Myocardial Blood Flow and Innervation Measures from a Single Scan: An Appealing Concept but a Challenging Paradigm.

The importance of neuronal dysfunction in the progression of heart failure and the utility of cardiac sympathetic imaging for identifying ischemic cardiomyopathy patients who are at high risk of sudden cardiac death is well established. On the basis of the results of the ADMIRE-HF (AdreView Myocardial Imaging for Risk Evaluation in Heart Failure) multicenter trial, 123I-meta-iodobenzylguanidine (123I-MIBG) has received Food and Drug Administration approval for imaging cardiac sympathetic innervation of the heart in the United States (1,2). The results validated the independent and incremental prognostic value of delayed heart-to-mediastinum ratio of 123I-MIBG in patients with heart failure beyond left ventricular ejection fraction. Whether cardiac sympathetic imaging will also play an important role in identifying or predicting sustained ventricular tachyarrhythmias in patients with cardiomyopathy and determining those who may benefit from cardioverter-defibrillator implantation is currently under investigation (3,4).