Abstract
A case of bidirectional tachycardia (BT) occuring during induction of anesthesia is reported, The patient was a 61 year old female with rectal carcinoma who was scheduled for elective surgical resection. She had no history of myocardial ischemia nor had she ever recieved digitalis. preoperative ECG and chest x-ray were normal. Lab data also revealed no abnormality except slight anemia. After the administration of thiopental 75mg and pancuronium 6mg IV, she was ventilated with oxygen 31, nitrous oxide 31, and halothane 3% by a mask. During this period, ECG suddenly changed from normal sinus rythm (NSR) to supraventricular tachycardia, then to the BT and BP was unmeasurable. Ventilation was continued with 100% oxygen, and soon ECG returned to NSR and BP became stable without any other treatment. The operation was completed uneventfully. Postoperative ECG showed NSR and no evidence of myocardial dysfunc-tion was noted. It is presumed that the BT resulted from myocardial ischemia induced by hypotention during induction.
