[Sick sinus syndrome discovered after induction of general anesthesia in a patient with normal preoperative Holter ECG].

We reported a case of 50-year-old male who was found to have SSS after induction of general anesthesia though his preoperative cardiac function studies including Holter ECG were normal. He was scheduled to have anterior transposition of ulnar nerve for idiopathic ulnar nerve palsy. He had suffered from lung edema during the same operation about 10 months previously at another hospital and the cause had been unknown. We monitored direct radial artery pressure continuously before induction of general anesthesia. About 5 minutes after the induction, ECG showed bradycardia of less than 40.min-1 and systolic blood pressure decreased to 40 mmHg. Intravenous injection of atropine increased heart rate to 60.min-1 only transiently. We began continuous infusion of isoproterenol. It was effective and no bradycardia and hypotension occurred afterwards throughout the operation. About 2 months later, he showed severe dizziness and Holter ECG revealed sinus arrest for 5 seconds. Therefore, a permanent pacemaker was implanted.