Treatment of patients suffering from atrial fibrillation pose problems when percutaneous coronary intervention with stent implantation (PCI-S) is performed. In the absence of solid evidence-based data, no definite recommendations for the management of this patient subset are currently given in the guidelines on percutaneous coronary intervention issued by the most prominent Cardiology Associations. The management of the antithrombotic treatment before invasive cardiac procedures is also incompletely defined. In this study we aim to determine in patients with atrial fibrillation undergoing PCI-S: