Twenty eight patients have been treated; 8 patients had atrial fibrillation (FA) and 20 supraventricular paroxysmal (SVPT) tachycardia. Both diseases followed interventions of major surgery. No patient had myocardial ischemia and/or damaged conduction system, took any heart-related drug, or showed any risk factor. The posologic plans was as follows: a) bolus i.v. (three minutes) with 2 Amiodarone vials and electrocardiographic monitoring, then b) 10-20 mg/kg/day for three days with electrocardiographic monitoring. Within 5 days, all patients attained the total recovery from SVPT; AF regressed during the bolus injection in 1 patient, on the first day in 5 patients, and on the third day in the remaining 2 patients. During the hospitalization no important side effects occurred, except for transient hypotension in three subjects. The 6 months follow up did not reveal signs of intolerance, either. Amiodarone thus showed to be useful and well tolerated in the treatment of post-surgical hyperkinetic arrhythmias in patients undergoing major surgery.