الفهرس | Only 14 pages are availabe for public view |
Abstract Regular blood transfusion in patients of thalassemia major leads to left ventricular remodeling which is a powerful risk factor for ventricular arrhythmias, congestive heart failure and sudden death. However, conventional echocardiography detects abnormalities in LV systolic function only in the advanced irreversible stages when a clear LV remodeling/hypertrophy is evident. Preclinical alterations of LV systolic function have been demonstrated in thalassemic patients with normal EF. Hence, early detection of such preclinical LV changes represents a clinical finding that would justify aggressive chelation therapy aiming at reducing cardiovascular risk. 2D STE is a new technique that enables assessment of regional myocardial deformation by assessment of strain and strain rate. In contrast to TDI, 2D STE is an angle-independent technique that may allow an accurate assessment of segmental myocardial deformation. This study was designed to evaluate LV systolic and diastolic functions in β- thalassemia patients using 2D STE based longitudinal strain and strain rate imaging and correlation with ferritin level. 75 individuals were enrolled, divided into two groups; group I (patients group): included 50 thalassemic patients. group II (control group): included 25 healthy ages and sex matched volunteers free from cardiovascular risk factors. Participants in the study were subjected to: Full history taking, thorough clinical examination and 12 lead ECG. 2D Echocardiography, M-mode and Doppler examination were performed; LV dimensions were measured including LVEDD, LVESD, IVSD, LVPWD, LVMI and left ventricular ejection fraction. Pulsed wave doppler echocardiography was performed for measuring mitral inflow velocities. Mitral annular TDI was performed in the septal and lateral mitral annuli. Strain and strain rate values were measured by 2D STE. Results of the current study showed that: Regarding conventional echocardiographic parameters: LVESD, LA, LVM, LVMI, LA/Ao and MAPSE in thalassemic patients highly significantly exceeded that of controls. Regarding the left ventricular systolic function as assessed by strain and strain rate and LV ejection fraction: No significant difference between the studied groups regarding LV ejection fraction. The study showed subtle or subclinical impairment of LV systolic function in thalassemic group as evidenced by highly significant reduction of LV systolic longitudinal strain in patient group. Moreover, significant reduction of LV strain was found in thalassemic patients. 106 Also, there was significant reduction of systolic strain rate values in thalassemic patients compared with controls which confirms subtle impairment of LV systolic function. It was noted that, the systolic impairment in thalassemic patients detected by strain and strain rate occurs earlier than impairment of ejection fraction that results from changes in stroke volume and systolic pump performance. Regarding the left ventricular diastolic function as measured by strain rate and TDI: The findings of this study indicated that significant LV diastolic impairment was common in thalassemic group than control group, as shown by significant difference of E/A ratio, and changes in TDI derived indices namely E/e` ratio. Regarding serum ferritin level: The current study showed that serum ferritin level was higher in thalassemic patients than controls and is negatively related to LVESD, LVEDD, global LV systolic strain and global LV late diastolic strain rate but positively related to LVMI. Cutoff point of serum ferritin at which LV diastolic dysfunction starts to occur is 3000 micrograms/l. Cutoff point of serum ferritin at which LV systolic dysfunction starts to occur is 4100 micrograms/l. |