NPPB and pericardial effusion: In addition, patients in the validation cohort were more likely to have a greater 6-minute walk distance (6MWD), lower right atrial pressure, higher brain-type natriuretic peptide (BNP) or N-terminal (NT)-pro hormone BNP (NT-proBNP) levels, and a higher proportion of patients with pericardial effusion than those in the derivation cohort.