Cardias autonomic neuropathy in patients with chronic renal failure on hemodialysis

To characterize uremic cardiac autonomic neuropathy, we measured plasma cat echolamines, analyzed the 24-hour heart rate variability (HRV), and acquire d serial images with I-123-metaiodobenzylguanidine (MIBG) in 44 patients wi th chronic renal failure on hemodialysis and in 14 controls. Time-domain me asures were calculated using the Marquette HRV program. MIBG clearance rate s from the heart and lung were evaluated on planar images, and the regional MIBG uptake in the left ventricular myocardium was evaluated with single-p hoton emission computed tomography. Compared with controls, plasma dopamine and norepinephrine levels were elevated (p<0.004 and p = 0.03, respectivel y), and ail the time-domain measures of HRV were reduced in the patients (p < 0.001). The MIBG clearance rate from the heart was higher (p < 0.001), t hat from the lung was lower (p < 0.001), and the myocardial MIBG distributi on was more heterogeneous in patients than in controls (total uptake score p less than or equal to 0.03). These variables were similar between 26 pati ents without and 18 patients with hypertension. Uremic cardiac autonomic ne uropathy may be characterized by high plasma levels of dopamine and norepin ephrine, reduced HRV, and abnormal MIBG kinetics in the heart with heteroge neous myocardial MIBG distribution, suggesting cardiac sympathetic overacti vity and parasympathetic deterioration. In addition, abnormal MIBG kinetics in the lung may imply pulmonary sympathetic nervous dysfunction and/or end othelial dysfunction in uremic patients. Copyright (C) 2000 S.Karger AG, Ba sel.