LEFT ATRIAL SIZE AND FUNCTION ASSESSMENT BY CARDIAC MAGNETIC RESONANCE IN THALASSEMIA MAJOR PATIENTS WITH DIFFERENT IRON OVERLOAD CONDITIONS

Objective: Background. Heart disease is still Thalassemia Major (TM) patients’ leading cause of death. Growing evidences point out atrial function and global longitudinal strain (GLS) as early hallmarks of iron cardiomyopathy. Purpose. To investigate left atrial size and function and GLS in TM patients with different iron overload status, in order to detect early myocardial iron overload (MIO) induced heart damage. Methods. 1.5T CMR classified 81 white TM patients in “MIO+” (T2* < 20ms, T1 mapping < 918ms), “discrepancy” (T2*>20ms, T1 mapping<918ms) and “MIO-” (T2* > 20ms, T1 mapping>918ms). In addition to normal structure and function, biplane measurement method at 3 time points (maximum, minimum and pre-atrial contraction) were used to calculate atrial functions (reservoir, conduit and emptying function); LV GLS from 2- and 4-chambers cines was also calculated. Results: See Table1. body surface area (1.6 ± 0.2 vs 1.6 ± 0.2, vs 1.6 ± 0.2, p = 0.5) and Hb (9.6 ± 0.6 vs 9.9 ± 0.9 vs 9.7 ± 0.8 g/L, p = 0.9) were balanced; age was smaller in MIO+ (38 ± 8 vs 39 ± 8 vs 35 ± 7y p = 0.04). No differences were observed in LV size, EF. Left atrial (LA) indexed total emptying volume was similar between groups (30 ± 13 vs 29 ± 14, vs 32 ± 14 ml/m2, p0.6), However, the contribution of passive emptying to LA total emptying was reduced in MIO+, intermediate in “discrepancy” and higher in MIO-. Conclusions: 1) In TM patients with preserved LV size and systolic function, the contribution of passive emptying to total LA emptying is reduced proportionally to the amount of iron overload, as observed in restrictive LV filling pattern. We hypothesise that iron deposition in the atria may be contributing to these pathophysiological changes.2) The % of atrial emptying due to atrial contraction observed in TM MIO- patients is higher than the published reference values in general population, suggesting that a different threshold for atrial function should be used, as for LVEF, in TM patients, accounting for hyperdynamic circulation in residual anaemia.