During central venous catheterization, a guidewire may cause various complications ranging from temporary arrhythmia to a pericardial tamponade. The arrhythmia occurring during the insertion of a guidewire is not uncommon and requires almost no therapy. However, persistent atrial fibrillation during and after central venous catheterization is a rare complication. We report a case of persistent atrial fibrillation that occurred during the insertion of a guidewire and was, treated with electric cardioversion.