Svetoslav Georgiev

Early effects of paroxysmal atrial fibrillation on plasma markers of fibrinolysis.

AbstractThere are no studies to date on the early changes in the hemostasis profile of patients with paroxysmal atrial fibrillation (PAF).Given the key role of the fibrinolytic system in maintaining blood fluidity, our aim was to examine its activity in patients with clinical manifestation of the disease <24 hours.We studied 51 nonanticoagulated patients with a first episode of the disease (26 men, 25 women; mean age 59.84 ± 1.60 years) and 52 controls (26 men, 26 women; mean age 59.50 ± 1.46 years) who matched the patients in terms of gender, age, comorbidities, and conducted treatment. Using enzyme-linked immunoassays and colorimetric assays we assessed the plasminogen activity, tissue plasminogen activator level (t-PA), plasminogen activator inhibitor 1 activity (PAI-1), &agr;2-antiplasmin activity (&agr;2-AP), D-dimer level, and vitronectin level. Blood samples were collected immediately after hospitalization.Patients were hospitalized between the second and twenty fourth hours (mean 8.14 ± 0.76 hours) after the onset of PAF. Compared to controls, plasminogen (159.40 ± 4.81 vs 100.2 ± 2.88%, P < 0.001) and t-PA levels (11.25 ± 0.35 vs 6.05 ± 0.31 ng/mL, P < 0.001) were significantly higher in the patient group. PAI-1 activity (7.33 ± 0.37 vs 15.15 ± 0.52 AU/mL, P < 0.001) and &agr;2-AP (112.9 ± 2.80 vs 125.60 ± 3.74%, P < 0.05) as well as vitronectin plasma levels (134.7 ± 5.83 vs 287.3 ± 10.44 mcg/mL, P < 0.001) were lower in the PAF group. Conversely, the levels of D-dimer in patients were significantly higher (0.53 ± 0.07 vs 0.33 ± 0.02 ng/mL, P < 0.05).Early changes in the fibrinolytic system occur in PAF, suggesting their close relationship with the manifestation of the disease. There is high plasma fibrinolytic activity, during the very first 24 hours of the disease, which is most likely a pathophysiological response to the intensified procoagulation process.

Decreased Activity of the Protein C Anticoagulant Pathway in the Early Hours of Paroxysmal Atrial Fibrillation

Background: Increased coagulation activity has been established in paroxysmal atrial fibrillation (PAF), but data on the anticoagulant system are scarce. Purpose: To examine the protein C anticoagulant pathway in the early hours of the disease. Materials and Methods: Fifty-one patients (26 men and 25 women; mean age 59.84 ± 1.60 years) and 52 controls (26 men and 26 women; mean age 59.50 ± 1.46 years) were selected for the study. Protein C antigen and its activity, total protein S, free protein S and its activity, soluble forms of endothelial protein C receptor (sEPCR), and thrombomodulin (sTM) were examined in the plasma. Results: The indicators were studied in patients between the 2nd and the 24th hour after the onset of arrhythmia. Levels of protein C were significantly elevated in patients compared to controls (111.40% ± 6.66% vs 94.83% ± 4.47%; P = .039). Protein C activity showed significant reduction in PAF (73.13% ± 5.80% vs 103.3% ± 3.80%; P < .001). Total protein S levels did not differ significantly (108.20% ± 4.07% vs 102.40% ± 3.65%; P = .30). Free protein S (76.81% ± 6.01% vs 122.10% ± 3.97%; P < .001) and its activity (71.39% ± 6.27% vs 119.50% ± 6.54%; P < .001) were reduced in patients. Higher levels of sEPCR (203.10 ± 10.33 vs 133.10 ± 7.37 ng/mL; P < .001) and sTM (6.50±0.40 vs 4.48±0.28 ng/mL; P < .001) were measured in PAF. Conclusion: Protein C activity is reduced still in the first hours (until the 24th hour) of PAF clinical manifestation, determining reduced activity of the anticoagulant pathway as a whole. The established low levels of free protein S and its activity as well as low sEPCR and sTM levels are a possible explanation of the changes in protein C activity.

Paroxysmal atrial fibrillation: dynamics of the main antioxidant enzymes--superoxide dismutase and catalase.

Abstract INTRODUCTION: Researchers have a particularly strong interest in the mechanisms implicated in the clinical manifestation of atrial fibrillation. OBJECTIVE: To examine dynamically the activity of the antioxidant enzymes, su-peroxide dismutase and catalase in patients with paroxysmal atrial fibrillation (duration ⋋ 48 hours). MATERIALS AND METHODS: The studied parameters were examined in the erythrocytes of 51 patients (59.84 ± 1.60, 26 men) immediately after their hospitalization, at 24 hours and 28 days after restoration of sinus rhythm. 52 controls (59.50 ± 1.46, 26 men) were also included, none of which had a history of arrhythmia. Propafenone was used to manage the rhythm abnormality. The enzyme activity was determined by a spectrophotometric method. RESULTS: The average duration of atrial fibrillation episodes until the time of hospitalization was 8.14 hours (from 2 to 24 hours). During patient hospitalization the activity of superoxide dismutase and catalase was considerably higher compared to that of the controls (8.46 ± 0.26 vs 5.81 ± 0.14 U/mg Hb; 7.36 ± 0.25 vs 4.76 ± 0.12 E240/min/mg Hb; P ⋋ 0.001). This difference was maintained 24 hours after the rhythm regularization (7.19 ± 0.25 vs 5.81 ± 0.14 U/mg Hb, p ⋋ 0.001; 5.30 ± 0.21 vs 4.76 ± 0.12 E240/min/mg Hb, p ⋋ 0.05). Twenty-eight days after the restoration of sinus rhythm, the activity of catalase remained increased (5.11 ± 0.08 vs 4.76 ± 0.12 E240/min/mg Hb, p ⋋ 0.05). CONCLUSION: The paroxysmal atrial fibrillation in our study was characterized with significantly increased activity of superoxide dismutase and catalase even in the early hours of clinical manifestation of the disorder, which then slowly decreased with the restoration of sinus rhythm. Therefore, we can conclude that changes in oxidative status are closely related to the disease and are probably a part of the intimate mechanisms related to its initiation and clinical course.