T1 mapping and speckle tracking echocardiography for the assessment of early mechanical dysfunction in transfusion-dependent β-thalassemia with normal T2

Background A T2* ≤20 ms in cardiovascular magnetic resonance (CMR) sequences suggests the presence of iron overload cardiomyopathy in patients with transfusion-dependent β-thalassemia (TDT). However, there is still a gap in evidence regarding the independent role of T1 mapping in identifying early myocardial dysfunction. The aim of this study is to investigate the role of T1 mapping in identifying early cardiac mechanical dysfunction in TDT patients with normal T2* values. Methods About 154 consecutive TDT patients with T2* >20 ms were enrolled and stratified by reduced (≤955 ms) or normal (>955 ms) T1 mapping values. CMR T1 mapping and speckle tracking echocardiography (STE) indices were evaluated. The primary endpoint was the correlation between T1 mapping and STE indices. The secondary endpoint was the prevalence of cardiac mechanical dysfunction between patients with reduced or normal T1 mapping. Result T1 mapping showed statistically significant correlations with global longitudinal strain (GLS, r = −0.19, p = 0.01), global work index (GWI, r = 0.15, p = 0.04), global constructive work (GCW, r = 0.18, p = 0.02), and peak atrial longitudinal strain (PALS, r = 0.2, p<0.01). The prevalence of cardiac mechanical dysfunction was low, without any difference between patients with reduced or normal T1 mapping. Conclusions In TDT patients with normal T2*, T1 mapping demonstrated a weak but significant correlation with echocardiographic indices of cardiac mechanics. The prevalence of cardiac mechanical dysfunction was low without any difference between those with reduced or normal T1 mapping.