***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Aims VENTURE-AF is the first prospect i ve r and omized trial of uninterrupted rivaroxaban and vitamin K antagonists ( VKAs ) in patients with non-valvular atrial fibrillation ( NVAF ) undergoing catheter ablation ( CA ) . Methods and results Trial size was administratively set at 250 , the protocol -specified target . Events were independently and blindly adjudicated . We r and omly assigned 248 NVAF patients  to uninterrupted rivaroxaban ( 20 mg once-daily ) or to an uninterrupted VKA prior to CA and for 4 weeks afterwards . The primary endpoint was major bleeding events after CA . Secondary endpoints included thromboembolic events ( composite of stroke , systemic embolism , myocardial infa rct ion , and vascular death ) and other bleeding or procedure-attributable events . Patients were 59.5 ± 10 years of age , 71 % male , 74 % paroxysmal AF , and had a CHA2DS2-VASc score of 1.6 .  The average total heparin dose used to manage activated clotting time ( ACT ) was slightly higher ( 13 871 vs. 10 964 units ; P < 0.001 ) and the mean ACT level attained slightly lower ( 302 vs. 332 s ; P < 0.001 ) in rivaroxaban and VKA arms , respectively . The incidence of major bleeding was low ( 0.4 % ; 1 major bleeding event ) . Similarly , thromboembolic events were low ( 0.8 % ; 1 ischemic stroke and 1 vascular death ) . All events occurred in the VKA arm and all after CA . The number of any adjudicated events ( 26 vs. 25 ) , any bleeding events ( 21 vs. 18 ) , and any other procedure-attributable events ( 5 vs. 5 ) were similar . Conclusion In patients undergoing CA for AF , the use of uninterrupted oral rivaroxaban was feasible and event rates were similar to those for uninterrupted VKA therapy . Name of the Trial Registry Clinical trials.gov trial registration number is NCT01729871 OBJECTIVES The purpose of this study was to evaluate the feasibility and safety of periprocedural dabigatran during atrial fibrillation ( AF ) ablation . BACKGROUND AF ablation requires optimal periprocedural anticoagulation for minimizing bleeding and thromboembolic complications . The safety and efficacy of dabigatran as a periprocedural anticoagulant for AF ablation are unknown . METHODS We performed a multicenter , observational study from a prospect i ve registry including all consecutive patients undergoing AF ablation in 8 high-volume centers in the United States . All patients receiving dabigatran therapy who underwent AF ablation on periprocedural dabigatran , with the dose held on the morning of the procedure , were matched by age , sex , and type of AF with an equal number of patients undergoing AF ablation with uninterrupted warfarin therapy over the same period . RESULTS A total of 290 patients , including 145 taking periprocedural dabigatran and an equal number of matched patients taking uninterrupted periprocedural warfarin , were included in the study . The mean age was 60 years with 79 % being male and 57 % having paroxysmal AF . Both groups had a similar CHADS(2 ) score , left atrial size , and left ventricular ejection fraction . Three thromboembolic complications ( 2.1 % ) occurred in the dabigatran group compared with none in the warfarin group ( p = 0.25 ) . The dabigatran group had a significantly higher major bleeding rate ( 6 % vs. 1 % ; p = 0.019 ) , total bleeding rate ( 14 % vs. 6 % ; p = 0.031 ) , and composite of bleeding and thromboembolic complications ( 16 % vs. 6 % ; p = 0.009 ) compared with the warfarin group . Dabigatran use was confirmed as an independent predictor of bleeding or thromboembolic complications ( odds ratio : 2.76 , 95 % confidence interval : 1.22 to 6.25 ; p = 0.01 ) on multivariate regression analysis . CONCLUSIONS In patients undergoing AF ablation , periprocedural dabigatran use significantly increases the risk of bleeding or thromboembolic complications compared with uninterrupted warfarin therapy INTRODUCTION Stroke can be a life-threatening complication of atrial fibrillation ( AF ) catheter ablation . Uninterrupted warfarin treatment contributes to minimizing the risk of stroke complications . METHODS AND RESULTS This was a prospect i ve , open-label , r and omized , multicenter study assessing the safety and efficacy of apixaban for the prevention of cerebral thromboembolism complicating AF catheter ablation . Two hundred patients with drug-resistant AF were equally assigned to take either apixaban ( 5 mg or 2.5 mg twice daily ) or warfarin ( target international normalized ratio , 2 - 3 ) for at least 1 month before AF ablation . Neither drug regimen was interrupted throughout the operative period . Diffusion-weighted magnetic resonance imaging was performed for all patients to detect silent cerebral infa rct ion ( SCI ) after the ablation . Primary outcomes were defined as the occurrence of stroke , transient ischemic attack , SCI , or major bleeding that required intervention . The secondary outcome was minor bleeding . The groups did not statistically differ in patients ' background s or procedural parameters . During AF ablation , the apixaban group required administration of more heparin to maintain an activated clotting time > 300 seconds than the warfarin group ( apixaban , 14,000 ± 4,000 units ; warfarin , 9,000 ± 3,000 units ) . Three primary outcome events occurred in each group ( apixaban , 2 SCI and 1 major bleed ; warfarin , 3 SCI , P = 1.00 ) , and 3 and 4 secondary outcome events occurred in the apixaban and warfarin groups ( P = 0.70 ) , respectively . CONCLUSION Apixaban has similar safety and effectiveness to warfarin for the prevention of cerebral thromboembolism during the periprocedural period of AF ablation Background Systemic thromboembolism and bleeding remain the two most common and serious complications of catheter ablation of atrial fibrillation . A variety of periprocedure anticoagulation strategies have been proposed to mitigate these risks . Although operators are now routinely administering dabigatran for anticoagulation in this setting , its relative safety and effectiveness compared to warfarin are unknown . Methods and results A total of 202 patients received dabigatran  as part of their periprocedural anticoagulation regimen at the time of initial or redo catheter ablation for symptomatic atrial fibrillation . A comparison group of 202 patients treated with warfarin was r and omly selected from patients undergoing atrial fibrillation ( AF ) ablation during the same time period . AF types were paroxysmal in 223 patients , persistent in 158 patients , and longst and ing persistent in 13 patients . Mean age was 60.0 ± 10.5 years , 55 % had a history of hypertension , and mean CHADS-VASc score was 1.7 ± 1.3 . “ Continuous ” warfarin or dabigatran was administered in 80 and 32 % of patients , respectively . Time to first dose  of dabigatran post-procedure was 12.2 ± 10.3 h. Two dabigatran and no warfarin-treated patients had systemic thromboembolism ( p = NS ) ; five dabigatran and three warfarin-treated patients had bleeding complications ( p = NS , combined endpoint p = 0.116 ) . One dabigatran patient had severe pericardial bleeding ( 3 L blood loss ) . Conclusions In a retrospective pilot trial comparing the risks of systemic thromboembolism or bleeding complications in patients treated  with warfarin or dabigatran anticoagulation , the outcomes were similar . A prospect i ve trial is warranted OBJECTIVES The purpose of this study was to evaluate the feasibility and safety of uninterrupted rivaroxaban therapy during atrial fibrillation ( AF ) ablation . BACKGROUND Optimal periprocedural anticoagulation strategy is essential for minimizing bleeding and thromboembolic complications during and after AF ablation . The safety and efficacy of uninterrupted rivaroxaban therapy as a periprocedural anticoagulant for AF ablation are unknown . METHODS We performed a multicenter , observational , prospect i ve study of a registry of patients undergoing AF ablation in 8 centers in North America . Patients taking uninterrupted periprocedural rivaroxaban were matched by age , sex , and type of AF with an equal number of patients taking uninterrupted warfarin therapy who were undergoing AF ablation during the same period . RESULTS A total of 642 patients were included in the study , with 321 in each group . Mean age was 63 ± 10 years , with 442 ( 69 % ) males and 328 ( 51 % ) patients with paroxysmal AF equally distributed between the 2 groups . Patients in the warfarin group had a slightly higher mean HAS- BLED ( hypertension , abnormal renal/liver function , stroke , bleeding history or predisposition , labile international normalized ratio , elderly , drugs/alcohol concomitantly ) score ( 1.70 ± 1.0 vs. 1.47 ± 0.9 , respectively ; p = 0.032 ) . Bleeding and embolic complications occurred in 47 ( 7.3 % ) and 2 ( 0.3 % ) patients ( both had transient ischemic attacks ) respectively . There were no differences in the number of major bleeding complications ( 5 [ 1.6 % ] vs. 7 [ 1.9 % ] , respectively ; p = 0.772 ) , minor bleeding complications ( 16 [ 5.0 % ] vs. 19 [ 5.9 % ] , respectively ; p = 0.602 ) , or embolic complications ( 1 [ 0.3 % ] vs. 1 [ 0.3 % ] , respectively ; p = 1.0 ) between the rivaroxaban and warfarin groups in the first 30 days . CONCLUSIONS Uninterrupted rivaroxaban therapy appears to be as safe and efficacious in preventing bleeding and thromboembolic events in patients undergoing AF ablation as uninterrupted warfarin therapy Advances in antithrombotic therapy , along with an early invasive strategy , have reduced the incidence of recurrent ischemic events and death in patients with acute coronary syndromes ( ACS ; unstable angina , non – ST-segment – elevation myocardial infa rct ion [ MI ] , and ST-segment – elevation MI).1,–,4 However , the combination of multiple pharmacotherapies , including aspirin , platelet P2Y12 inhibitors , heparin plus glycoprotein IIb/IIIa inhibitors , direct thrombin inhibitors , and the increasing use of invasive procedures , has also been associated with an increased risk of bleeding . Editorial see p 2664 Bleeding complications have been associated with an increased risk of subsequent adverse outcomes , including MI , stroke , stent thrombosis , and death , in patients with ACS and in those undergoing percutaneous coronary intervention (PCI),5,–,10 as well as in the long-term antithrombotic setting .11,12 Thus , balancing the anti-ischemic benefits against the bleeding risk of antithrombotic agents and interventions is of paramount importance in assessing new therapies and in managing patients . Prior r and omized trials comparing antithrombotic agents suggest that a reduction in bleeding events is associated with improved survival.13,14 Because prevention of major bleeding may represent an important step in improving outcomes by balancing safety and efficacy in the contemporary treatment of ACS , bleeding events have been systematic ally identified as a crucial end point for the assessment of the safety of drugs during the course of r and omized clinical trials , and are an important aspect of the evaluation of new devices and interventional therapies.15 Unlike ischemic clinical events ( eg , cardiac death , MI , stent thrombosis ) , for which there is now general consensus on end-point definitions,16,17 there is substantial heterogeneity among the many bleeding definitions currently in use . Lack of st and ardization makes it difficult to optimally organize key clinical trial processes such as adjudication , and even more difficult to interpret relative Purpose Left atrial catheter ablation for patients with atrial fibrillation ( AF ) requires periprocedural anticoagulation to minimize thromboembolic complications . High rates of major bleeding complications using dabigatran etexilate for periprocedural anticoagulation have been reported , raising concerns regarding its safety during left atrial catheter ablation . We sought to evaluate the safety and efficacy of a dabigatran use strategy versus warfarin , at a single high-volume AF ablation center . Methods We performed a retrospective analysis on consecutive patients undergoing left atrial ablation at V and erbilt Medical Center from January 2011 through August 2012 with a minimum follow-up of 3 months . Patient cohorts were divided into two groups , those utilizing dabigatran etexilate pre- and post-ablation and those undergoing ablation on 
    Output:
    
Conclusion An uninterrupted DOACs strategy for CA of NVAF appears to be as safe as uninterrupted VKA without a significantly increased risk of minor or major bleeding events .
There was a trend favouring DOACs in terms of major bleeding .