en Pediatric Hematology & Oncology Pediatric Hematology & Oncology پژوهشي Original Article Background: Atrial fibrillation (AF) is the most common arrhythmia in patients with &beta;-thalassemia major (&beta;-TM) due to cardiac iron overload. AF may be predicted by changes in P wave parameters. The aim of this study was to evaluate the correlation between P-wave parameters and atrial markers with mean serum ferritin levels measured yearly.<br> Methods: Fifty patients with &beta;-TM and 50 healthy subjects as control group were enrolled in the study. Both groups underwent electrocardiography (ECG) and echocardiography. P-wave dispersion (PWd), maximum and minimum P-wave duration (P-max and P-min) were measured. Echocardiography was performed by pulse wave Doppler of the lateral mitral valve. Annual mean serum ferritin level was calculated through monthly sampling.<br> Results: There were 22 men and 28 women with &beta;-TM (mean age: 21.4&plusmn;8.3 years). Mean serum ferritin levels were 1476.8&plusmn;919.2 ng/ml. Systolic and diastolic blood pressure were significantly different between thalassemia and control groups (P<0.002 and P<0.004, respectively). There were significant differences between BMI, PWd, P-max and P-min (P<0.0001, respectively). A cut off value of 40 msec for PWd had a sensitivity of 100% and a specificity of 90.7% in identifying mean serum ferritin levels higher than 1078 ng/ml. Mean serum ferritin level of 1024 or more was associated with sensitivity of 100% and specificity of 90.1% for inter-atrial block > 110 msec. There were correlations between mean serum ferritin level and age of the patients along with PWd, P-min and P-max (P<0.0001, respectively).<br> Conclusion: In &beta;-TM, atrial parameters in ECG were correlated with both mean serum ferritin levels measured yearly and patients&rsquo; age. We recommend that in patients with thalassemia major with mean serum ferritin levels higher than 1000 ng/ml, P wave parameters should be carefully evaluated and closely followed. Beta-Thalassemia major, Cardiac dysfunction, Arrhythmia, Serum ferritin level, P wave dispersion, Inter atrial block, Atrial fibrillation 76 81 http://ijbc.ir/browse.php?a_code=A-10-369-1&slc_lang=en&sid=1 Yazdan Ghandi fa.farokhi@gmail.com 10031947532846004332 10031947532846004332 Yes Aziz Eghbali 10031947532846004333 10031947532846004333 No Fatemeh Rafie 10031947532846004334 10031947532846004334 No