Characteristic of birohythm in spontaneous subarachnoid hemorrhage onset

Objective Study of characteristic of biorhythm in subarachnoid hemorrhage onset.Methods326 cases of subarachnoid hemorrhage onset were studied.We analyzed characteristic of onset in 12 periods of 24h a day.Results6 to 8 am and 16 to 18 pm are two peak time of spontaneous subarachnoid hemorrhage.There was a significant difference of onset between day time and night time.There is more number of cases in day time than night time.Conclusion Spontaneous subarachnoid hemorrhage onset has a typical circadian rhythm.The peak of incidence of spontaneous subarachnoid hemorrhage would be 6 to 8 am and 16 to 18 pm a day.