ABSTRACT

Cardiac involvement in thalassemia major (TM) is mainly characterized by left ventricular dysfunction caused by iron overload. Cardiovascular magnetic resonance imaging (MRI) including myocardial T2* measurement is becoming increasingly popular for quantitatively evaluating myocardial iron overload. The aim of this study was to evaluate the relationship between the myocardial T2* value and left ventricular functional parameters and to examine the associations between the degree of cardiac iron load and various clinical parameters.

A retrospective analysis of 47 patients (25 males and 22 females; mean age, 23.0±5.4 years) with TM was performed. Myocardial iron load was assessed by T2* measurements, and volumetric functions were analyzed using the steady state free precession sequence.

In patients with myocardial iron deposition (T2* <20 ms), the mean left ventricular ejection fraction (LVEF) was 64.73±4.94%. The LVEF of patients with myocardial siderosis was significantly lower than that of patients without myocardial siderosis (r=0.35, P = 0.014). Inverse and significant correlations between both the left ventricular (LV) end-systolic volume index and the LV end-diastolic volume index and the myocardial T2* value (r=-0.32, P = 0.027 and r=-0.29, P = 0.046, respectively) were observed. There was an inverse correlation between the myocardial T2* value and the liver iron concentration (r=-0.31, P = 0.037). Cardiac T2* was not associated with serum ferritin levels, pre-transfusion hemoglobin levels or the annual red cell consumption rate.

Myocardial iron load assessed by cardiac MRI (T2*) is associated with deterioration in left ventricular function. Thalassemia major patients with myocardial siderosis may have LVEF values within normal limits, but this result must be interpreted cautiously.

Keywords: magnetic resonance imaging, iron overload, left ventricle