Subclinical hyperthyroidism presenting with bradycardia-associated syncope.

Correspondence: Dr Alper, Orkide Apt D: 9 No 17, Idealtepe/Maltepe, Istanbul/Turkey. Fax: +90 216 4899587, e-mail: [email protected] or [email protected]. tectable on both initial and repeat tests, although T3 and T4 were not grossly elevated, consistent with the diagnosis of subclinical hyperthyroidism [TSH = 0.02 μU/ml (normal = 0.35–4.94 μU/ml); free T3 = 75 ng/dl (normal = 60–181 ng/dl); free T4 = 1.1 ng/dl (normal = 0.7–1.48 ng/dl)]. Thyroid ultrasonography indicated multinodular hyper/hypoechogenic nodules with a maximum nodule size of 1.24 x 1.04 cm. Thyroid scintigraphy confirmed the diagnosis of multinodular goiter. One nodule was hyperactive whereas other nodules were hypoactive as indicated by decreased global uptake of Tc-99m pertechnetate of the whole gland. After endocrine consultation, 300 mg/day propylthiouracyl was started. Within one month of starting treatment with propylthiouracil, control thyroid function test results revealed that she was euthyroid. The patient was discharged without any need for a pacemaker. Six months later, exercise test was normal and no arrhythmia was detected on holter monitor.