Background -Obesity is associated with heart failure, but an effect of weight , independent of comorbidities, on cardiac structure and function is not well es tablished. We sought whether body mass index(BMI) and insulin levels were associ ated with subclinical myocardial disturbances. Methods and Results-Transthoraci c echocardiography, myocardial Doppler-derived systolic(sm) and early diastolic velocity(em), strain and strain rate imaging and tissue characterization with c yclic variation(CVIB), and calibrated integrated backscatter(cIB) were obtained in 109 overweight or obese subjects and 33 referents(BMI< 25 kg/m2). BMI correla ted with left ventricular(LV)-mass and wall thickness(P< 0.001). Severely obese subjects(BMI >35) had reduced LV systolic and diastolic function and increased myocardial reflectivity compared with referents, evidenced by lower average long -axis strain, sm, cIB, lower CVIB, and reduced em, whereas LV ejection fraction remained normal. Differences in regional or global strain, sm, and em were iden tified between the severely obese(BMI >35) and the referent patients(N< 0.001). Similar but lesser degrees of reduced function by sm, em, and basal septal str ain and increased reflectivity by cIB were present in overweight(BMI, 25 to 29.9 ) and mildly obese(BMI, 30 to 35) groups(P< 0.05). Although tissue Doppler measu res were not associated with duration of obesity, they did correlate with fastin g insulin levels and reduced exercise capacity. BMI was independently related to average LV strain(β=0.40, P=0.02), sm (β=-0.36, P=0.002), and em(β=-0.41, P< 0.001). Conclusions -Overweight subjects without overt heart disease have su bclinical changes of LV structure and function even after adjustment for mean ar terial pressure, age, gender, and LV mass. Background -Obesity is associated with heart failure, but an effect of weight, independent of comorbidities, on cardiac structure and function is not well es tablished. We sought whether body mass index (BMI) and insulin levels were associ ated with subclinical myocardial disturbances. Methods and Results-Transthoraci c echocardiography, myocardial Doppler-derived systolic (sm) and early diastolic velocity (em), strain and strain rate imaging and tissue characterization with c yclic variation (CVIB), and calibrated integrated backscatter (cIB) 109 BMI correla ted with left ventricular (LV) -mass and wall thickness (P <0.001). Severely obese subjects (BMI> 35) had reduced LV systolic and diastolic function and increased myocardial reflectivity compared with referents, evidenced by lower average long-axis strain, sm, cIB, lower CVIB, and reduced em, l or global strain, sm, and em were iden tified between severely obese (BMI> 35) and the referent patients (n <0.001). Similar but lesser degrees of reduced function by sm, em, and basal septal str ain and increased reflectivity by cIB were present in overweight (BMI, 25 to 29.9) and mildly obese (BMI, 30 to 35) groups (P <0.05). Although tissue Doppler measu res were not associated with duration of obesity, they did correlate with fastin g BMI was independently related to average LV strain (β = 0.40, P = 0.02), sm (β = -0.36, P = 0.002), and em (β = -0.41, P <0.001). Conclusions-Overweight subjects without overt heart disease have su bclinical changes of LV structure and function even after adjustment for mean ar terial pressure, age, gender, and LV mass.