Free triiodothyronine: a novel predictor of postoperative atrial fibrillation

Area of Science:

• Cardiology
• Endocrinology
• Thoracic Surgery

Background:

• Postoperative atrial fibrillation (AF) is a common complication following coronary artery bypass grafting (CABG).
• The exact mechanisms underlying AF after CABG are not fully understood.
• Previous studies suggest a potential protective role for tri-iodothyronine (T3) in preventing postoperative AF.

Purpose of the Study:

• To investigate the association between thyroid hormone levels and the incidence of AF after CABG.
• To determine if basal free tri-iodothyronine (fT3) concentration is a predictor of postoperative AF in CABG patients.

Main Methods:

• 107 patients undergoing isolated CABG were assessed for preoperative thyroid function (fT3, fT4, TSH).
• Exclusion criteria included pre-existing thyroid disease, interfering medications, and non-sinus rhythm preoperatively.
• Postoperative AF incidence was recorded, and predictors were analyzed using univariate and multivariate models.

Main Results:

• 30.8% of patients developed postoperative AF.
• Univariate analysis identified older age, absence of beta-blocker therapy, COPD, lower ejection fraction, and lower fT3 as AF predictors.
• Multivariate analysis confirmed low fT3 concentration (OR 4.425) and lack of beta-blocker therapy (OR 3.107) as independent predictors of postoperative AF.

Conclusions:

• Low basal free tri-iodothyronine (fT3) levels are a significant predictor of postoperative atrial fibrillation in patients undergoing CABG.
• These findings highlight the role of thyroid metabolism in the pathogenesis of postoperative AF.
• Identifying patients with low fT3 may allow for targeted interventions to reduce AF incidence.