title: Invited commentary.
authors.affiliation: Division of Cardiac Surgery, S. Raffaele University Hospital, Via Olgettina 60, Milan, 20132 Italy. stefano.benussi@hsr.it
authors.forename: Stefano
authors.initials: S
authors.lastname: Benussi
authors.forename: Ottavio
authors.initials: O
authors.lastname: Alfieri
mesh_terms: D001281:Atrial Fibrillation / Q000473:pathology*; D001706:Biopsy; D002196:Capillaries / Q000648:ultrastructure*; D003331:Coronary Vessels / Q000648:ultrastructure; D006801:Humans; D046529:Microscopy, Electron, Transmission; D009206:Myocardium / Q000473:pathology; D012849:Sinoatrial Node / Q000473:pathology*; D013997:Time Factors