Alterations of left ventricular myocardial characteristics associated with obesity.
BACKGROUND
Obesity is associated with heart failure, but an effect of weight, independent of comorbidities, on cardiac structure and function is not well established. We sought whether body mass index (BMI) and insulin levels were associated with subclinical myocardial disturbances.


RESULTS
Transthoracic echocardiography, myocardial Doppler-derived systolic (sm) and early diastolic velocity (em), strain and strain rate imaging and tissue characterization with cyclic variation (CVIB), and calibrated integrated backscatter (cIB) were obtained in 109 overweight or obese subjects and 33 referents (BMI <25 kg/m2). BMI correlated 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 identified between the severely obese (BMI >35) and the referent patients (P<0.001). Similar but lesser degrees of reduced function by sm, em, and basal septal strain 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 measures were not associated with duration of obesity, they did correlate with fasting insulin levels and reduced exercise capacity. BMI was independently related to average LV strain (beta=0.40, P=0.02), sm (beta=-0.36, P=0.002), and em (beta=-0.41, P<0.001).


CONCLUSIONS
Overweight subjects without overt heart disease have subclinical changes of LV structure and function even after adjustment for mean arterial pressure, age, gender, and LV mass.
Wong
Chiew Y
CY
University of Queensland, Brisbane, Australia.
O'Moore-Sullivan
Trisha
T
Leano
Rodel
R
Byrne
Nuala
N
Beller
Elaine
E
Marwick
Thomas H
TH
D000328:Adult; D015992:Body Mass Index; D003971:Diastole; D004452:Echocardiography; D015150:Echocardiography, Doppler; D005080:Exercise Test; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D007328:Insulin / Q000097:blood; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000503:physiopathology*; D015588:Observer Variation; D013318:Stroke Volume; D013599:Systole; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology
D007328:Insulin