Background: With respect to prevalence of cardiovascular involvement in Guillain-Barre syndrome (GBS) , this study was carried out to assess autonomic dysfunction signs and symptoms and also heart rate variation (HRV) with respiration in the acute phase of GBS and it's prognostic value.

Materials and Methods: Forty-three patients with GBS who referred for electrodiagnostic study in the first week of their disease were studied. Autonomic system involvement detected with careful clinical examination and heart rate variation with deep breathing were studied in all patients and Prognostic value of test was evaluated with proper analytical tests.

Results: HRV was abnormal in five patients (11.6%) and expiratory to inspiratory ratio (E/I) was abnormal in eight patients (18.6%). In 9 Patients (20/9%) each of the tests were abnormal. There was no significant correlation between HRV and E/I Ratio between axonal and demyelinating types. (P=0.88) but there were significant correlation between abnormal results and respiratory failure (P<0.001), (P<0.011) and also severity of weakness (P<0.05).

Conclusion: Autonomic dysfunction is common in acute phase of GBS (60%). Our results showed cardiovascular involvement with abnormal HRV and E/I Ratio tests could be alarming for sever respiratory involvement in the course of disease.