Cardiac arrest (CA) is a public health problem in industrialized countries. The prognosis of these patients remains poor with significant mortality and severe neurological sequelae in survivors.

The objective of the present study is to determine whether cyclosporine can improve patient clinical outcome after shockable CA. 520 patients with CA will be entered into a multicentre, randomized, placebo-controlled study. They will receive one single injection of cyclosporine (or placebo) prior to resuscitation. The incidence of the combined endpoint (mortality, irreversible brain damage informations such as bilateral abolition of N20 wave or absent motor response or extension to the nociceptive stimulation…) will be assessed 7 days after CA.

Inclusion Criteria:

• Witnessed out-of-hospital cardiac arrest
• Shockable cardiac rhythm at first medical contact (ventricular fibrillation, ventricular tachycardia)

Exclusion Criteria:

• Evidence of trauma
• Evidence of pregnancy
• Duration of no flow more than 30 minutes
• Rapidly fatal underlying disease
• Allergy to cyclosporin A