Patients at 40 years of age or older, with an LVEF > 40%, evidence of structural heart disease and elevation in natriuretic peptides [N-terminal pro B-type natriuretic peptide (NT-proBNP) ≥300 pg/mL (≥600 pg/mL for patients in atrial fibrillation or flutter). This evidence concerns the gene NPPB and atrial fibrillation.