Apical-Predominant Myocardial Fibrosis in Hypertensive Heart Disease Revealed by CMR Feature Tracking and T1 Mapping

Objective: To evaluate the utility of cardiac magnetic resonance feature tracking (CMR-FT) and T1 mapping in quantifying myocardial injury in early hypertensive heart disease, focusing on segmental parameter differences. Methods: A total of 156 hypertensive patients were enrolled and divided into a left ventricular hypertrophy (LVH) group (n=63) and a non-hypertrophy (Non-LVH) group (n=93) based on the left ventricular mass index (LVMI). All patients underwent CMR examination. Left ventricular function, myocardial strain, global and segmental native T1 values, and extracellular volume (ECV) were obtained using post-processing software. Parameters were compared between the two groups, with special attention to differences among myocardial segments to identify regional characteristics of fibrosis distribution. Results: Compared with the Non-LVH group, the LVH group showed significantly lower absolute values of global longitudinal strain (GLS; median: − 10.80% vs − 15.75%), global circumferential strain (GCS), and global radial strain (GRS) (all P < 0.05), while global native T1 (median: 1080 ms vs 1036 ms) and ECV (median: 29.8% vs 27.0%) were significantly elevated (P < 0.05). Notably, myocardial fibrosis exhibited an apical-predominant distribution pattern, with the most significant parameter differences observed in the apical segments. For instance, in the LVH group, ECV in the apical septal segment (segment 14) was significantly higher [33.50% (30.40, 36.15) vs 26.70% (26.70, 27.90) in Non-LVH, P=0.001], and native T1 in the apical anterior segment (segment 13) was elevated [1105.65 ± 72.31 ms vs 1039.80 ± 47.77 ms, P=0.006], suggesting a possible apical-predominant pattern of myocardial fibrosis.These changes correlated with high diagnostic accuracy for LVH: GLS showed the highest AUC (0.91) in ROC analysis. In the LVH group, global ECV positively correlated with native T1 and LGE positivity, and negatively with GCS and GLS (P < 0.05). Conclusion: CMR-FT and T1 Mapping techniques can effectively and quantitatively assess myocardial injury and fibrosis in hypertensive patients. Global longitudinal strain (GLS) is a sensitive parameter for diagnosing left ventricular hypertrophy (LVH), and myocardial fibrosis in patients with hypertension-induced LVH exhibits an apical-predominant distribution pattern.This spatial pattern, if validated prospectively, could serve as a potential imaging biomarker for monitoring in hypertensive patients. Keywords: cardiac magnetic resonance feature tracking, myocardial strain, hypertension, left ventricular hypertrophy, LVH, T1 mapping, extracellular volume, ECV