Portrayal of adrenergic denervation in the presence of myocardial infarction: a feasibility study.

Abstract

Myocardial infarction interrupts adrenergic neurons beyond the region of necrosis to give peri-infarct denervation. A method to define the regions of denervation would be a valuable aid in determining the role that loss of adrenergic neurons plays in myocardial infarction and particularly in causing arrhythmias. [123I] meta-iodobenzylguanidine (MIBG) was used to portray scintigraphically the intact neurons in dog hearts. Occlusion of the left circumflex (LCX) or the left anterior descending coronary artery (LAD) produced defects that appeared to be regularly larger in the [123I]MIBG images than in the [201T1]images of the same heart; the differences were considered to be the regions of denervation which were relatively larger after LCX than LAD infarcts. Ex vivo measurements of endogenous norepinephrine and residual [125I]MIBG concentrations gave confirmation of neuronal injury. A computer program to quantify the regions of denervation appeared imprecise, but gave some promise. Scintigraphy of [123I]MIBG offers a method to define patterns of denervation in the living animal and man.