NPPB and pulmonary arterial hypertension: Markers of ventricular wall tension such as B-type natriuretic peptide (BNP) and N-terminal pro-BNP (NT-proBNP), correlate with increased ventricular pressures [70, 71] and are negatively correlated with RV ejection fraction in pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) [72].