P-Wave and QT Dispersion in Children With βeta-Thalassemia

Aim: This study aimed at assessing P-wave and QT interval dispersion in children with β-thalassemia and to correlate them with various laboratory and echocardiographic data.

Methodology: Subjects comprised of 30 children with β-thalassemia major as the patient group. 30 healthy children matched for age and sex served as the control group. All patients were evaluated clinically as well as by echocardiography and 12 leads ECG. The type of study is prospective case control study.

Results: There was a statistically significant increase of Interventricular Septal end diastole (IVSd), Interventricular Septal end systole (IVSs), Left Ventricular Internal Diameter end diastole (LVIDd), Left Ventricular Internal Diameter end systole (LVIDs) and Left Ventricular Posterior Wall end diastole (LVPWd) in patients as compared to controls (Mean ±SD = 0.950±0.166, 0.863±0.103, 3.983±0.456, 2.947±0.535a nd 0.797±0.165 respectively) (P < 0.05). Moreover, there were a significant increase of LV mass (Mean ±SD = 107.267±26.736, P= 0.002) and LV mass index of the studied patients (Mean ±SD = 106.900±22.651, P = 0.005) compared to the controls. There were significant decrease of ejection fraction (EF%)( Mean ±SD = 60.373 ± 8.088, P = 0.032)and fractional shortening (FS%) (Mean ±SD = 29.495 ± 4.171, P = 0.026) of the studied patients compared to control group. Both P wave dispersion (PWd) (Mean ±SD = 33.667 ± 13.767, P = 0.029) and QT dispersion (QTd) (Mean ±SD = 53.000 ± 18.411, P = 0.001) were significantly higher in patients compared to controls. There was a significant positive correlation between PWd and serum ferritin (r =0.551, P-value= 0.002), LVIDd (r =0.406, P-value= 0.026), LVPWd (r =0.461, P-value= 0.010), LV mass (r =0.412, P-value= 0.024), and LV mass index(r = 0.379, P-value= 0.039). While, there were a significant positive correlations between QTd and serum ferritin (r =0.654, P-value <0.001), LVIDd (r = 0.388, P-value = 0.034), LV mass (r = 0.454, P-value = 0.012) and LV mass index (r = 0.456, P-value = 0.011).

Conclusion: P wave dispersion and QT dispersion were prolonged in children with β-thalassemia major denoting cardiac autonomic dysfunction with homogeneity disorders of atrial conduction and ventricular repolarization in these patients.