Prognostic value of MIBG imaging in idiopathic dilated cardiomyopathy

Alterations of cardiac sympathetic innervation are likely to contribute to fatal outcomes in patients with heart failure. These alterations can be eva luated noninvasively by I-123-metaiodobenzylguanidine (MIBG) imaging. Metho ds: The hypothesis that impaired cardiac sympathetic innervation, as assess ed using MIBG imaging, is related to adverse outcomes was tested in 112 pat ients with heart failure resulting from idiopathic cardiomyopathy. Main inc lusion criteria were New York Heart Association classes Ii-IV and radionucl ide left ventricular ejection fraction (LVEF) < 40%. Patients were assessed for cardiac MIBG uptake, circulating norepinephrine concentration, LVEF, p eak Vo(2), x-ray cardiothoracic ratio, M-mode echographic end-diastolic dia meter and right-sided heart catheterization parameters. Results: During a m ean follow-up of 27 +/- 20 mo, 19 patients had transplants, 25 died of card iac death (8 sudden deaths), 2 died of noncardiac death and 66 survived wit hout transplantation. The only independent predictors for mortality were lo w MIBG uptake (P < 0.001) and LVEF (P = 0.02) when using multivariate discr iminant analysis. Moreover, MIBG uptake (P < 0.001) and circulating norepin ephrine concentration (P = 0.001) were the only independent predictors for life duration when using multivariate life table analysis. Conclusion: Impa ired cardiac adrenergic innervation as assessed by MIBG imaging is strongly related to mortality. MIBG imaging may help risk stratify patients with he art failure resulting from idiopathic dilated cardiomyopathy.