Heterogeneity of Cardiac Sympathetic Nerve Activity and Systolic Dysfunction in Patients

Cardiac sympathetic nerve activity is changed in patients with hypertrophic cardiomyopathy (HCM). However, the relationship between heterogeneity of this activity and systolic left ventric-ular dysfunction in patients with HCM is not well established. This study was performed to evaluate the sympathetic nerve activity in various cardiac regions and to investigate the rela-tionship between cardiac dysfunction and heterogeneity of the cardiac sympathetic nerve activity in patients with HCM. Meth-ods: Cardiac sympathetic nerve activity was evaluated in 25 patients with HCM and 10 control subjects using planar imaging and SPECT by 123I-metaiodobenzylguanidine (MIBG) myocar-dial scintigraphy. With planar 123I-MIBG imaging, the heart-to-mediastinum activity ratios (H/M), at early (20 min) and delayed (3 h) acquisition, and the washout rate were calculated. Polar maps of the left ventricular myocardium were divided into 2