RESUMEN
Specific mechanisms of supraventricular tachycardia include sinoatrial, intraatrial, atrioventricular nodal as well as manifest and concealed bypass tract. The concealed bypass tract is an anoamalous atriventricular conduction via an accessory pathway and the conduction pathway is always retrograde direction. A 29-year-old woman with a history of palpitation arrived at the operating room for her emergency cesarean section at 39 weeks' gestation. The heart rate was about 200 beats/min, and the blood pressure was 90/40 mmHg. After injection of beta blocker, the heart rate transiently decreased and we tried the epidural anesthesia for her delivery but the tachycardia sustained throughout the operation. The patient's tachycardia was recovered at the postanesthetic care unit spontaneously.