Impairment of Cardiac Neuronal Function in Childhood Dilated Cardiomyopathy: An 123I-MIBG Scintigraphic Study

Abnormalities of norepinephrine uptake have been found to reflect impairment of cardiac adrenergic neuronal function in adults with heart failure. To our knowledge, no data on childhood dilated cardiomyopathy (DCM) are available. The aim of this study was to assess the cardiac neuronal function using 123 I-metaiodobenzylguanidine (MIBG) scintigraphy in children with idiopathic DCM. Methods: We studied 26 patients (mean age, 44 ± 50 mo) with DCM and left ventricular dysfunction and 12 control subjects (mean age, 49 ± 65 mo) with normal left ventricular function. All subjects underwent planar cardiac imaging after intravenous injection of 20-75 MBq 123 I-MIBG. A static anterior view was acquired 4 h after injection. The heart-to-mediastinum count ratio was measured as described previously. Results: On the basis of a reduction of the heart-to-mediastinum count ratio, cardiac neuronal uptake of 123 I-MIBG was significantly decreased in patients with DCM compared with cardiac uptake in control subjects (172% ± 34% versus 277% ± 14%; P < 0.0001). A significant correlation was found between left ventricular ejection fraction and 123 I-MIBG cardiac uptake in patients with DCM (y = 2.5x + 113.3; r = 0.80; P < 0.0001). Conclusion: Cardiac adrenergic neuronal function is impaired in children with idiopathic DCM. 123 I-MIBG cardiac scintigraphy is a useful tool to assess cardiac neuronal function in childhood DCM.