CONTEXT:

Atrial fibrillation occurs frequently in patients with thyrotoxicosis, while it has low prevalence in adults of the general population. The prevalence of thyroid dysfunction in subjects with atrial fibrillation is 0 to 24 percent, a wide variation that is attributed to the different methodologies applied. However, continuous use of amiodarone in patients with previous atrial fibrillation may interfere with these prevalence rates.

OBJECTIVE:

In this study, we present the prevalence of thyroid dysfunction in adult patients who presented at a cardiac emergency room with acute atrial fibrillation, using a sensitive thyroid-stimulating hormone (TSH) assay and triiodothyronine (T3) and thyroxine (T4) determination.

TYPE OF STUDY:

Cross-sectional study SETTING: Emergency room of a tertiary care facility.

PARTICIPANTS:

A total of 72 patients with atrial fibrillation who presented at the emergency room not more than 48 hours after its onset.

PROCEDURES:

A standardized questionnaire and 12-lead electrocardiogram were applied, and T3, T4 and TSH were determined.

MAIN MEASUREMENTS:

TSH, T3 and T4 determination.

RESULTS:

Among these patients, 16.

6 percent had altered thyroid function tests:

6.9 percent had hyperthyroidism, 5.6 percent hypothyroidism and 4.2 percent had increased T4 levels, by means of amiodarone use.

CONCLUSION:

The high prevalence of thyroid dysfunction in our study, especially hyperthyroidism, suggests that routine thyroid testing with sensitivethyroid-stimulating hormone assay is required in patients with acute atrial fibrillation