High Quality Content by WIKIPEDIA articles! Amiodarone is an antiarrhythmic agent (medication used for irregular heart beat) used for various types of tachyarrhythmias (fast forms of irregular heart beat), both ventricular and supraventricular (atrial) arrhythmias. Discovered in 1961, it was not approved for use in the United States until 1985. Despite relatively common side-effects, it is used in arrhythmias that are otherwise difficult to treat with medication. Related newer compounds, such as dronedarone, have lower efficacy but a reduced rate of side-effects.