Introduction: Minor stroke or transient ischemic attack (TIA) is considered to have little effect on autonomic functions. However, it is unclear whether autonomic dysfunction in patients with minor stroke develops during acute stroke phase.
Hypothesis: We evaluated whether patients with minor stroke had autonomic dysfunction during acute stroke phase.
Methods: Patients with ischemic stroke or TIA were included. Those with diabetes and urological problems were excluded. Quantitative sudomotor axon reflex test (QSART), head-up tilt test (HUTT), sympathetic skin response (SSR), and heart rate variability (HRV) were performed during admission after acute stroke onset. HRV frequency measurements included time-domain and frequency-domain parameters. We analyzed the difference of autonomic function among patients with minor stroke (NIHSS score ≤ 3), major stroke (NIHSS score≥3) and TIA.
Results: Total of 81 patients was included. There were 55 with minor ischemic stroke, 15 with major ischemic stroke, and 11 with TIA. RR interval of HRV was significantly different among three groups (938.8 ± 99.1 ms in TIA, 871.4 ± 104.9 ms in minor stroke, and 832.7 ± 107.8 ms in major stroke, P = 0.042). Parameters of HRV in patients with stroke had significantly lower compared to those with TIA [high frequency (HF) 8.9 ± 3.6 ms2 vs 12.2 ± 5.0 ms2, respectively, P = 0.013; the square root of the mean of the sum of the squares of differences between adjacent NN intervals (RMSSD), 23.5 ± 9.3 ms vs 30.7 ± 11.6 ms, respectively, P = 0.023]. Moreover, HF and RMSSD significantly decreased in patients with minor stroke compared to those with TIA (HF, 8.9 ± 3.6 ms2 vs 12.2 ± 5.0 ms2, respectively, P = 0.038; RMSSD, 23.2 ± 9.4 ms vs 30.7 ± 11.6 ms, respectively, P = 0.05). Results of QSART, HUTT and SSR were not different among three groups.
Conclusion: Patients with minor stroke had decreased HRV compared to those with TIA, indicating that even minor stroke could be associated with decreased parasympathetic activity at early stroke phase. Further studies will be needed to evaluate effects of autonomic dysfunction on clinical outcome in patients with minor stroke.