An 81-year-old man was referred to our emergency department with severe persistent chest pain. One year before presentation at our department, his 12-lead electrocardiogram (ECG) revealed a normal QRS pattern during the period of normal conduction with intermittent left bundle branch block (LBBB). His ECG immediately after arrival showed deep T-wave inversion in the precordial leads during normal conduction. During LBBB, there was mild ST-segment elevation with poor R-wave progression across the precordial leads. Emergent cardiac catheterization was performed to rule out acute coronary syndrome. Coronary angiography showed no significant stenosis, and coronary spasm was not provoked by the administration of intracoronary ergonovine. Left ventriculography demonstrated persistent left ventricular apical akinesis with systolic ballooning. Based on these findings, the patient was diagnosed to have takotsubo cardiomyopathy (TCM). After 6 months, echocardiography demonstrated the recovery of the left ventricular regional wall motion abnormality. An ECG performed 6 months after the presentation showed incomplete resolution of T-wave inversion in the periods of normal conduction. ST elevation and poor R-wave progression were improved during LBBB. In a case with acute chest pain and an ECG changes incompatible with acute ischemia superimposed on a pattern of LBBB, TCM should be considered as a differential diagnosis.