Recent studies have suggested that arginine-vasopressin could be more effective in the treatment of cardiac arrests. The last published study did not outline obvious improvements in the prognosis of all cardiac arrests but pointed out a possible increased survival rate when arginine-vasopressin is associated with epinephrine. The aim of this study is to compare the efficacy of two successive injections of epinephrine (1 mg) with two successive injections of epinephrine associated with arginine-vasopressin (40 UI) in out-of-hospital cardiac arrests occurring in adult patients. The primary endpoint is the survival rate at hospital admission. The inclusion period lasts 18 months and 2416 patients are planned to be enrolled.