Evaluation of Fondaparinux in Patients With a Heart Rhythm Disturbance Who Undergo Restoration of Normal Heart Rhythm

An International, Multicentre, Randomised, Open, Controlled, Two-parallel Group, Phase II Pilot Study to Evaluate the Efficacy and Safety of ARIXTRA™ for Anticoagulation of Patients With Atrial Fibrillation Undergoing Electric Cardioversion Following Transesophageal Echocardiography

The purpose of this study is to test whether Fondaparinux is effective and safe to prevent thromboembolic events (like for example strokes) and bleeding events in patients who undergo a normalisation of their heart rhythm disturbance. Fondaparinux will be compared with Heparin and tablets containing Vitamin-K-Antagonists (Phenprocoumon, Fluindione, or Warfarin).

Inclusion Criteria:

• Male or female patients aged at least 18 years with atrial fibrillation (AF) meeting at least one of the following criteria (a, b, c): a. Acute clinical symptoms (like palpitations, chest pain, dyspnea, fatigue, lightheadedness, or syncope) for at least 48 hours and AF on baseline ECG b. Newly discovered AF persisting for >=7 days c. Recurrent AF persisting for >=7 days

Exclusion Criteria:

• No documented sinus rhythm on ECG for more than 1 year
• Acute neurological deficits (TIA, stroke, intracranial bleeding), or known disease which may cause neurological deficits (e.g., multiple sclerosis, seizure disorder)
• Treatment with antithrombotic agents, including low-dose anticoagulation, for more than 48 hours prior to randomisation
• Treatment with oral NSAIDs or ASA at doses greater than 325 mg per day for more than 72 hours prior to randomisation
• Anticoagulant therapy required or likely to be required during the study period
• Treatment with ASA at a dose greater than 325 mg per day or oral NSAIDs (at any dose) required or likely to be required during the study period
• Treatment with two or more antiplatelet agents (e.g. clopidogrel and ASA) at any dose at the same time (i.e., within 24 hours)
• Known hypersensitivity to UFH, VKA, or Fondaparinux or one of these drugs' excipients
• Active, clinically significant bleeding or clinically significant bleeding within the past month
• Major surgery within the previous three months
• Uncontrolled arterial hypertension (persistent systolic blood pressure over 180 mm Hg or diastolic blood pressure over 110 mm Hg)
• Bacterial endocarditis
• Calculated creatinine clearance < 30 mL/min
• Body weight < 50 kg
• Planned surgery or intervention within the next 65 days