A 7-year-old boy with atrial tachycardia was scheduled to undergo a video-assisted thoracoscopic left atrial appendectomy. After anesthesia induction and before the start of the operation, the child had repeated atrial tachycardia with hypotension. Synchronized electrical cardioversion was not effective. The heartbeat was converted to sinus rhythm after intravenous administration of amiodarone and propafenone. During the video-assisted thoracoscopic surgery, a bronchial blocker was used to block the left lung.