Impacts of obesity on global subclinical left cardiac function represented by CMR-derived myocardial strain, TyG index may be a predictor

Obesity is a recognized risk factor for heart failure. People with similar weights may have different metabolic health. Notably, insulin resistance is a hallmark of obesity and a feature of heart failure. We aimed to evaluate the effects of obesity and metabolic health status on subclinical left cardiac function. We also investigated whether insulin resistance (TyG index) plays a role in BMI-linked subclinical left cardiac dysfunction. The study involved 403 volunteers. Hierarchical multiple regression models were used to assess associations between obesity, metabolic health, and overall subclinical left cardiac function. Mediating analysis was used to explore the role of the TyG index in the association between BMI and left cardiac function. Finally, ROC analysis was performed to explore the predictive value of the TyG index in subclinical left cardiac dysfunction. The correlation analysis showed that metabolic unhealth increased the risk of subclinical left ventricular (LV) dysfunction; obesity was associated with an increased risk of global left cardiac dysfunction regardless of metabolic health status. The TyG index mediated 25% of the associations between BMI and Left atrial (LA) functional parameters. ROC analysis exhibited that the TyG index can be used as a predictor of LA dysfunction (AUC = 0.63), and the optimal cut-off point for the TyG index is 9.33. Even a “non-obese metabolically unhealthy” is a detrimental state of early LV function; obesity remains a major risk factor for global subclinical left cardiac dysfunction. Using the TyG index could allow early identification of individuals at high risk of subclinical left cardiac dysfunction. Registration number: ChiCTR2200057991; Date of registration: 2022-03-25. URL: http://www.chictr.org.cn/showproj.aspx?proj=162316.