he sympathetic nervous system (SNS) is an important control mechanisms of the body, dysfunction of which is well known to be associated with the development of various common cardiovascular diseases, such as ischemic heart disease, 1 congestive heart failure, 2 arrhythmias, 3 and sudden death. 4 It is also well known that the frequency and the onset of these diseases have age-and gender-related differences. 5,6 Likewise, the SNS shows physiologic fluctuations with age and sex, 7-15 which are considered to be related to gender differences in the frequency of cardiovascular diseases and the markedly increased risk of cardiovascular diseases with aging. Therefore, it is very important to assess physiological changes in sympathetic cardiovascular control in humans, especially in the cardiac SNS, because many cardiovascular diseases originate from the heart. However, as there are no appropriate methods of measuring the cardiac SNS in vivo, the precise physiological changes remain unclear.123 I-metaiodobenzylguanidine (MIBG) imaging has become widely used to evaluate human cardiac sympathetic nervous function [14][15][16][17][18][19][20] because it gives information about cardiac sympathetic nerve endings. Using MIBG imaging, the aim of this study was to assess the age-and gender-related differences in the global cardiac SNS in normal subjects.
Methods
PatientsWe investigated 153 patients whose ages ranged from 40 to 89 years were referred for cardiac catheterization because of chest pain or electrocardiogram (ECG) abnormality, and which revealed a nearly normal coronary artery without coronary spasm induced by acetylcholine and with normal cardiac function and hemodynamics. After cardiac catheterization, they underwent MIBG imaging. The subjects were 74 men and 79 women who did not have obvious heart disease, hypertension (≥140 mmHg systolic blood pressure, or ≥90 mmHg diastolic blood pressure), obesity (body mass index (BMI) >25 kg/m 2 ), diabetes mellitus or any other diseases affecting the autonomic nervous system. In addition, they did not take any drugs known to affect MIBG kinetics. We included 10 women who fulfilled the inclusion criteria and had undergone surgical menopause without oral hormone replacement therapy before physiological menopause because we wanted to investigate the effect of menopause on the cardiac SNS. Written informed consent was given by the each patient and the study was approved by the hospital's ethics committee.
Cardiac CatheterizationAfter right-heart catheterization with a Swan-Ganz catheter, all patients underwent coronary angiography (CAG) performed by the Judkins technique. Prior to CAG, a tem- Michitoshi Ito, RT*; Yoshihiro Nakaya, RT* Background Physiologic changes in the human sympathetic nervous system (SNS) may be associated with cardiovascular diseases, so the present study assessed the age and gender differences in global cardiac SNS in normal subjects.
Methods and ResultsThe 163 subjects (74 men, 89 women; age range 40-89 years) whose coronary arteriogram was normal, and w...