Relationship between cardiac metaiodobenzylguanidine uptake and hemodynamic, functional and neurohormonal parameters in patients with heart failure

Background: Sympathetic activation plays a pivotal role in heart failure attributing to the disease process and symptoms of the patient. Myocardial sympathetic activity can be visualized using radioiodinated metaiodobenzylguanidine 123I-MIBG, a structural analogue of norepinephrine (NE). Aim of the study: We investigated whether a relation exists between myocardial MIBG uptake and different functional, hemodynamic and neurohormonal parameters in patients with chronic heart failure. Methods and results: The study comprised 52 patients with stable congestive heart failure functional class II or III and left ventricular ejection fractions of <35%. The heart/mediastinum ratio (H/M ratio) was calculated to quantify myocardial MIBG uptake. A significant correlation was found between peak oxygen consumption and maximal exercise duration as exercise parameters and H/M ratio of MIBG (R, respectively, 0.36 and 0.4, P<0.05). From all other measured parameters, only plasma NE showed a significant correlation with the H/M ratio of MIBG. Conclusion: Cardiac sympathetic activity, as measured by myocardial MIBG uptake, is correlated with peak exercise parameters.