Selective Cardiac Neuroadrenergic Abnormalities in Hypertensive Patients with Left Ventricular Hypertrophy

Background Increased sympathetic drive to the heart might contribute to the development and progression of myocardial damage in hypertensive patients (HTs). This study assessed the possible presence of abnormalities in myocardial uptake of123 I-metaiodobenzylguanidine (MIBG), a marker of sympathetic activity, in HTs with left ventricular hypertrophy (LVH). Methods Eleven HTs with LVH and 10 matched normotensive controls underwent clinical and laboratory examination, as well as LVH determination by echocardiography. The presence of myocardial ischemia was ruled out by exercise stress testing. Global and regional myocardial uptake of123 I-MIBG was determined in both groups using planar and single proton emission tomography scintigraphy. In addition, thallium-201 (Tl-201) myocardial scintigraphy was performed in HTs. The heart/mediastinum (H/M) ratio on planar123 I-MIBG images at different time points was compared between HTs and controls. Moreover, regional cardiac uptake of123 I-MIBG was compared between groups and, within the HTs group, with regional Tl-201 uptake. Results At all study times, the H/M ratio was lower in HTs than in controls (all p