Istituto di Cardiologia, Università Cattolica del Sacro Cuore, Rome, Italy.
J Cardiovasc Med (Hagerstown). 2010 Mar;11(3):151-6. doi: 10.2459/JCM.0b013e328330321d.
We previously found a severe impairment of cardiac uptake of I-metaiodobenzylguanidine (MIBG), an analogue of norepinephrine, on myocardial scintigraphy in a small group of patients with cardiac syndrome X (CSX), suggesting a dysfunction of cardiac adrenergic nerve fibres. In this study, we assessed the consistency of these previous findings in a larger group of these patients.
Planar and single-photon emission computed tomography MIBG myocardial scintigraphy was performed in 40 CSX patients (58 +/- 7 years, 17 men). Cardiac MIBG uptake was measured by the heart/mediastinum ratio and by a single-photon emission computed tomography regional cardiac MIBG uptake defect score (higher values = lower uptake). As a control group, we studied 20 healthy individuals (56 +/- 6 years, nine men). An exercise stress Tc-SestaMIBI myocardial scintigraphy was performed in 34 CSX patients (85%).
Cardiac MIBG defects were observed in 30 patients (75%), with nine (22.5%) showing no cardiac MIBG uptake at all. Compared with controls, CSX patients showed a significantly lower heart/mediastinum ratio (1.70 +/- 0.35 vs. 2.1 +/- 0.22, P < 0.001) and a higher cardiac MIBG defect score (27 +/- 25 vs. 4.4 +/- 2.5, P < 0.001). No differences were found in lung MIBG uptake between the two groups. Reversible perfusion defects on stress myocardial scintigraphy were found in 17 out of 34 CSX patients (50%), all of whom also had abnormal cardiac MIBG uptake; cardiac MIBG uptake abnormalities were also present in nine of 17 patients with normal perfusion scintigraphic images. Cardiac MIBG uptake findings were similar in our first 12 patients and in the 28 patients studied subsequently.
Our data show a relevant impairment of cardiac MIBG uptake in patients with CSX, suggesting that functional abnormalities in cardiac adrenergic nerve function may play a significant role in the mechanisms responsible for the syndrome.
我们之前在一小部分心脏综合征 X (CSX) 患者的心肌闪烁显像中发现,去甲肾上腺素类似物 I-间碘苄胍 (MIBG) 的心脏摄取严重受损,提示心脏肾上腺素能神经纤维功能障碍。在这项研究中,我们在更大的 CSX 患者群体中评估了这些先前发现的一致性。
对 40 例 CSX 患者(58 ± 7 岁,17 名男性)进行平面和单光子发射计算机断层扫描 MIBG 心肌闪烁显像。通过心脏/纵隔比和单光子发射计算机断层扫描局部心脏 MIBG 摄取缺陷评分来测量心脏 MIBG 摄取(值越高,摄取越低)。作为对照组,我们研究了 20 名健康个体(56 ± 6 岁,9 名男性)。34 例 CSX 患者(85%)进行了运动应激 Tc-SestaMIBI 心肌闪烁显像。
30 例(75%)患者出现心脏 MIBG 缺损,其中 9 例(22.5%)完全无心脏 MIBG 摄取。与对照组相比,CSX 患者的心脏/纵隔比显著降低(1.70 ± 0.35 比 2.1 ± 0.22,P < 0.001),心脏 MIBG 缺损评分更高(27 ± 25 比 4.4 ± 2.5,P < 0.001)。两组之间的肺 MIBG 摄取无差异。34 例 CSX 患者中有 17 例(50%)出现应激心肌闪烁显像时可逆性灌注缺损,这些患者均有异常的心脏 MIBG 摄取;17 例灌注显像正常的患者中有 9 例也存在心脏 MIBG 摄取异常。我们的前 12 例患者和随后研究的 28 例患者的心脏 MIBG 摄取结果相似。
我们的数据显示 CSX 患者心脏 MIBG 摄取明显受损,提示心脏肾上腺素能神经功能的功能异常可能在该综合征的发病机制中起重要作用。