Iron overload cardiomyopathy (IOC) refers to a secondary form of cardiomyopathy resulting from the accumulation of iron in the myocardium. It occurs mainly due to genetically determined disorders of iron metabolism (e.g. cardiomyopathy in haemochromatosis, thalassaemia 6,7) or multiple transfusions.
It been mostly described as a dilated cardiomyopathy, characterised by:
- left ventricular (LV) remodeling with chamber dilatation and
- reduced LV ejection fraction (LVEF)
In primary haemochromatosis leading to iron overload, the cardiomyopathy is classically categorised as an infiltrative cause of restrictive cardiomyopathy. While in those with secondary haemochromatosis, there may be severe diastolic LV dysfunction in the early stages of the disease, before LVEF is affected 3.
CMR-derived T2* relaxation time is currently the mainstay for the quantitative assessment of cardiac iron deposition.
Measured in a full-thickness area of interest in the interventricular septum, T2* is highly representative of global myocardial iron.
A value of 20 ms is considered to be the threshold for myocardial siderosis.
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