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Title: Occult thyrotoxicosis: a correctable cause of idiopathic atrial fibrillation

Journal Article · · Am. J. Cardiol.; (United States)

Serum total thyroxine, triiodothyronine and thyrotropin response to thyrotropin-releasing hormone were measured in 75 consecutive patients presenting to a cardiology clinic with atrial fibrillation with no obvious cardiovascular cause. A lack of response of serum thyrotropin to thyrotropin-releasing hormone, indicative of thyrotoxicosis, was found in 10 patients (13%), not all whom had raised serum thyroid hormone levels. These 10 patients were predominantly male, had no clinical signs of thyrotoxicosis and a relative excess of nonpalpable autonomous thyroid nodules demonstrated with scintigraphy. Eight of the 10 patients had reversion to stable sinus rhythm after treatment with iodine-131 or carbimazole, either spontaneously or after direct current cardioversion. It would appear that clinically occult thyrotoxicosis can be identified consistently only with the thyrotropin-releasing hormone test and is the cause of idiopathic atrial fibrillation in a significant proportion of patients.

Research Organization:
Royal Infirmary, Edinburgh, Scotland
OSTI ID:
6113575
Journal Information:
Am. J. Cardiol.; (United States), Vol. 44:1
Country of Publication:
United States
Language:
English