Use of strain and tissue velocity imaging for early detection of regional myocardial dysfunction in patients with beta thalassemia

Iron overload contributes to cardiac dysfunction in patients with beta thalassemia (Th). Tissue velocity and strain imaging (TVI and SI) might prove useful in early detection of regional myocardial dysfunction in these patients. The aim of this study is to clarify the value of TVI and SI in early detection of regional myocardial dysfunction in thalassemia patients. This study included two age-matched groups; G1: 27 Th patients and G2: 14 normal subjects. Conventional echo-Doppler measures of LV and RV dimensions and function were obtained. TVI measures included systolic and diastolic myocardial velocities (Sm, Em, Am and Em/Am) of the basal segments of septal wall, lateral LV and RV free walls. Systolic strain values were measured in the same basal segments and included S-septal, S-LV and S-RV. Strain and TVI data were compared in the two groups. Sm and strain values were compared in the different walls (LV, RV and septum) in each group separately. S-LV was lower in G1 than G2 (20.9 +/- 6.8 vs 27.2 +/- 4.3, p < 0.001), while S-septal was higher in G1 than G2 (31.1 +/- 8.3 vs 25.1 +/- 3.8, p < 0.01). TVI measures of diastolic performance of the septal and RV walls were different in G1 compared to G2. Septal-Em was lower, septal-Am was higher and septal-Em/Am was lower in G1 compared to G2. RV-Am was higher and RV-Em/Am was lower in G1 compared to G2. Other SI and TVI measures were not significantly different in G1 from G2. Sm and strain values were lower in the lateral LV wall compared to septal wall in G1 but not in G2, while the corresponding values of the RV wall were higher than those of the septal and LV walls in both groups (G1 and G2). Thalassemia patients have regional systolic dysfunction in the lateral LV wall and regional diastolic dysfunction in the septal and RV wall. TVI and the newer modality SI are promising tools for quantitative assessment of regional myocardial function. SI seems more capable of early detection of regional myocardial dysfunction.