Gholamrezanezhad Ali, Mirpour Sahar, Sarabandi Farhad, Jazayeri Behnam
Research Institute for Nuclear Medicine, Tehran University of Medical Sciences, Shariati Hospital, Tehran, Iran.
Nucl Med Rev Cent East Eur. 2012 Aug 25;15(2):143-8.
We report myocardial perfusion SPECT pattern in four subsequent patients with rate dependent left bundle branch block (LBBB). Three females and one male (aged 48, 51, 63 and 67 years) were studied. None of the patients had history of typical chest pain and all suffered from atypical chest pain or dyspnea on exertion. All patients were tested for baseline and serial heart rate, blood pressure, and electrocardiogram recordings. The exercise treadmill tests (ETT) were carried out under the strict supervision of a cardiologist, a nuclear medicine physician and close availability of an expert cardio-pulmonary resuscitation team and cardiac care unit within just few seconds. Maximal stress test (at least 85% of calculated heart rate, following development of LBBB) was achieved in all four patients according to standard Bruce protocol. No adverse cardiac events were noted and all ETT stress protocols terminated completely and safely. Myocardial perfusion SPECT imaging showed no evidence of reversible perfusion defects. The only patient with past history of exercise induced LBBB showed nonreversible perfusion defects in the septal and anteroseptal regions and mild LV cavity dilatation. The limited number of patients enrolled in our study does not allow us to draw a definite conclusion. Despite the presence of false-positive defects in myocardial perfusion SPECT in patients with sustained LBBB, such a finding is not a consistent finding in patients with rate dependent or exercised-induced LBBB, unlike that which we expected to see. Maybe it is possible to continue ETT for those patients undergoing myocardial perfusion scintigraphy and developing rate dependent LBBB.
我们报告了4例连续的心率依赖性左束支传导阻滞（LBBB）患者的心肌灌注单光子发射计算机断层扫描（SPECT）表现。研究对象为3名女性和1名男性（年龄分别为48岁、51岁、63岁和67岁）。所有患者均无典型胸痛病史，均有非典型胸痛或劳力性呼吸困难。所有患者均进行了基线及系列心率、血压和心电图记录。运动平板试验（ETT）在心脏病专家、核医学医师的严格监督下进行，且有专业心肺复苏团队和心脏监护病房在数秒内随时待命。根据标准Bruce方案，所有4例患者均达到了最大负荷试验（至少达到计算心率的85%，出现LBBB后）。未观察到不良心脏事件，所有ETT负荷试验方案均完全且安全地终止。心肌灌注SPECT成像未显示可逆性灌注缺损。唯一有运动诱发LBBB既往史的患者在间隔和前间隔区域显示出不可逆性灌注缺损及轻度左心室腔扩张。我们研究纳入的患者数量有限，无法得出明确结论。尽管持续性LBBB患者的心肌灌注SPECT存在假阳性缺损，但与我们预期的情况不同，这种发现并非心率依赖性或运动诱发LBBB患者的一致表现。对于那些正在进行心肌灌注闪烁显像且出现心率依赖性LBBB的患者，或许可以继续进行ETT。
