الفهرس 
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Abstract
Beta thalassaemias are a group of hereditary diseases caused by more than 200 mutations of human globin gene leading to low or abscent production of adult β globin chain and an excess of α globin chain causing ineffective erythropoiesis and lower or absent production of adult haemoglobin (HbA). The conventional treatment for these patients is based on regular blood transfusion and iron chelation therapy. Despite the progress in chelation therapy, heart failure is still the main cause of death in patients with beta thalassaemia major. Haemochromatosis alone or in combination immunogenic factors is the main pathogenic mechanism of heart failure development, usually expressed as either left ventricular (LV) systolic or diastolic dysfunction.Brain natriuretic peptide (BNP) is a hormone with natriuretic and vasodilator properties. It is synthesized by cardiomyocytes in response to elevated ventricular wall stress or ischemia. There are two main types of BNP that are available for testing. The first is B-type Natriuretic Peptide (BNP) which is a hormone secreted in the ventricular myocardium during periods of increased ventricular stretch and wall tension. Once secreted, the BNP precursor is split into the biologically active peptide and the second type of BNP, the more stable, amino-terminal prohormone fragment (N-BNP or NT proBNP) .This work aimed to examine the role of B-type natriuretic peptide (BNP) in the diagnosis of left ventricular dysfunction in comparison with echocardiographic Doppler indeces in asymptomatic B-thalassaemia major patients.In order to do this, we examined twenty five thalassaemic patients (14 males and 11 females) and ten apparently healthy individuals (5 males and 5 females) with matched gender and age with thalassaemic patients. Thalassaemic patients were further subdivided into 2 groups according to the echocardiographic presence or absence of diastolic dysfunction.All individuals were subjected to detailed history taking, full clinical examination, echocardiography, Tissue Doppler and laboratory investigations in the form of complete blood count, serum iron and ferritin and serum BNP levels.Our results showed that:1. While Hb levels and RBCs count were significantly reduced, Serum iron and ferritin levels were significantly elevated in thalassaemic patients compared to the control group.2. Echocardiographic and Doppler findings showed a significant differnce in the presence of diastolic dysfunction in thalassaemic patients compared to the control group.3. Serum BNP levels show a high significant elevation in thalassaemic patients compared to the control group, also there was a highly significant elevation in BNP levels in thalassaemic patients with diastolic dysfunction compared to those without diastolic dysfunction.4. There was a significant positive correlation between serum BNP levels and serum ferritin as well as echocardiographic findings of diastolic dysfunction in thalassaemic patients.5. Receiver operating characteristic (ROC) graph revealed that the best cut off level of serum BNP to detect diastolic dysfunction was 28.5 ng/ml with a diagnostic sensitivity of 100%, specificity of 81.9% and an area under the curve of 0.86.