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: 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 Our aim was to identify shortcomings in the management of patients with both atrial fibrillation ( AF ) and heart failure ( HF ) . BACKGROUND AF and HF often coincide in cardiology practice , and they are known to worsen each other 's prognosis , but little is known about the quality of care of this combination . METHODS In the observational Euro Heart Survey on AF , 5,333 AF patients were enrolled in 182 centers across 35 European Society of Cardiology member countries in 2003 and 2004 . A follow-up survey was performed after 1 year . RESULTS At baseline , 1,816 patients ( 34 % ) had HF .  Recommended therapy for HF with left ventricular systolic dysfunction ( LVSD ) with a beta-blocker and either an angiotensin-converting enzyme inhibitor ( ACEI ) or angiotensin II receptor blocker was prescribed in 40 % of HF patients , while 29 % received the recommended drug therapy for both LVSD-HF and AF , consisting of the combination of a beta-blocker , either ACEI or angiotensin II receptor blocker , and oral anticoagulation .  Rate control was insufficient with 40 % of all HF patients with permanent AF having a heart rate < or = 80 beats/min . In the total cohort , HF patients had a higher risk for mortality ( 9.5 % vs. 3.3 % ; p < 0.001 ) , ( progression of ) HF ( 24.8 % vs. 5.0 % ; p < 0.001 ) , and AF progression ( 35 % vs. 19 % ; p < 0.001 ) during 1-year follow-up . Of all recommended drugs for AF and LVSD-HF , only ACEI prescription was associated with improved survival during 1-year follow-up ( odds ratio : 0.51 [ 95 % confidence interval : 0.31 to 0.85 ] ; p = 0.011 ) . CONCLUSIONS The prescription rate of guideline -recommended drug therapy for AF and LVSD-HF is low . R and omized controlled trials targeting this highly prevalent subgroup with AF and HF are warranted 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 The CONSORT ( Consoli date d St and ards of Reporting Trials ) statement is used worldwide to improve the reporting of r and omized , controlled trials . Schulz and colleagues describe the latest version , CONSORT 2010 , which up date s the reporting guideline based on new method ological evidence and accumulating experience . 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 ) . However , the impact of pulmonary vein isolation ( PVI ) on cardiac function in patients with paroxysmal AF and impaired LVEF remains under discussion . This study aim ed to evaluate the impact of PVI for paroxysmal AF on cardiac function in patients with impaired LVEF using cardiac magnetic resonance imaging ( CMRI ) . METHODS AND RESULTS A total number of 70 patients with paroxysmal AF and episodes < or = 24 h were  scanned on a 1.5-T-CMRI before and 6 months after PVI during sinus rhythm . End-diastolic volume , end-systolic volume , and LVEF were determined by epicardial and endocardial measurements . Patients were categorized into two groups regarding cardiac function as assessed by CMRI : group 1 patients ( n = 18 ) with an LVEF < 50 % and patients with an LVEF > 50 % ( group 2 , n = 52 ) . Group 1 patients demonstrated a significant lower success rate than patients of group 2 after a follow-up of 152 + /- 40 days ( 50 vs. 73 % , P < 0.05 ) . Cardiac magnetic resonance imaging in group 1 patients demonstrated a significant improvement in cardiac function after AF ablation ( 41 + /- 6 vs. 51 + /- 12 % , P = 0.004 ) , whereas group 2 patients did not show significant differences ( 60 + /- 6 vs. 59 + /- 9 % , P = 0.22 ) after a 6 months follow-up . CONCLUSION Pulmonary vein isolation improves cardiac function in patients with paroxysmal AF and impaired LVEF . These data suggest that an impaired LV function can be partially attributed to AF with short-lasting paroxysms Aims The objective of the study was to analyse the influence of left ventricular ( LV ) ejection fraction ( EF ) on the outcomes of  atrial fibrillation ( AF ) ablation after a first procedure . Pre-procedural predictors of recurrences after AF ablation can be useful for patient information and selection of c and i date s. The independent influence of LV systolic dysfunction on recurrence rate has not been studied . Methods and results A case – control study ( 1:1 ) was conducted with a total of 72 patients : 36 cases ( depressed LVEF ) and 36 controls ( normal LVEF ) . Patients were matched by left atrial diameter ( LAD ) , the presence of arterial hypertension , and other variables that might influence the results ( age , gender and paroxysmal vs. persistent AF ) . There were no statistical differences in the variables used to perform the matching . Patients with depressed LVEF had higher LV end diastolic diameter ( 55.6 ± 6.2 vs. 52.4 ± 5.5 , P = 0.03 ) , higher LV end systolic diameter ( 40.3 ± 6.9 vs. 32.6 ± 4.3 , P < 0.001 ) , lower LVEF ( 41.4 ± 8.0 vs. 63.1 ± 5.5 , P < 0.001 ) and were more likely to have structural heart disease . After a mean follow-up of 16 ± 13 months , survival analysis for AF recurrences showed no differences between patients with depressed vs. normal LVEF ( 50.0 vs. 55.6 % , log rank = 0.82 ) . Cox regression analysis revealed LAD to be the only variable correlated to recurrence [ OR 1.11 ( 1.01–1.22 ) , P = 0.03 ] . Analysis at 6 months showed a significant increase in LVEF ( 43.23 ± 7.61 to 51.12 ± 13.53 % , P = 0.01 ) for the case group . Conclusion LV systolic dysfunction by itself is not a predictor of outcome after AF ablation . LAD independently correlates with outcome in patients with low or normal LVEF BACKGROUND Electrical isolation of the pulmonary veins by catheter ablation is an emerging treatment modality for the treatment of atrial fibrillation ( AF ) and is increasingly used in patients with heart failure . METHODS The catheter ablation versus st and ard conventional treatment in patients with left ventricular dysfunction and atrial fibrillation trial ( CASTLE-AF ) is a r and omized evaluation of ablative treatment of atrial fibrillation in patients with left ventricular dysfunction . The primary endpoint is the composite of all-cause mortality or worsening of heart failure requiring unplanned hospitalization using a time to first event analysis . Secondary endpoints are all-cause mortality , cardiovascular mortality , cerebrovascular accidents , worsening of heart failure requiring unplanned hospitalization , unplanned hospitalization due to cardiovascular reason , all-cause hospitalization , quality of life , number of therapies ( shock and antitachycardia pacing ) delivered by the implantable cardioverter-defibrillator ( ICD ) , time to first ICD therapy , number of device-detected ventricular tachycardia and ventricular fibrillation episodes , AF burden , AF free interval , left ventricular function , exercise tolerance , and percentage of right ventricular pacing . CASTLE-AF will r and omize 420 patients for a minimum of 3 years at 48 sites in the United 
    Output:
    
agent
AF ablation in patients with systolic LV dysfunction results in significant improvement of LV function , but the extent of this improvement is heterogeneous .
Patients with coronary artery disease seem to benefit less than patients with other underlying diseases .
These results may be explained by patient selection
***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: 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 Our aim was to identify shortcomings in the management of patients with both atrial fibrillation ( AF ) and heart failure ( HF ) . BACKGROUND AF and HF often coincide in cardiology practice , and they are known to worsen each other 's prognosis , but little is known about the quality of care of this combination . METHODS In the observational Euro Heart Survey on AF , 5,333 AF patients were enrolled in 182 centers across 35 European Society of Cardiology member countries in 2003 and 2004 . A follow-up survey was performed after 1 year . RESULTS At baseline , 1,816 patients ( 34 % ) had HF .  Recommended therapy for HF with left ventricular systolic dysfunction ( LVSD ) with a beta-blocker and either an angiotensin-converting enzyme inhibitor ( ACEI ) or angiotensin II receptor blocker was prescribed in 40 % of HF patients , while 29 % received the recommended drug therapy for both LVSD-HF and AF , consisting of the combination of a beta-blocker , either ACEI or angiotensin II receptor blocker , and oral anticoagulation .  Rate control was insufficient with 40 % of all HF patients with permanent AF having a heart rate < or = 80 beats/min . In the total cohort , HF patients had a higher risk for mortality ( 9.5 % vs. 3.3 % ; p < 0.001 ) , ( progression of ) HF ( 24.8 % vs. 5.0 % ; p < 0.001 ) , and AF progression ( 35 % vs. 19 % ; p < 0.001 ) during 1-year follow-up . Of all recommended drugs for AF and LVSD-HF , only ACEI prescription was associated with improved survival during 1-year follow-up ( odds ratio : 0.51 [ 95 % confidence interval : 0.31 to 0.85 ] ; p = 0.011 ) . CONCLUSIONS The prescription rate of guideline -recommended drug therapy for AF and LVSD-HF is low . R and omized controlled trials targeting this highly prevalent subgroup with AF and HF are warranted 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 The CONSORT ( Consoli date d St and ards of Reporting Trials ) statement is used worldwide to improve the reporting of r and omized , controlled trials . Schulz and colleagues describe the latest version , CONSORT 2010 , which up date s the reporting guideline based on new method ological evidence and accumulating experience . 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 ) . However , the impact of pulmonary vein isolation ( PVI ) on cardiac function in patients with paroxysmal AF and impaired LVEF remains under discussion . This study aim ed to evaluate the impact of PVI for paroxysmal AF on cardiac function in patients with impaired LVEF using cardiac magnetic resonance imaging ( CMRI ) . METHODS AND RESULTS A total number of 70 patients with paroxysmal AF and episodes < or = 24 h were  scanned on a 1.5-T-CMRI before and 6 months after PVI during sinus rhythm . End-diastolic volume , end-systolic volume , and LVEF were determined by epicardial and endocardial measurements . Patients were categorized into two groups regarding cardiac function as assessed by CMRI : group 1 patients ( n = 18 ) with an LVEF < 50 % and patients with an LVEF > 50 % ( group 2 , n = 52 ) . Group 1 patients demonstrated a significant lower success rate than patients of group 2 after a follow-up of 152 + /- 40 days ( 50 vs. 73 % , P < 0.05 ) . Cardiac magnetic resonance imaging in group 1 patients demonstrated a significant improvement in cardiac function after AF ablation ( 41 + /- 6 vs. 51 + /- 12 % , P = 0.004 ) , whereas group 2 patients did not show significant differences ( 60 + /- 6 vs. 59 + /- 9 % , P = 0.22 ) after a 6 months follow-up . CONCLUSION Pulmonary vein isolation improves cardiac function in patients with paroxysmal AF and impaired LVEF . These data suggest that an impaired LV function can be partially attributed to AF with short-lasting paroxysms Aims The objective of the study was to analyse the influence of left ventricular ( LV ) ejection fraction ( EF ) on the outcomes of  atrial fibrillation ( AF ) ablation after a first procedure . Pre-procedural predictors of recurrences after AF ablation can be useful for patient information and selection of c and i date s. The independent influence of LV systolic dysfunction on recurrence rate has not been studied . Methods and results A case – control study ( 1:1 ) was conducted with a total of 72 patients : 36 cases ( depressed LVEF ) and 36 controls ( normal LVEF ) . Patients were matched by left atrial diameter ( LAD ) , the presence of arterial hypertension , and other variables that might influence the results ( age , gender and paroxysmal vs. persistent AF ) . There were no statistical differences in the variables used to perform the matching . Patients with depressed LVEF had higher LV end diastolic diameter ( 55.6 ± 6.2 vs. 52.4 ± 5.5 , P = 0.03 ) , higher LV end systolic diameter ( 40.3 ± 6.9 vs. 32.6 ± 4.3 , P < 0.001 ) , lower LVEF ( 41.4 ± 8.0 vs. 63.1 ± 5.5 , P < 0.001 ) and were more likely to have structural heart disease . After a mean follow-up of 16 ± 13 months , survival analysis for AF recurrences showed no differences between patients with depressed vs. normal LVEF ( 50.0 vs. 55.6 % , log rank = 0.82 ) . Cox regression analysis revealed LAD to be the only variable correlated to recurrence [ OR 1.11 ( 1.01–1.22 ) , P = 0.03 ] . Analysis at 6 months showed a significant increase in LVEF ( 43.23 ± 7.61 to 51.12 ± 13.53 % , P = 0.01 ) for the case group . Conclusion LV systolic dysfunction by itself is not a predictor of outcome after AF ablation . LAD independently correlates with outcome in patients with low or normal LVEF BACKGROUND Electrical isolation of the pulmonary veins by catheter ablation is an emerging treatment modality for the treatment of atrial fibrillation ( AF ) and is increasingly used in patients with heart failure . METHODS The catheter ablation versus st and ard conventional treatment in patients with left ventricular dysfunction and atrial fibrillation trial ( CASTLE-AF ) is a r and omized evaluation of ablative treatment of atrial fibrillation in patients with left ventricular dysfunction . The primary endpoint is the composite of all-cause mortality or worsening of heart failure requiring unplanned hospitalization using a time to first event analysis . Secondary endpoints are all-cause mortality , cardiovascular mortality , cerebrovascular accidents , worsening of heart failure requiring unplanned hospitalization , unplanned hospitalization due to cardiovascular reason , all-cause hospitalization , quality of life , number of therapies ( shock and antitachycardia pacing ) delivered by the implantable cardioverter-defibrillator ( ICD ) , time to first ICD therapy , number of device-detected ventricular tachycardia and ventricular fibrillation episodes , AF burden , AF free interval , left ventricular function , exercise tolerance , and percentage of right ventricular pacing . CASTLE-AF will r and omize 420 patients for a minimum of 3 years at 48 sites in the United 
    Output:
    