“…With progression of cardiac dysfunction there is diminished pre-synaptic function from loss of neurons and downregulation of NET-1, likely accounting for decreased cardiac uptake (lower H/M) in advanced disease. 52 Following the initial report by Kline et al of human cardiac 123 I-mIBG imaging, Schofer et al 65 were the first to describe a potential role for 123 I-mIBG imaging in HF, finding decreased cardiac uptake in 28 patients with idiopathic dilated cardiomyopathy that correlated inversely with LVEF, but surprisingly did not relate to circulating catecholamine. Prognostic utility was first reported in a 1992 landmark study by Merlet et al of 90 patients with advanced HF (NY Heart Association (NYHA) Class II-III symptoms and LVEF \45%), finding that H/M was superior to and independent of cardiac size on chest x-ray, echocardiographic enddiastolic diameter, and LVEF in predicting survival.…”