A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether the administration of amiodarone or lidocaine in patients with refractory VT/VF after cardiac surgery results in successful cardioversion. Altogether more than 434 papers were found using the reported search, from which 23 articles were used to answer the clinical question. No randomized trials have been found in which amiodarone was studied in patients with refractory VF/VT after cardiac surgery. Recommendations on the use of amiodarone in patients with refractory VF/VT in both European and American 2005 Guidelines on Resuscitation are mainly based on expert consensus and are supported by a few randomized trials in patients with out-of-hospital cardiac arrest. We would therefore recommend that amiodarone is the first line drug that should be used in patients with refractory ventricular arrhythmias after cardiac surgery that persist after three failed attempts at cardioversion. Lidocaine should only be used if amiodarone is not available or if its use is contraindicated. Amiodarone should be administered as an intravenous bolus of 300 mg after the third unsuccessful shock.