Abstract 12320: Left ventricular Torsional Mechanics Remains Impaired in Patients with Beta-Thalassaemia Major Despite Bone Marrow Transplantation
Background: Free iron within cardiomyocytes may damage sarcomeric proteins with potential alteration of left ventricular (LV) torsional mechanics before changes in conventional indices of LV function.
Objective: This study aimed to test the hypothesis that LV torsional mechanics are altered in patients with beta-thalassaemia major and related to myocardial iron load.
Methods: We studied a cohort of 98 subjects, comprising 44 (aged 25±7 yrs) transfusion-dependent thalassaemia patients (group I), 16 patients (aged 18±7 yrs) after bone marrow transplantation (group II), and 38 healthy control subjects (aged 23±6 yrs) (group III). Left ventricular torsion and torsional velocities were determined using speckle tracking echocardiography. Cardiac T2* magnetic resonance was performed in 39 (31 group I and 8 group II) patients to assess myocardial iron load and LV ejection fraction.
Results: Compared with controls, both group I and II patients had significantly reduced apical rotation, torsion, systolic twisting velocity, and diastolic untwisting velocity (all p<0.05). On the other hand, LV shortening fraction (p=0.47) and basal rotation (p=0.41) were similar among groups. Compared with group I, group II patients had similarly impaired LV torsion and twisting and untwisting velocities (all p>0.05). T2* in the 39 patients as a whole correlated with LV early diastolic untwisting velocity (r=0.43, p=0.009) and ejection fraction (r=0.40, p=0.013) but not with torsion or systolic twisting velocity (p>0.05).
Conclusions: Left ventricular torsional mechanics remains impaired in patients with beta-thalassaemia major despite bone marrow transplantation. In particular, the rate of LV diastolic untwisting correlated significantly with myocardial iron load.
- © 2011 by American Heart Association, Inc.