Quantitative MRI Values for Atrial and Ventricular Parameters in Altitude-Dwelling Youth.

Background: The hypoxic environment on the Qinghai Plateau significantly exacerbates myocardial remodeling, with sex/ethnicity-specific variations in cardiac parameters among local youth. Current cardiac MRI reference values lack data from physiologically adapted populations on this plateau.

Purpose: To establish sex- and ethnicity-specific normative reference values for cardiac structure and function in native Qinghai Plateau young adults and to analyze their correlations.

Study type: Prospective.

Subjects: 101 healthy young volunteers (15-24 years) residing on the Qinghai Plateau, including 44 males and 57 females; 37 Han people (20 males and 17 females), 20 Tibetan people (3 males and 17 females); the remaining 44 people are from the Hui, Tu, Salar, and Mongolian ethnic groups.

Field strength/sequence: Steady state free precession cine sequence at 3.0 T.

Assessment: Circle CVI42 software was used to quantify cardiac chamber structural and functional parameters from cine images. All parameters were normalized to body surface area (BSA).

Statistical tests: Sex- and ethnicity-specific reference ranges were defined as mean ± 1.96 SD. Sex/ethnicity group comparisons were assessed with independent samples t-tests. Correlations between parameters were visualized through correlation heatmaps. A p value < 0.05 was considered significant.

Results: Compared to females, males exhibited significantly larger cardiac parameters, including left atrial (LA) and right atrial (RA) diameters (p < 0.05). In the four-chamber view, the left atrial area was larger in males (end-systolic 1688.57 ± 326.75 vs. 1562.68 ± 238.01 mm², p < 0.05; end-diastolic 1178.18 ± 268.09 vs. 1018.81 ± 201.04 mm², p < 0.05). The right atrial area was larger in males (end-systolic 1835.86 ± 360.73 vs. 1567.98 ± 276.84 mm², p < 0.05; end-diastolic 1387.75 ± 319.39 vs. 1106.09 ± 228.78 mm², p < 0.05). Males also had significantly higher left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), stroke volume (LVSV), cardiac output (LVCO), and left ventricular mass (LVM) (p < 0.05). After body surface area (BSA) normalization, males still had higher LVEDVi and LVESVi, while no significant difference was found in left ventricular ejection fraction (LVEF) (p = 0.334). Regarding ethnicity, there were no significant differences between Han and Tibetan participants in left ventricular volumes or systolic function (p > 0.05), but Han individuals had significantly higher left ventricular mass and mass index (LVM 93.37 ± 15.82 vs. 63.72 ± 11.97 g, p < 0.05; LVMI 44.60 ± 7.71 vs. 38.89 ± 4.72 g/m², p < 0.05). Correlation heatmaps showed significant positive correlations (p < 0.05) between body size (height, weight, BSA, BMI) and heart parameters. Left atrial 4-chamber end-diastolic area (LA Area 4ch D) was positively correlated with height (R = 0.66, moderate, p < 0.05), weight (R = 0.66, moderate, p < 0.05), BSA (R = 0.65, moderate, p < 0.05), and BMI (R = 0.62, moderate, p < 0.05). Right atrial 4-chamber end-diastolic area (RA Area 4ch D) showed similar correlations (R = 0.65-0.68, moderate, p < 0.05). LVEF was positively correlated with height (R = 0.45, weak, p < 0.05) and weight (R = 0.51, moderate, p < 0.05). Left ventricular mass (LVM) strongly correlated with BMI (R = 0.70, moderate, p < 0.05).

Conclusion: The results showed that plateau environment, gender differences, and ethnic differences are all influencing factors of atrioventricular parameters and emphasized the strong correlation between physical parameters and cardiac structure.

Stages of technical efficacy: Stage 1.

Evidence level: Evidence Level 1.