Utility of routine thyroid-stimulating hormone determination in new-onset atrial fibrillation in the ED.
BACKGROUND
Hyperthyroidism is a relative uncommon but important cause of atrial fibrillation. The aim of this study was to investigate the utility of routine thyroid-stimulating hormone (TSH) determination in the emergency department (ED) in patients presenting to the ED with stable, new-onset atrial fibrillation. We derive a set of clinical criteria in which TSH is likely to be normal and therefore thyroid function evaluation deferrable to a different time from ED visit.


METHODS
Cross-sectional observational study in a university hospital. Thyroid-stimulating hormone was measured in all patients admitted to the ED observational unit for new-onset atrial fibrillation in a 30 consecutive months' period. Patients' clinical characteristics and treatment received in the ED were recorded. Recursive partitioning analysis technique was used to determine which predictors were associated with a TSH level less than 0.35 μIU/mL.


RESULTS
Of 433 patients enrolled, 47 (10.8%) had a low TSH. Thyroid-stimulating hormone highly correlated with FT3 and FT4 levels (P < .001) confirming its good predictive value as screening tool. Recursive partitioning analysis showed that previous thyroid disease (P < .01), stroke/transient ischemic attack (P < .01), and hypertension (P = .10) were associated with low TSH. The final model had sensitivity of 93% and specificity of 31%, corresponding to a negative likelihood ratio of 0.02 (0.01-0.07).


CONCLUSIONS
Hyperthyroidism is present in nearly 10% of new-onset atrial fibrillation. Although thyroid function screening is recommended in all patients, a simple model that included previous thyroid disease, stroke, and hypertension might help to identify those patients at high risk (low TSH) in the ED.
Buccelletti
Francesco
F
Department of Emergency Medicine, Catholic University of the Sacred Heart, Rome, Italy. f.buccelletti@rm.unicatt.it
Carroccia
Annarita
A
Marsiliani
Davide
D
Gilardi
Emanuele
E
Silveri
Nicolò Gentiloni
NG
Franceschi
Francesco
F
D000368:Aged; D001281:Atrial Fibrillation / Q000097:blood* / Q000209:etiology; D016009:Chi-Square Distribution; D016001:Confidence Intervals; D003430:Cross-Sectional Studies; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood / Q000150:complications / Q000175:diagnosis; D016013:Likelihood Functions; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011237:Predictive Value of Tests; D012372:ROC Curve; D012680:Sensitivity and Specificity; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine