Is myocardial iron content associated with left atrial systolic function in asymptomatic hereditary hemochromatosis?

Abstract

We previously reported that left atrial (LA) systolic function is augmented in asymptomatic hereditary hemochromatosis subjects (HH) as compared to the age/gender‐matched volunteer control subjects (VC). In this study, we analyzed the relationship between elevated myocardial iron content (MIC) and LA systolic function in these subjects. All HH were NYHA functional class I and homozygous for the HFE gene C282Y mutation under standard therapy. VC did not have HFE mutations. 29 HH (ages; 56±10, 9 females) and 18 VC (ages; 55±8, 5 females) underwent LA function assessment by echocardiography and MRI‐based MIC assessment with T2*. LA ejection force (LAF) was significantly elevated in HH as to VC (14.0±8.3 vs. 9.4±4.7 kdyne, P=0.016) indicating augmented LA systolic function in HH. However, MIC did not significantly differ between the groups (27.6±7.8 msec vs. 28.6±5.5 msec, HH vs. VC, the values were in the normal range) and MIC failed to correlate with LAF or the other parameters of LA systolic function. Our findings suggest that the augmented LA function in asymptomatic HH subjects is independent from MIC and additional factors associated with HH, such as elevated oxidative stress may be responsible for this. However, this study does not address the possibility of elevated MIC to induce abnormal diastolic function in iron overload populations. (This research was supported by the intramural research program of the NHLBI, NIH.)