Background: Sick sinus syndrome (SSS) is a abnormality of a cardiac impulse formation as a result of sinus node dysfunction that could be presented as a diverse abnormalities in the heart rate and rhythm.SSS is most common in the elderly where the mean age of patients is 68 years.In most of the cases the etiology of the SSS remains unknown but the majority of the patients are experiencing some stage of coronary artery disease(1).
Case Report: We present a 89 years old female patient undergoing pertrochanteric fracture repair under spinal anesthesia. Her preoperative evaluation did not revealed any pathologyc findings. All vital signs were stable prior to surgery. The patient has received 2.4ml of Bupivacaine 0.5% and 10mcg of Fentanyl. Dural puncture was done in an aseptic technicque at the L3-L4 level and clear liquor was seen prior to anesthetic application. The first hour of surgery went uneventful after what abrupt onset of tachycardia of 109bpm followed by bradycardia of 48bpm were seen. The episodes od tachycardia followed with bradycardia were repeating till the patient entered a bigeminy rythm with the lowest hearth rate of 45 after what 0.5mg of atropine was given and restoration of normal sinus rhythm was seen. The patient was monitored postoperatively in PACU and followed up at the Traumatology ward while there were not seen any vital signs deterioration. 
Discussion: We’ve found 8 case reports in a patients undergoing general anesthesia and one undergoing general and epidural anesthesia but none of them under spinal anesthesia. Seven of eight patients were previously healthy without known cardiac disease. Different types of conduction and heart rate abnormalities, including asystole, were presented in all of the cases after induction of the patients under general anesthesia. In our case during the surgery the patient developed multiple episodes of tachycardia followed with bradycardia without subjective discomfort. The resolution of the tachycardia-bradycardia syndrome after giving the 0.5mg of atropine shows a possible relationship between the local anesthetic application and the onset of the SSS manifestation.
References: 1. Brignole M1.; Sick sinus syndrome.; Clin Geriatr Med. 2002 May;18(2):211-27
Learning points: SSS can be precipitated perioperatively because of increased vagal tone caused by anesthesia or surgical intervention. As general anesthetics, local anesthetics also could trigger intraoperative manifestation of SSS.


09 / Tachycardia-bradycardia syndrome in a patient undergoing pertrochanteric fracture repair under spinal anesthesia.