The relation of glucose metabolism to left ventricular mass and function and sympathetic nervous system activity in obese subjects with metabolic syndrome

Abstract

Context: Altered cardiac structure and function have been reported in prediabetic and diabetic populations; however, the contribution of the sympathetic nervous system (SNS) to these changes has yet to be delineated. Objective: Our objective was to examine interrelationships between glucose metabolism, left ventricular mass and function, and SNS activity in obese metabolic syndrome subjects. Participants and Methods: Unmedicated impaired glucose tolerant (IGT) (n = 31) or treatmentnaive type 2 diabetic (T2D) (n = 25) subjects, matched for age (mean 58 ± 1 years), gender, body mass index (32.2 ± 0.5 kg/m2), and blood pressure, participated. They underwent echocardiography and assessments of whole-body norepinephrine kinetics, muscle sympathetic nerve activity, and insulin sensitivity by euglycemic clamp (M value). Results: T2D subjects had higher left ventricular mass index (LVMI) (93.6 ± 3.5 vs 77.2 ± 3.4 g/m2, P = .002) and Doppler-derived isovolumetric relaxation and deceleration times (both P