Quantification of Left Atrial Strain in patients with idiopathic inflammatory myopathy Using Cardiovascular Magnetic Resonance Feature Tracking

Background Left atrial (LA) dysfunction is involved in idiopathic inflammatory myopathy (IIM). Multiparametric cardiovascular magnetic resonance (CMR) strain imaging is a feasible and reproducible tool for examining global and regional LA functions, as well as left ventricular (LV) function in IIM patients. OBJECTIVES To evaluate the feasibility and reproducibility of LA strain occurrence and strain rate for LA function assessment using CMR in IIM cases. METHODS A total of 36 IIM and 42 healthy control cases were included. Baseline ventricular function was comparatively assessed in both groups. LA strain occurrence and strain rate were examined by cine cardiac MRI utilizing an in-house semi-automated technique. LA global function indexes were quantitated, including reservoir, conduit, and booster pump functions. RESULTS A total of 78 participants were enrolled in this study. There was no significant difference in left/right ventricular routine functions between IIM patients and control individuals (p>0.05),the same results (p>0.05) also happened between patients with high hs-cTnI and normal. However, Left ventricular mass index had significant difference (p1 = 0.003,p2<0.01). Compared with IIM patients and control individuals, only total strain (εs) (p4 = 0.046) and passive strain (εe) (p4 = 0.002) showed significant difference. And in cases with high hs-cTnI and normal hs-cTnI, there are differences for εs (p3 = 0.012), εe (p4 = 0.047). The strongest association was found between εe and LVEF (r=0.581, p<0.01). Conclusions IIM cases have altered LA reservoir and conduit functions, and LA strain could reflect LA function.