Right-Ventricular Remodeling Mechanics: From Fiber Architecture and Constitutive Modeling to Imaging Biomarkers and Clinical Endpoints

Right‑ventricular (RV) remodeling is a decisive determinant of symptoms, decompensation, and survival across pulmonary arterial hypertension, chronic thromboembolic pulmonary hypertension, chronic lung disease, left‑heart disease with secondary pulmonary hypertension, congenital heart disease, and selected post–myocardial infarction (MI) phenotypes in which RV dysfunction emerges through infarction, ischemia, or ventriculo‑pulmonary interactions. Compared with the left ventricle (LV), RV remodeling mechanics is less often reviewed as a coherent multiscale field that links fiber architecture and extracellular matrix remodeling to constitutive parameters, imaging‑derived deformation, and clinically interpretable endpoints. This review unifies these layers with a specific aim that is useful to both cardiovascular mechanicians and medical imaging researchers: to clarify what RV mechanics quantities are measured, what are inferred, and what must be assumed. We synthesize RV geometry and microstructure, pressure–volume based coupling metrics, tissue‑scale passive and active mechanics, and the dominant constitutive modeling families used in RV finite element studies. We then map imaging observables from echocardiography and cardiac magnetic resonance (CMR) to mechanical interpretation, focusing on deformation (strain, strain‑rate), chamber performance (volumes, ejection fraction), afterload characterization, and tissue substrate proxies (late gadolinium enhancement and mapping methods). Throughout, we show how septal mechanics and pericardial constraint shape RV stress–strain relationships and can confound biomarker interpretation if omitted. We propose an implementable mechanics‑aware interpretation framework that decomposes RV remodeling into load, pump–arterial coupling, passive stiffness/substrate, and activation/coordination components, each tied to measurable quantities and model parameters. Finally, we argue that transferable “reference ranges” for RV mechanics should be expressed as physiology‑conditioned envelopes that specify loading state, acquisition protocol, and analysis software rather than as single numbers. The review concludes with a practical research agenda centered on multi‑modal datasets with synchronized pressures, transparent segmentation and region definitions, uncertainty reporting, and open modeling pipelines that enable prospective prediction of decompensation and therapy response.