RISK ESTIMATIONS OF THE THROMBOEMBOLIC COMPLICATIONS DURING PLANNED ELECTRICAL CARDIOVERSION IN PATIENTS WITH PERSISTENT ATRIAL FIBRILLATION.

Pravosudovich S.A., Bondarenko O.B., Misyura D.A., Suschenko L.D., Belmas L.L., Anosova N.P., Yakovleva N.V.

Dnipropetrovsk regional clinical center of cardiologi and cardiac surgery, Ukraine.

During 3 months after the electrical cardioversion the retrospective analysis of the thromboembolic complications was performed on the patients with persistent atrial fibrillation, who were taking the anticoagulant therapy with use of warfarin or rivaroxaban, or dabigatran. Any differences of the efficiency of the used anticoagulants weren't needed. The organized thrombuses in the atrial appendage, that were found during transesophageal echoocardiography didn't raise the risk of the thromboembolic complications. Used anticoagulants were effective for the prevention of the valvular as well as nonvalvular atrial fibrillation.
Keywords: persistent atrial fibrillation, electrical cardioversion, anticoagulation, warfarin, rivaroxaban, dabigatran.

Purpose: 
Estimate the risk of the thromboembolic complications during planned electrical cardioversion in patients with persistent atrial fibrillation, who take various anticoagulants.

Materials and methods:
The retrospective analysis of the thromboembolic complications was performed on the patients who had the electrical cardioversion  (ECV) on the subject of persistent atrial fibrillation. 247 planned ECV, performed during 2014 on 221 patients (162 males) in age of 61-20 were analyzed. All patients were put on anticoagulation with warfarin in not less than 1 month before ECV with doses adjusted individually (target INR 2-3) or rivaroxaban (20 mg daily), or dabigatran (300 mg daily),  or the disaggregant therapy with acetylsalicylic acid (300 mg daily) was carried out. Anticoagulation was continued after ECV during 3 months. In 1-5 days before EKV all patients undertook transesophageal echocardiography (TEE).
Antiarrhythmic preparation treatment was performed with amiodaron (600-800 mg daily with total dose saturation not less than 20 g) or propafenon (450-600 mg  not less than a day), or sotalol (240-320 mg not less than a day).
ECV was performed with intravenous anesthesia (thiopentalum natrium or propofol) by placing the plate of defibrillator on the front surface of the chest (active electrode 2-3 intercostal space to the right of the sternum, passive electrode 6-7 intercostal space at the anterior axillary line on the left)  and applying biphasic unsynchronized with ECG discharge capacity 200-300 J. 
According to TEE, sings of the presence (localization) and quality (density and movability) of the thrombotic massesbefore ECV were took into account. After the procedure the existence of the thromboembolic complications were monitored during first three days and after three months. Cardiovascular disease background was considered.

Results:
Most of the patients (168 people, 79.6%) took warfarin. Fundamental importance in the prescription of warfarin was the price of the medicine. The same situation with rivaroxaban (was prescribed to 21 persons, 9.7%) and dabigatran (was prescribed to 20 persons, 9.3%). Because the price is relatively the same and surpasses the price of the warfarin greatly, those medicines were rarely prescribed and in almost equal proportions.  Acetylsalicylic acid was taken by only 3 people (1.4%). It was prescribed in cases of low trombosis risks or impossibility of taking the anticoagulants. The main prescribed antiarrhythmic drug was amiodaron, because of its effectiveness in precaution of atrial fibrillation relapse against propafenon and sotalol. Amiodaron was taken by 188 patients (85%). In case of intolerance of the amiodaron, propafenon (13 (6%) persons) or sotalol (18 (8%) persons) were prescribed. The next abnormity was found in all patients: coronary artery disease (CAD) in 190 (86%), myocarditic sclerosis in 13 (6%), rheumatism in 18 (8%). Arterial hypertension was found in 201 patients (91%).
212 patients (96%) who had ECV, while getting TEE performed in the left or right atrial appendage positive homogeneous sedentary inclusion intensive echo signal mark was found. Which was estimated as organized thrombus fixed. In other cases atrial appendages thrombus was not found. 
3 patients (1 took dabigatran, 1 – warfarin, 1 – rivaroksaban, all patients with CAD) during first 3-7 days after having ECV performed, had expressed increased dyspnea, increased pressure in the pulmonary artery, according to transthoracic echocardiography an increase of 25-100% from baseline was noticed, which aroused suspicious of thromboembolism pulmonary artery branches. However, after the examination diagnosis wasn't confirmed. Symptoms stoped during 1-3 weeks. Other patients didn't have any thromboembolic complications during first 3 months after the ECV.
Thromboembolic complications risk in patients having organized thrombus fixed in the atrial appendage was sufficiently low. Even with 3 cases of  suspected thromboembolism it won't surpass 1,4%. However, the results on the conduction doesn't show cumulative risk of thromboembolic complications in long terms. It requires more detailed conductions and patients monitoring for longer periods of time. 

Conclusions:
1. Anticoagulation for prevention of thromboembolic complications in patients with persistent atrial fibrillation after ECV was equaly effective both in cases with use of the warfarin and rivaroxaban or dabigatran.

2. After performing anticoagulation in 96% of cases, TEE reveals organized thrombus fixed in the atrial appendage, without reference to used anticoagulant.

3. Organized thrombus fixed in the atrial appendage does not affect the risk of the thromboembolic complications during the first month after the ECV in patients with persistent atrial fibrillation.

4. Performing the anticoagulation using the criteria of the preparation non-valvular persistent atrial fibrillation guarantees same preventive effect in patients with valvular persistent atrial fibrillation.

References
1.	Асоціація аритмологів України. Діагностика та лікування фібрілляції передсердь. Рекомендації Робочої групи з порушень ритму серця Асоціації кардіологів України. Київ. 2014.
2.	2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation. A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society. Circulation. 2014; 129: 1-124.
3.	Turpie A. New oral anticoagulants in atrial fibrillation. Eur Heart J 2008 29 (2): 155-65.
4.	Connolly S., Ezekowitz M., Yusuf S. et al. RE-LY Steering Committee and Investigation. Dabigatran versus warfarin in patients with atrial fibrillation. N Engl J Med. 2009 361: 1139-1151.
5.	Patel M., Mahaffey K., Garg J. et al. ROCKET AF Investigators. Rivaroxaban versus warfarin in non-valvular atrial fibrillation. N Engl J Med. 2011 365: 883-891.
6.	Hart R., Pearce L., Aguilar M. Meta-analysis: antithrombotic therapy to prevent stroke in patients who have nonvalvular atrial fibrillation. Ann Intern Med. 2007; 146: 857-67.