Purpose: The Cardiovascular Magnetic Resonance by the multislice T2* technique allows to detect different patterns of myocardial iron overload (MIO). The analysis of cine images allows the quantification of the left ventricular global function index (LVGFI). A LVGFI<37% was shown to be strongly predictive of cardiovascular events.

We verified the association between different patterns of MIO and the LVGFI vs the LV ejection fraction (EF) in thalassemia major (TM) patients.

Methods: We considered 812 TM patients (391 M, 30.4±8.6 yrs) enrolled in the MIOT network. The T2* value in all the 16 cardiac segments was evaluated. LVGFI and LVEF were quantified by SSFP cine images.

Results: We identified 4 groups of patients: 138 with homogeneous MIO (all segments with T2*<20 ms), 97 with heterogeneous MIO (some segments with T2*<20 ms, others with T2*≥20 ms) and significant global heart iron (global heart T2*<20 ms), 238 with heterogeneous MIO and no significant global heart iron, and 339 with no MIO (all segments with T2*≥20 ms).

The mean LVFGI was significantly different among the 4 groups (Fig. 1).

Compared to the group with no MIO, all the other 3 groups were significantly more likely to have a LVGFI<37%. Only the groups with homogeneous MIO and with heterogeneous MIO and significant global heart iron had a significant higher risk to have LV dysfunction. The association between different patterns of MIO with a LVGFI<37% was stronger than the association with LV dysfunction (Fig. 1).

Conclusions: LVGFI is a functional parameter integrating structural as well as mechanical behaviour more stronly associated to different patterns of MIO than the LVEF. Thus, a LVGFI<37% could better identify a significant higher risk of adverse cardiovascular events beyond heart failure in iron loaded patients.