Figure 1.

Study protocol. This study included patients who were referred to our centre over a 8-year period (2012–2020) for further assessment of breathlessness. Right heart catheterization and cardiac magnetic resonance were performed within 24 h in all cases. Eight hundred and thirty-five patients were included and allocated to derivation (85%) and validation (15%) cohorts. In the validation cohort, we obtained transthoracic echocardiography results within 24 h for comparison with cardiac magnetic resonance. CMR, cardiac magnetic resonance; HF, heart failure; LA, left atrial; LV, left ventricular; PCWP, pulmonary capillary wedge pressure; RHC, right heart catheterization; SOB, shortness of breath; TTE, transthoracic echocardiography.