Left Ventricular Remodeling, Systolic Function, and Diastolic Function in Young Adults With β-Thalassemia Intermedia: A Doppler Echocardiography Study

Abstract

The aim of this study was to investigate the left ventricular (LV) remodeling and function in 24 asymptomatic young adults affected by beta-thalassemia intermedia (TI), in order to compare the obtained data with that of 80 patients affected by beta-thalassemia major (TM) and 65 healthy subjects. LV volumes and shapes, mass index, mass/volume ratio, systolic and diastolic function, stroke volume, and cardiac index were determined by two-dimensional and M-mode echocardiography. In the TM and TI groups, LV volumes, diastolic and systolic shapes were significantly different from the control subjects, but the ejection fraction was slightly reduced only in the TM group. The TI group had larger LV volumes than did the TM group (mean [+/- SD] end-diastolic volume index, 99.4 +/- 21.9 vs 82.7 +/- 21.5 mL/m(2), respectively [p < 0.005]; mean end-systolic volume index, 42.8 +/- 12.2 vs 36.1 +/- 12.9 mL/m(2), respectively [p < 0.05]). Both groups showed an increase of the LV mass index, but the mass/volume ratio did not differ from the control subjects. The systolic volume index and the cardiac index were increased in both groups, but the increase was more pronounced in the TI group. Fractional shortening (FS) and the mean velocity of circumferential shortening (mVCFc) were decreased in the TM group (FS, 33.6 +/- 5.5% vs 36.9 +/- 4.1, respectively [p < 0.001]; mVCFc, 1.06 +/- 0.18 vs 1.17 +/- 0.12 circumference per second, respectively [p < 0.0001]). The LV contractile state was depressed only in the TM group, and the preload index was normal in both. LV filling showed an increase in the total flow velocity integral due to increases in the peak E wave (E) and peak A wave (A) velocities and integrals, with an increase of the E/A ratio in the TM group and a slight decrease in the TI group. The isovolumic relaxation time was prolonged in both groups. There was no major derangement in the pulmonary venous flow. Asymptomatic young adults with TI show significant increases in LV volumes, LV mass, and cardiac index that are more pronounced than those in TM patients. LV systolic function is preserved in the TI group but is slightly depressed in the TM group due to the increase of afterload and to reduced contractility. The hemodynamic and hematologic factors involved in the etiopathogenesis of these findings are discussed, such as the treatment strategy.