BACKGROUND: The pathophysiology of cardiovascular disease (CVD) in chronic kidney disease (CKD) remains uncertain, but autonomic dysfunction seems to be involved. The aim of the study is to investigate the cardiac dysautonomia in uremic pediatric individuals through iodine 123 metaiodobenzylguanidine (MIBG) scintigraphy and heart rate variability (HRV) analysis. METHODS AND RESULTS: We divided 40 CKD patients (aged 5-21 years) into 4 groups according to the treatment for CKD: conservative (n = 7), continuous ambulatory peritoneal dialysis (n = 5), hemodialysis (n = 13), and kidney transplantation (n = 15). Planar and tomographic I-123 MIBG images were acquired, and early and late cardiac uptake, cardiac and lung washout, and regional I-123 MIBG uptake were evaluated. Hemodialysis patients showed increased cardiac washout (P = .002), a heterogeneous pattern of I-123 MIBG distribution (P = .036), and lower values of the low-frequency (LF) component of HRV (P = .040). Subjects undergoing continuous ambulatory peritoneal dialysis had reduced lung washout (P = .030). The cardiac washout correlated positively with parathyroid hormone levels and negatively with creatinine clearance. There was a significant negative association between the LF component and cardiac washout. CONCLUSIONS: Uremic cardiac dysautonomia may be characterized by a decreased LF component of HRV, increased I-123 MIBG washout, and a heterogeneous distribution pattern in the left ventricular walls; these abnormalities were not present after kidney transplantation.