[Thyrotoxicosis in patients hospitalized because for atrial fibrillation].

The thyroid parameters were investigated in 99 out of 167 patients with atrial fibrillation as the main diagnosis during a period of two years. Out of these, 22 had current or previous thyrotoxicosis. Sixteen patients with thyrotoxicosis out of 93 (17%) had raised thyroid parameters in connection with the present admission with atrial fibrillation. The mean age was 72 years. The indication for measurement of the thyroid parameters in the 16 patients with thyrotoxicosis and atrial fibrillation was the clinical suspicion of thyrotoxicosis in half of the patients while the remaining half had monosymptomatic atrial fibrillation. Thus, in eight out of 85 patients, the diagnosis of thyrotoxicosis was established solely by screening. Thyrotoxicosis should always be considered as a possible precipitating cause in patients with atrial fibrillation. On account of the frequency (15-20%) and the uncharacteristic symptoms, the thyroid parameters should always be examined routinely.