Determinants and prognostic significance of reduced heart rate variability for mortality and functional outcome after acute ischemic stroke

Objective: The study aimed to determine the predictors of reduced heart rate variability (HRV) in patients with stroke and to examine its relationship with functional outcomes and all-cause mortality.Methods:The 24-h Holter electrocardiographic recordings of patients referred to the cardiology outpatient clinic after acute ischemic stroke were retrospectively analyzed.Patients were grouped according to the standard deviation of normal-to-normal intervals (SDNN).Clinical and laboratory data, HRV parameters, and follow-up outcomes were evaluated.Results: The study included 163 patients (mean age, 66.7 ± 12.1 years). Compared with those with normal SDNN, patients with reduced SDNN had a higher heart rate, systolic and diastolic blood pressure, and modified Rankin Scale (mRS) scores. In multivariable logistic regression analysis, heart rate (OR 1.76, 95% CI 1.32–2.66, p = 0.001) and systolic blood pressure (OR 1.95, 95% CI 1.11–2.94, p = 0.01) were independent predictors of reduced SDNN. Over a median follow-up of 38 months, all-cause mortality was higher in the reduced SDNN group (22.4% vs. 10.5%, p = 0.039). Multivariable Cox analysis identified age (HR 1.063, 95% CI 1.012–1.117, p = 0.015), mRS score (HR 4.410, 95% CI 2.319–8.112, p < 0.001), and reduced SDNN (HR 1.976, 95% CI 1.112–4.121, p = 0.02) as independent predictors of all-cause mortality.Patients with reduced SDNN demonstrated a significantly decreased survival probability on Kaplan–Meier analysis (log-rank = 4.218, p = 0.004).Conclusion: Impaired HRV is associated with unfavorable functional outcomes and increased all-cause mortality in patients with ischemic stroke. The identification of autonomic dysfunction may provide additional insights into post-stroke prognosis.