Metabolic syndrome and insulin resistance are associated with abnormal left ventricular diastolic function and structure independent of blood pressure and fasting plasma glucose level

Background: Abnormal left ventricular (LV) structure and diastolic function are frequently detected in a variety of heart diseases, and insulin resistance has been suggested to be associated with LV diastolic dysfunction (LVDD). The aims of this study were to determine the association between LVDD or LV structure and metabolic syndrome (MetS) or insulin resistance, and whether or not the associations are independent of age, blood pressure, and plasma glucose level. Methods: A total of 1599 subjects (1161 men and 398 women), 25-83 years of age, who underwent medical health check-ups at two institutions, were enrolled. LV diastolic function and structure were assessed by echocardiographic evaluation, including tissue Doppler imaging (TDI). Results: The subjects with MetS had significant differences in the level of parameters reflecting cardiac structure and LV diastolic function compared to those without MetS, even after adjustment for age, gender, blood pressure, and fasting plasma glucose level (P < 0.001). MetS was independently associated with an increased risk for LVDD (OR, 1.67; 95% CI, 1.18-2.37; P = 0.004). In addition, as the HOMA-IR value increased, the level of parameters reflecting cardiac structure and LVDD significantly increased and the E/A ratio significantly decreased (P < 0.001). Furthermore, the LV mass, E/A ratio, and E/E′ ratio were significantly different across the HOMA-IR quartiles, even after adjustment for other confounders. Conclusions: MetS and insulin resistance are associated with abnormal LV diastolic function and structure independent of age, gender, blood pressure, and fasting plasma glucose level.