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 Although atrial fibrillation ( AF ) is a risk factor for endothelial dysfunction ( ED ) , the effect of catheter ablation ( CA ) on AF-associated ED has not been evaluated . The aims of this study are to determine if the degree of ED predicts the outcome of AF ablation and to evaluate whether ED can be improved through restoring sinus rhythm ( SR ) by successful CA . METHODS This study prospect ively enrolled 80 subjects who underwent CA for AF ( paroxysmal AF = 61 , persistent AF = 19 ) . Eighty subjects with no history of AF were enrolled as controls , all of whom were matched by age , gender , body mass index , and atherosclerotic risk factor distribution . Brachial artery flow-mediated dilatation ( FMD ) was measured at baseline , and at 1 month and 6 months post CA in AF subjects who remained in SR . Among controls , FMD was measured at baseline and at 6 months . We used high sensitivity C-reactive protein ( hs-CRP ) , interleukin-6 , soluble E- or P-selectin , and endothelin-1 as biomarker indices for inflammation and /or ED . RESULTS Compared with controls , AF subjects had lower FMD at baseline ( FMD(baseline ) , P < 0.001 ) . After successful CA , FMD was significantly improved at 1 month and 6 months , nearly approaching control levels . A multivariate analysis revealed that FMD(baseline ) , hs-CRP , and left atrial volume ( LAV ) were independent predictors for arrhythmia recurrence after CA . Other biomarkers were not related to rhythm outcome . CONCLUSION AF subjects have significantly impaired FMD , which can be reversed through maintenance of SR by successful CA . FMD(baseline ) , hs-CRP , and LAV are important predictors for AF recurrence after CA AIMS This study examined the difference in autonomic modification ( AM ) and its effect on paroxysmal atrial fibrillation ( PAF ) recurrence between segmental pulmonary vein isolation ( S-PVI ) and circumferential PVI ( C-PVI ) . METHODS AND RESULTS Successful S-PVI or C-PVI with a basket catheter was achieved in 120 consecutive PAF patients . Serial 24 Holter-recordings were obtained before , immediately , and 1 , 3 , 6 , 12 months after the PVI to analyse the heart rate variability ( HRV ) .  Nineteen patients were excluded from analysis because of additional ablation for recurrent PAF after successful PVI . Among the residual 101 patients , 33 had PAF recurrences ( S-PVI = 44.0 % , C-PVI = 21.6 % ) at 1 year of follow-up . The root mean square of successive differences and high-frequency power reflecting parasympathetic nervous activity were significantly lower in patients with and without PAF recurrences after C-PVI and patients without PAF recurrences after S-PVI than patients with PAF recurrences after S-PVI ( P < 0.005 - 0.0001 ) . However , there were no significant differences in any HRV parameters in the immediate aftermath of PVI among the patients without PAF recurrences after S-PVI and those with and without PAF recurrences after C-PVI . CONCLUSION Although additional radiofrequency ablation for AM may be recommended after S-PVI to reduce PAF recurrences , it should be carefully determined after C-PVI INTRODUCTION Ablation has emerged as a major treatment option for atrial fibrillation ( AF ) . However , this procedure is limited by a significant rate of AF recurrence . We aim ed to examine the effects of statins , angiotensin-converting enzyme inhibitors ( ACE-I ) , and angiotensin receptor blockers ( ARB ) on the recurrence rate of AF following ablation . METHODS We conducted a retrospective study of 177 consecutive patients ( mean age = 56 + /- 11 yrs , 69 % males ) who underwent ablation for paroxysmal ( n = 132 ) or persistent AF ( n = 45 ) . Patients were treated with ACE-I ( n = 31 ) or ARB ( n = 18 ) or statins ( n = 50 ) prior to ablation and for the duration of follow-up . RESULTS After a mean follow-up of 13.8 + /- 8.6 months , 72 % of patients were free of AF . For patients taking statins , 33 of 50 ( 60 % ) were free of AF . In patients treated with ACE-I , 17 of 31 ( 55 % ) were free from AF , while in the group of patients treated with ARB , 17 of 18 ( 94 % ) were free from AF . Using Cox regression analysis to correct for baseline variables , treatment with statins did not decrease the recurrence rate ( HR = 1.10 [ 95 % CI : 0.55 - 2.27 ] p = 0.79 ) ; nor did treatment with renin angiotensin system ( RAS ) blockers ( HR 0.94 [ 95 % CI : 0.46 - 1.93 ] p = 0.87 ) . However , subgroup analysis showed that treatment with ARB was associated with a trend towards lower AF recurrence [ HR 0.17 , ( 95 % CI : 0.02 - 1.34 ) p = 0.09 ] . CONCLUSIONS Even though statins and RAS blockers possess anti-inflammatory properties , they did not decrease the recurrence of AF following ablation . However , the subset of patients taking ARB exhibited a trend towards lower AF recurrence . Larger , r and omized studies are needed to address this observation Background — Atrial fibrillation ( AF ) is associated with diffuse left atrial fibrosis and a reduction in endocardial voltage . These changes are indicators of AF severity and appear to be predictors of treatment outcome . In this study , we report the utility of delayed-enhancement magnetic resonance imaging ( DE-MRI ) in detecting abnormal atrial tissue before radiofrequency ablation and in predicting procedural outcome . Methods and Results — Eighty-one patients presenting for pulmonary vein antrum isolation for treatment of AF underwent  3-dimensional DE-MRI of the left atrium before the ablation .  Six healthy volunteers also were scanned . DE-MRI images were manually segmented to isolate the left atrium , and custom software was implemented to quantify the spatial extent of delayed enhancement , which was then compared with the regions of low voltage from electroanatomic maps from the pulmonary vein antrum isolation procedure . Patients were assessed for AF recurrence at least 6 months after pulmonary vein antrum isolation , with an average follow-up of 9.6±3.7 months ( range , 6 to 19 months ) . On the basis of the extent of preablation enhancement , 43 patients were classified as having minimal enhancement ( average enhancement , 8.0±4.2 % ) , 30 as having moderate enhancement ( 21.3±5.8 % ) , and 8 as having extensive enhancement ( 50.1±15.4 % ) . The rate of AF recurrence was 6 patients ( 14.0 % ) with minimal enhancement , 13 ( 43.3 % ) with moderate enhancement , and 6 ( 75 % ) with extensive enhancement ( P<0.001 ) . Conclusions — DE-MRI provides a noninvasive means of assessing left atrial myocardial tissue in patients suffering from AF and might provide insight into the progress of the disease . Preablation DE-MRI holds promise for predicting responders to AF ablation and may provide a metric of overall disease progression Background — The mainstay of treatment for atrial fibrillation ( AF ) remains pharmacological ; however , catheter ablation has increasingly been used over the last decade . The relative merits of each strategy have not been extensively studied . Methods and Results — We conducted a r and omized multicenter comparison of these 2 treatment strategies in patients with paroxysmal AF resistant to at least 1 antiarrhythmic drug . The primary end point was absence of recurrent AF between months 3 and 12 , absence of recurrent AF after up to 3 ablation procedures , or changes in antiarrhythmic drugs during the first 3 months . Ablation consisted of pulmonary vein isolation in all cases , whereas additional extrapulmonary vein lesions were at the discretion of the physician . Crossover was permitted at 3 months in case of failure . Echocardiographic data , symptom score , exercise capacity , quality of life , and AF burden were evaluated at 3 , 6 , and 12 months by the supervising committee . Of 149 eligible patients , 112 ( 18 women [ 16 % ] ; age , 51.1±11.1 years ) were enrolled and r and omized to ablation ( n=53 ) or “ new ” antiarrhythmic drugs alone or in combination ( n=59 ) . Crossover from the antiarrhythmic drugs and ablation groups occurred in 37 ( 63 % ) and 5 patients ( 9 % ) , respectively ( P=0.0001 ) . At the 1-year follow-up , 13 of 55 patients ( 23 % ) and 46 of 52 patients ( 89 % ) had no recurrence of AF in the antiarrhythmic drug and ablation groups , respectively ( P<0.0001 ) . Symptom score , exercise capacity , and quality of life were significantly higher in the ablation group . Conclusion — This r and omized multicenter study demonstrates the superiority of catheter ablation over antiarrhythmic drugs in patients with AF with regard to maintenance of sinus rhythm and improvement in symptoms , exercise capacity , and quality of life OBJECTIVES The purpose of this study was to evaluate the associations of transthoracic echocardiographic parameters with recurrent atrial fibrillation ( AF ) and /or stroke . BACKGROUND The Atrial Fibrillation Follow-up Investigation of Rhythm Management ( AFFIRM ) study , an evaluation of elderly patients with AF at risk for stroke , provided an opportunity to evaluate the implication s of echocardiographic parameters in patients with AF . METHODS  Transthoracic echocardiographic measures of mitral regurgitation ( MR ) , left atrial ( LA ) diameter , and left ventricular ( LV ) function were evaluated in the AFFIRM rate- and rhythm-control patients who had sinus rhythm resume and had these data available .  Risk for recurrent AF or stroke was evaluated with respect to transthoracic echocardiographic measures . RESULTS Of 2,474 patients studied , 457 had > or = 2(+)/4(+ ) MR , and 726 had a LA diameter > 4.5 cm . The  LV ejection fraction was abnormal in 543 patients . The cumulative probabilities of at least one AF recurrence/stroke were 46%/1 % after 1 year and 84%/5 % by the end of the trial ( > 5 years ) , respectively . Multivariate analysis showed that r and omization to the rhythm-control arm ( hazard ratio [ HR ] = 0.64 ; p < 0.0001 ) and a qualifying episode of AF being the first known episode ( HR = 0.70 ; p < 0.0001 ) were associated with decreased risk . Duration of qualifying AF episode > 48 h ( HR = 1.55 ; p < 0.0001 ) and LA diameter ( p = 0.008 ) were associated with an increased risk of recurrent AF . Recurrent AF was more likely with larger LA diameters ( HR = 1.21 , 1.16 , and 1.32 for mild , moderate , and severe enlargement , respectively ) . No transthoracic echocardiographic measures were associated with risk of stroke . CONCLUSIONS In the AF 
    Output:
    
agent
Dilated LA significantly increases the risk of AF recurrence after  single CPVI .
This is especially applicable to the patients with long-term follow-up
***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 Although atrial fibrillation ( AF ) is a risk factor for endothelial dysfunction ( ED ) , the effect of catheter ablation ( CA ) on AF-associated ED has not been evaluated . The aims of this study are to determine if the degree of ED predicts the outcome of AF ablation and to evaluate whether ED can be improved through restoring sinus rhythm ( SR ) by successful CA . METHODS This study prospect ively enrolled 80 subjects who underwent CA for AF ( paroxysmal AF = 61 , persistent AF = 19 ) . Eighty subjects with no history of AF were enrolled as controls , all of whom were matched by age , gender , body mass index , and atherosclerotic risk factor distribution . Brachial artery flow-mediated dilatation ( FMD ) was measured at baseline , and at 1 month and 6 months post CA in AF subjects who remained in SR . Among controls , FMD was measured at baseline and at 6 months . We used high sensitivity C-reactive protein ( hs-CRP ) , interleukin-6 , soluble E- or P-selectin , and endothelin-1 as biomarker indices for inflammation and /or ED . RESULTS Compared with controls , AF subjects had lower FMD at baseline ( FMD(baseline ) , P < 0.001 ) . After successful CA , FMD was significantly improved at 1 month and 6 months , nearly approaching control levels . A multivariate analysis revealed that FMD(baseline ) , hs-CRP , and left atrial volume ( LAV ) were independent predictors for arrhythmia recurrence after CA . Other biomarkers were not related to rhythm outcome . CONCLUSION AF subjects have significantly impaired FMD , which can be reversed through maintenance of SR by successful CA . FMD(baseline ) , hs-CRP , and LAV are important predictors for AF recurrence after CA AIMS This study examined the difference in autonomic modification ( AM ) and its effect on paroxysmal atrial fibrillation ( PAF ) recurrence between segmental pulmonary vein isolation ( S-PVI ) and circumferential PVI ( C-PVI ) . METHODS AND RESULTS Successful S-PVI or C-PVI with a basket catheter was achieved in 120 consecutive PAF patients . Serial 24 Holter-recordings were obtained before , immediately , and 1 , 3 , 6 , 12 months after the PVI to analyse the heart rate variability ( HRV ) .  Nineteen patients were excluded from analysis because of additional ablation for recurrent PAF after successful PVI . Among the residual 101 patients , 33 had PAF recurrences ( S-PVI = 44.0 % , C-PVI = 21.6 % ) at 1 year of follow-up . The root mean square of successive differences and high-frequency power reflecting parasympathetic nervous activity were significantly lower in patients with and without PAF recurrences after C-PVI and patients without PAF recurrences after S-PVI than patients with PAF recurrences after S-PVI ( P < 0.005 - 0.0001 ) . However , there were no significant differences in any HRV parameters in the immediate aftermath of PVI among the patients without PAF recurrences after S-PVI and those with and without PAF recurrences after C-PVI . CONCLUSION Although additional radiofrequency ablation for AM may be recommended after S-PVI to reduce PAF recurrences , it should be carefully determined after C-PVI INTRODUCTION Ablation has emerged as a major treatment option for atrial fibrillation ( AF ) . However , this procedure is limited by a significant rate of AF recurrence . We aim ed to examine the effects of statins , angiotensin-converting enzyme inhibitors ( ACE-I ) , and angiotensin receptor blockers ( ARB ) on the recurrence rate of AF following ablation . METHODS We conducted a retrospective study of 177 consecutive patients ( mean age = 56 + /- 11 yrs , 69 % males ) who underwent ablation for paroxysmal ( n = 132 ) or persistent AF ( n = 45 ) . Patients were treated with ACE-I ( n = 31 ) or ARB ( n = 18 ) or statins ( n = 50 ) prior to ablation and for the duration of follow-up . RESULTS After a mean follow-up of 13.8 + /- 8.6 months , 72 % of patients were free of AF . For patients taking statins , 33 of 50 ( 60 % ) were free of AF . In patients treated with ACE-I , 17 of 31 ( 55 % ) were free from AF , while in the group of patients treated with ARB , 17 of 18 ( 94 % ) were free from AF . Using Cox regression analysis to correct for baseline variables , treatment with statins did not decrease the recurrence rate ( HR = 1.10 [ 95 % CI : 0.55 - 2.27 ] p = 0.79 ) ; nor did treatment with renin angiotensin system ( RAS ) blockers ( HR 0.94 [ 95 % CI : 0.46 - 1.93 ] p = 0.87 ) . However , subgroup analysis showed that treatment with ARB was associated with a trend towards lower AF recurrence [ HR 0.17 , ( 95 % CI : 0.02 - 1.34 ) p = 0.09 ] . CONCLUSIONS Even though statins and RAS blockers possess anti-inflammatory properties , they did not decrease the recurrence of AF following ablation . However , the subset of patients taking ARB exhibited a trend towards lower AF recurrence . Larger , r and omized studies are needed to address this observation Background — Atrial fibrillation ( AF ) is associated with diffuse left atrial fibrosis and a reduction in endocardial voltage . These changes are indicators of AF severity and appear to be predictors of treatment outcome . In this study , we report the utility of delayed-enhancement magnetic resonance imaging ( DE-MRI ) in detecting abnormal atrial tissue before radiofrequency ablation and in predicting procedural outcome . Methods and Results — Eighty-one patients presenting for pulmonary vein antrum isolation for treatment of AF underwent  3-dimensional DE-MRI of the left atrium before the ablation .  Six healthy volunteers also were scanned . DE-MRI images were manually segmented to isolate the left atrium , and custom software was implemented to quantify the spatial extent of delayed enhancement , which was then compared with the regions of low voltage from electroanatomic maps from the pulmonary vein antrum isolation procedure . Patients were assessed for AF recurrence at least 6 months after pulmonary vein antrum isolation , with an average follow-up of 9.6±3.7 months ( range , 6 to 19 months ) . On the basis of the extent of preablation enhancement , 43 patients were classified as having minimal enhancement ( average enhancement , 8.0±4.2 % ) , 30 as having moderate enhancement ( 21.3±5.8 % ) , and 8 as having extensive enhancement ( 50.1±15.4 % ) . The rate of AF recurrence was 6 patients ( 14.0 % ) with minimal enhancement , 13 ( 43.3 % ) with moderate enhancement , and 6 ( 75 % ) with extensive enhancement ( P<0.001 ) . Conclusions — DE-MRI provides a noninvasive means of assessing left atrial myocardial tissue in patients suffering from AF and might provide insight into the progress of the disease . Preablation DE-MRI holds promise for predicting responders to AF ablation and may provide a metric of overall disease progression Background — The mainstay of treatment for atrial fibrillation ( AF ) remains pharmacological ; however , catheter ablation has increasingly been used over the last decade . The relative merits of each strategy have not been extensively studied . Methods and Results — We conducted a r and omized multicenter comparison of these 2 treatment strategies in patients with paroxysmal AF resistant to at least 1 antiarrhythmic drug . The primary end point was absence of recurrent AF between months 3 and 12 , absence of recurrent AF after up to 3 ablation procedures , or changes in antiarrhythmic drugs during the first 3 months . Ablation consisted of pulmonary vein isolation in all cases , whereas additional extrapulmonary vein lesions were at the discretion of the physician . Crossover was permitted at 3 months in case of failure . Echocardiographic data , symptom score , exercise capacity , quality of life , and AF burden were evaluated at 3 , 6 , and 12 months by the supervising committee . Of 149 eligible patients , 112 ( 18 women [ 16 % ] ; age , 51.1±11.1 years ) were enrolled and r and omized to ablation ( n=53 ) or “ new ” antiarrhythmic drugs alone or in combination ( n=59 ) . Crossover from the antiarrhythmic drugs and ablation groups occurred in 37 ( 63 % ) and 5 patients ( 9 % ) , respectively ( P=0.0001 ) . At the 1-year follow-up , 13 of 55 patients ( 23 % ) and 46 of 52 patients ( 89 % ) had no recurrence of AF in the antiarrhythmic drug and ablation groups , respectively ( P<0.0001 ) . Symptom score , exercise capacity , and quality of life were significantly higher in the ablation group . Conclusion — This r and omized multicenter study demonstrates the superiority of catheter ablation over antiarrhythmic drugs in patients with AF with regard to maintenance of sinus rhythm and improvement in symptoms , exercise capacity , and quality of life OBJECTIVES The purpose of this study was to evaluate the associations of transthoracic echocardiographic parameters with recurrent atrial fibrillation ( AF ) and /or stroke . BACKGROUND The Atrial Fibrillation Follow-up Investigation of Rhythm Management ( AFFIRM ) study , an evaluation of elderly patients with AF at risk for stroke , provided an opportunity to evaluate the implication s of echocardiographic parameters in patients with AF . METHODS  Transthoracic echocardiographic measures of mitral regurgitation ( MR ) , left atrial ( LA ) diameter , and left ventricular ( LV ) function were evaluated in the AFFIRM rate- and rhythm-control patients who had sinus rhythm resume and had these data available .  Risk for recurrent AF or stroke was evaluated with respect to transthoracic echocardiographic measures . RESULTS Of 2,474 patients studied , 457 had > or = 2(+)/4(+ ) MR , and 726 had a LA diameter > 4.5 cm . The  LV ejection fraction was abnormal in 543 patients . The cumulative probabilities of at least one AF recurrence/stroke were 46%/1 % after 1 year and 84%/5 % by the end of the trial ( > 5 years ) , respectively . Multivariate analysis showed that r and omization to the rhythm-control arm ( hazard ratio [ HR ] = 0.64 ; p < 0.0001 ) and a qualifying episode of AF being the first known episode ( HR = 0.70 ; p < 0.0001 ) were associated with decreased risk . Duration of qualifying AF episode > 48 h ( HR = 1.55 ; p < 0.0001 ) and LA diameter ( p = 0.008 ) were associated with an increased risk of recurrent AF . Recurrent AF was more likely with larger LA diameters ( HR = 1.21 , 1.16 , and 1.32 for mild , moderate , and severe enlargement , respectively ) . No transthoracic echocardiographic measures were associated with risk of stroke . CONCLUSIONS In the AF 
    Output:
    