Acute termination of atrial fibrillation is the starting point of any therapy aimed at preventing atrial fibrillation and improves cardiac output in patients with hemodynamic compromise due to the arrhythmia. External electrical cardioversion is a simple procedure to terminate persistent atrial fibrillation in the majority of cases. Initially, Lown et al. used an anterior-lateral position of electrodes to apply a cardioversion shock. Recent pathophysiological studies have shown that atrial fibrillation is maintained by functional re-entry circuits anchored in the left atrium. As the left atrium is located posteriorly in the thorax, an anterior-posterior electrode position may be more efficient for external cardioversion of atrial fibrillation than the commonly used anterior-lateral electrode position. Several recent studies have confirmed that an anterior-posterior electrode position is superior to an anterior-lateral electrode position for external cardioversion of atrial fibrillation. There are no indications that an anterior-posterior electrode position is less safe than an anterior-lateral electrode position. We therefore suggest that an anterior-posterior electrode position should initially be used for external cardioversion of atrial fibrillation.