Neuronal dysfunction in heart failure assessed by cardiac 123-iodine metaiodobenzylguanidine scintigraphy

Abstract

In patients with chronic heart failure, increased sympathetic activity and cardiac sympathetic neuronal dysfunction are present and have been related to unfavourable clinical outcome. Modification of these alterations with the objective to improve prognosis has become an important aim of pharmacological therapy for these patients. A noninvasive technique to assess sympathetic neuronal function at the cardiac level may be valuable in evaluating newly developed therapeutic strategies. 123-iodine metaiodobenzylguanidine can be used to visualize cardiac sympathetic nerve function and activity. Single photon emission computerized tomographic is preferred to planar scintigraphy since it does not depend on superposition of other anatomical structures and may allow assessment of regional cardiac 123-iodine metaiodobenzylguanidine uptake. Although the quantitation of cardiac uptake in these tomographic images has several limitations, the use of the left ventricular cavity as a reference, calibrated by the 123-iodine activity in a blood sample drawn at the time of acquisition, may have clinical applications, with respect to the evaluation of therapeutical intervention in patients with heart failure.

Differential pre- and postsynaptic effects of desipramine on cardiac sympathetic nerve terminals in RHF

“…The pathophysiological importance of the cardiac sympathetic nerve terminal NE uptake function is further supported by a recent study (55) of carvedilol in rats with dilated cardiomyopathy, in which the beneficial effects of carvedilol on cardiac function and myocardial fibrosis are associated with reduction of cardiac adrenergic neuronal damage as measured by [ 123 I]-metaiodobenzylguanidine (MIBG). Cardiac MIBG imaging has been used to assess cardiac sympathetic nerve terminal function in humans (52). These studies have shown that impaired cardiac adrenergic innervation as assessed by MIBG imaging is a valuable prognostic indicator, independent of left ventricular ejection fraction and circulating plasma NE, for increased mortality and morbidity in patients with chronic congestive heart failure (39,43).…”

Cardiac Resynchronization Induces Favorable Neurohumoral Changes

“…Cardiac adrenergic nerve activity can be estimated using several techniques: first, using iodine‐123metaiodobenzylguanidine ( 123 I‐MIBG) as a noradrenaline analog 9 . 123 I‐MIBG is a guanethidine analog that shares the same uptake, storage, and release pathway as norephinephrine and has the potential to reflect the whole myocardial adrenergic pathway 9,10 . 123 I‐MIBG myocardial uptake indices can be used as a predictor of prognosis in patients with chronic HF 11–14 .…”