Background Despite the substantial overlap of obesity and metabolic disease, there is hetereogeneity with respect to cardiovascular risk. We sought to investigate preclinical differences in systolic and diastolic function in obesity, and specifically compare obese individuals with and without metabolic syndrome (MS). Methods and Results Obese individuals without cardiac disease with (OB/MS+, n=124) and without MS (OB/MS−, n=37) were compared to non-obese controls (n=29). Diastolic function was assessed by transmitral and tissue Doppler. Global longitudinal strain (LS) and time-based dyssynchrony were assessed by speckle tracking. Both Ob/MS− and OB/MS+ groups had similar ejection fraction but worse systolic mechanics as assessed by LS and dyssynchrony compared with non-obese controls. Specifically, OB/MS− had 2.5% lower LS (s.e. 0.7%, P=0.001 in multivariable-adjusted analyses) and 10.8 ms greater dyssynchrony (s.e. 3.3, P=0.002), and OB/MS+ had 1.0% lower LS (s.e. 0.3%, P<0.001) and 7.8 ms greater dyssynchrony (s.e. 1.5, P<0.001) compared with controls. Obesity was associated with impaired diastolic function regardless of MS status, as evidenced by greater left atrial diameter and left ventricular mass, though diastolic dysfunction was more pronounced in OB/MS+ compared with OB/MS− individuals. Conclusions Obesity is associated with subclinical differences in both systolic and diastolic function regardless of the presence or absence of MS, although MS appears to be associated with worse diastolic dysfunction. Compared to controls, ‘metabolically healthy’ obese had lower LS, greater dyssynchrony, and early diastolic dysfunction, supporting the notion that obesity per se may have adverse cardiovascular effects regardless of metabolic disease.

Objective Metabolic syndrome (MetS) can lead to myocardial fibrosis, diastolic dysfunction and eventual heart failure. We evaluated alterations in myocardial microstructure in people with MetS using a novel algorithm to characterize ultrasonic signal intensity variation. Methods Among 254 participants without existing cardiovascular disease (mean age 42 ± 11 years, 75% women), there were 162 with MetS, 47 with obesity without MetS, and 45 non-obese controls. Standard echocardiography was performed, and a novel validated computational algorithm was used to investigate myocardial microstructure based on sonographic signal intensity and distribution. We examined the signal intensity coefficient (SIC, left ventricular microstructure). Results The SIC was significantly higher in people with MetS compared with people with (P<0.001) and without obesity (P=0.04), even after adjustment for age, sex, body mass index, hypertension, diabetes mellitus and triglyceride to HDL cholesterol (TG/HDL) ratio (P<0.05 for all). Clinical correlates of SIC included TG concentrations (r=0.21, P=0.0007) and the TG/HDL ratio (r=0.2, P=0.001). Conclusions Our findings suggest that preclinical MetS and dyslipidemia in particular, are associated with altered myocardial signal intensity variation. Future studies are needed to determine whether the SIC may help detect subclinical disease in people with metabolic disease, with the ultimate goal of targeting preventive efforts.

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