Is cardiac and hepatic iron status assessed by MRI T2* associated with left ventricular function in patients with idiopathic cardiomyopathy?

Excess accumulation of iron in the heart is known to aggravate cardiac function in some cases of genetic and acquired iron overload. We investigated the possible association between cardiac function and iron content in the heart and liver, estimated non-invasively by T2 star (T2*)-weighted magnetic resonance (MR) imaging among patients with cardiomyopathy. MR images were acquired on a 3.0 T MR imaging system using an 8-channel phased-array cardiac coil. Average T2* values of the heart were estimated at regions of interest that were located on short axis mid-ventricular slices positioned at the cardiac septum. In total, 82 patients were enrolled: 48 patients with dilated cardiomyopathy (DCM), 16 patients with hypertrophic cardiomyopathy (HCM), and 18 patients without apparent cardiovascular abnormalities. Cardiac T2* values were lower in the DCM group (median 18.6 ms) than in the HCM (22.0 ms) and control (21.4 ms) groups, although hepatic T2* values did not differ significantly across the groups. Among the whole population, the highest cardiac T2* tertile (≥21.2 ms) was significantly negatively associated with a low left ventricular ejection fraction (LVEF) of <50 %, and this association retained statistical significance after adjustment for sex, age, renal function, hemoglobin and hepatic T2*. Among DCM patients, both hemoglobin and cardiac T2* were selected as parameters that were, respectively, negatively and positively, associated with LVEF (P < 0.05). DCM patients with lower cardiac T2*, and thus higher iron content, were found to have lower LVEF. The possibility that cardiac iron overload may have a role in reducing the systolic cardiac function in DCM patients who do not have systemic iron overload requires further investigation in the future.