Authors
1 Assistant Professor, Department of Pediatric Cardiology, Faculty of Medicine, Arak University of Medical Sciences, Arak, Iran.
2 Assistant Professor, Department of Cardiac Surgery, Faculty of Medicine, Arak University of Medical Sciences, Arak, Iran.
3 Assistant Professor, Department of Pediatric Hematology and Oncology, Faculty of Medicine, Arak University of Medical Sciences, Arak, Iran.
4 Master of Sciences in Biostatistics, Department of Biostatistics, Faculty of Medicine, Arak University of Medical Sciences, Arak, Iran.
Abstract
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.
Keywords
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