The aim of this study is to determine whether the prophylactic amiodarone can prevent re-arrest with ventricular shockable rhythm in patients who treated with targeted temperature management after return of spontaneous circulation from cardiac arrest which had been shockable rhythm during CPR.

Patients with cardiac arrest are in high risk of re-arrest during post cardiac arrest care due to vulnerable heart state electrically and hemodynamically. Especially if patients who had experienced shockable rhythms such as ventricular fibrillation or pulseless ventricular tachycardia during CPR, then they are at high risk of developing shockable re-arrest.

However until now there has not been any evidence of prophylactic anti arrhythmic drug effect during post cardiac arrest care.

Amiodarone is class III anti arrhythmic drug which has been used for conversion of ventricular arrhythmia during CPR.

In this study we want to determine whether the prophylactic amiodarone can prevent re-arrest with ventricular shockable rhythm or not.

Inclusion Criteria:

• Non traumatic cardiac arrest patients who had VF or pVT during CPR in ER

Exclusion Criteria:

• age < 18 yr
• pregnancy
• non cardiac caused arrest such as hanging
• previous amiodarone continuous infusion before radomization
• sustained ventricular arrhythmia recurrence after ROSC
• extracorporeal membrane oxygenation
• contra indication for amiodarone
• disagree with this research