Adrenergic innervation of the myocardium in patients with cardiac syndrome X]

11 syndrome X patients and 8 healthy controls were investigated by myocardial scintigraphy (SPECT) with 123-I-MIBG. Regional defects in cardiac 123-I-MIBG uptake were found in 90% syndrome X patients. Total cardiac 123-I-MIBG uptake appeared significantly higher in syndrome X patients. Perfusion defects on stress 99m-Tc-MIBI scintigraphy were found in 10 syndrome X patients who had also abnormal 123-I-MIBG scintigrams. It is suggested that impairment of efferent cardiac adrenergic nerve fiber function in syndrome X patients may contribute to pathophysiologic and clinical features of syndrome X.