A study on the correlation between cardiac magnetic resonance characteristics and myocardial fibrosis in overweight and obese individuals

BACKGROUND: Overweight and obesity are major risk factors for adverse cardiovascular outcomes. Cardiac magnetic resonance (CMR) can detect subclinical cardiac dysfunction through myocardial strain and quantify epicardial adipose tissue volume (EATV). This study aimed to investigate the differences in cardiac structure, function, myocardial strain, and EATV among individuals with normal weight, overweight, and obesity using CMR, and to evaluate their value for myocardial fibrosis (LGE positivity). METHODS: In this study, 192 subjects undergoing CMR were classified into control (n = 77), overweight (n = 37), and obesity (n = 78) groups based on body mass index (BMI). CMR-derived parameters included cardiac function, left ventricular global/segment strain (radial, circumferential, longitudinal), left atrial strain, EATV, and late gadolinium enhancement (LGE). Differences among groups were compared. Spearman correlation analyzed relationships between BMI, EATV, and strain parameters. Logistic regression and ROC curve analyses assessed factors independently associated with LGE positivity. RESULTS: Compared to the control group, the overweight and obesity groups showed significantly increased left ventricular volumes, mass, and EATV, but decreased left ventricular ejection fraction (LVEF), global longitudinal strain (GLS), and left atrial reservoir strain (εs), with the most pronounced changes in the obesity group. EATV was highly correlated with BMI (r = 0.72). Both BMI and EATV showed low-to-moderate inverse correlations with impaired myocardial strain parameters (|r| = 0.22-0.31). Multivariate logistic regression identified higher BMI (OR = 1.22, 95% CI:1.07-1.40), larger EATV (OR = 1.03, 95% CI:1.01-1.04), and lower left ventricular apical segment radial strain (A-PRS) (OR = 0.93, 95% CI:0.87-0.98) as factors independently associated with LGE positivity. CONCLUSIONS: Overweight and obesity are associated with adverse cardiac remodeling, subclinical systolic dysfunction, impaired myocardial strain, and increased EATV. BMI, EATV, and A-PRS are factors independently associated with myocardial fibrosis. These findings underscore the presence of early cardiac alterations in the overweight stage, highlighting the need for early cardiovascular risk assessment in this population.