OBJECTIVE: It was our aim to study the outcome of autonomic nervous function (ANF), heart rate variability (HRV) and arrhythmias in patients with acute viral myocarditis in a 6-month follow-up period after the diagnosis. METHODS: ANF was measured in patients with acute viral myocarditis 1, 3 and 6 months after the disease was diagnosed. HRV and arrhythmias were monitored by 24-hour electrocardiogram during the follow-up examination. RESULTS: Ninety-six patients with acute viral myocarditis were enrolled in this study; 58% showed abnormal ANF tests, and the incidence was reduced to 17% after 6 months (p < 0.01). Time and frequency domain analyses of HRV were significantly reduced in the early stage of the disease and recovered after 6 months (p < 0.05). The incidence of arrhythmias in patients with abnormal ANF was significantly higher than in patients with normal ANF (p < 0.05). The incidence of arrhythmias in patients with abnormal ANF at 6 months was significantly lower than that at the first month (p < 0.05). CONCLUSIONS: There is a significant impairment of ANF and a higher incidence of arrhythmias in the early stage of acute myocarditis. ANF and HRV abnormalities are significantly improved, and the incidence of arrhythmia is significantly reduced after 6 months in patients with acute myocarditis.