[A case of bradycardia in a patient with secondary hypothyroidism].

A 68-year-old patient was scheduled for subtotal gastrectomy. Preoperative examination showed heart rate of 30-40 beats.min-1 caused by secondary hypothyroidism. Triiodothyronine and thyroid stimulating hormone concentrations were 1.9 pg.ml-1 and 0.17 microU.ml-1 respectively. To treat bradycardia, the patient was given isoproterenol hydrochloride (ISP: 0.01-0.03 microgram.kg-1.hr-1) for 5 days before surgery. Heart rate recovered to 70-80 beats.min-1, and the dosage could be tapered off before surgery without return of bradycardia. The operation was performed successfully under general anesthesia. We reported the anesthetic management of this patient with severe bradycardia due to secondary hypothyroidism. This case suggests that preoperative treatment for the symptoms is important for anesthetic management of a patient with hypothyroidism.