BACKGROUND AND PURPOSE: We aimed to determine whether heart rate variability (HRV) was correlated to long-term outcome in patients who received mechanical thrombectomy (MT) under general anesthesia for emergent large vessel occlusion (ELVO). METHODS: Data from 106 patients receiving MT under general anesthesia to treat ELVO between January 1, 2017 and December 31, 2019 were collected in a multicenter chart review. Univariate analysis, Chi-square test, and bivariate logistic regression were performed to assess the correlations between preoperative risk factors such as HRV and long-term outcome (as indicated by the modified Rankin score [mRS] at 90 days after MT). RESULTS: Bivariate logistic regression revealed that decreased LF/HF (low frequency/high frequency in HRV) ratio was correlated with unfavorable functional outcome as indicated by mRS >/= 2 (odds ratio [OR], 0.650; 95% confidence interval [CI], 0.157-0.839; p = 0.018), and functionally dependent outcome as indicated by mRS >/= 3 (OR, 0.704; 95% CI, 0.360-0.914; p = 0.021). It was also found that ELVO in the right anterior circulation was correlated with lower LF/HF ratio, as compared with ELVO in the contralateral side (p < 0.05). CONCLUSION: Our retrospective study demonstrated that worse outcome in patients with ELVO who received MT under general anesthesia induced autonomic changes and that decreased LF/HF ratio.