Background: Ecocardiography is currently the gold standard imaging method for the diagnosis of most congenital and acquired cardiopathies and for the evaluation of myocardial function and cardiac chamber size and overload. Ecocardiographic measures of left ventricular and right ventricular structure and function are used to define ventricular function and guide medical decisions.The objective of this study is to assess the reproducibility of echocardiographic cardiac chamber measurements in infants in utero exposed to Zika virus.
Methods: Masked cross-sectional diagnostic study with two independent measurements of cardiac chamber dimensions using echocardiography. We studied 50 infants with in utero exposure to Zika virus ranging from 30 to 270 days old of the outpatient clinic of a national reference center for maternal and child health, Rio de Janeiro, Brazil.The analysis included the measurements of the aortic root, left atrium, end diastolic left ventricle, systolic left ventricule, left ventricular ejection fraction, ventricular end diastolic septal thickness, end diastolic thickness of the left ventricular posterior wall and right ventricule. Bland-Altman plots were used to explore differences. Agreement according to intraclass correlation coefficients (ICC) was interpreted as follows: excellent≥0.75, fair to good 0.4≤ICC<0.75, and poor with ICC<0.4.
Results: All parameters had mean difference of diameters near to zero, excluding left ventricule ejection fraction. Ventricular end-diastolic septal thickness and end-diastolic-thickness of the left ventricular posterior wall showed few unique mean values. Reproducibility was excellent for the aortic root and end diastolic left ventricule (ICC=0.86 and 0.91, respectively), fair/good to poor for other parameters and the left ventricule ejection fraction, ventricular end diastolic septal thickness and the end diastolic thickness of the left ventricular posterior wall showed the lowest reproducibility (ICC=0.46,0.37,0.53, respectively).
Conclusions: The minor divergences did not affect the echocardiography results in our sample. However, caution is required to interpret results of measures with low reproducibility.