There were no differences between the HFrEF and HFpEF groups in terms of age, sex, heart rate, systemic or diastolic arterial pressure, incidence of comorbidities (hypertension, diabetes, coronary artery disease, atrial fibrillation or flutter), NYHA functional class, level of hemoglobin, estimated glomerular filtration rate (eGFR), N-terminal pro-B type natriuretic peptide (NT-proBNP), or hemodynamics of the PCWP, RAP, or PCWP-RAP. The gene discussed is NPPB; the disease is atrial fibrillation.