Comparison of myocardial performance index and right ventricular myocardial acceleration during isovolumic contraction in detection of right ventricular dysfunction in obese patients

OBJECTIVE
Although obesity is a risk factor for heart failure, studies analyzing the effect of obesity on heart functions have primarily examined the left side of the heart. This study is an analysis of the effect of the severity of obesity on right heart functions and a comparison of the sensitivity and specificity of different echocardiographic modalities in the detection of right heart dysfunction.

METHODS
A total of 116 subjects were included and divided into 4 age- and sex-matched groups according to body mass index (BMI) values. Right heart functions were evaluated with transthoracic echocardiography.

RESULTS
The right atrium (RA) diameter was significantly larger in the obese group (OBG) and the morbidly obese group (MOG); the right ventricle (RV) diameter was significantly larger only in the MOG. In the overweight group, the OBG, and the MOG, the RV isovolumic acceleration (R-IVA) was significantly lower (p=0.020; p<0.001; p<0.001, respectively) and the myocardial performance index (MPI)
value was significantly higher (p=0.015; p<0.001; p<0.001, respectively). There was a strong positive correlation between the MPI and the BMI (r=0.833, p<0.001), and a moderate negative correlation between the R-IVA and the BMI (r=-0.547, p<0.001). A cut-off value of 30.45 kg/m2 was associated with 93.3% sensitivity and 94.3% specificity in the prediction of RV systolic dysfunction defined by the MPI. A cut-off value of 30.50 kg/m2 was associated with 76.7% sensitivity and 72.3% specificity in the prediction of RV systolic dysfunction defined by the R-IVA.

CONCLUSION
Obesity significantly affected right heart function and there was a significant correlation between the degree of obesity and right heart functional deterioration. The BMI could be used to predict RV systolic dysfunction.