title: Early Changes in the Antithrombin and Thrombin-Antithrombin Complex in Patients With Paroxysmal Atrial Fibrillation.
abstract: BACKGROUND
  Data on coagulation changes in paroxysmal atrial fibrillation (PAF) are scarce. The aim of this study was to examine plasma antithrombin (AT) levels and activity as well as thrombin-antithrombin (TAT) complex levels in the early hours of the clinical manifestation of PAF.
  
  
  METHODS
  Fifty-one patients (26 men and 25 women; mean age 59.84 ± 1.60 years) were consecutively selected with PAF duration < 24 hours, and 52 controls (26 men and 26 women; mean age 59.50 ± 1.46 years) matched the patients in terms of gender, age and comorbidities. Plasma levels and activity of AT and levels of the covalent TAT complex were studied once in each study participant.
  
  
  RESULTS
  AT plasma levels in PAF patients were statistically significantly lower compared to controls (164.69 ± 10.51 vs. 276.21 ± 8.29 μg/mL, P < 0.001). Plasma activity of the anticoagulant was also significantly lower in PAF (71.33±4.87 vs. 110.72±3.09%, P < 0.001). TAT complex concentration in plasma was higher in the patient group (5.32 ± 0.23 vs. 3.20 ± 0.14 μg/L, P < 0.001).
  
  
  CONCLUSIONS
  We can say that PAF is associated with significantly reduced AT levels and activity and increased levels of TAT complex during the first 24 hours after its manifestation. These changes indicate a reduced activity of AT anticoagulant system, which is a probable prerequisite for the established enhanced coagulation (high TAT complex levels).
authors.affiliation: First Clinic of Cardiology, Varna University Hospital "St. Marina", Bulgaria.
authors.forename: Mariya
authors.initials: M
authors.lastname: Negreva
authors.affiliation: Second Clinic of Cardiology, Varna University Hospital "St. Marina", Varna, Bulgaria.
authors.forename: Svetoslav
authors.initials: S
authors.lastname: Georgiev
authors.affiliation: Faculty of Applied Mathematics and Informatics, Technical University of Sofia, Sofia, Bulgaria.
authors.forename: Krasimira
authors.initials: K
authors.lastname: Prodanova
authors.affiliation: Department of Physiology, Plovdiv Medical University, Plovdiv, Bulgaria.
authors.forename: Julia
authors.initials: J
authors.lastname: Nikolova
keywords: Anticoagulant system; Coagulation; Paroxysmal atrial fibrillation