Inclusion Criteria:  Admission after syncope or seizure Age of 18 years or older First bleed not later than two hours after event (syncope or seizure) Written informed consent obtained  Exclusion Criteria:  Results of thyroid hormones not available within two hours after event Pituitary dysfunction Thyroid dysfunction Use of iodinated radiocontrast agents less than three months ago Therapy with amiodarone in the previous three years Pregnancy