To assess the effects of obesity on right ventricular (RV) characteristics and function.

To study the effect of obesity alone, all participants underwent polysomnography to exclude sleep apnea. We included nineteen healthy obese subjects (BMI>30kg/m²) and 19 healthy controls (BMI<25kg/m²). All included subjects had no evidence of hypertension, diabetes mellitus or ischemic heart disease. The 2 groups had similar mean ages, mean blood pressures and glucose levels. We used standard echocardiography and tissue Doppler imaging.

RV diastolic diameter, RV ejection fraction, the Tei index and pulmonary arterial pressure were similar in both groups. The tricuspid annulus systolic velocities obtained at the basal RV free wall were significantly decreased in obese subjects (7.6±2.1cm/s vs. 13.6±2.3cm/s, p<0.01) reflecting the better sensitivity of tissue Doppler to identify subclinical RV systolic dysfunction. Also tricuspid annulus early diastolic velocities were markedly reduced in obese subjects (−7.0±1.8cm/s vs. −11.1±1.9cm/s, p<0.01) with lower ration of early to late diastolic velocities reflecting impaired relaxation of the RV in obesity.

Our data show the presence of subclinical RV dysfunction in obese subjects that was not related to other comorbidities such as sleep apnea. Tissue Doppler imaging is a useful tool to demonstrate RV abnormalities.