Association of Heart Rate Variability with Outcomes of Acute Ischemic Stroke

Abstract

Background: Reduced Heart Rate Variability (HRV) is associated with autonomic dysfunction and may influence stroke recovery. This study investigated the association between HRV parameters and functional outcomes in acute ischemic stroke (AIS).  

Methods: A prospective cohort study was conducted from May 2024 to June 2025. Consecutive AIS patients underwent 48-hour Holter monitoring within 72 hours of admission. HRV parameters (SDNN, RMSSD, pNN50, Mean RR interval, HRV Triangular Index) were analyzed. Primary outcome was unfavorable functional status at discharge (death or NIHSS ≥9). Secondary outcomes included NIHSS, mRS, mortality, and hospitalization duration. Statistical analyses included Mann-Whitney U tests and Pearson correlations.  

Results: Among 248 patients 133 (54.3% unfavorable outcome), no significant differences in HRV parameters were observed between outcome groups (all p>0.05). SDNN was weakly correlated with reduced mortality (r = -0.208, p=0.001). Other HRV metrics showed no clinically relevant correlations with NIHSS, mRS, or hospitalization duration. Baseline characteristics (age, gender, comorbidities) and early stroke severity scores (admission NIHSS, 24-hour NIHSS) did not differ between groups.  

Conclusion: Standard HRV parameters did not predict functional outcomes post-AIS in this cohort. However, SDNN may be weakly associated with reduced mortality, warranting further investigation.