Myocardial Fibrosis by Cardiovascular Magnetic Resonance T1 Mapping Indicates Adverse Ventricular Interactions at the Tissue Level in Congenital Pressure and Volume Overload of the Left Ventricle

All articles of this category (opens in new window) Background: Myocardial fibrosis (MF) has been described as a risk factor for heart failure in congenital heart disease (CHD). Adverse loading conditions lead to ventricular remodeling, which is characterized by progressive expansion of the extracellular matrix with accumulation of MF. The aim of this study was to assess native T1 and myocardial extracellular volume (ECV) as noninvasive measures of diffuse MF using cardiovascular magnetic resonance (CMR) in patients with congenital pressure and/or volume overload of the left ventricle (LV). Methods: We prospectively enrolled CHD patients ( n = 20, median age 25.9 years) and compared them to healthy controls ( n = 15, 24.4 years). Patients with the following CHD diagnoses were included: coarctation of the aorta (CoA, n = 9), aortic valve stenosis (AS, n = 2), aortic valve regurgitation (AR, n = 6), and AS + AR ( n = 3). Participants underwent standardized CMR at 1.5 Tesla with modified Look-Locker Inversion recovery (MOLLI) T1 mapping to quantify native T1 and ECV of the LV and the right ventricle (RV). Results: RV ECV was significantly higher in patients than controls (median: 33 vs. 28%, p = 0.041). LV ECV was elevated above the upper limit of normal (>30%) in 31% of the patients. RV native T1 correlated with LV muscle mass ( r = 0.64, p = 0.020), while for LV native T1, correlations were seen with LV end-diastolic and end-systolic volume ( r = 0.52, p = 0.020, and r = 0.47, p = 0.035, respectively) as well as RV stroke volume ( r = −0.53, p = 0.021). Subgroup analysis revealed the highest LV and RV ECV values in patients with CoA (28 and 37%, respectively), whereby RV native T1 was significantly higher in female than in male patients ( p = 0.024). In AR patients, LV native T1 was related to regurgitation fraction ( r = 0.89, p = 0.019). LV ECV was associated with RV ECV as well as RV ejection fraction in patients with severe AR, albeit without statistical significance ( r = 0.95, p = 0.051, and r = −0.95, p = 0.051, respectively). Conclusion: Evidence of elevated LV and RV ECV, as well as correlations of RV and LV native T1 with biventricular functional parameters, indicates adverse ventricular interactions at the tissue level in patients with LV pressure and/or volume overload. Female patients with CoA may be at increased risk for developing MF as a key factor in heart failure. In AR, LV native T1 was associated with regurgitation fraction, pointing to the potential prognostic value of noncontrast MF assessment. Further research is needed to analyze the role of MF in interventricular remodeling and the utility of CMR-based tissue markers for disease monitoring and treatment planning in CHD. Publication History Article published online: 17 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany