The role of tissue Doppler study in the assessment of left ventricular dysfunction in obesity

The purpose of this study was to investigate the potential utility of tissue Doppler echocardiography in the assessment of left ventricular systolic and diastolic function in the obese population.

96 obese (48 male, 48 female) patients and 50 normal weight (25 male, 25 female) control subjects were enrolled. Obese patients were subgrouped into mild (25-29.9 kg/m2), moderate (30-34.9 kg/m2) and significant (> or =35 kg/m2) according to their body mass index (BMI). Left ventricular systolic and diastolic functions were evaluated by tissue Doppler imaging with conventional transthoracic echocardiography. Peak systolic velocity (Sm) of the lateral mitral annulus, the duration from electrocardiographic Q wave to Sm and early and late diastolic velocities (Em,Am) were recorded with tissue Doppler imaging.

The ejection fraction and fractional shortening values were found to be increased in the mildly and moderately obese subjects. Left ventricular diameters were increased in all of the patients in the obesity group; however, relative wall thicknesses were similar to control subjects.The peak systolic velocities of the mitral lateral annular area (Sm) were lower in moderately and significantly obese subjects compared to the control subjects. None of the study patients had systolic dysfunction by conventional echocardiographic assessment while prevalence of diastolic dysfunction was significantly higher in the obese group of which the prevalence proportionally increased with BMI. Diastolic dysfunction was also more prevalent in the subjects with abdominal obesity which was determined by waist circumference (WC).

The ejection phase indices were increased in mildly and moderately obese subjects. However, in significantly obese subjects they were similar to control subjects by conventional echocardiographic methods. Sm values of the moderately and significantly obese patients were significantly lower when measured by tissue Doppler imaging. Diastolic function was also shown to be impaired in the moderately and significantly obese subjects when measured by tissue Doppler imaging.