Novel CMR Indices of Cardiac Function and Remodeling in Right Heart Disease

Right ventricular (RV) remodeling is an important determinant of prognosis in conditions marked by chronic RV volume or pressure overload, including functional tricuspid regurgitation (TR) and pulmonary hypertension (PH). Conventional volumetric and functional measures, including RV ejection fraction (RVEF), often fail to detect adverse remodeling until it is advanced, particularly in significant TR, where regurgitant flow inflates total stroke volume and can mask a reduction in effective forward output. Cardiac magnetic resonance (CMR) is well suited to address this gap, combining highly reproducible chamber quantification with novel measures of myocardial deformation, tissue characterization, RV–pulmonary artery (PA) interaction, and flow hemodynamics. This narrative review examines emerging CMR-derived indices of adverse right heart remodeling, including effective RVEF, the RV/left ventricular volume ratio, the right atrioventricular coupling index, nonischemic septal fibrosis, and hepatic extracellular volume (ECV). We further review functional CMR markers, including surrogates of RV-PA coupling, RV and right atrial strain, myocardial T1 and ECV mapping, markers of treatment response and reverse remodeling, and 4D-flow assessment of PA hemodynamics. For each, we discuss underlying physiology, supporting data, proposed clinical thresholds, and current barriers to clinical adoption, and we compare the maturity of the supporting evidence across indices. Collectively, these indices represent a shift toward physiologically based, mechanism-specific risk stratification in right heart disease and may help identify patients at risk for adverse outcomes before conventional volumetric or functional parameters decline. However, their supporting evidence varies considerably in maturity, proposed thresholds are population- and methodology-dependent, and whether their use improves the timing of intervention or patient outcomes remains to be established in prospective studies.