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 — Data regarding the long-term efficacy of atrial fibrillation ( AF ) ablation are still lacking . Methods and Results —Two hundred four consecutive patients symptomatic for paroxysmal or persistent/permanent AF were r and omly assigned to 2 different ablation schemes : pulmonary vein isolation ( PVI ) and PVI plus left linear lesions ( LL ) . Primary end point was to assess the maintenance of sinus rhythm ( SR ) after procedures 1 and 2 in the absence of antiarrhythmic drugs in a long-term follow-up of at least 3 years . Paroxysmal AF — With a single procedure at 12-month follow-up , 46 % of patients treated with PVI maintained SR , whereas at 3-year follow-up , 29 % were in SR ; using the “ PVI plus LL ” at the 12-month follow-up , 57 % of patients were in SR , whereas at the 3-year follow-up , 53 % remained in SR . After a second procedure , the long-term overall success rate without antiarrhythmic drugs was 62 % with PVI and 85 % with PVI plus LL . Persistent/Permanent AF — With a single procedure at the 12-month follow-up , 27 % of patients treated with PVI were in SR , whereas at the 3-year follow-up , 19 % maintained SR ; using the PVI plus LL with a single procedure at the 12-month follow-up 45 % of patients were in SR , whereas at the 3-year follow-up , 41 % remained in SR . After a second procedure , the long-term overall success rate without antiarrhythmic drugs was 39 % with PVI and 75 % with PVI plus LL . Conclusions —A long-term follow-up of AF ablation shows that short-term results can not be considered permanent because AF recurrences are still present after the first year especially in patients who have had “ PVI ” strategy .  PVI isolation plus LL is superior to the PVI strategy in maintaining SR without antiarrhythmic drugs after procedures 1 and 2 both in paroxysmal and persistent AF OBJECTIVES This study sought to assess the safety and effectiveness of a novel cryoballoon ablation technology design ed to achieve single-delivery pulmonary vein ( PV ) isolation . BACKGROUND St and ard radiofrequency ablation is effective in eliminating atrial fibrillation ( AF ) but requires multiple lesion delivery at the risk of significant complications . METHODS Patients with documented symptomatic paroxysmal AF and previously failed therapy with ≥ 1 membrane active antiarrhythmic drug underwent 2:1 r and omization to either cryoballoon ablation ( n = 163 ) or drug therapy ( n = 82 ) . A 90-day blanking period allowed for optimization of antiarrhythmic drug therapy and reablation if necessary . Effectiveness of the cryoablation procedure versus drug therapy was determined at 12 months . RESULTS Patients had highly symptomatic AF ( 78 % paroxysmal , 22 % early persistent ) and experienced failure of at least one antiarrhythmic drug . Cryoablation produced acute isolation of three or more PVs in 98.2 % and all four PVs in 97.6 % of patients . PVs isolation was achieved with the balloon catheter alone in 83 % . At 12 months , treatment success was 69.9 % ( 114 of 163 ) of cryoblation patients compared with 7.3 % of antiarrhythmic drug patients ( absolute difference , 62.6 % [ p < 0.001 ] ) . Sixty-five ( 79 % ) drug-treated patients crossed over to cryoablation during 12 months of study follow-up due to recurrent , symptomatic AF , constituting drug treatment failure . There were 7 of the result ing 228 cryoablated patients ( 3.1 % ) with a > 75 % reduction in PV area during 12 months of follow-up . Twenty-nine of 259 procedures ( 11.2 % ) were associated with phrenic nerve palsy as determined by radiographic screening ; 25 of these had resolved by 12 months . Cryoablation patients had significantly improved symptoms at 12 months . CONCLUSIONS The STOP AF trial demonstrated that cryoballoon ablation is a safe and effective alternative to antiarrhythmic medication for the treatment of patients with symptomatic paroxysmal AF , for whom at least one antiarrhythmic drug has failed , with risks within accepted st and ards for ablation therapy . ( A Clinical Study of the A rct ic Front Cryoablation Balloon for the Treatment of Paroxysmal Atrial Fibrillation [ Stop AF ] ; NCT00523978 ) BACKGROUND The Medical ANtiarrhythmic Treatment or Radiofrequency Ablation in Paroxysmal Atrial Fibrillation ( MANTRA-PAF ) is a r and omized trial comparing radiofrequency catheter ablation ( RFA ) to antiarrhythmic drugs ( AADs ) as first-line treatment of paroxysmal atrial fibrillation ( PAF ) . In order to eliminate the clouding effect of crossover we performed an on-treatment analysis of the data . METHODS AND RESULTS Patients ( n=294 ) were divided into three groups : those receiving only the assigned therapy ( RFA and AAD groups ) and those receiving both therapies ( crossover group ) . The primary end points were AF burden in 7-day Holter recordings at 3 , 6 , 12 , 18 , and 24 months and cumulative AF burden in all recordings . At 24 months , AF burden was significantly lower in the RFA ( n=110 ) than in the AAD ( n=92 ) and the crossover ( n=84 ) groups ( 90th percentile 1 % vs. 10 % vs. 16 % , P=0.007 ) , and more patients were free from any AF ( 89 % vs. 73 % vs. 74 % , P=0.006 ) . In the RFA , AAD and the crossover groups 63 % , 59 % and 21 % ( P<0.001 ) of the patients had no AF episodes in any Holter recording , respectively . Quality of life improved significantly in all groups . There were no differences in serious adverse events between the RFA , AAD and crossover groups ( 19 % vs. 8 % vs. 23 % ) ( P=0.10 ) . CONCLUSIONS In the treatment of antiarrhythmic therapy naïve patients with PAF long-term efficacy of RFA was superior to AAD therapy . Thus , it is reasonable to offer RFA as first-line treatment for highly symptomatic patients who accept the risks of the procedure and are aware of frequent need for reablation(s ) CONTEXT Treatment with antiarrhythmic drugs and anticoagulation is considered first-line therapy in patients with symptomatic atrial fibrillation ( AF ) .  Pulmonary vein isolation ( PVI ) with radiofrequency ablation may cure AF , obviating the need for antiarrhythmic drugs and anticoagulation . OBJECTIVE To determine whether PVI is feasible as first-line therapy for treating patients with symptomatic AF . DESIGN , SETTING , AND PARTICIPANTS A multicenter prospect i ve r and omized study conducted from December 31 , 2001 , to July 1 , 2002 , of 70 patients aged 18 to 75 years who experienced monthly symptomatic AF episodes for at least 3 months and had not been treated with antiarrhythmic drugs . INTERVENTION Patients were r and omized to receive either PVI using radiofrequency ablation ( n=33 ) or antiarrhythmic drug treatment ( n=37 ) , with a 1-year follow-up . MAIN OUTCOME MEASURES Recurrence of AF , hospitalization , and quality of life assessment . RESULTS Two patients in the antiarrhythmic drug treatment group and 1 patient in the PVI group were lost to follow-up . At the end of 1-year follow-up , 22 ( 63 % ) of 35 patients who received antiarrhythmic drugs had at least 1 recurrence of symptomatic AF compared with 4 ( 13 % ) of 32 patients who received PVI ( P<.001 ) . Hospitalization during 1-year follow-up occurred in 19 ( 54 % ) of 35 patients in the antiarrhythmic drug group compared with 3 ( 9 % ) of 32 in the PVI group ( P<.001 ) . In the antiarrhythmic drug group , the mean ( SD ) number of AF episodes decreased from 12 ( 7 ) to 6 ( 4 ) , after initiating therapy ( P = .01 ) . At 6-month follow-up , the improvement in quality of life of patients in the PVI group was significantly better than the improvement in the antiarrhythmic drug group in 5 subclasses of the Short-Form 36 health survey . There were no thromboembolic events in either group . Asymptomatic mild or moderate pulmonary vein stenosis was documented in 2 ( 6 % ) of 32 patients in the PVI group . CONCLUSION Pulmonary vein isolation appears to be a feasible first-line approach for treating patients with symptomatic AF . Larger studies are needed to confirm its safety and efficacy BACKGROUND Left atrial ( LA ) circumferential ablation has been reported to eliminate atrial fibrillation ( AF ) . Whether an ablation without encirclement of the pulmonary veins ( PVs ) is as effective as LA circumferential ablation is not clear . OBJECTIVES The purpose of this study was to compare the efficacy of LA circumferential ablation and nonencircling linear ablation in patients with chronic AF . METHODS Eighty patients with chronic AF were r and omized to undergo LA circumferential ablation ( n = 40 ) or nonencircling linear ablation ( n = 40 ) . In LA circumferential ablation , the PVs were encircled , with additional lines made in the mitral isthmus and posterior wall or roof . In nonencircling linear ablation , 4 + /- 1 ablation lines were created through areas of complex electrograms , with lines in the roof ( 38 ) , anterior wall ( 36 ) , septum ( 40 ) , mitral isthmus ( 32 ) , and posterior annulus ( 6 ) . The endpoint of LA circumferential ablation and nonencircling linear ablation was voltage abatement . RESULTS LA flutter occurred in 15 % after LA circumferential ablation and in 18 % after nonencircling linear ablation ( P = .8 ) . A repeat ablation procedure was performed for recurrent AF in 7 and 11 patients or for atrial flutter in 6 and 4 patients after LA circumferential ablation and nonencircling linear ablation , respectively ( P = .8 ) . At 9 + /- 4 months , the prevalence of AF was 28 % in the LA circumferential ablation and 25 % in the nonencircling linear ablation group ( P = .8 ) . Sixty-eight percent and 60 % of patients were in sinus rhythm and free of AF and atrial flutter in the absence of antiarrhythmic drug therapy after LA circumferential ablation and nonencircling linear ablation , respectively ( P = .5 ) . There were no complications . CONCLUSION Nonencircling linear ablation and LA circumferential ablation are equally efficacious in eliminating chronic AF . However , the advantage of nonencircling linear ablation is that it eliminates the need for ablation along the posterior wall of the LA . Therefore , nonencircling linear ablation may avoid the small but real risk of atrioesophageal fistula formation associated with LA circumferential ablation BACKGROUND This prospect i ve multicenter r and omized study aim ed to compare the efficacy of 3 common ablation methods used for longst and ing permanent atrial fibrillation ( AF ) . METHODS A total of 144 patients with longst and ing permanent AF ( median duration 28 months ) were r and omly assigned to circumferential pulmonary vein ablation ( CPVA , group 1 , n = 47 ) , to pulmonary vein antrum isolation ( PVAI , group 2 , n = 48 ) or to a hybrid strategy combining ablation of complex fractionated or rapid atrial electrograms ( CFAE ) in both atria followed by a pulmonary vein antrum isolation ( CFAE + PVAI , group 3 , n = 49 ) . RESULTS Scarring in the left atrium and structural heart disease/hypertension were present in most patients ( 65 % ) . After a mean follow-up of 16 months , 11 % of patients in group 1 , 40 % of patients in group 2 and 61 % of patients in group 3 were in sinus rhythm after one procedure and with no antiarrhythmic drugs ( P < .001 ) . Sinus rhythm maintenance would increase respectively to 28 % ( group 1 ) , 83 % ( group 2 ) , and 94 % ( group 3 ) after 2 procedures and with antiarrhythmic drugs ( AADs , P < .001 ) . The AF terminated during ablation , either by conversion to sinus rhythm or organization into an atrial tachyarrhythmia , in 13 % of patients ( group 1 ) , 44 % ( group 2 ) , and 74 % ( group 3 ) respectively . CFAE alone , performed as the first step of the ablation in group 3 , organized AF in only 1 patient . CONCLUSION In this study , the hybrid AF ablation strategy including antrum isolation and CFAE ablation had the highest likelihood of maintaining sinus rhythm in patients with longst and ing permanent AF . Electrical isolation of the PVs , although inadequate if performed alone , is relevant to achieve long-term sinus rhythm maintenance after ablation . Bi-atrial CFAE 
    Output:
    
agent
In people with non-paroxysmal atrial fibrillation , evidence suggests a superiority of RFCA to antiarrhythmic drugs in achieving freedom from atrial arrhythmias , reducing the need for cardioversion , and reducing cardiac-related hospitalisations .
***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 — Data regarding the long-term efficacy of atrial fibrillation ( AF ) ablation are still lacking . Methods and Results —Two hundred four consecutive patients symptomatic for paroxysmal or persistent/permanent AF were r and omly assigned to 2 different ablation schemes : pulmonary vein isolation ( PVI ) and PVI plus left linear lesions ( LL ) . Primary end point was to assess the maintenance of sinus rhythm ( SR ) after procedures 1 and 2 in the absence of antiarrhythmic drugs in a long-term follow-up of at least 3 years . Paroxysmal AF — With a single procedure at 12-month follow-up , 46 % of patients treated with PVI maintained SR , whereas at 3-year follow-up , 29 % were in SR ; using the “ PVI plus LL ” at the 12-month follow-up , 57 % of patients were in SR , whereas at the 3-year follow-up , 53 % remained in SR . After a second procedure , the long-term overall success rate without antiarrhythmic drugs was 62 % with PVI and 85 % with PVI plus LL . Persistent/Permanent AF — With a single procedure at the 12-month follow-up , 27 % of patients treated with PVI were in SR , whereas at the 3-year follow-up , 19 % maintained SR ; using the PVI plus LL with a single procedure at the 12-month follow-up 45 % of patients were in SR , whereas at the 3-year follow-up , 41 % remained in SR . After a second procedure , the long-term overall success rate without antiarrhythmic drugs was 39 % with PVI and 75 % with PVI plus LL . Conclusions —A long-term follow-up of AF ablation shows that short-term results can not be considered permanent because AF recurrences are still present after the first year especially in patients who have had “ PVI ” strategy .  PVI isolation plus LL is superior to the PVI strategy in maintaining SR without antiarrhythmic drugs after procedures 1 and 2 both in paroxysmal and persistent AF OBJECTIVES This study sought to assess the safety and effectiveness of a novel cryoballoon ablation technology design ed to achieve single-delivery pulmonary vein ( PV ) isolation . BACKGROUND St and ard radiofrequency ablation is effective in eliminating atrial fibrillation ( AF ) but requires multiple lesion delivery at the risk of significant complications . METHODS Patients with documented symptomatic paroxysmal AF and previously failed therapy with ≥ 1 membrane active antiarrhythmic drug underwent 2:1 r and omization to either cryoballoon ablation ( n = 163 ) or drug therapy ( n = 82 ) . A 90-day blanking period allowed for optimization of antiarrhythmic drug therapy and reablation if necessary . Effectiveness of the cryoablation procedure versus drug therapy was determined at 12 months . RESULTS Patients had highly symptomatic AF ( 78 % paroxysmal , 22 % early persistent ) and experienced failure of at least one antiarrhythmic drug . Cryoablation produced acute isolation of three or more PVs in 98.2 % and all four PVs in 97.6 % of patients . PVs isolation was achieved with the balloon catheter alone in 83 % . At 12 months , treatment success was 69.9 % ( 114 of 163 ) of cryoblation patients compared with 7.3 % of antiarrhythmic drug patients ( absolute difference , 62.6 % [ p < 0.001 ] ) . Sixty-five ( 79 % ) drug-treated patients crossed over to cryoablation during 12 months of study follow-up due to recurrent , symptomatic AF , constituting drug treatment failure . There were 7 of the result ing 228 cryoablated patients ( 3.1 % ) with a > 75 % reduction in PV area during 12 months of follow-up . Twenty-nine of 259 procedures ( 11.2 % ) were associated with phrenic nerve palsy as determined by radiographic screening ; 25 of these had resolved by 12 months . Cryoablation patients had significantly improved symptoms at 12 months . CONCLUSIONS The STOP AF trial demonstrated that cryoballoon ablation is a safe and effective alternative to antiarrhythmic medication for the treatment of patients with symptomatic paroxysmal AF , for whom at least one antiarrhythmic drug has failed , with risks within accepted st and ards for ablation therapy . ( A Clinical Study of the A rct ic Front Cryoablation Balloon for the Treatment of Paroxysmal Atrial Fibrillation [ Stop AF ] ; NCT00523978 ) BACKGROUND The Medical ANtiarrhythmic Treatment or Radiofrequency Ablation in Paroxysmal Atrial Fibrillation ( MANTRA-PAF ) is a r and omized trial comparing radiofrequency catheter ablation ( RFA ) to antiarrhythmic drugs ( AADs ) as first-line treatment of paroxysmal atrial fibrillation ( PAF ) . In order to eliminate the clouding effect of crossover we performed an on-treatment analysis of the data . METHODS AND RESULTS Patients ( n=294 ) were divided into three groups : those receiving only the assigned therapy ( RFA and AAD groups ) and those receiving both therapies ( crossover group ) . The primary end points were AF burden in 7-day Holter recordings at 3 , 6 , 12 , 18 , and 24 months and cumulative AF burden in all recordings . At 24 months , AF burden was significantly lower in the RFA ( n=110 ) than in the AAD ( n=92 ) and the crossover ( n=84 ) groups ( 90th percentile 1 % vs. 10 % vs. 16 % , P=0.007 ) , and more patients were free from any AF ( 89 % vs. 73 % vs. 74 % , P=0.006 ) . In the RFA , AAD and the crossover groups 63 % , 59 % and 21 % ( P<0.001 ) of the patients had no AF episodes in any Holter recording , respectively . Quality of life improved significantly in all groups . There were no differences in serious adverse events between the RFA , AAD and crossover groups ( 19 % vs. 8 % vs. 23 % ) ( P=0.10 ) . CONCLUSIONS In the treatment of antiarrhythmic therapy naïve patients with PAF long-term efficacy of RFA was superior to AAD therapy . Thus , it is reasonable to offer RFA as first-line treatment for highly symptomatic patients who accept the risks of the procedure and are aware of frequent need for reablation(s ) CONTEXT Treatment with antiarrhythmic drugs and anticoagulation is considered first-line therapy in patients with symptomatic atrial fibrillation ( AF ) .  Pulmonary vein isolation ( PVI ) with radiofrequency ablation may cure AF , obviating the need for antiarrhythmic drugs and anticoagulation . OBJECTIVE To determine whether PVI is feasible as first-line therapy for treating patients with symptomatic AF . DESIGN , SETTING , AND PARTICIPANTS A multicenter prospect i ve r and omized study conducted from December 31 , 2001 , to July 1 , 2002 , of 70 patients aged 18 to 75 years who experienced monthly symptomatic AF episodes for at least 3 months and had not been treated with antiarrhythmic drugs . INTERVENTION Patients were r and omized to receive either PVI using radiofrequency ablation ( n=33 ) or antiarrhythmic drug treatment ( n=37 ) , with a 1-year follow-up . MAIN OUTCOME MEASURES Recurrence of AF , hospitalization , and quality of life assessment . RESULTS Two patients in the antiarrhythmic drug treatment group and 1 patient in the PVI group were lost to follow-up . At the end of 1-year follow-up , 22 ( 63 % ) of 35 patients who received antiarrhythmic drugs had at least 1 recurrence of symptomatic AF compared with 4 ( 13 % ) of 32 patients who received PVI ( P<.001 ) . Hospitalization during 1-year follow-up occurred in 19 ( 54 % ) of 35 patients in the antiarrhythmic drug group compared with 3 ( 9 % ) of 32 in the PVI group ( P<.001 ) . In the antiarrhythmic drug group , the mean ( SD ) number of AF episodes decreased from 12 ( 7 ) to 6 ( 4 ) , after initiating therapy ( P = .01 ) . At 6-month follow-up , the improvement in quality of life of patients in the PVI group was significantly better than the improvement in the antiarrhythmic drug group in 5 subclasses of the Short-Form 36 health survey . There were no thromboembolic events in either group . Asymptomatic mild or moderate pulmonary vein stenosis was documented in 2 ( 6 % ) of 32 patients in the PVI group . CONCLUSION Pulmonary vein isolation appears to be a feasible first-line approach for treating patients with symptomatic AF . Larger studies are needed to confirm its safety and efficacy BACKGROUND Left atrial ( LA ) circumferential ablation has been reported to eliminate atrial fibrillation ( AF ) . Whether an ablation without encirclement of the pulmonary veins ( PVs ) is as effective as LA circumferential ablation is not clear . OBJECTIVES The purpose of this study was to compare the efficacy of LA circumferential ablation and nonencircling linear ablation in patients with chronic AF . METHODS Eighty patients with chronic AF were r and omized to undergo LA circumferential ablation ( n = 40 ) or nonencircling linear ablation ( n = 40 ) . In LA circumferential ablation , the PVs were encircled , with additional lines made in the mitral isthmus and posterior wall or roof . In nonencircling linear ablation , 4 + /- 1 ablation lines were created through areas of complex electrograms , with lines in the roof ( 38 ) , anterior wall ( 36 ) , septum ( 40 ) , mitral isthmus ( 32 ) , and posterior annulus ( 6 ) . The endpoint of LA circumferential ablation and nonencircling linear ablation was voltage abatement . RESULTS LA flutter occurred in 15 % after LA circumferential ablation and in 18 % after nonencircling linear ablation ( P = .8 ) . A repeat ablation procedure was performed for recurrent AF in 7 and 11 patients or for atrial flutter in 6 and 4 patients after LA circumferential ablation and nonencircling linear ablation , respectively ( P = .8 ) . At 9 + /- 4 months , the prevalence of AF was 28 % in the LA circumferential ablation and 25 % in the nonencircling linear ablation group ( P = .8 ) . Sixty-eight percent and 60 % of patients were in sinus rhythm and free of AF and atrial flutter in the absence of antiarrhythmic drug therapy after LA circumferential ablation and nonencircling linear ablation , respectively ( P = .5 ) . There were no complications . CONCLUSION Nonencircling linear ablation and LA circumferential ablation are equally efficacious in eliminating chronic AF . However , the advantage of nonencircling linear ablation is that it eliminates the need for ablation along the posterior wall of the LA . Therefore , nonencircling linear ablation may avoid the small but real risk of atrioesophageal fistula formation associated with LA circumferential ablation BACKGROUND This prospect i ve multicenter r and omized study aim ed to compare the efficacy of 3 common ablation methods used for longst and ing permanent atrial fibrillation ( AF ) . METHODS A total of 144 patients with longst and ing permanent AF ( median duration 28 months ) were r and omly assigned to circumferential pulmonary vein ablation ( CPVA , group 1 , n = 47 ) , to pulmonary vein antrum isolation ( PVAI , group 2 , n = 48 ) or to a hybrid strategy combining ablation of complex fractionated or rapid atrial electrograms ( CFAE ) in both atria followed by a pulmonary vein antrum isolation ( CFAE + PVAI , group 3 , n = 49 ) . RESULTS Scarring in the left atrium and structural heart disease/hypertension were present in most patients ( 65 % ) . After a mean follow-up of 16 months , 11 % of patients in group 1 , 40 % of patients in group 2 and 61 % of patients in group 3 were in sinus rhythm after one procedure and with no antiarrhythmic drugs ( P < .001 ) . Sinus rhythm maintenance would increase respectively to 28 % ( group 1 ) , 83 % ( group 2 ) , and 94 % ( group 3 ) after 2 procedures and with antiarrhythmic drugs ( AADs , P < .001 ) . The AF terminated during ablation , either by conversion to sinus rhythm or organization into an atrial tachyarrhythmia , in 13 % of patients ( group 1 ) , 44 % ( group 2 ) , and 74 % ( group 3 ) respectively . CFAE alone , performed as the first step of the ablation in group 3 , organized AF in only 1 patient . CONCLUSION In this study , the hybrid AF ablation strategy including antrum isolation and CFAE ablation had the highest likelihood of maintaining sinus rhythm in patients with longst and ing permanent AF . Electrical isolation of the PVs , although inadequate if performed alone , is relevant to achieve long-term sinus rhythm maintenance after ablation . Bi-atrial CFAE 
    Output:
    