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: AIMS The European cardiac resynchronization therapy ( CRT ) survey is a joint initiative taken by the Heart Failure Association and the European Heart Rhythm Association of the European Society of Cardiology . The primary aim of this survey is to describe current European practice associated with CRT implantations . METHODS AND RESULTS A total of 140 centres from 13 European countries contributed data from consecutive patients successfully implanted with a CRT device with or without an ICD between November 2008 and June 2009 . The total number of patients enrolled was 2438 . The median age of the patients was 70 years ( IQR 62 - 76 ) and 31 % were > or = 75 years . It was found that 78 % were in NYHA functional class III or IV and 22 % in I or II . The mean ejection fraction was 27 % + /- 8 and the mean QRS duration 157 ms + /- 32 . The QRS duration was < 120 ms in 9 % . Atrial fibrillation was reported in 23 % . It was found that 26 % of patients had a previously implanted permanent pacemaker or ICD ; 76 % of procedures were performed by an electrophysiologist ; 82 % had an elective admission for implantation and the median duration of hospitalization was 3 days ( IQR 2 - 7 ) ; and 73 % received a CRT-D device which was more often implanted in men , younger patients , and with ischaemic aetiology . The mean QRS duration was reduced to 133 ms + /- 27 ( P < 0.0001 ) at discharge . Peri-procedural complication rates were comparable to the rates reported in r and omized trials . CONCLUSION This CRT survey provides important information describing current European practice with regard to patient demographics , selection criteria , procedural routines , and status at discharge . These data should be useful for benchmarking individual patient management and national practice against wider experience OBJECTIVES The main objective of this study was to assess if the benefits of biventricular ( BiV ) pacing observed during the crossover phase were sustained over 12 months . BACKGROUND MUltisite STimulation In Cardiomyopathies ( MUSTIC ) is a r and omized controlled study intended to evaluate the effects of BiV pacing in patients with New York Heart Association ( NYHA ) class III heart failure and intraventricular conduction delay . METHODS Of 131 patients included , 42/67 in sinus rhythm ( SR ) and 33/64 in atrial fibrillation ( AF ) were followed up longitudinally at 9 and 12 months by 6-min walked distance , peak oxygen uptake ( peak VO(2 ) ) , quality of life by the Minnesota score , NYHA class , echocardiography , and left ventricular ejection fraction by radionuclide technique . RESULTS At 12 months , all SR and 88 % of AF patients were programmed to BiV pacing . Compared with baseline , the 6-min walked distance increased by 20 % ( SR ) ( p = 0.0001 ) and 17 % ( AF ) ( p = 0.004 ) ; the peak VO(2 ) by 11 % ( SR ) and 9 % ( AF ) ; quality of life improved by 36 % ( SR ) ( p = 0.0001 ) and 32 % ( AF ) ( p = 0.002 ) ; NYHA class improved by 25 % ( SR ) ( p = 0.0001 ) and 27 % ( AF ) ( p = 0.0001 ) . The ejection fraction improved by 5 % ( SR ) and 4 % ( AF ) . Mitral regurgitation decreased by 45 % ( SR ) and 50 % ( AF ) . CONCLUSIONS The clinical benefits of BiV pacing appeared to be significantly maintained over a 12-month follow-up period Objective : To compare the effects of cardiac resynchronisation therapy ( CRT ) in patients with heart failure ( HF ) in either atrial fibrillation ( AF ) or sinus rhythm ( SR ) . Design : Prospect i ve observational study . Patients : 295 consecutive patients with HF ( permanent AF in 66 , paroxysmal AF in 20 , SR in 209 ; New York Heart Association ( NYHA ) class III or IV ; left ventricular ejection fraction ( LVEF ) ⩽35 % , QRS ⩾120 ms ) . Interventions : All patients underwent CRT without atrioventricular junction ablation . Main outcome measures : The primary end point was the composite of cardiovascular death or unplanned hospitalisation for major cardiovascular events . Secondary end points included the composite of cardiovascular death or hospitalisation for worsening HF . Cardiovascular mortality , total mortality and changes in NYHA class , 6-minute walking distance , quality of life ( Minnesota Living with Heart Failure question naire ) and echocardiographic variables were also considered . Results : Over a follow-up period of up to 6.8 years , no differences emerged between patients in AF or SR in any of the mortality or morbidity end points . The AF and SR groups derived similar improvements in mean NYHA class ( −1.3 vs –1.2 ) , 6-minute walking distance ( 92.3 vs 78.4 m ) and quality of life scores ( −25.2 vs –18.7 ) ( all p<0.001 ) . In both the AF and the SR groups , reductions were seen in left ventricular end-systolic ( −25.9 vs –34.5 ml , both p<0.001 ) and end-diastolic ( −20.2 ml , p = 0.001 vs 26.2 ml , p<0.001 ) volumes and improvements in LVEF ( 4.69 % vs 7.86 % , both p<0.001 ) . Conclusions : Cardiac resynchronisation therapy leads to similar prognostic and symptomatic benefits in patients in AF and SR , even without atrioventricular junction ablation . Echocardiographic improvements are also comparable OBJECTIVES The goal of this study was to investigate the effects of cardiac resynchronization therapy ( CRT ) in heart failure patients with permanent atrial fibrillation ( AF ) and the role of atrioventricular junction ( AVJ ) ablation . BACKGROUND Cardiac resynchronization therapy has been proven effective in heart failure patients with sinus rhythm ( SR ) . However , little is known about the effects of CRT in heart failure patients with permanent AF . METHODS Efficacy of CRT on ventricular function , exercise performance , and reversal of maladaptive remodeling process was prospect ively compared in 48 patients with permanent AF in whom ventricular rate was controlled by drugs , thus result ing in apparently adequate delivery of biventricular pacing ( > 85 % of pacing time ) , and in 114 permanent AF patients , who had undergone AVJ ablation ( 100 % of resynchronization therapy delivery ) . The clinical and echocardiographic long-term outcomes of both groups were compared with those of 511 SR patients treated with CRT . RESULTS Both SR and AF groups showed significant and sustained improvements of all assessed parameters ( model p < 0.001 for all parameters ) . However , within the AF group , only patients who underwent ablation showed a significant increase of ejection fraction ( p < 0.001 ) , reverse remodeling effect ( p < 0.001 ) , and improved exercise tolerance ( p < 0.001 ) ; no improvements were observed in AF patients who did not undergo ablation . CONCLUSIONS Heart failure patients with ventricular conduction disturbance and permanent AF treated with CRT showed large and sustained long-term ( up to 4 year ) improvements of left ventricular function and functional capacity , similar to patients in SR , only if AVJ ablation was performed INTRODUCTION The precise role of irregular ventricular response in atrial fibrillation ( AF ) has not been fully eluci date d. This study examined the independent effects of rhythm regularity in patients with chronic AF . METHODS AND RESULTS This study included 50 patients who had chronic lone AF and a normal ventricular rate . Among these patients , 21 who underwent AV junction ablation and implantation of a VVIR pacemaker constituted the ablation group ; the other 29 patients were the medical group .  Acute hemodynamic findings were measured in 21 ablation patients before ablation ( during AF , baseline ) and 15 minutes after ablation ( during right ventricular pacing ) . Compared with baseline data , ablation and pacing therapy increased cardiac output ( 4.7 + /- 0.8 vs 5.2 + /- 0.9 L/min ; P = 0.05 ) , decreased pulmonary capillary wedge pressure ( 16 + /- 5 vs 13 + /- 4 mmHg ; P = 0.001 ) , and decreased left ventricular end-diastolic pressure ( 14 + /- 4 vs 11 + /- 3 mmHg ; P < 0.05 ) . After 12 months , the ablation group patients showed lower scores in general quality of life ( -20 % ; P < 0.001 ) , overall symptoms ( -24 % ; P < 0.001 ) , overall activity scale ( -23 % ; P = 0.004 ) , and significant increase of left ventricular ejection fraction ( 44 % + /- 6 % vs 49 % + /- 5 % ; P = 0.02 ) by echocardiographic examination . CONCLUSION AV junction ablation and pacing in patients with chronic AF and normal ventricular response may confer acute and long-term benefits beyond rate control by eliminating rhythm irregularity BACKGROUND One third of chronic heart failure patients have major intraventricular conduction and uncoordinated ventricular contraction . Non-controlled studies suggest that biventricular pacing may improve haemodynamics and well-being by reducing ventricular asynchrony . The aim of this trial was to assess the clinical efficacy and safety of this new therapy in patients with chronic atrial fibrillation . METHODS Fifty nine NYHA class III patients with left ventricular systolic dysfunction , chronic atrial fibrillation , slow ventricular rate necessitating permanent ventricular pacing , and a wide QRS complex ( paced width > or=200 ms ) , were implanted with transvenous biventricular-VVIR pacemakers . This single-blind , r and omized , controlled , crossover study compared the patients ' parameters , as monitored during two 3-month treatment periods of conventional right-univentricular vs biventricular pacing . The primary end-point was the 6-min walked distance , secondary end-points were peak oxygen uptake , quality -of-life , hospitalizations , patients ' preferred study period and mortality . RESULTS Because of a higher than expected drop-out rate ( 42 % ) , only 37 patients completed both crossover phases . In the intention-to-treat analysis , we did not observe a significant difference . However , in the patients with effective therapy the mean walked distance increased by 9.3 % with biventricular pacing ( 374+/-108 vs 342+/-103 m in univentricular;P = 0.05 ) . Peak oxygen uptake increased by 13 % ( P=0.04 ) . Hospitalizations decreased by 70 % and 85 % of the patients preferred the biventricular pacing period ( P<0.001 ) . CONCLUSION As compared with conventional VVIR pacing , effective biventricular pacing seems to improve exercise tolerance in NYHA class III heart failure patients with chronic atrial fibrillation and wide paced-QRS complexes . Further r and omized controlled studies are required to definitively vali date this therapy in such patients The prevalence of atrial fibrillation ( AF ) in patients with heart failure is high , but data about the effects of cardiac resynchronization therapy ( CRT ) in patients with chronic AF are scarce . In this prospect i ve observational study of 263 consecutive patients , CRT was performed in 96 patients ( 37 % ) with chronic AF and 167 patients ( 63 % ) with sinus rhythm ( SR ) .  Echocardiographic and clinical parameters were evaluated at baseline and 3 and 12 months . Reverse left ventricular ( LV ) remodeling is defined as LV end-systolic volume decrease > or = 10 % . Hospitalization rates for heart failure in the year before and after implantation were compared . Baseline characteristics between patients with and without AF were similar , but the AF group had smaller LV end-systolic and end-diastolic volumes and larger left atrial dimensions . New York Heart Association class , 6-minute walking distance , quality -of-life score , LV ejection fraction , and mitral regurgitation improved significantly at 3 and 12 months in both groups , and the changes were similar . Reverse LV remodeling after 3 and 12 months was 74 % and 82 % ( AF group ) versus 77 % and 83 % , respectively ( SR group , p = 0.79 ) . After 1 year , cardioversion had occurred in 25 % of patients with AF . In the year after implantation , significant decreases in hospitalizations for heart failure in both groups ( 84 % and 90 % ) were documented . Long-term mortality was almost equal in both groups . In conclusion , this large-scale study shows that the benefit of CRT in patients with chronic AF and heart failure is similar to that in patients with SR . Patients with chronic AF and heart failure should be considered c and i date s for CRT 
    Output:
    
agent
AV nodal ablation was associated with a substantial reduction in all-cause mortality and cardiovascular mortality and with improvements in New York Heart Association functional class compared with medical therapy in CRT-AF patients .
***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: AIMS The European cardiac resynchronization therapy ( CRT ) survey is a joint initiative taken by the Heart Failure Association and the European Heart Rhythm Association of the European Society of Cardiology . The primary aim of this survey is to describe current European practice associated with CRT implantations . METHODS AND RESULTS A total of 140 centres from 13 European countries contributed data from consecutive patients successfully implanted with a CRT device with or without an ICD between November 2008 and June 2009 . The total number of patients enrolled was 2438 . The median age of the patients was 70 years ( IQR 62 - 76 ) and 31 % were > or = 75 years . It was found that 78 % were in NYHA functional class III or IV and 22 % in I or II . The mean ejection fraction was 27 % + /- 8 and the mean QRS duration 157 ms + /- 32 . The QRS duration was < 120 ms in 9 % . Atrial fibrillation was reported in 23 % . It was found that 26 % of patients had a previously implanted permanent pacemaker or ICD ; 76 % of procedures were performed by an electrophysiologist ; 82 % had an elective admission for implantation and the median duration of hospitalization was 3 days ( IQR 2 - 7 ) ; and 73 % received a CRT-D device which was more often implanted in men , younger patients , and with ischaemic aetiology . The mean QRS duration was reduced to 133 ms + /- 27 ( P < 0.0001 ) at discharge . Peri-procedural complication rates were comparable to the rates reported in r and omized trials . CONCLUSION This CRT survey provides important information describing current European practice with regard to patient demographics , selection criteria , procedural routines , and status at discharge . These data should be useful for benchmarking individual patient management and national practice against wider experience OBJECTIVES The main objective of this study was to assess if the benefits of biventricular ( BiV ) pacing observed during the crossover phase were sustained over 12 months . BACKGROUND MUltisite STimulation In Cardiomyopathies ( MUSTIC ) is a r and omized controlled study intended to evaluate the effects of BiV pacing in patients with New York Heart Association ( NYHA ) class III heart failure and intraventricular conduction delay . METHODS Of 131 patients included , 42/67 in sinus rhythm ( SR ) and 33/64 in atrial fibrillation ( AF ) were followed up longitudinally at 9 and 12 months by 6-min walked distance , peak oxygen uptake ( peak VO(2 ) ) , quality of life by the Minnesota score , NYHA class , echocardiography , and left ventricular ejection fraction by radionuclide technique . RESULTS At 12 months , all SR and 88 % of AF patients were programmed to BiV pacing . Compared with baseline , the 6-min walked distance increased by 20 % ( SR ) ( p = 0.0001 ) and 17 % ( AF ) ( p = 0.004 ) ; the peak VO(2 ) by 11 % ( SR ) and 9 % ( AF ) ; quality of life improved by 36 % ( SR ) ( p = 0.0001 ) and 32 % ( AF ) ( p = 0.002 ) ; NYHA class improved by 25 % ( SR ) ( p = 0.0001 ) and 27 % ( AF ) ( p = 0.0001 ) . The ejection fraction improved by 5 % ( SR ) and 4 % ( AF ) . Mitral regurgitation decreased by 45 % ( SR ) and 50 % ( AF ) . CONCLUSIONS The clinical benefits of BiV pacing appeared to be significantly maintained over a 12-month follow-up period Objective : To compare the effects of cardiac resynchronisation therapy ( CRT ) in patients with heart failure ( HF ) in either atrial fibrillation ( AF ) or sinus rhythm ( SR ) . Design : Prospect i ve observational study . Patients : 295 consecutive patients with HF ( permanent AF in 66 , paroxysmal AF in 20 , SR in 209 ; New York Heart Association ( NYHA ) class III or IV ; left ventricular ejection fraction ( LVEF ) ⩽35 % , QRS ⩾120 ms ) . Interventions : All patients underwent CRT without atrioventricular junction ablation . Main outcome measures : The primary end point was the composite of cardiovascular death or unplanned hospitalisation for major cardiovascular events . Secondary end points included the composite of cardiovascular death or hospitalisation for worsening HF . Cardiovascular mortality , total mortality and changes in NYHA class , 6-minute walking distance , quality of life ( Minnesota Living with Heart Failure question naire ) and echocardiographic variables were also considered . Results : Over a follow-up period of up to 6.8 years , no differences emerged between patients in AF or SR in any of the mortality or morbidity end points . The AF and SR groups derived similar improvements in mean NYHA class ( −1.3 vs –1.2 ) , 6-minute walking distance ( 92.3 vs 78.4 m ) and quality of life scores ( −25.2 vs –18.7 ) ( all p<0.001 ) . In both the AF and the SR groups , reductions were seen in left ventricular end-systolic ( −25.9 vs –34.5 ml , both p<0.001 ) and end-diastolic ( −20.2 ml , p = 0.001 vs 26.2 ml , p<0.001 ) volumes and improvements in LVEF ( 4.69 % vs 7.86 % , both p<0.001 ) . Conclusions : Cardiac resynchronisation therapy leads to similar prognostic and symptomatic benefits in patients in AF and SR , even without atrioventricular junction ablation . Echocardiographic improvements are also comparable OBJECTIVES The goal of this study was to investigate the effects of cardiac resynchronization therapy ( CRT ) in heart failure patients with permanent atrial fibrillation ( AF ) and the role of atrioventricular junction ( AVJ ) ablation . BACKGROUND Cardiac resynchronization therapy has been proven effective in heart failure patients with sinus rhythm ( SR ) . However , little is known about the effects of CRT in heart failure patients with permanent AF . METHODS Efficacy of CRT on ventricular function , exercise performance , and reversal of maladaptive remodeling process was prospect ively compared in 48 patients with permanent AF in whom ventricular rate was controlled by drugs , thus result ing in apparently adequate delivery of biventricular pacing ( > 85 % of pacing time ) , and in 114 permanent AF patients , who had undergone AVJ ablation ( 100 % of resynchronization therapy delivery ) . The clinical and echocardiographic long-term outcomes of both groups were compared with those of 511 SR patients treated with CRT . RESULTS Both SR and AF groups showed significant and sustained improvements of all assessed parameters ( model p < 0.001 for all parameters ) . However , within the AF group , only patients who underwent ablation showed a significant increase of ejection fraction ( p < 0.001 ) , reverse remodeling effect ( p < 0.001 ) , and improved exercise tolerance ( p < 0.001 ) ; no improvements were observed in AF patients who did not undergo ablation . CONCLUSIONS Heart failure patients with ventricular conduction disturbance and permanent AF treated with CRT showed large and sustained long-term ( up to 4 year ) improvements of left ventricular function and functional capacity , similar to patients in SR , only if AVJ ablation was performed INTRODUCTION The precise role of irregular ventricular response in atrial fibrillation ( AF ) has not been fully eluci date d. This study examined the independent effects of rhythm regularity in patients with chronic AF . METHODS AND RESULTS This study included 50 patients who had chronic lone AF and a normal ventricular rate . Among these patients , 21 who underwent AV junction ablation and implantation of a VVIR pacemaker constituted the ablation group ; the other 29 patients were the medical group .  Acute hemodynamic findings were measured in 21 ablation patients before ablation ( during AF , baseline ) and 15 minutes after ablation ( during right ventricular pacing ) . Compared with baseline data , ablation and pacing therapy increased cardiac output ( 4.7 + /- 0.8 vs 5.2 + /- 0.9 L/min ; P = 0.05 ) , decreased pulmonary capillary wedge pressure ( 16 + /- 5 vs 13 + /- 4 mmHg ; P = 0.001 ) , and decreased left ventricular end-diastolic pressure ( 14 + /- 4 vs 11 + /- 3 mmHg ; P < 0.05 ) . After 12 months , the ablation group patients showed lower scores in general quality of life ( -20 % ; P < 0.001 ) , overall symptoms ( -24 % ; P < 0.001 ) , overall activity scale ( -23 % ; P = 0.004 ) , and significant increase of left ventricular ejection fraction ( 44 % + /- 6 % vs 49 % + /- 5 % ; P = 0.02 ) by echocardiographic examination . CONCLUSION AV junction ablation and pacing in patients with chronic AF and normal ventricular response may confer acute and long-term benefits beyond rate control by eliminating rhythm irregularity BACKGROUND One third of chronic heart failure patients have major intraventricular conduction and uncoordinated ventricular contraction . Non-controlled studies suggest that biventricular pacing may improve haemodynamics and well-being by reducing ventricular asynchrony . The aim of this trial was to assess the clinical efficacy and safety of this new therapy in patients with chronic atrial fibrillation . METHODS Fifty nine NYHA class III patients with left ventricular systolic dysfunction , chronic atrial fibrillation , slow ventricular rate necessitating permanent ventricular pacing , and a wide QRS complex ( paced width > or=200 ms ) , were implanted with transvenous biventricular-VVIR pacemakers . This single-blind , r and omized , controlled , crossover study compared the patients ' parameters , as monitored during two 3-month treatment periods of conventional right-univentricular vs biventricular pacing . The primary end-point was the 6-min walked distance , secondary end-points were peak oxygen uptake , quality -of-life , hospitalizations , patients ' preferred study period and mortality . RESULTS Because of a higher than expected drop-out rate ( 42 % ) , only 37 patients completed both crossover phases . In the intention-to-treat analysis , we did not observe a significant difference . However , in the patients with effective therapy the mean walked distance increased by 9.3 % with biventricular pacing ( 374+/-108 vs 342+/-103 m in univentricular;P = 0.05 ) . Peak oxygen uptake increased by 13 % ( P=0.04 ) . Hospitalizations decreased by 70 % and 85 % of the patients preferred the biventricular pacing period ( P<0.001 ) . CONCLUSION As compared with conventional VVIR pacing , effective biventricular pacing seems to improve exercise tolerance in NYHA class III heart failure patients with chronic atrial fibrillation and wide paced-QRS complexes . Further r and omized controlled studies are required to definitively vali date this therapy in such patients The prevalence of atrial fibrillation ( AF ) in patients with heart failure is high , but data about the effects of cardiac resynchronization therapy ( CRT ) in patients with chronic AF are scarce . In this prospect i ve observational study of 263 consecutive patients , CRT was performed in 96 patients ( 37 % ) with chronic AF and 167 patients ( 63 % ) with sinus rhythm ( SR ) .  Echocardiographic and clinical parameters were evaluated at baseline and 3 and 12 months . Reverse left ventricular ( LV ) remodeling is defined as LV end-systolic volume decrease > or = 10 % . Hospitalization rates for heart failure in the year before and after implantation were compared . Baseline characteristics between patients with and without AF were similar , but the AF group had smaller LV end-systolic and end-diastolic volumes and larger left atrial dimensions . New York Heart Association class , 6-minute walking distance , quality -of-life score , LV ejection fraction , and mitral regurgitation improved significantly at 3 and 12 months in both groups , and the changes were similar . Reverse LV remodeling after 3 and 12 months was 74 % and 82 % ( AF group ) versus 77 % and 83 % , respectively ( SR group , p = 0.79 ) . After 1 year , cardioversion had occurred in 25 % of patients with AF . In the year after implantation , significant decreases in hospitalizations for heart failure in both groups ( 84 % and 90 % ) were documented . Long-term mortality was almost equal in both groups . In conclusion , this large-scale study shows that the benefit of CRT in patients with chronic AF and heart failure is similar to that in patients with SR . Patients with chronic AF and heart failure should be considered c and i date s for CRT 
    Output:
    