Risk Factors for New Onset Atrial Fibrillation During Thyroid Gland Surgery.

OBJECTIVE: Thyroid dysfunction is a common cause of atrial fibrillation (AF). Incidence of AF is high in patients with both expressed hyperthyroidism and subclinical hyperthyroidism. The aim of our study was to determine the incidence and predictors of new onset atrial fibrillation (NOAF) in euthyroid patients undergoing thyroid surgery.

SUBJECT AND METHODS: The study included 1252 euthyroid patients American Society of Anesthesiologists (ASA) physical status ASA 2 and ASA 3 status, who were 18 years and older and were in sinus rhythm. Patients without comorbidity and patients with persistent AF were excluded. We investigated the influence of the following preoperative characteristics on the occurrence of NOAF: age, sex, body mass index, ASA score, admission diagnoses and comorbidity. We noted the influence of characteristics: difficult intubation of trachea, type and duration of surgery, time under general anesthesia. Univariate and multivariate logistic regression were used in order to determine predictors of occurrence of NOAF.

RESULTS: NOAF was registered at 0.72 % of patients. Patients with NOAF were older (63.11 vs. 56.81 years) than patients without NOAF, but not statistically significantly (p>0.05). Significantly more patients from the NOAF group had preoperatively some sort of heart rhythm disturbance and a history of angina pectoris, in contrast to patients without registered NOAF (p=0.001; p=0.017). Multivariate analysis showed that independent predictor of NOAF was only a history of heart rhythm disturbances.

CONCLUSIONS: Incidence of NOAF during thyroid surgery is similar to other type of surgery, if the values of thyroid hormones are normal.