Repeated supraventricular tachycardia in an asymptomatic patient with Wolff-Parkinson-White syndrome during Cesarean delivery

To the Editor: Several reports have indicated that pregnancy predisposes asymptomatic patients with Wolff-ParkinsonWhite (WPW) syndrome to supraventricular tachycardia (SVT).1,2 We report a case of repeated SVT in a 36-yr-old woman with WPW syndrome during anesthesia for Cesarean delivery (C/D). The patient was scheduled for C/D due to cephalopelvic disproportion. WPW syndrome had been diagnosed at age 18, however, she had had no attacks for 18 years and was not taking any medication. Her heart rate (HR) was regular with sinus rhythm before C/D. Mepivacaine (2%; 13 mL) was injected into the epidural space and sensory analgesia reached the T4 level. The baby was born uneventfully and blood losses were 450 mL. At the end of the operation, SVT occurred suddenly, HR increased to 190 beats·min–1 and blood pressure decreased. At first, we tried vagal stimulation (Valsalva maneuver and carotid massage) but the SVT did not stabilize. Next, verapamil (3.7 mg) was administered and the HR stabilized to sinus rhythm. Postoperatively, SVT occurred three other times and we administered verapamil (5 mg) and disopyramide (50 mg) to stabilize the HR. Oxytocin administration, anxiety, pain, etc., have been reported to trigger SVT in parturients with WPW syndrome.3 Because of the timing in our case, it is difficult to say what triggered the SVT exactly. However, anesthesiologists should be aware of the possible recurrence of repeated SVT, even in the asymptomatic patient, with WPW syndrome. 752 CANADIAN JOURNAL OF ANESTHESIA