title: Evaluation of coagulation and fibrinolysis in horses with atrial fibrillation.
abstract: OBJECTIVE
  To evaluate horses with atrial fibrillation for hypercoagulability; plasma D-dimer concentrations, as a marker of a procoagulant state; and a relationship between coagulation profile results and duration of atrial fibrillation or presence of structural heart disease.
  
  
  METHODS
  Case-control study.
  
  
  METHODS
  Plasma samples from 42 horses (25 with atrial fibrillation and 17 without cardiovascular or systemic disease [control group]).
  
  
  METHODS
  Results of hematologic tests (ie, plasma fibrinogen and D-dimer concentrations, prothrombin and activated partial thromboplastin times, and antithrombin activity) in horses were recorded to assess coagulation and fibrinolysis. Historical and clinical variables, as associated with a hypercoagulable state in other species, were also recorded.
  
  
  RESULTS
  Horses with atrial fibrillation and control horses lacked clinical signs of hypercoagulation or thromboembolism. Compared with control horses, horses with atrial fibrillation had significantly lower antithrombin activity. No significant differences in plasma fibrinogen and D-dimer concentrations and prothrombin and activated partial thromboplastin times existed between horse groups. In horses with atrial fibrillation versus control horses, a significantly larger proportion had an abnormal plasma D-dimer concentration (10/25 vs 2/17), test results indicative of subclinical activated coagulation (18/25 vs 6/17), or abnormal coagulation test results (25/121 vs 7/85), respectively.
  
  
  CONCLUSIONS
  Horses with atrial fibrillation did not have clinical evidence of a hypercoagulable state, but a higher proportion of horses with atrial fibrillation, compared with control horses, did have subclinical activated coagulation on the basis of standard coagulation test results.
authors.forename: Cristobal
authors.initials: C
authors.lastname: Navas de Solís
authors.forename: Virginia B
authors.initials: VB
authors.lastname: Reef
authors.forename: JoAnn
authors.initials: J
authors.lastname: Slack
authors.forename: Eduard
authors.initials: E
authors.lastname: Jose-Cunilleras
mesh_terms: D000818:Animals; D001281:Atrial Fibrillation / Q000097:blood / Q000662:veterinary*; D015415:Biomarkers; D001777:Blood Coagulation / Q000502:physiology*; D016022:Case-Control Studies; D006734:Horse Diseases / Q000097:blood*; D006736:Horses
chemical_list: D015415:Biomarkers