La Canna G, Giubbini R, Cicogna R, Curnis A, Guerra U P, Arosio G, Visioli O
Cattedra di Cardiologia, Università degli Studi di Brescia.
G Ital Cardiol. 1987 Jun;17(6):498-504.
Myocardial perfusion scintigraphy with 201-TL was performed in a group of subjects affected by exercise-induced, rate-dependent left bundle branch block (LBBB). The aim of the study was: to define the significance of the exercise-induced conduction abnormality: "primitive" or "ischemic". 14 patients, aging 28-58 years (x = 42), 8 with chest pain (4 typical angina, 4 atypical angina) and 6 without any symptoms were studied. None had history of prior myocardial infarction or clinical and echocardiographic signs of heart disease. LBBB appeared at a heart rate ranging from 70 to 160 beats/min. 6 patients showed repolarization abnormalities (ST changes, deep and negative T wave) suggestive for ischemia, during successive QRS normalization. 201-TL-uptake was normal in 5 subjects; in the remaining 9 ones reversible TL defects were demonstrated in the septum (6), in the septum and apex (2), in the septum and inferior-apical wall (1). No patients had irreversible impaired perfusion. All the patients had normal coronary angiography, with negative ergonovine test for coronary artery spasm. In conclusion, in the majority of our subjects (64%) with exercise-induced LBBB, a reversible TL-uptake defect, usually located in the septum without diagnostic value of obstructive CAD, has been observed. Further studies will establish if the TL-defect is only an "apparent phenomenon" due to contraction abnormality secondary to LBBB, or, on the contrary, an expression of myocardial ischemia with normal coronary vessels as a consequence of the LBBB.
对一组患有运动诱发的、心率依赖性左束支传导阻滞（LBBB）的受试者进行了铊-201心肌灌注闪烁显像。该研究的目的是：确定运动诱发的传导异常的意义：“原发性”还是“缺血性”。研究了14例患者，年龄在28 - 58岁之间（平均年龄42岁），其中8例有胸痛（4例典型心绞痛，4例非典型心绞痛），6例无任何症状。所有患者均无既往心肌梗死病史，也无心脏病的临床及超声心动图体征。LBBB出现在心率70至160次/分钟时。6例患者在连续QRS波正常化过程中出现复极异常（ST段改变、深倒置T波），提示缺血。5例受试者的铊-201摄取正常；其余9例在间隔（6例）、间隔和心尖（2例）、间隔和下壁-心尖壁（1例）显示可逆性铊缺损。无患者有不可逆的灌注受损。所有患者冠状动脉造影均正常，麦角新碱试验阴性，排除冠状动脉痉挛。总之，在我们大多数（64%）运动诱发LBBB的受试者中，观察到可逆性铊摄取缺损，通常位于间隔，对阻塞性冠心病无诊断价值。进一步的研究将确定铊缺损是仅由于LBBB继发的收缩异常导致的“表观现象”，还是相反，是冠状动脉正常时LBBB导致的心肌缺血的表现。
