Effect of Average Annual Mean Serum Ferritin Levels on QTc Interval and QTc Dispersion in Beta-Thalassemia Major

Background there is evidence indicating impaired cardiomyocytic contractility, delayed electrical conduction and increased electrophysiological heterogeneities due to iron toxicity in beta-thalassemia major patients. in the present study, we compared the electrocardiographic and echocardiographic features of beta-thalassemia major patients with a healthy control group. materials and methods the average annual serum ferritin levels of fifty beta-thalassemia major patients were assessed. for each patient, corrected qt (qtc) intervals and qtc dispersions (qtcd) were calculated and v1s and v5r were measured. all subjects underwent two-dimensional m-mode echocardiography and doppler study and were compared with 50 healthy subjects as a control group. results qtc interval and dispersion were significantly higher in beta-thalassemia major patients (p= 0.001). the mean v5r (20.04 ± 4.34 vs. 17.14 ± 2.55 mm) and v1s (10.24 ± 2.62 vs. 7.83 ± 0.38 mm) showed considerably higher mean values in patients in comparison with control group. peak mitral inflow velocity at early diastole and early to late ratio in the case- group was markedly higher (p<0.001), whereas, early deceleration time (p=0.01) and isovolumic relaxation time (ivrt) (p=0.001), were meaningfully lower than the control group. there was positive correlation between age and qtc (r= 0.831, p=0.001) and qtc dispersion (r= 0.710, p=0.001) and negative correlation between serum level of ferritin and v5r (r= -0.271, p= 0.05). conclusion measurement of the qtc interval and dispersion can be used for early detection of cardiac involvement, especially in asymptomatic beta-thalassemia patients with ferritin levels higher than 2,500 ng/dl.