Abstract
To elucidate the relationship between regional myocardial adrenergic innervation and left venticular hypertrophy in patients with hypertrophic cardiomyopathy(HCM), simultaneous iodine-123 metaiodobenzylguanidine (123IMIBG)and thallium-201 (201T1) myocardial scintigraphies were performed in 21 patients with HCM. In 7 patients both 123I-MIBG and 201T1 images showed a normal distribution pattern, and in 13 patients 202T1 showed a normal distribution,but 123I-MIBG showed a low distribution or defect. Myocardial uptake of 123I-MIBG was reduced even in the segments where myocardial hypertrophy was confirmed by the échocardiographie method. The incidence of a low distribution or defect in 123I-MIBG was significantly higher in the posterior,lateral and apical segments than in the anterior and septal segments in HCM patients (each, p <0.01). The difference in the distribution pattern between 123I-MIBG and 201T1 may reflect adrenergic nerve dysfunction. The disorder of adrenergic innervation seems to precede myocardial damage. From these findings, we conclude that a good correlation between myocardial adrenergic innervation and left ventricular hypertrophy is not necessarily observed, and the difference in distribution pattern between 123I-MIBG and 20IT1 usually takes place in the advanced stage of HCM.