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 Background — Information on comparative outcome between radiofrequency catheter ablation ( RFA ) and antiarrhythmic drugs ( AADs ) > 1 year after r and omization is important for clinical decision-making . Methods and Results — A total of 198 patients ( age , 56±10 years ) with paroxysmal atrial fibrillation were r and omly assigned to RFA ( 99 patients ) or to AADs ( 99 patients ) . We evaluated efficacy of RFA or AADs in a comparable 48-month follow-up period according to intention-to-treat analysis . Cardiac rhythm was assessed with daily transtelephonic transmissions . Quality of life was also analyzed . At 4 years , among the 99 patients first assigned to RFA , the procedure was repeated because of recurrent atrial fibrillation/atrial tachycardia in 27 patients ( 27.3 % ) . Among the 99 patients r and omly assigned to AADs , 87 ( 87.9 % ) crossed over to undergo RFA and 4 years after r and om assignment only 12 ( 12.1 % ) were in sinus rhythm with AAD alone without ablation . Despite the high level of crossovers , at 4 years the intention-to-treat analysis showed that 72.7 % of patients in the ablation arm and 56.5 % of those initially r and omly assigned to AADs were free of recurrent atrial fibrillation/atrial tachycardia ( P=0.017 ) . During the follow-up , 19.2 % of AAD patients progressed to persistent atrial fibrillation before switching to RFA . RFA significantly improved quality of life ( P<0.001 ) , whereas before crossing over to RFA , patients receiving AADs showed poorer quality of life . Except for new left atrial tachycardia , there were no serious complications caused by RFA . Conclusions — With follow-up extended to 4 years after r and omly assigned , ablation remains superior to antiarrhythmic drug in these patients with paroxysmal atrial fibrillation . Clinical Trial Registration — URL : http://www . clinical trials.gov . Unique identifier : NCT00340314 Small , single-center studies suggest that catheter ablation of atrial fibrillation ( AF )  can improve ventricular function and reduce symptoms in patients with left ventricular ( LV ) dysfunction . However , ablation has not been compared with a pharmacologic strategy for AF . The authors evaluated patients with AF and symptomatic LV dysfunction ( ejection fraction < or = 45 % ) referred for pulmonary vein isolation ( PVI ) . They compared these patients with a matched cohort treated medically for AF and LV dysfunction via a retrospective case-control method . Fifteen patients ( 14 men , 56+/-11 years , 10 [ 67 % ] paroxysmal AF ) with AF for 4+/-3 years underwent PVI .  Baseline ejection fraction was 37%+/-6 % and New York Heart Association ( NYHA ) class was 2.0+/-1.0 . Fifteen controls ( 13 men , 63+/-14 years , 11 [ 73 % ] paroxysmal AF ) with AF for 5+/-4 years were treated medically for AF . Baseline ejection fraction was 34%+/-11 % and NYHA class was 2.0+/-0.7 . The groups were similar in all respects . During a follow-up of 16+/-13 months after complete PVI , ejection fraction improved ( P=.001 ) to 50%+/-13 % and normalized in 8 patients ( 53 % ) . NYHA class improved to 1.3+/-0.5 ( P=.01 ) . In the medically treated group , after follow-up of 16+/-12 months , no improvement in ejection fraction ( 36%+/-12 % ) or NYHA class ( 1.8+/-0.7 ) was seen . Compared with pharmacologic therapy , PVI significantly improved LV function and NYHA class in patients with AF and symptomatic LV dysfunction . These provocative findings provide potent rationale for a r and omized clinical trial comparing ablation with pharmacologic therapy OBJECTIVES The purpose of this study was to investigate long-term outcomes of freedom from atrial fibrillation ( AF ) after pulmonary vein ( PV ) isolation using cryoballoon ablation with balloon-size selection based on individual PV diameters . BACKGROUND Data are lacking on long-term outcomes from cryoablation and on the most effective balloon size . METHODS This was a prospect i ve observational study involving 605 consecutively enrolled patients with symptomatic paroxysmal AF ( n = 579 ) or persistent AF .  Cryoballoon size was based on magnetic resonance imaging and /or conventional angiograms . Patients were followed up every 3 months during the first year after discharge and every 6 months in the second year . After 24 months , follow-up was on an outpatient basis with documented AF episodes recorded . RESULTS The PV isolation was achieved without touch-up in 91.1 % of patients , using the smaller balloon in 26.7 % , the larger balloon in 25.6 % , and both balloons in 47.7 % of patients . Follow-up data for > 12 months ( median 30 months ; interquartile range 18 to 48 months ) were available for 451 patients , 278 ( 61.6 % ) of whom were free of AF recurrence with no need for repeat procedures after the 3-month blanking period . Rates of freedom from AF after 1 , 2 , and 3 repeat procedures ( using cryoballoon or radiofrequency ablation with similar success rates ) were 74.9 % , 76.2 % , and 76.9 % , respectively . Use of the smaller balloons or both balloons produced the highest rates of long-term freedom from AF . Phrenic nerve palsy occurred in 12 patients ( 2 % ) , resolving within 3 to 9 months . CONCLUSIONS Rates of long-term freedom from AF after cryoballoon ablation are similar to those reported for radiofrequency ablation . A choice between balloons may improve outcomes OBJECTIVES We aim ed to determine the safety and efficacy of pulmonary vein isolation ( PVI ) in atrial fibrillation ( AF ) patients with impaired left ventricular ( LV ) systolic function . BACKGROUND To date , PVI has been performed primarily in patients with normal LV function . Yet , many AF patients have impaired LV systolic function . The outcomes of PVI in patients with impaired LV systolic function are unknown . METHODS We included 377 consecutive patients undergoing PVI between December 2000 and January 2003 . Ninety-four patients had impaired LV function ( ejection fraction [ EF ] < 40 % ) , and they comprised the study group . The control group was the remaining 283 patients who had a normal EF . End points included AF recurrence and changes in EF and quality of life ( QoL ) . RESULTS Mean EF was 36 % in our study group , compared with 54 % in controls . After initial PVI , 73 % of patients with impaired EF and 87 % of patients with normal EF were free of AF recurrence at 14 + /- 6 months ( p = 0.03 ) . In the study group , there was a nonsignificant increase in EF of 4.6 % and significant improvement in QoL. Complication rates were low and included a 1 % risk of pulmonary vein stenosis . CONCLUSIONS Although the AF recurrence rate after initial PVI in impaired EF patients was higher than in normal EF subjects , nearly three-fourths of patients with impaired EF remained AF-free . Although our sample size was nonr and omized , our results suggest PVI may be a feasible therapeutic option in AF patients with impaired EF . R and omized studies with more patients and longer follow-up are warranted Objective To determine whether or not radiofrequency ablation ( RFA ) for persistent atrial fibrillation in patients with advanced heart failure leads to improvements in cardiac function . Setting Patients were recruited from heart failure outpatient clinics in Scotl and . Design and intervention Patients with advanced heart failure and severe left ventricular dysfunction were r and omised to RFA ( rhythm control ) or  continued medical treatment  ( rate control ) . Patients were followed up for a minimum of 6 months . Main outcome measure Change in left ventricular ejection fraction ( LVEF ) measured by cardiovascular MRI . Results 22 patients were r and omised to RFA and 19 to medical treatment . In the RFA group , 50 % of patients were in sinus rhythm at the end of the study ( compared with none in the medical treatment group ) . The increase in cardiovascular magnetic resonance ( CMR ) LVEF in the RFA group was 4.5±11.1 % compared with 2.8±6.7 % in the medical treatment group ( p=0.6 ) . The RFA group had a greater increase in radionuclide LVEF ( a prespecified secondary end point ) than patients in the medical treatment group ( + 8.2±12.0 % vs + 1.4±5.9 % ; p=0.032 ) . RFA did not improve N-terminal pro-B-type natriuretic peptide , 6 min walk distance or quality of life . The rate of serious complications related to RFA was 15 % . Conclusions RFA result ed in long-term restoration of sinus rhythm in only 50 % of patients . RFA did not improve CMR LVEF compared with a strategy of rate control . RFA did improve radionuclide LVEF but did not improve other secondary outcomes and was associated with a significant rate of serious complications . Clinical trials registration number NCT00292162 Background —The effect of successful catheter ablation on left ventricular ( LV ) strain in patients with preserved LV systolic function is unknown . The aim of the present study was to assess the long-term effects of catheter ablation for atrial fibrillation ( AF )  on LV strain and strain rate in patients with preserved LV ejection fraction . Methods and Results —In 78 patients undergoing catheter ablation for AF  , speckle tracking strain imaging was performed to assess LV strain in 3 directions ( radial , circumferential , and longitudinal ) at baseline and after 12-month follow-up . The study population was divided into 2 groups , according to the maintenance of sinus rhythm ( SR ) during follow-up . After 13.8±4.7 months of follow-up , 54 patients ( 69 % ) were in SR ( SR group ) , whereas 24 patients ( 31 % ) had recurrence of AF ( AF group ) . No significant changes in LV ejection fraction from baseline to follow-up were noted ( 60±7 % versus 59±7 % , P = NS ) . Circumferential strain improved significantly in the SR group ( −18.3±3.2 % versus −20.4±3.8 % , P<0.001 ) , whereas it remained unchanged in the AF group ( −18.9±3.5 % versus −17.9±3.1 % , P = NS ) . In the SR group , significant improvements in LV longitudinal strain and strain rate were noted , whereas in the AF group , LV longitudinal strain and strain rate deteriorated significantly at long-term follow-up . Conclusions —After successful catheter ablation , LV circumferential and longitudinal strain and strain rate improve significantly in patients who maintain SR . In contrast , a decrease in LV longitudinal strain and strain rate is observed in patients with recurrence of AF AIMS Beneficial effects of atrial fibrillation ( AF ) ablation have been demonstrated in patients with congestive heart failure ( CHF ) and significantly impaired left ventricular ejection fraction ( LVEF ) . 
    Output:
    
agent
AFCA efficacy in patients with impaired left ventricular systolic function improves when performed early in the natural history of atrial fibrillation and heart failure .
AFCA provides long-term benefits on left ventricular function , significantly reducing the number of patients with severely impaired systolic function
***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 Background — Information on comparative outcome between radiofrequency catheter ablation ( RFA ) and antiarrhythmic drugs ( AADs ) > 1 year after r and omization is important for clinical decision-making . Methods and Results — A total of 198 patients ( age , 56±10 years ) with paroxysmal atrial fibrillation were r and omly assigned to RFA ( 99 patients ) or to AADs ( 99 patients ) . We evaluated efficacy of RFA or AADs in a comparable 48-month follow-up period according to intention-to-treat analysis . Cardiac rhythm was assessed with daily transtelephonic transmissions . Quality of life was also analyzed . At 4 years , among the 99 patients first assigned to RFA , the procedure was repeated because of recurrent atrial fibrillation/atrial tachycardia in 27 patients ( 27.3 % ) . Among the 99 patients r and omly assigned to AADs , 87 ( 87.9 % ) crossed over to undergo RFA and 4 years after r and om assignment only 12 ( 12.1 % ) were in sinus rhythm with AAD alone without ablation . Despite the high level of crossovers , at 4 years the intention-to-treat analysis showed that 72.7 % of patients in the ablation arm and 56.5 % of those initially r and omly assigned to AADs were free of recurrent atrial fibrillation/atrial tachycardia ( P=0.017 ) . During the follow-up , 19.2 % of AAD patients progressed to persistent atrial fibrillation before switching to RFA . RFA significantly improved quality of life ( P<0.001 ) , whereas before crossing over to RFA , patients receiving AADs showed poorer quality of life . Except for new left atrial tachycardia , there were no serious complications caused by RFA . Conclusions — With follow-up extended to 4 years after r and omly assigned , ablation remains superior to antiarrhythmic drug in these patients with paroxysmal atrial fibrillation . Clinical Trial Registration — URL : http://www . clinical trials.gov . Unique identifier : NCT00340314 Small , single-center studies suggest that catheter ablation of atrial fibrillation ( AF )  can improve ventricular function and reduce symptoms in patients with left ventricular ( LV ) dysfunction . However , ablation has not been compared with a pharmacologic strategy for AF . The authors evaluated patients with AF and symptomatic LV dysfunction ( ejection fraction < or = 45 % ) referred for pulmonary vein isolation ( PVI ) . They compared these patients with a matched cohort treated medically for AF and LV dysfunction via a retrospective case-control method . Fifteen patients ( 14 men , 56+/-11 years , 10 [ 67 % ] paroxysmal AF ) with AF for 4+/-3 years underwent PVI .  Baseline ejection fraction was 37%+/-6 % and New York Heart Association ( NYHA ) class was 2.0+/-1.0 . Fifteen controls ( 13 men , 63+/-14 years , 11 [ 73 % ] paroxysmal AF ) with AF for 5+/-4 years were treated medically for AF . Baseline ejection fraction was 34%+/-11 % and NYHA class was 2.0+/-0.7 . The groups were similar in all respects . During a follow-up of 16+/-13 months after complete PVI , ejection fraction improved ( P=.001 ) to 50%+/-13 % and normalized in 8 patients ( 53 % ) . NYHA class improved to 1.3+/-0.5 ( P=.01 ) . In the medically treated group , after follow-up of 16+/-12 months , no improvement in ejection fraction ( 36%+/-12 % ) or NYHA class ( 1.8+/-0.7 ) was seen . Compared with pharmacologic therapy , PVI significantly improved LV function and NYHA class in patients with AF and symptomatic LV dysfunction . These provocative findings provide potent rationale for a r and omized clinical trial comparing ablation with pharmacologic therapy OBJECTIVES The purpose of this study was to investigate long-term outcomes of freedom from atrial fibrillation ( AF ) after pulmonary vein ( PV ) isolation using cryoballoon ablation with balloon-size selection based on individual PV diameters . BACKGROUND Data are lacking on long-term outcomes from cryoablation and on the most effective balloon size . METHODS This was a prospect i ve observational study involving 605 consecutively enrolled patients with symptomatic paroxysmal AF ( n = 579 ) or persistent AF .  Cryoballoon size was based on magnetic resonance imaging and /or conventional angiograms . Patients were followed up every 3 months during the first year after discharge and every 6 months in the second year . After 24 months , follow-up was on an outpatient basis with documented AF episodes recorded . RESULTS The PV isolation was achieved without touch-up in 91.1 % of patients , using the smaller balloon in 26.7 % , the larger balloon in 25.6 % , and both balloons in 47.7 % of patients . Follow-up data for > 12 months ( median 30 months ; interquartile range 18 to 48 months ) were available for 451 patients , 278 ( 61.6 % ) of whom were free of AF recurrence with no need for repeat procedures after the 3-month blanking period . Rates of freedom from AF after 1 , 2 , and 3 repeat procedures ( using cryoballoon or radiofrequency ablation with similar success rates ) were 74.9 % , 76.2 % , and 76.9 % , respectively . Use of the smaller balloons or both balloons produced the highest rates of long-term freedom from AF . Phrenic nerve palsy occurred in 12 patients ( 2 % ) , resolving within 3 to 9 months . CONCLUSIONS Rates of long-term freedom from AF after cryoballoon ablation are similar to those reported for radiofrequency ablation . A choice between balloons may improve outcomes OBJECTIVES We aim ed to determine the safety and efficacy of pulmonary vein isolation ( PVI ) in atrial fibrillation ( AF ) patients with impaired left ventricular ( LV ) systolic function . BACKGROUND To date , PVI has been performed primarily in patients with normal LV function . Yet , many AF patients have impaired LV systolic function . The outcomes of PVI in patients with impaired LV systolic function are unknown . METHODS We included 377 consecutive patients undergoing PVI between December 2000 and January 2003 . Ninety-four patients had impaired LV function ( ejection fraction [ EF ] < 40 % ) , and they comprised the study group . The control group was the remaining 283 patients who had a normal EF . End points included AF recurrence and changes in EF and quality of life ( QoL ) . RESULTS Mean EF was 36 % in our study group , compared with 54 % in controls . After initial PVI , 73 % of patients with impaired EF and 87 % of patients with normal EF were free of AF recurrence at 14 + /- 6 months ( p = 0.03 ) . In the study group , there was a nonsignificant increase in EF of 4.6 % and significant improvement in QoL. Complication rates were low and included a 1 % risk of pulmonary vein stenosis . CONCLUSIONS Although the AF recurrence rate after initial PVI in impaired EF patients was higher than in normal EF subjects , nearly three-fourths of patients with impaired EF remained AF-free . Although our sample size was nonr and omized , our results suggest PVI may be a feasible therapeutic option in AF patients with impaired EF . R and omized studies with more patients and longer follow-up are warranted Objective To determine whether or not radiofrequency ablation ( RFA ) for persistent atrial fibrillation in patients with advanced heart failure leads to improvements in cardiac function . Setting Patients were recruited from heart failure outpatient clinics in Scotl and . Design and intervention Patients with advanced heart failure and severe left ventricular dysfunction were r and omised to RFA ( rhythm control ) or  continued medical treatment  ( rate control ) . Patients were followed up for a minimum of 6 months . Main outcome measure Change in left ventricular ejection fraction ( LVEF ) measured by cardiovascular MRI . Results 22 patients were r and omised to RFA and 19 to medical treatment . In the RFA group , 50 % of patients were in sinus rhythm at the end of the study ( compared with none in the medical treatment group ) . The increase in cardiovascular magnetic resonance ( CMR ) LVEF in the RFA group was 4.5±11.1 % compared with 2.8±6.7 % in the medical treatment group ( p=0.6 ) . The RFA group had a greater increase in radionuclide LVEF ( a prespecified secondary end point ) than patients in the medical treatment group ( + 8.2±12.0 % vs + 1.4±5.9 % ; p=0.032 ) . RFA did not improve N-terminal pro-B-type natriuretic peptide , 6 min walk distance or quality of life . The rate of serious complications related to RFA was 15 % . Conclusions RFA result ed in long-term restoration of sinus rhythm in only 50 % of patients . RFA did not improve CMR LVEF compared with a strategy of rate control . RFA did improve radionuclide LVEF but did not improve other secondary outcomes and was associated with a significant rate of serious complications . Clinical trials registration number NCT00292162 Background —The effect of successful catheter ablation on left ventricular ( LV ) strain in patients with preserved LV systolic function is unknown . The aim of the present study was to assess the long-term effects of catheter ablation for atrial fibrillation ( AF )  on LV strain and strain rate in patients with preserved LV ejection fraction . Methods and Results —In 78 patients undergoing catheter ablation for AF  , speckle tracking strain imaging was performed to assess LV strain in 3 directions ( radial , circumferential , and longitudinal ) at baseline and after 12-month follow-up . The study population was divided into 2 groups , according to the maintenance of sinus rhythm ( SR ) during follow-up . After 13.8±4.7 months of follow-up , 54 patients ( 69 % ) were in SR ( SR group ) , whereas 24 patients ( 31 % ) had recurrence of AF ( AF group ) . No significant changes in LV ejection fraction from baseline to follow-up were noted ( 60±7 % versus 59±7 % , P = NS ) . Circumferential strain improved significantly in the SR group ( −18.3±3.2 % versus −20.4±3.8 % , P<0.001 ) , whereas it remained unchanged in the AF group ( −18.9±3.5 % versus −17.9±3.1 % , P = NS ) . In the SR group , significant improvements in LV longitudinal strain and strain rate were noted , whereas in the AF group , LV longitudinal strain and strain rate deteriorated significantly at long-term follow-up . Conclusions —After successful catheter ablation , LV circumferential and longitudinal strain and strain rate improve significantly in patients who maintain SR . In contrast , a decrease in LV longitudinal strain and strain rate is observed in patients with recurrence of AF AIMS Beneficial effects of atrial fibrillation ( AF ) ablation have been demonstrated in patients with congestive heart failure ( CHF ) and significantly impaired left ventricular ejection fraction ( LVEF ) . 
    Output:
    