BACKGROUND: Even established and effective antiarrhythmic drugs (AADs) in atrial fibrillation (AF) are limited by their pro-arrhythmic and non-target organ side effects. Therefore the search continues for safer and effective new AADs. OBJECTIVE: This review will examine a novel AAD, tedisamil--a multichannel potassium channel blocker--and its antiarrhythmic properties, focusing on AF. METHODS: Review of the literature and studies assessing the effect of tedisamil in humans and animal models with atrial arrhythmia(s). CONCLUSION: Tedisamil appears to be effective for rhythm restoration in acute-onset AF patients. The proven anti-ischemic effect with tedisamil may be an added benefit. Further studies with tedisamil are needed to confirm its safety and long-term efficacy.