***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 
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    Input: AIMS Current guidelines recommend discontinuation of oral anticoagulation treatment ( OAT ) and switch to heparin 2 - 5 days before catheter ablation of  atrial fibrillation ( AF ) . However , increasing evidence leans against the ' bridge therapy ' and support continuation of OAT during the procedure . METHODS AND RESULTS We evaluated the safety of AF ablation among patients with therapeutic OAT . The study population comprised 193 consecutive patients who underwent 228 AF ablation procedures guided by electroanatomical mapping .  Periprocedural international normalized ratio was < 2 ( 1.6 ± 0.3 ) in 103 cases ( Group 1 ) and ≥2 ( 2.4 ± 0.4 ) in 125 cases ( Group 2 ) . Heparin ( 5000 IU bolus followed by continuous infusion through an open-irrigated ablation catheter ) was used in both groups . No intracardiac echocardiographic guidance was used and activated clotting time ( ACT ) was not monitored . The incidence of major ( intracranial bleeding , tamponade , bleeding that required surgical intervention , or blood transfusion ) and minor bleeding complications and all thrombo-embolic events were registered during the 3-month follow-up . There was no statistical difference in major ( P = 1.0 ) and minor complications ( P = 0.74 ) between the groups . The bleeding complications included one surgically corrected groin haematoma in both groups ( 0.9 % ) , 25 small haematomas at the puncture site ( 11 in Group 1 ( 10.7 % ) and 14 in Group 2 ( 11.2 % ) , P = 0.90 ) , and two minor pericardial effusions in Group 1 . In Group 2 , one patient had ischaemic stroke 16 days after the procedure . CONCLUSION Transseptal puncture and AF ablation can be performed safely in patients with ongoing OAT without intracardiac echocardiographic guidance and ACT monitoring Background — The best approach to management of anticoagulation before and after atrial fibrillation ablation is not known . Methods and Results — We compared outcomes in consecutive patients undergoing pulmonary vein antrum isolation for persistent atrial fibrillation . Early in our practice , warfarin was stopped 3 days before ablation , and a transesophageal echocardiogram was performed to rule out clot . Enoxaparin , initially 1 mg/kg twice daily ( group 1 ) and then 0.5 mg/kg twice daily ( group 2 ) , was used to “ bridge ” patients after ablation . Subsequently , warfarin was continued to maintain the international normalized ratio between 2 and 3.5 ( group 3 ) . Minor bleeding was defined as hematoma that did not require intervention . Major bleeding was defined as either cardiac tamponade , hematoma that required intervention , or bleeding that required blood transfusion .  Pulmonary vein ablation was performed in 355 patients ( group 1=105 , group 2=100 , and group 3=150 ) . More patients had spontaneous echocardiographic contrast in groups 1 and 2 . One patient in group 1 had an ischemic stroke compared with 2 patients in group 2 and no patients in group 3 . In group 1 , 23 patients had minor bleeding , 9 had major bleeding , and 1 had pericardial effusion but no tamponade . In group 2 , 19 patients had minor bleeding , and 2 patients developed symptomatic pericardial effusion with need for pericardiocentesis 1 week after discharge . In group 3 , 8 patients developed minor bleeding , and 1 patient developed pericardial effusion with no tamponade . Conclusions — Continuation of warfarin throughout pulmonary vein ablation without administration of enoxaparin is safe and efficacious . This strategy can be an alternative to bridging with enoxaparin or heparin in the periprocedural period INTRODUCTION Many patients undergoing catheter ablation of atrial flutter ( AFL ) require periprocedural anticoagulation . We compared a strategy of conversion to low molecular weight heparin ( LMWH ) periprocedure to uninterrupted warfarinization in a nonr and omized , case-controlled study . METHODS One hundred and one consecutive patients requiring periprocedural anticoagulation for catheter ablation of typical AFL were studied . The first 51 patients underwent conversion to LMWH ( enoxaparin 1 mg/kg bd ) with a warfarin pause ( LMWH group ) , the subsequent 50 continued with uninterrupted oral anticoagulation ( Warfarin group ) . Primary endpoint was a composite of major and minor bleeding complications and groin symptoms . RESULTS Fewer patients in the Warfarin group reached the primary endpoint ( 36.0 % vs 56.8 % , P = 0.013 ) . Four patients in the LMWH group but no patient in the Warfarin group required hospital admission for bleeding-related complications . Cost analysis showed mean cost per patient of anticoagulation with LMWH to be pounds sterling 100.9 ( 95 % CI 94.46 - 107.30 ) compared to pounds sterling 10.23 ( 4.49 - 15.97 ) in the Warfarin group ( P < 0.0001 ) . Transesophageal echocardiography ( TEE ) was performed prior to ablation in 11 patients in the Warfarin group and in 3 patients in the LMWH ( P = 0.019 ) . When TEE costs were included , costs were pounds sterling 125.00 ( $ 188.25 ) ( 96.80 - 153.60 ) for the LMWH strategy and pounds sterling 108.5 ( $ 163.40 ) ( 54.92 - 162.1 ) for the Warfarin group ( P < 0.0001 ) . CONCLUSIONS Catheter ablation of typical AFL without interruption of warfarin appears safer and more cost-effective than periprocedural conversion to LMWH . It could be used as a routine anticoagulation strategy for the ablation of right-sided arrhythmias Background — Periprocedural thromboembolic and hemorrhagic events are worrisome complications of catheter ablation for atrial fibrillation ( AF ) . The periprocedural anticoagulation management could play a role in the incidence of these complications . Although ablation procedures performed without warfarin discontinuation seem to be associated with lower thromboembolic risk , no r and omized study exists . Methods and Results — This was a prospect i ve , open-label , r and omized , parallel-group , multicenter study assessing the role of continuous warfarin therapy in preventing periprocedural thromboembolic and hemorrhagic events after radiofrequency catheter ablation . Patients with CHADS2 score ≥1 were included . Patients were r and omly assigned in a 1:1 ratio to the off-warfarin or on-warfarin arm . The incidence of thromboembolic events in the 48 hours after ablation was the primary end point of the study . The study enrolled 1584 patients : 790 assigned to discontinue warfarin ( group 1 ) and 794 assigned to continuous warfarin ( group 2 ) . No statistical difference in baseline characteristics was observed . There were 39 thromboembolic events ( 3.7 % strokes [ n=29 ] and 1.3 % transient ischemic attacks [ n=10 ] ) in group 1 : two events ( 0.87 % ) in patients with paroxysmal AF , 4 ( 2.3 % ) in patients with persistent AF , and 33 ( 8.5 % ) in patients with long-st and ing persistent AF . Only 2 strokes ( 0.25 % ) in patients with long-st and ing persistent AF were observed in group 2 ( P<0.001 ) . Warfarin discontinuation emerged as a strong predictor of periprocedural thromboembolism ( odds ratio , 13 ; 95 % confidence interval , 3.1–55.6 ; P<0.001 ) . Conclusion — This is the first r and omized study showing that performing catheter ablation of AF without warfarin discontinuation reduces the occurrence of periprocedural stroke and minor bleeding complications compared with bridging with low-molecular-weight heparin . Clinical Trial Registration — URL : http://www . clinical trials.gov . Unique identifier : NCT01006876 AIMS Pulmonary vein antrum isolation ( PVAI ) plays a pivotal role in the comprehensive treatment of atrial fibrillation ( AF ) . The need for effective anticoagulation bridging following PVAI is associated with significant vascular complication rates and increased costs . We investigated the safety of PVAI in patients with therapeutic international normalized ratios ( INR ) the day of the procedure . METHODS A case-control analysis was performed on patients who underwent PVAI with therapeutic INR ( > 2 ) . Patients with normal preprocedure INR served as controls . The incidence of major and minor hematomas , fistulas , vascular injury , and cardiac perforation or tamponade were catalogued . PVAI was performed under fluoroscopic , electro-anatomical , and intracardiac echocardiographic guidance , with an open irrigation ablation technique . RESULTS A total of 194 patients ( mean age 64 + /- 12 ) were included ; 87 patients underwent PVAI with therapeutic INR ( cases ) and 107 with normal INR ( controls ) . Persistent AF was more prevalent than paroxysmal AF in the therapeutic INR group . The mean INR for cases was 2.8 + /- 0.7 compared to 1.4 + /- 0.3 in the control group ( P < 0.01 ) . All procedures were completed without acute complications . Two major adverse events were observed , one in each arm . No significant difference in terms of minor ( 6.5 % vs. 5.7 % , P = 0.23 ) or major ( 0.93 % vs. 1.15 % , P = 0.49 ) vascular events or bleeding was detected between the therapeutic INR and the control group . The combined endpoint of major and minor complications did not differ among groups ( 9.35 % vs. 8.05 % , P = 0.19 ) . CONCLUSION Atrial fibrillation ablation in patients with therapeutic INR on the day of a procedure appears to be safe and feasible . Expensive outpatient anti-coagulation bridging may be safely avoided in this type of population Aims Current guidelines recommend stopping oral anticoagulation ( OAC ) and starting heparin infusion before implanting/replacing a pacemaker/implantable cardioverter-defibrillator ( ICD ) in patients with high risk for thrombo-embolic events . The aim of this study was to demonstrate that the maintenance of OAC during device implantation/replacement is as safe as bridging to intravenous heparin and shortens in-hospital stay . Methods and results A cohort of 101 consecutive patients with high risk for embolic events and indication for implant/replacement of a pacemaker/ICD were r and omized to two anticoagulant strategies : bridging from OAC to heparin infusion ( n = 51 ) vs. maintenance of OAC to reach an INR = 2 ± 0.3 at the day of the procedure ( n = 50 ) . Haemorrhagic and thrombo-embolic complications were evaluated at discharge , 15 and 45 days after the procedure . A total of 4/51 patients ( 7.8 % ) from heparin group and 4/50 ( 8.0 % ) from the OAC group developed pocket haematoma following the implant ( P = 1.00 ) . One haematoma in each group required evacuation ( 1.9 vs. 2 % , P = 1.00 ) . No other haemorrhagic events or embolic complications developed during the follow-up . Duration of the hospital stay was longer in the heparin group [ median of 5 ( 4–7 ) vs. 2 ( 1–4 ) days ; P < 0.001 ] . Conclusion Implant of devices maintaining OAC is as safe as bridging to heparin infusion and allows a significant reduction of in-hospital stay BACKGROUND The anti-thrombotic strategy during coronary stenting is challenging in patients on long-term oral anticoagulation ( OAC ) because of atrial fibrillation ( AF ) .  Uninterrupted OAC ( UAC ) is increasingly used , but bridging therapy ( BT ) is still in common use . METHODS AND RESULTS Management of patients with Atrial Fibrillation undergoing Coronary Artery Stenting ( AFCAS ) is a prospect i ve multicenter European registry that recruited 963 patients with AF undergoing coronary stenting . To compare the safety of UAC and BT , bleeding complications and major adverse cardiac and cerebrovascular events ( MACCE ; death , myocardial infa rct ion , target vessel revascularization , stent thrombosis and stroke ) were assessed in 290 patients treated with UAC and 161 patients with BT during a 30-day follow-up period . In the BT group , OAC was interrupted for a median of 5 days . Overall bleeding complications tended to be more common in the BT group ( 18.6 % vs. 12.1 % , P=0.07 ) , with no significant difference in the rate of major bleeding ( 2.5 % vs. 1.4 % ) or MACCE ( 6. 
    Output:
    
Uninterrupted perioperative warfarin therapy is safe for patients undergoing arterial procedures , but interrupted warfarin may be preferred for those undergoing venous procedures ; no differences in outcome rates were found in the r and omized controlled trials .