Evaluation of Abbreviated Versus Conventional Course of Dabigatran Etexilate Before Electric Cardioversion in Patients With Atrial Fibrillation (RE-SOUND Study)

The purpose of the study is to evaluate the efficacy of abbreviated 3-day anticoagulation with dabigatran etexilate before cardioversion guided by trans-oesophageal echocardiography in comparison with conventional 3- week course of dabigatran etexilate before cardioversion

Current guidelines recommend for stroke prevention in patients with atrial fibrillation (AF) lasting more than 48 h designated for cardioversion standard approach with anticoagulation for a minimum 3 weeks before anticoagulation. The alternative is abbreviated anticoagulation in case of using trans-oesophageal echocardiography (TEE)-guided approach with quick cardioversion if no thrombus or high-grade spontaneous echo contrast is seen. There is currently no data on the direct comparison of efficacy and safety of conventional and abbreviated courses of non-vitamin K antagonist oral anticoagulants (NOAC) before cardioversion in AF.

The RE-SOUND study is prospective open label study with blinded outcome evaluation (PROBE design) multicenter active control trial comparing efficacy of 3-day abbreviated TEE-guided and conventional 3-week courses of NOAC dabigatran etexilate before cardioversion in adult patients with AF lasting more than 48 h

Eligibility Criteria:
Inclusion Criteria:

* male and female subjects aged \>18 years old and \<75 years old
* the diagnosis of non-valvular atrial fibrillation/atrial flutter duration of 48 hours or more (or unknown) documented by ECG. Duration of AF will be defined on the base of patient source documents
* documented physician's decision to conduct electrical cardioversion
* written informed consent form (ICF) signed by patient

Exclusion Criteria:

* effective treatment with oral anticoagulants within the last 30 days
* need in anticoagulant treatment for disorder other than AF
* rheumatic heart disease
* mitral stenosis of unknown origin
* mechanic heart valve
* acute coronary syndrome within 12 months
* percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) surgery within the last 12 month or planned for the next 8 weeks
* known hypersensitivity for dabigatran, dabigatran etexilate or to any of capsul's components
* creatinine clearance \<30 ml/min
* active bleeding, haemorrhagic diathesis, coagulopathy
* major surgery within the previous month, surgery planned for the next 8 weeks,
* clinically relevant bleeding within the last 30 days
* symptomatic or endoscopically documented gastroduodenal ulcers within the last 30 days
* intracranial haemorrhages in medical history
* organ damages resulted from clinically relevant bleeding within 6 months before randomization.
* major trauma or any craniocerebral trauma within 30 days before randomization.
* any cancer within last 5 years
* uncontrolled hypertension (systolic blood pressure \>180mm Hg and/or diastolic blood pressure \>100 mmHg).
* chronic heart failure (CHF) III-IV functional classes (by NYHA)
* severe ischemic stroke within the last 12 month before randomization
* changes of liver functions with alanine aminotransferase (ALT)/aspartate aminotransferase (AST) \>3 upper limit of normal (ULN)
* liver disease having impact on survival
* pregnancy and breast feeding. Women of child bearing potential must agree to the requirements for pregnancy testing and contraceptive methods
* any contraindications for electric cardioversion (see attachment # 1 for details).
* any contraindications to cerebral MRI
* any contraindications to TEE ( perforated viscus; esophageal pathology (stricture, trauma, tumor, scleroderma, Mallory-Weiss tear, diverticulum); tracheoesophageal fistula; active upper GI bleeding; recent upper GI surgery; esophagectomy, esophagogastrectomy.)
* patients who on the discretion of physician will not benefit from 150 BID dose of dabigatran during study course
* active hepatitis
* anemia (hemoglobin level \<100g/L) or thrombocytopenia (platelet count \<100 × 109/L)
* alcohol abuse
* hyperthyroidism