We report a case of intraoperative cardiac arrest in a patient with mitochodorial encephalomyopathy undergoing pulmonary wedge resection. The patient is a 50-year-old female who had been diagnosed as progressive external ophthalmoplegia at the age of 44 and underwent resection of mediastinal tumor 11 months before without major events. The patient was found to have lung cancer in the left lung and scheduled for wedge resection. Induction and maintenance of anesthesia using remifentanil and propofol infusion with rocuronium were uneventful until traction and resection of the left bronci when profound hypotension with systolic arterial pressure of 20 mmHg and sinus bradycardia occurred. The rhythm deteriorated to ventricular fibrillation which was refractory to pharmacological therapy including adrenaline (a total dose of 5 mg), lidocaine and nifekalant, and DC shock. The patient was finally stabilized after intraaortic balloon pumping and percutaneous cardiopulmonary support. Although the diagnosis of Takotsubo myopathy was made by echocardiography after surgery, the cause of cardiac arrest was not known.