[Scintigraphic imaging of adrenergic structures of the heart with 123(I)-metaiodobenzylguanidine in cardiomyopathy].

In 14 patients with various kinds of cardiomyopathy (DCM, HCM with and without obstruction, latent cardiomyopathy (= LCM], after confirmation of diagnosis, myocardial imaging with the recently developed substance 123I-metaiodobenzylguanidine (MIBG), an analog to guanethidine, was performed. In comparison, four patients in whom cardiac disease had been excluded, were evaluated. Myocardial uptake and washout were evaluated quantitatively. As a result, each kind of cardiomyopathy showed a significantly higher activity uptake versus normals, especially in patients with DCM. In all patients, the washout rate was increased compared to normals. The higher uptake is caused by depletion of catecholamine stores, as already known in DCM. On the other hand, the increased washout rate is considered to be a sign of a high sympathetic tone found in patients with HCM and LCM. The results seem to demonstrate a primary or secondary involvement of the sympathetic nervous system in these entities of hitherto unknown etiology.