Relation between Cardiac T2∗ Values and Electrocardiographic Parameters in Children with Transfusion-dependent Thalassemia

Abstract

Background/Objectives:Cardiac T2∗ magnetic resonance imaging (MRI) is the gold standard to determine myocardial iron overload. As availability of Cardiac T2∗ is not uniform across developing nations, our strategy was to identify a more accessible and cost effective tool to assess myocardial iron accumulation. As children with transfusion-dependent thalassemia also experience various electrocardiographic abnormalities, we performed electrocardiography (ECG) as well as Cardiac T2∗ MRI on all children registered in our thalassemia unit.Materials and Methods:Forty-eight transfusion-dependent thalassemia children with transfusion burden ≥12 times/y (6 to 19 y) in the Thalassemia Unit of the Division of Hematology Oncology, Department of Pediatrics were enrolled. Patients were divided into 3 groups based on severity of T2∗ value, that is group I (T2∗<10), group II (T2∗ 10 to 20), group III (T2∗>20). A T2∗ value >20 was taken as normal. ECG and serum ferritin was also performed on the day of MRI.Results:Among the various ECG parameters, QRS duration, and QTc interval were significantly increased if cardiac iron overload was high with a P-value of 0.036 and 0.000, respectively. Also, high serum ferritin predicted a decline in T2∗ value with a P-value of 0.001. QT interval and QTc interval significantly correlated inversely with T2∗ (P=0.042, r=-0.295 and P=0.002, r=-0.446, respectively) but not QRS duration (P=0.05, r=-0.282). Serum ferritin also was found to have a significant inverse correlation with T2∗ value (P=0.000, r=-0.497).Conclusions:Abnormalities on ECG, that is prolongation of QRS duration, QT interval, and QTc interval were significantly associated with cardiac iron overload, that is decrease in the value of Cardiac T2∗ in our study. © 2020 Lippincott Williams and Wilkins. All rights reserved.