Right heart flow hemodynamic assessment using 4D flow CMR: a systematic review

Right heart dysfunction increases morbidity and mortality in cardiovascular diseases. Four-dimensional flow cardiovascular magnetic resonance (4D flow CMR) imaging evaluates detailed right heart physiology, including vorticity, flow dynamics, kinetic energy (KE) and energy loss (EL). This systematic review synthesized literature using 4D flow CMR to assess right atrial (RA) and right ventricular (RV) hemodynamics in health and disease. A systematic search of the Scopus database (up to March 2025) identified observational studies investigating 4D flow CMR of right heart function in adults. Data on RA flow dynamics, RV flow components, KE, EL, and hemodynamic parameters were narratively synthesized. Quality assessment used the AXIS tool From 240 identified articles, 17 studies (894 participants) met eligibility criteria, including healthy individuals and patients with pulmonary hypertension (PH). RA flow dynamics, described in five studies, were characterized by a dominant vortex in health, interrupted with disease. RV flow components consistently showed a decline in direct flow and increased residual volume with disease. Atrial and ventricular KE assessments revealed age, sex, and disease-specific alterations, with rotational flow appearing to conserve right atrial KE. Increased EL was noted in PH. 4D flow CMR is a powerful tool for assessing novel right heart hemodynamic parameters. Quantifying flow patterns, components, and energetics provides a comprehensive overview of right heart function, promising to improve the diagnosis, management, and prognostic stratification of right heart diseases.