human
***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: Background — MRI-detected brain lesions are common after  left atrial catheter ablation for symptomatic atrial fibrillation . The clinical relevance of these acute ischemic lesions is not fully understood , but ablation-related cerebral injury could contribute to cognitive dysfunction . Methods and Results — In the prospect i ve Mesh Ablator versus Cryoballoon Pulmonary Vein Ablation of Symptomatic Paroxysmal Atrial Fibrillation ( MACPAF ) study , serial 3-T brain MRIs and neuropsychological assessment were performed to analyze the rate of ablation-related brain lesions and their effect on cognitive function .  Thirty-seven patients with paroxysmal atrial fibrillation ( median age , 63.0 [ interquartile range , 57–68 ] years ; 41 % female ; median CHA2DS2VASc score 2 [ interquartile range , 1–3 ] ) underwent 41 ablation procedures according to study criteria . None of these patients had overt neurological deficits after ablation . High-resolution diffusion-weighted imaging , performed within 48 hours after ablation , showed that new brain lesions ( range , 1–17 ) were present in 16 ( 43.2 % ) patients after 18 ( 43.9 % ) left atrial catheter ablation procedures . Follow-up MRI at 6 months ( median , 6.5 ; interquartile range , 6–7 ) revealed that 7 ( 12.5 % ) of the 56 total acute brain lesions after ablation formed a persistent glial scar in 5 ( 31.3 % ) patients . Large diffusion-weighted imaging lesions and a corresponding fluid-attenuated inversion recovery lesion 48 hours after ablation predicted lesion persistence on 6-month follow-up . Neither persistent brain lesions nor the ablation procedure itself had a significant effect on attention or executive functions , short-term memory , or verbal and nonverbal learning after 6 months . Conclusions — Ablation-related acute ischemic brain lesions persist to some extent but do not cause cognitive impairment 6 months after the ablation procedure . Clinical Trial Registration — URL : http://www . clinical trials.gov . Unique identifier : NCT01061931 BACKGROUND Asymptomatic cerebral lesions ( ACL ) may occur during  atrial fibrillation ( AF ) ablation . We sought to compare the ACL incidence between 3 contemporary technologies : ( 1 ) irrigated radiofrequency current ( RFC ) , ( 2 ) the single big cryoballoon ( CB ) , and ( 3 ) the endoscopic laser-balloon ( LB ) in a prospect i ve r and omized pilot study . METHODS AND RESULTS Ninety-nine patients were treated in 3 groups .  Diffusion weighted MRI was acquired pre- ( n = 20 ) and 24 - 48 h postablation ( n = 99 ) . After ablation , new ACL were detected in 22 % of patients without significant differences between groups ( RFC 8/33 ; CB 6/33 ; LB 8/33 ; P = 0.8 ) . The presence of hypertension was identified as the only independent predictor of ACL by univariate regression analysis . During LB ablation , more ablation lesions ( 140 ± 19 vs 119 ± 18 ; P = 0.007 ) were applied during longer procedures ( 166 ± 36 vs 143 ± 32 min ; P = 0.05 ) in patients with ACL . Univariate analysis revealed that a higher number of ablation lesions predicted ACL ( P = 0.02 ) . CONCLUSION In this prospect i ve , r and omized , single-center pilot study , ablation technology did not influence the occurrence of ACL during AF ablation INTRODUCTION There are limited comparative data on catheter ablation of atrial fibrillation ( CAAF ) using the second-generation cryoballoon ( CB-2 ) versus point-by-point radiofrequency ( RF ) . This study examines the acute/long-term CAAF outcomes using these 2 strategies . METHODS AND RESULTS In this multicenter , retrospective , nonr and omized analysis , procedural and clinical outcomes of 1,196 patients ( 76 % with paroxysmal AF ) undergoing CAAF using CB-2 ( n = 773 ) and open-irrigated , non-force sensing RF ( n = 423 ) were evaluated . Pulmonary vein isolation was achieved in 98 % with CB-2 and 99 % with RF ( P = 0.168 ) . CB-2 was associated with shorter ablation time ( 40 ± 14 min vs. 66 ± 26 min ; P < 0.001 ) and procedure time ( 145 ± 49 minutes vs. 188 ± 42 minutes ; P < 0.001 ) , but greater fluoroscopic utilization ( 29 ± 13 minutes vs. 23 ± 14 minutes ; P < 0.001 ) . While transient ( 7.6 % vs. 0 % ; P < 0.001 ) and persistent ( 1.2 % vs. 0 % ; P = 0.026 ) phrenic nerve palsy occurred exclusively with CB-2 , other adverse event rates were similar between CB-2 ( 1.6 % ) and RF ( 2.6 % ) ; P = 0.207 . However , freedom from AF/atrial flutter/tachycardia at 12 months following a single procedure without antiarrhythmic therapy was greater with CB-2 ( 76.6 % ) versus RF ( 60.4 % ) ; P < 0.001 . While this difference was evident in patients with paroxysmal AF ( P < 0.001 ) , it did not reach significance in those with persistent AF ( P = 0.089 ) . Additionally , CB-2 was associated with reduced long-term need for antiarrhythmic therapy ( 16.7 % vs. 22.0 % ; P = 0.024 ) and repeat ablations ( 14.6 % vs. 24.1 % ; P < 0.001 ) . CONCLUSION In this multicenter , retrospective , nonr and omized study , CAAF using CB-2 coupled with RF as occasionally required was associated with greater freedom from atrial arrhythmias at 12 months following a single procedure without antiarrhythmic therapy when compared to open-irrigated , non-force sensing RF , alone BACKGROUND Contact force ( CF ) monitoring could be useful in accomplishing circumferential pulmonary vein ( PV ) isolation ( CPVI ) for atrial fibrillation ( AF ) . OBJECTIVE The purpose of this study was to compare procedure parameters and outcomes between CF-guided and non-guided CPVI . METHODS Thirty-eight consecutive AF patients ( mean age 60 ± 11 years , 28 paroxysmal AF ) undergoing CPVI were r and omized to non-CF-guided ( n = 19 ) and CF-guided ( n = 19 ) groups .  CPVI was performed with the ThermoCool SmartTouch catheter in both groups . The end-point was bidirectional block between the left atrium ( LA ) and PV . In the CF group , CF was kept between 10 and 20 g during CPVI , whereas in the non-CF group , all CF information was blanked . Radiofrequency energy at 30 W in the anterior and 25 W in the posterior LA wall was applied for 20 - 25 seconds at each point . RESULTS CPVI was successfully accomplished without any major complications in both groups . Mean CF in the non-CF and CF groups were 5.9 ± 4.5 g and 11.1 ± 4.3 g , respectively , for left-side CPVI , and 9.8 ± 6.6 g and 12.1 ± 4.8 g , respectively , for right-side CPVI ( both P < .001 ) . The procedure and fluoroscopy times  for CPVI in the non-CF and CF groups were 96 ± 39 minutes and 59 ± 16 minutes , respectively ( P < .001 ) , and 22 ± 63 seconds and 9 ± 20 seconds ( P = NS ) , respectively . Total number of residual conduction gaps was 6.3 ± 3.0 in the non-CF group and 2.8 ± 1.9 in the CF group ( P < .001 ) . During 6-month follow-up , 84.2 % of patients in the non-CF group and 94.7 % in the CF group were free from any atrial tachyarrhythmias ( P = .34 ) . CONCLUSION CF-guided CPVI  is effective in reducing procedure time and additional touch-up ablation and may improve long-term outcome Background — There is a lack of data on the comparative efficacy and procedural safety of open irrigated radiofrequency ( RF ) and cryoballoon catheter ( CB ) ablation for pulmonary vein isolation in patients with paroxysmal atrial fibrillation . Methods and Results — In a prospect i ve , noninferiority study , 315 patients were r and omly assigned to RF ( n=159 ) or CB ( n=156 ) ablation . The primary end point was freedom from atrial arrhythmia with absence of persistent complications . Patients were largely comparable between groups with more vascular disease in the RF group ( 8.2 % versus 2.6 % for CB ; P=0.028 ) . The primary end point at 12 months was achieved by 70.7 % with RF and 73.6 % with CB ( multiple procedure success ) , including 31 redo procedures in each group ( 19.5 % of RF versus 19.9 % of CB ; P=0.933 ) . For the intention-to-treat population , noninferiority of CB was revealed for the predefined inferiority margin ( risk difference , 0.029 ; 95 % confidence interval , −0.074 to 0.132 ; P<0.001 ) . Rates at 6 months were 63.1 % and 64.1 % for the RF and CB groups ( single procedure success ) , and noninferiority was confirmed ( risk difference , 0.010 ; 95 % confidence interval , −0.097 to 0.116 ; P=0.002 ) . Periprocedural complications for the index procedure were more frequent in the CB group ( 5.0 % RF , 12.2 % CB ; P=0.022 ) with a significant difference in phrenic nerve palsies ( 0 % RF , 5.8 % CB ; P=0.002 ) . Conclusion — This large , prospect i ve , r and omized , controlled study demonstrates noninferiority of CB ablation versus RF ablation for treating patients with paroxysmal atrial fibrillation . Clinical Trial Registration — URL : http://www . clinical trials.gov . Unique identifier : NCT00774566 AIMS Catheter ablation of the pulmonary veins ( PVs ) is a promising therapeutic approach for symptomatic atrial fibrillation ( AF ) . The prospect i ve r and omized single-centre study ' Mesh Ablator versus Cryoballoon Pulmonary Vein Ablation of Symptomatic Paroxysmal Atrial Fibrillation ' ( MACPAF ; clinical trials.gov NCT01061931 ) compared the efficacy and safety of two balloon-based PV ablation systems . METHODS AND RESULTS Thirty-two patients underwent PV ablation for symptomatic paroxysmal AF using the A rct ic Front ® or the HD Mesh Ablator ® catheter  according to study protocol . The primary endpoint was complete PV isolation ( PVI ) at the end of the ablation procedure , determined by exit block after achieving entrance block . Long-term follow-up data are not included in this publication . Patients ' mean age was 61.7 ± 8.9 years , 43.2 % were female , and median CHA₂DS₂-VASc score was 2.0 . In the intention-to-treat analysis , the rate of the primary endpoint was 56.5 % in patients r and omized to the A rct ic Front ® and 9.5 % in patients r and omized to the HD Mesh Ablator ® catheter ( P = 0.001 ) . In the per- protocol analysis , complete PVI was achieved in 13 ( 76.5 % ) of 17 A rct ic Front ® patients but in none of the 15 HD Mesh Ablator ® patients ( P < 0.0001 ) . There were one major and two minor complications in each study arm but no clinical ly evident stroke . Post-procedural AF recurrence was detected within hospital stay in two ( 11.8 % ) A rct ic Front ® patients and in seven ( 46.7 % ) HD Mesh Ablator ® patients ( P = 0.049 ) . CONCLUSION The MACPAF study revealed a superiority of the A rct ic Front ® catheter concerning complete PVI . Owing to the insufficient efficacy of the HD Mesh Ablator ® catheter , the safety board decided to stop MACPAF prematurely BACKGROUND Catheter ablation is an established treatment for atrial fibrillation ( AF ) .  Cryoballoon ablation ( CBA ) has emerged as an alternative to radiofrequency ablation ( RFA ) . However , there are few data comparing these modalities for treatment of paroxysmal AF ( pAF ) in the U.S. POPULATION The purpose of this study was to 
    Output:
    
agent
Pool analyses indicated that CB ablation was more beneficial in terms of procedural time [ st and ard mean difference = −0.58 ; 95 % confidence interval ( CI ) , −0.85 to −0.30 ] , complications without phrenic nerve injury ( PNI ) [ odds ratio ( OR ) = 0.79 ; 95 % CI , 0.67–0.93 ; I2 = 16 % ] , and recrudescence ( OR = 0.83 ; 95 % CI , 0.70–0.97 ; I2 = 63 % ) for PAF ; however , the total complications of CB was higher than RF .
The subgroup analysis found that , compared with non-contact force radiofrequency ( non-CF-RF ) , both first-generation cryoballoon ( CB1 ) and second-generation cryoballoon ( CB2 ) ablation  could reduce complications with PNI , procedural time , and recrudescence .
However , the safety and efficacy of CB2 was similar to those of CF-RF .
Conclusion Available overall and subgroup data suggested that both CB1 and CB2 were more beneficial than RF ablation , and the main advantages were reflected in comparing them with non-CF-RF .
However , CF-RF and CB2 showed similar clinical benefits
***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: Background — MRI-detected brain lesions are common after  left atrial catheter ablation for symptomatic atrial fibrillation . The clinical relevance of these acute ischemic lesions is not fully understood , but ablation-related cerebral injury could contribute to cognitive dysfunction . Methods and Results — In the prospect i ve Mesh Ablator versus Cryoballoon Pulmonary Vein Ablation of Symptomatic Paroxysmal Atrial Fibrillation ( MACPAF ) study , serial 3-T brain MRIs and neuropsychological assessment were performed to analyze the rate of ablation-related brain lesions and their effect on cognitive function .  Thirty-seven patients with paroxysmal atrial fibrillation ( median age , 63.0 [ interquartile range , 57–68 ] years ; 41 % female ; median CHA2DS2VASc score 2 [ interquartile range , 1–3 ] ) underwent 41 ablation procedures according to study criteria . None of these patients had overt neurological deficits after ablation . High-resolution diffusion-weighted imaging , performed within 48 hours after ablation , showed that new brain lesions ( range , 1–17 ) were present in 16 ( 43.2 % ) patients after 18 ( 43.9 % ) left atrial catheter ablation procedures . Follow-up MRI at 6 months ( median , 6.5 ; interquartile range , 6–7 ) revealed that 7 ( 12.5 % ) of the 56 total acute brain lesions after ablation formed a persistent glial scar in 5 ( 31.3 % ) patients . Large diffusion-weighted imaging lesions and a corresponding fluid-attenuated inversion recovery lesion 48 hours after ablation predicted lesion persistence on 6-month follow-up . Neither persistent brain lesions nor the ablation procedure itself had a significant effect on attention or executive functions , short-term memory , or verbal and nonverbal learning after 6 months . Conclusions — Ablation-related acute ischemic brain lesions persist to some extent but do not cause cognitive impairment 6 months after the ablation procedure . Clinical Trial Registration — URL : http://www . clinical trials.gov . Unique identifier : NCT01061931 BACKGROUND Asymptomatic cerebral lesions ( ACL ) may occur during  atrial fibrillation ( AF ) ablation . We sought to compare the ACL incidence between 3 contemporary technologies : ( 1 ) irrigated radiofrequency current ( RFC ) , ( 2 ) the single big cryoballoon ( CB ) , and ( 3 ) the endoscopic laser-balloon ( LB ) in a prospect i ve r and omized pilot study . METHODS AND RESULTS Ninety-nine patients were treated in 3 groups .  Diffusion weighted MRI was acquired pre- ( n = 20 ) and 24 - 48 h postablation ( n = 99 ) . After ablation , new ACL were detected in 22 % of patients without significant differences between groups ( RFC 8/33 ; CB 6/33 ; LB 8/33 ; P = 0.8 ) . The presence of hypertension was identified as the only independent predictor of ACL by univariate regression analysis . During LB ablation , more ablation lesions ( 140 ± 19 vs 119 ± 18 ; P = 0.007 ) were applied during longer procedures ( 166 ± 36 vs 143 ± 32 min ; P = 0.05 ) in patients with ACL . Univariate analysis revealed that a higher number of ablation lesions predicted ACL ( P = 0.02 ) . CONCLUSION In this prospect i ve , r and omized , single-center pilot study , ablation technology did not influence the occurrence of ACL during AF ablation INTRODUCTION There are limited comparative data on catheter ablation of atrial fibrillation ( CAAF ) using the second-generation cryoballoon ( CB-2 ) versus point-by-point radiofrequency ( RF ) . This study examines the acute/long-term CAAF outcomes using these 2 strategies . METHODS AND RESULTS In this multicenter , retrospective , nonr and omized analysis , procedural and clinical outcomes of 1,196 patients ( 76 % with paroxysmal AF ) undergoing CAAF using CB-2 ( n = 773 ) and open-irrigated , non-force sensing RF ( n = 423 ) were evaluated . Pulmonary vein isolation was achieved in 98 % with CB-2 and 99 % with RF ( P = 0.168 ) . CB-2 was associated with shorter ablation time ( 40 ± 14 min vs. 66 ± 26 min ; P < 0.001 ) and procedure time ( 145 ± 49 minutes vs. 188 ± 42 minutes ; P < 0.001 ) , but greater fluoroscopic utilization ( 29 ± 13 minutes vs. 23 ± 14 minutes ; P < 0.001 ) . While transient ( 7.6 % vs. 0 % ; P < 0.001 ) and persistent ( 1.2 % vs. 0 % ; P = 0.026 ) phrenic nerve palsy occurred exclusively with CB-2 , other adverse event rates were similar between CB-2 ( 1.6 % ) and RF ( 2.6 % ) ; P = 0.207 . However , freedom from AF/atrial flutter/tachycardia at 12 months following a single procedure without antiarrhythmic therapy was greater with CB-2 ( 76.6 % ) versus RF ( 60.4 % ) ; P < 0.001 . While this difference was evident in patients with paroxysmal AF ( P < 0.001 ) , it did not reach significance in those with persistent AF ( P = 0.089 ) . Additionally , CB-2 was associated with reduced long-term need for antiarrhythmic therapy ( 16.7 % vs. 22.0 % ; P = 0.024 ) and repeat ablations ( 14.6 % vs. 24.1 % ; P < 0.001 ) . CONCLUSION In this multicenter , retrospective , nonr and omized study , CAAF using CB-2 coupled with RF as occasionally required was associated with greater freedom from atrial arrhythmias at 12 months following a single procedure without antiarrhythmic therapy when compared to open-irrigated , non-force sensing RF , alone BACKGROUND Contact force ( CF ) monitoring could be useful in accomplishing circumferential pulmonary vein ( PV ) isolation ( CPVI ) for atrial fibrillation ( AF ) . OBJECTIVE The purpose of this study was to compare procedure parameters and outcomes between CF-guided and non-guided CPVI . METHODS Thirty-eight consecutive AF patients ( mean age 60 ± 11 years , 28 paroxysmal AF ) undergoing CPVI were r and omized to non-CF-guided ( n = 19 ) and CF-guided ( n = 19 ) groups .  CPVI was performed with the ThermoCool SmartTouch catheter in both groups . The end-point was bidirectional block between the left atrium ( LA ) and PV . In the CF group , CF was kept between 10 and 20 g during CPVI , whereas in the non-CF group , all CF information was blanked . Radiofrequency energy at 30 W in the anterior and 25 W in the posterior LA wall was applied for 20 - 25 seconds at each point . RESULTS CPVI was successfully accomplished without any major complications in both groups . Mean CF in the non-CF and CF groups were 5.9 ± 4.5 g and 11.1 ± 4.3 g , respectively , for left-side CPVI , and 9.8 ± 6.6 g and 12.1 ± 4.8 g , respectively , for right-side CPVI ( both P < .001 ) . The procedure and fluoroscopy times  for CPVI in the non-CF and CF groups were 96 ± 39 minutes and 59 ± 16 minutes , respectively ( P < .001 ) , and 22 ± 63 seconds and 9 ± 20 seconds ( P = NS ) , respectively . Total number of residual conduction gaps was 6.3 ± 3.0 in the non-CF group and 2.8 ± 1.9 in the CF group ( P < .001 ) . During 6-month follow-up , 84.2 % of patients in the non-CF group and 94.7 % in the CF group were free from any atrial tachyarrhythmias ( P = .34 ) . CONCLUSION CF-guided CPVI  is effective in reducing procedure time and additional touch-up ablation and may improve long-term outcome Background — There is a lack of data on the comparative efficacy and procedural safety of open irrigated radiofrequency ( RF ) and cryoballoon catheter ( CB ) ablation for pulmonary vein isolation in patients with paroxysmal atrial fibrillation . Methods and Results — In a prospect i ve , noninferiority study , 315 patients were r and omly assigned to RF ( n=159 ) or CB ( n=156 ) ablation . The primary end point was freedom from atrial arrhythmia with absence of persistent complications . Patients were largely comparable between groups with more vascular disease in the RF group ( 8.2 % versus 2.6 % for CB ; P=0.028 ) . The primary end point at 12 months was achieved by 70.7 % with RF and 73.6 % with CB ( multiple procedure success ) , including 31 redo procedures in each group ( 19.5 % of RF versus 19.9 % of CB ; P=0.933 ) . For the intention-to-treat population , noninferiority of CB was revealed for the predefined inferiority margin ( risk difference , 0.029 ; 95 % confidence interval , −0.074 to 0.132 ; P<0.001 ) . Rates at 6 months were 63.1 % and 64.1 % for the RF and CB groups ( single procedure success ) , and noninferiority was confirmed ( risk difference , 0.010 ; 95 % confidence interval , −0.097 to 0.116 ; P=0.002 ) . Periprocedural complications for the index procedure were more frequent in the CB group ( 5.0 % RF , 12.2 % CB ; P=0.022 ) with a significant difference in phrenic nerve palsies ( 0 % RF , 5.8 % CB ; P=0.002 ) . Conclusion — This large , prospect i ve , r and omized , controlled study demonstrates noninferiority of CB ablation versus RF ablation for treating patients with paroxysmal atrial fibrillation . Clinical Trial Registration — URL : http://www . clinical trials.gov . Unique identifier : NCT00774566 AIMS Catheter ablation of the pulmonary veins ( PVs ) is a promising therapeutic approach for symptomatic atrial fibrillation ( AF ) . The prospect i ve r and omized single-centre study ' Mesh Ablator versus Cryoballoon Pulmonary Vein Ablation of Symptomatic Paroxysmal Atrial Fibrillation ' ( MACPAF ; clinical trials.gov NCT01061931 ) compared the efficacy and safety of two balloon-based PV ablation systems . METHODS AND RESULTS Thirty-two patients underwent PV ablation for symptomatic paroxysmal AF using the A rct ic Front ® or the HD Mesh Ablator ® catheter  according to study protocol . The primary endpoint was complete PV isolation ( PVI ) at the end of the ablation procedure , determined by exit block after achieving entrance block . Long-term follow-up data are not included in this publication . Patients ' mean age was 61.7 ± 8.9 years , 43.2 % were female , and median CHA₂DS₂-VASc score was 2.0 . In the intention-to-treat analysis , the rate of the primary endpoint was 56.5 % in patients r and omized to the A rct ic Front ® and 9.5 % in patients r and omized to the HD Mesh Ablator ® catheter ( P = 0.001 ) . In the per- protocol analysis , complete PVI was achieved in 13 ( 76.5 % ) of 17 A rct ic Front ® patients but in none of the 15 HD Mesh Ablator ® patients ( P < 0.0001 ) . There were one major and two minor complications in each study arm but no clinical ly evident stroke . Post-procedural AF recurrence was detected within hospital stay in two ( 11.8 % ) A rct ic Front ® patients and in seven ( 46.7 % ) HD Mesh Ablator ® patients ( P = 0.049 ) . CONCLUSION The MACPAF study revealed a superiority of the A rct ic Front ® catheter concerning complete PVI . Owing to the insufficient efficacy of the HD Mesh Ablator ® catheter , the safety board decided to stop MACPAF prematurely BACKGROUND Catheter ablation is an established treatment for atrial fibrillation ( AF ) .  Cryoballoon ablation ( CBA ) has emerged as an alternative to radiofrequency ablation ( RFA ) . However , there are few data comparing these modalities for treatment of paroxysmal AF ( pAF ) in the U.S. POPULATION The purpose of this study was to 
    Output:
    