Is abnormal iodine-123-MIBG kinetics associated with left ventricular dysfunction in patients with diabetes mellitus?

Background. Although autonomic neuropathy is frequently recognized in patie nts with diabetes mellitus, it is uncertain whether cardiac sympathetic neu ropathy may play a role In the development of diabetic cardiomyopathy. Methods and Results. In 10 control subjects and 61 patients with diabetes m ellitus who did not have coronary artery disease, cardiac sympathetic funct ion and left ventricular ejection fraction (LVEF) were evaluated by using i odine-123 metaiodobenzylguanidine (MIBG) imaging and echocardiography, resp ectively Dynamic acquisitions and planar images obtained 15 and 150 minutes after injection were used as a means of measuring early and late myocardia l uptake and clearance rates of MIBG from the heart. Eight patients with an LVEF less than 50% demonstrated a lower late myocardial MIBG uptake (0.004 3 % +/- 0.0017 % vs 0.0024 % +/- 0.0009 %/pixel, P =.002) and a higher clea rance rate (22.9% +/- 17.7% vs 49.3% +/- 12.2%, P <.0001) than the 53 patie nts with an LVEF of 50% or greater, although the age, sex, type of diabetes mellitus, and frequency of neuropathy, retinopathy, and nephropathy were n ot significantly different between the 2 subgroups. The LVEF correlated wea kly but significantly with early and late myocardial uptake and clearance r ate (r = 0.277, P =.03; r = 0.421, P =.001; r = 0.382, P =.002; respectivel y) in patients with diabetes mellitus. Conclusion. Marked MIBG abnormalities are associated with left ventricular dysfunction in patients with diabetes mellitus, However, long-term follow-u p of patients with diabetes mellitus who have marked MIBG abnormalities and normal LVEF will be required to determine whether these patients would dem onstrate systolic dysfunction earlier than patients without an MIBG abnorma lity.