The subgroup of patients in the bio-humoral substudy of GISSI-AF [14, 15] was deemed adequate to test independently two features of an exploratory panel of nine circulating biomarkers, deglycosylated total NT-proBNP and NT-proBNP in AF: (1) the association of a biomarker with AF, when a blood sample is taken at the 6- or 12-month visit while AF is present in the electrocardiogram (ECG), and (2) the predictive power of the same biomarker at baseline, when the patient is in sinus rhythm, for recurrence of AF or incident hospitalization for CV reasons. This evidence concerns the gene NPPB and atrial fibrillation.