Free triiodothyronine: a novel predictor of postoperative atrial fibrillation

• Published in: European journal of cardio-thoracic surgery 2003-10, Vol.24 (4), p.487-492
• Main Authors: Cerillo, Alfredo Giuseppe, Bevilacqua, Stefano, Storti, Simona, Mariani, Massimiliano, Kallushi, Enkel, Ripoli, Andrea, Clerico, Aldo, Glauber, Mattia
• Format: Article
• Language: English
• Subjects: Adrenergic beta-Antagonists - therapeutic use; Aged; Aged, 80 and over; Atrial fibrillation; Atrial Fibrillation - blood; Atrial Fibrillation - diagnosis; Atrial Fibrillation - etiology; Biological and medical sciences; Biomarkers - blood; Cardiac dysrhythmias; Cardiology. Vascular system; Coronary Artery Bypass - adverse effects; Coronary artery bypass grafting; Female; Heart; Hospital Mortality; Humans; Length of Stay; Male; Medical sciences; Middle Aged; Prospective Studies; Risk Factors; ROC Curve; Thyroid hormone; Thyrotropin - blood; Thyroxine - blood; Treatment Outcome; Triiodothyronine - blood
• ISSN: 1010-7940; 1873-734X
• DOI: 10.1016/S1010-7940(03)00396-8

Objective: Despite improved perioperative management, atrial fibrillation (AF) after coronary artery bypass grafting (CABG) remains a relevant clinical problem, whose pathogenetic mechanisms remain incompletely explained. A reduced incidence of postoperative AF has been described in CABG patients receiving IV tri-iodothyronine (T3). This study was designed to define the role of thyroid metabolism on the genesis of postoperative AF. Methods and results: Free T3 (fT3), free thyroxine (fT4), and thyroid stimulating hormone were assayed at admission in 107 consecutive patients undergoing isolated CABG surgery. Patients with thyroid disease or taking drugs known to interfere with thyroid function were excluded. A preoperative rhythm other than sinus rhythm was considered an exclusion criterion. Thirty-three patients (30.8%) had postoperative AF. An older age (P=0.03), no therapy with β-blockers (P=0.08), chronic obstructive pulmonary disease (P=0.08), lower left ventricle ejection fraction (P=0.09) and lower fT3 concentration (P=0.001), were univariate predictors of postoperative AF. On multivariate analysis, low fT3 concentration and lack of β-blocking therapy were independently related with the development of postoperative AF (odds ratio, OR, 4.425; 95% confidence interval, CI, 1.745–11.235; P=0.001 and OR 3.107; 95% CI 1.087–8.875; P=0.03, respectively). Postoperative AF significantly prolonged postoperative hospital stay (P=0.002). Conclusions: Low basal fT3 concentration can reliably predict the occurrence of postoperative AF in CABG patients.