Analysis of heart rate variability in patients with acute stroke

Abstract

Objective To investigate the characteristics of heart rate variability (HRV) of ambulatory electrocardiogram in patients with acute stroke, and evaluate the predictive value of HRV in stroke prognosis. Methods Eighty-three patients acute stroke (study group) and 83 cases of healthy subjects (control group) from October 2016 to October 2017 in Dalian Municipal Central Hospital Affiliated of Dalian Medical University were selected. The 24 h ambulatory electrocardiogram was performed to determine HRV in 2 groups, including standard deviation of NN intervals (SDNN), standard deviation of the 5 min mean cycle lengths (SDANN), root-mean-square successive difference (RMSSD) and percentage value of NN50 count (PNN50). Results The SDNN, SDANN, RMSSD and PNN50 in study group were significantly lower than those in control group: (80.83 ± 10.52) ms vs. (148.11 ± 22.59) ms, (79.98 ± 8.89) ms vs. (129.35 ± 5.34) ms, (19.28 ± 4.25) ms vs. (39.57 ± 2.38) ms and (5.91 ± 2.12)% vs. (19.35 ± 12.15)%, and there were statistical differences (P 0.05). The SDNN, SDANN, RMSSD and PNN50 in right stroke (43 cases) were significantly lower than those in left stroke (40 cases):(75.18 ± 2.32) ms vs. (88.12 ± 3.58) ms, (73.36 ± 2.18) ms vs. (85.69 ± 7.29) ms, (17.57 ± 1.67) ms vs. (20.58 ± 4.23) ms and (4.39 ± 1.57)% vs. (8.61 ± 1.12)%, and there were statistical differences (P<0.05). Patients were followed up for 1 year, 24 died and 59 survived. The SDNN, SDANN, RMSSD and PNN50 in dead patients were significantly lower than those in survived patients: (92.35 ± 4.58) ms vs. (154.37 ± 4.65) ms, (76.23 ± 4.03) ms vs. (143.95 ± 4.34) ms, (7.43 ± 2.12) ms vs. (31.65 ± 1.52) ms and (2.35 ± 0.46)% vs. (11.65 ± 0.48)%, and there were statistical differences (P<0.05). Conclusions The autonomic nervous function of patients with acute stroke is seriously unbalanced, with increased sympathetic excitability and decreased vagus excitability. The decrease of HRV can easily induce cardiac events and seriously affect the prognosis. Key words: Stroke; Prognosis; Heart rate viability; Autonomic nervous function