Regular blood transfusions for children with beta thalassemia major (β- TM) results in iron overload cardiomyopathy/cardiac failure. Mortality in these children is most often because of heart failure. We compared Tissue Doppler Imaging (TDI) and conventional pulse wave Doppler (PWD) indices in evaluating diastolic function in chronically transfused β-TM children and correlated the Doppler indices with mean serum ferritin levels. This was a prospective cross-sectional study conducted at tertiary teaching hospital. β-TM children aged 3 to 18 years were enrolled as per inclusion criteria. PWD parameters at the mitral inflow (E, A, E/A and DT) and TDI parameters at the medial mitral annulus (E'and E/E') were used for estimation of diastolic dysfunction. Of the 66 children with thalassemia, the mean age was 10.2±3.77yrs and 60.6% were boys. The E/E' ratio estimated diastolic dysfunction (34/66, 51.5%) greater than four times that assessed by E/A ratio indices (8/66, 12.1%) in the subjects. Association of serum ferritin levels with E/E' ratio by chi square test was significant statistically (P=0.027), however was not significant with E/A ratio. By Mann Whitney test, the median serum ferritin levels (ng/ml) were higher [4034.50, (IQR-2084-5340.25) in those with diastolic dysfunction (abnormal E/E'), when compared to those with normal E/E'[2037.50(1510.75- 3572.25)], with their difference being significant (p=0.011), however serum ferritin levels were not significant with E/A ratio and DT. E/E' parameter had a sensitivity and specificity of 76.5% and 53.1% respectively at a mean serum ferritin cutoff level of 2076 ng/mL by ROC analysis. In conclusion, TDI is a more reliable modality for diagnosing early diastolic dysfunction when compared to PWD. Threshold level of serum ferritin greater than 2076 ng/mL is associated with increased incidence of diastolic dysfunction.

Keywords: beta thalassemia, child, diastole, ferritin, iron overload