive care unit. Patients were evaluated by means of Richmond Agitation Sedation Scale (RASS) and Confusion Assessment Method-Intensive Care Unit (CAM-ICU) at baseline, after 72 h, or when symptoms suggesting delirium occurred. For each patient, ECG was recorded at baseline assessment and HRV analysis was conducted on five consecutive minutes of artifact-free ECG traces. Results Fifty-six ECGs were available for analysis. During the study period, 11 patients developed delirium. Patients with and without delirium did not differ for sex, age, severity of stroke, and comorbidities. The delirium group had greater standard deviation of the heart rate (DLR − :9.16 ± 8.28; DLR + : 14.36 ± 5.55; p = 0.026) and lower power spectral density of the HF component (DLR − : 38.23 ± 19.23 n.u.; DLR + : 25.75 ± 8.77 n.u.; p = 0.031). Conclusions Acute non-cardioembolic stroke patients with increased variability of heart rate and decreased vagal control are at risk for delirium.

Preoperative slow‐wave sleep is associated with postoperative delirium after heart valve surgery: A prospective pilot study

“…Although this study evaluated autonomic nervous function postoperatively, a recent study showed that preoperative parasympathetic nervous activity was significantly lower in oesophageal cancer patients with postoperative delirium than in patients without POD (Echizen et al, 2021), suggesting that increased parasympathetic nervous activity before surgery may also play a positive role in inhibiting POD. Owing to the relatively small sample size, we found no significant difference in the HRV parameters between the groups, which is similar to previous research (Rollo et al, 2022; Zaal et al, 2015). In summary, a low cognitive level, low parasympathetic activity, and high inflammatory may play an important role in SWS and POD, but further research is needed.…”

Heart rate variability as a predictor of stroke course, functional outcome, and medical complications: A systematic review

“…Studies performed in stroke units have shown that the incidence of delirium in patients with AIS is approximately 30% ( Rollo et al, 2022 ). Moreover, delirium was an independent predictor of mortality during the 12 months period following hospital admission.…”

“…Moreover, delirium was an independent predictor of mortality during the 12 months period following hospital admission. Rollo et al (2022) enrolled 56 patients (32 men and 24 women; mean age was 69.9 ± 13.3 years) with diagnosis of stroke with onset within the previous 72 h. Delirium was evaluated by the Richmond Agitation Sedation Scale and the Confusion Assessment Method-Intensive Care Unit at baseline and 72 h after admission. At the time of enrolment, no patient had clinical signs or Confusion Assessment Method-Intensive Care Unit scores consistent with delirium diagnosis.…”