123I-mIBG (MIBG) cardiac scintigraphy can be used to assess cardiac sympathetic activity and predicts prognosis in patients with heart failure. The results of prognostic studies were validated in the AdreView Myocardial Imaging for Risk Evaluation in Heart Failure (ADMIRE-HF) trial, which was a large multi-centre prospective international study of 961 patients with NYHA Class II - III Heart Failure and LV ejection fraction > 35%2. This landmark study used planar imaging for calculation of the heart-to-mediastinal ratio (H/M) as a quantitative analysis of global uptake. The H/M on 4 hour delayed planar imaging was predictive of heart failure progression, arrhythmic events and cardiac death and provided incremental value to B-type natriuretic peptide and left ventricular (LV) ejection fraction.