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 This r and omized prospect i ve study compared three ablation strategies in patients with long-st and ing persistent atrial fibrillation ( LPeAF ) . It also explored the best procedural endpoint from among the following : circumferential pulmonary vein isolation ( PVI ) + left atrial ( LA ) linear lesions ( roofline , mitral isthmus ) + complex fractionated atrial electrogram ( CFAE ) ablation , PVI + LA linear lesions + cavotricuspid isthmus ( CTI ) ablation + CFAE ablation , and PVI + CFAE ablation . METHODS AND RESULTS A total of 210 patients with LPeAF referred for catheter ablation were enrolled and r and omized into three ablation groups . The patients in group A ( n = 70 ) underwent PVI followed by LA linear and CFAE ablation ; in 93 % of patients the primary endpoint was achieved ( five patients with incomplete linear lesions ) . Of the 70 patients in group B who were subjected to PVI followed by LA linear , CFAE , and CTI ablations , in 94 % of patients the primary endpoint was achieved ( four patients with incomplete linear lesions ) . All patients in group C ( n = 70 ) successfully underwent PVI and CFAE ablation . Direct current cardioversion was performed upon PVI , CFAE elimination , and completion of linear lesions . Patients were followed-up for atrial tachyarrhythmia recurrence for at least 24 months . After a single ablation procedure , group C ( 36 % ) exhibited the lowest success compared with group A ( 54 % ) and group B ( 51 % ) ( P = 0.06 ) . At the mean follow-up of 32 ± 9 months after the final ablation procedure , 53 patients ( 76 % ) in group A , 53 ( 76 % ) in group B , and 41 ( 59 % ) in group C were in sinus rhythm without antiarrhythmic drugs ( P = 0.03 ) . CONCLUSIONS In LPeAF , linear lesions in the LA help improve outcome of ablation , additional CTI ablation does not BACKGROUND Pulmonary vein ( PV ) electrical isolation is a therapeutic option in atrial fibrillation ( AF ) . New technologies may reduce the complexity of the procedure . OBJECTIVE The aim of the present study was to compare immediate results and short-term efficacy of a new circular ablation catheter ( PVAC ) with a conventional point-by-point ablation . METHODS The prospect i ve study enrolled 80 consecutive patients with paroxysmal AF or persistent AF , refractory to antiarrhythmic drugs , who were r and omized to radiofrequency ablation using duty-cycled bipolar and unipolar radiofrequency by a decapolar circular catheter ( PVAC group ) or to point-by-point ablation supported by a 3-dimensional mapping system ( 3D group ) . RESULTS Forty patients per group were included . Mean age was 58 ± 10 years , 64 % were male ; 55 % had paroxysmal AF , 45 % had persistent AF . There were no significant differences between groups . Complete electrical isolation was reached in all but 1 PV , which was not isolated in the PVAC group because of phrenic nerve capture . Procedure and fluoroscopy times were lower in the PVAC group : 171 ± 40 minutes vs. 224 ± 27 minutes , P < .001 ; 26 ± 8 minutes vs. 35 ± 9 minutes , P < .001 ; respectively . There were no major complications . During a mean follow-up of 254 ± 99 days , 72 % in the PVAC group and 68 % in the 3D group were free of AF recurrences irrespective of the initial AF type ( P = NS ) . CONCLUSION PVAC represents a safe alternative for PV isolation . It reduces both procedure and fluoroscopy time . The short- and middle-term efficacy is comparable to a conventional point-by-point antral ablation technique Objective : To assess the effectiveness and safety of pharmacological conversion of persistent atrial fibrillation ( AF ) with a combined propafenone plus ibutilide regimen . Methods and results : 100 consecutive patients ( 66 men , mean ( SD ) age 65 ( 10 ) years ) with persistent AF ( mean ( SD ) duration 99 ( 92 ) days ) admitted for elective pharmacological cardioversion were r and omly assigned to treatment with either intravenous ibutilide ( 1 mg plus an additional 1 mg , if required ; n = 51 ) or oral propafenone ( 600 mg ) plus intravenous ibutilide at the same dose ( n = 49 ) . Success rates were 41.1 % ( 21 of 51 patients ) for ibutilide alone and 71.4 % ( 35 of 49 patients ) for propafenone plus ibutilide ( p = 0.0044 ) . However , cardioversion occurred earlier in the ibutilide alone group ( 55 ( 20 ) minutes ) compared with the combination group ( 81 ( 32 ) minutes , p = 0.0019 ) . A comparable increase in the QTc interval was observed in both groups but one case of sustained torsade de pointes , requiring electrical cardioversion , was observed in the propafenone plus ibutilide group . No other complications were noted during the hospitalisation period . Conclusion : Concurrent administration of propafenone plus ibutilide for pharmacological cardioversion of persistent AF is safe and more effective than ibutilide alone AIMS To assess the effect of metoprolol in combination with repeated cardioversion on maintenance of sinus rhythm ( SR ) . METHODS AND RESULTS Consecutive out patients with persistent atrial fibrillation ( AF ) were r and omized to treatment with metoprolol CR or placebo in a double-blind fashion . Study treatment was started at least one week before direct current ( DC ) cardioversion . Patients were followed once a week during the first 6 weeks after cardioversion . In case of relapse during this period , a second cardioversion was performed . Total treatment time was 6 months . A total of 168 patients were r and omized to metoprolol  ( n = 83 ) or placebo ( n = 85 ) . The dose of study treatment at cardioversion was 169 + /- 47 mg in the metoprolol group and 180 + /- 40 mg in the placebo group ( P = 0.12 ) . In an intention-to-treat analysis , 46 patients ( 55 % ) in the metoprolol group and 34 patients ( 40 % ) in the placebo group ( P = 0.04 ) had SR 1 week after cardioversion , and 38 patients ( 46 % ) in the metoprolol group compared with 22 patients ( 26 % ) in the placebo group had SR after 6 months ( P < 0.01 ) . CONCLUSION A treatment strategy of metoprolol CR started before cardioversion in combination with prompt second cardioversion in case of early relapse ( 1 - 6 weeks ) significantly increases the proportion of patients in SR during six months of follow-up AIMS The AFFIRM and RACE studies showed that rate control is an acceptable treatment strategy for  atrial fibrillation ( AF ) .  We examined whether strict rate control offers benefit over more lenient rate control . METHODS AND RESULTS We compared the outcome of patients enrolled in the rate-control arms of AFFIRM and RACE , using data from patients who met a composite of overlapping inclusion and exclusion criteria . We evaluated 1091 patients , 874 from AFFIRM and 217 from RACE . In AFFIRM , the rate-control strategy aim ed for a resting heart rate < or = 80 bpm and heart rate during daily activity of < or = 110 bpm . In RACE , a more lenient approach was taken : resting heart rate < 100 bpm . Primary endpoint was a composite of mortality , cardiovascular hospitalization , and myocardial infa rct ion . Mean heart rate across all follow-up visits for patients in AF was lower in AFFIRM ( 76.1 vs. 83.4 bpm ) . Event-free survival for the occurrence of the primary endpoint did not differ ( 64 % in AFFIRM vs. 66 % in RACE ) . Patients with mean heart rates during AF within the AFFIRM ( < or = 80 ) or RACE ( < 100 ) criteria had a better outcome than patients with heart rates > or = 100 ( hazard ratios 0.69 and 0.58 , respectively , for < or = 80 and < 100 compared with > or = 100 bpm ) . CONCLUSION Stringency of the approach to rate control , based on the comparison of the AFFIRM and RACE studies , was not associated with an important difference in clinical events Background — Catheter ablation ( CA ) and minimally invasive surgical ablation ( SA ) have become accepted therapy for antiarrhythmic drug – refractory atrial fibrillation . This study describes the first r and omized clinical trial comparing their efficacy and safety during a 12-month follow-up . Methods and Results — One hundred twenty-four patients with antiarrhythmic drug – refractory atrial fibrillation with left atrial dilatation and hypertension ( 42 patients , 33 % ) or failed prior CA ( 82 patients , 67 % ) were r and omized to CA ( 63 patients ) or SA ( 61 patients ) . CA consisted of linear antral pulmonary vein isolation and optional additional lines . SA consisted of bipolar radiofrequency isolation of the bilateral pulmonary vein , ganglionated plexi ablation , and left atrial appendage excision with optional additional lines . Follow-up at 6 and 12 months was performed by ECG and 7-day Holter recording . The primary end point , freedom from left atrial arrhythmia > 30 seconds without antiarrhythmic drugs after 12 months , was 36.5 % for CA and 65.6 % for SA ( P=0.0022 ) . There was no difference in effect for subgroups , which was consistent at both sites . The primary safety end point of significant adverse events during the 12-month follow-up was significantly higher for SA than for CA ( n=21 [ 34.4 % ] versus n=10 [ 15.9 % ] ; P=0.027 ) , driven mainly by procedural complications such as pneumothorax , major bleeding , and the need for pacemaker . In the CA group , 1 patient died at 1 month of subarachnoid hemorrhage . Conclusion — In atrial fibrillation patients with dilated left atrium and hypertension or failed prior atrial fibrillation CA , SA is superior to CA in achieving freedom from left atrial arrhythmias after 12 months of follow-up , although the procedural adverse event rate is significantly higher for SA than for CA . Clinical Trial Registration — URL : http:// clinical trials.gov . Unique identifier : NCT00662701 AIMS With transthoracic cardioversion of atrial fibrillation ( AF ) , biphasic are more effective than monophasic waveforms . We sought to determine the ideal energy levels for biphasic waveforms . Methods We compared biphasic truncated exponential waveforms with monophasic damped sine waveform defibrillators , in a prospect i ve , single-centre , r and omized ( 1:1 ratio ) study . The study included 154 patients receiving concomitant amiodarone ;  77 received serial biphasic ( 50 , 100 , 150 , up to 175 J ) and 77 monophasic shocks ( 100 , 200 , 300 , up to 360 J ) , 
    Output:
    
agent
D. Restoration of sinus rhythm for monophasic vs. biphasic waveforms .
Another study showed that PVI result ed in long-term restoration
***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 This r and omized prospect i ve study compared three ablation strategies in patients with long-st and ing persistent atrial fibrillation ( LPeAF ) . It also explored the best procedural endpoint from among the following : circumferential pulmonary vein isolation ( PVI ) + left atrial ( LA ) linear lesions ( roofline , mitral isthmus ) + complex fractionated atrial electrogram ( CFAE ) ablation , PVI + LA linear lesions + cavotricuspid isthmus ( CTI ) ablation + CFAE ablation , and PVI + CFAE ablation . METHODS AND RESULTS A total of 210 patients with LPeAF referred for catheter ablation were enrolled and r and omized into three ablation groups . The patients in group A ( n = 70 ) underwent PVI followed by LA linear and CFAE ablation ; in 93 % of patients the primary endpoint was achieved ( five patients with incomplete linear lesions ) . Of the 70 patients in group B who were subjected to PVI followed by LA linear , CFAE , and CTI ablations , in 94 % of patients the primary endpoint was achieved ( four patients with incomplete linear lesions ) . All patients in group C ( n = 70 ) successfully underwent PVI and CFAE ablation . Direct current cardioversion was performed upon PVI , CFAE elimination , and completion of linear lesions . Patients were followed-up for atrial tachyarrhythmia recurrence for at least 24 months . After a single ablation procedure , group C ( 36 % ) exhibited the lowest success compared with group A ( 54 % ) and group B ( 51 % ) ( P = 0.06 ) . At the mean follow-up of 32 ± 9 months after the final ablation procedure , 53 patients ( 76 % ) in group A , 53 ( 76 % ) in group B , and 41 ( 59 % ) in group C were in sinus rhythm without antiarrhythmic drugs ( P = 0.03 ) . CONCLUSIONS In LPeAF , linear lesions in the LA help improve outcome of ablation , additional CTI ablation does not BACKGROUND Pulmonary vein ( PV ) electrical isolation is a therapeutic option in atrial fibrillation ( AF ) . New technologies may reduce the complexity of the procedure . OBJECTIVE The aim of the present study was to compare immediate results and short-term efficacy of a new circular ablation catheter ( PVAC ) with a conventional point-by-point ablation . METHODS The prospect i ve study enrolled 80 consecutive patients with paroxysmal AF or persistent AF , refractory to antiarrhythmic drugs , who were r and omized to radiofrequency ablation using duty-cycled bipolar and unipolar radiofrequency by a decapolar circular catheter ( PVAC group ) or to point-by-point ablation supported by a 3-dimensional mapping system ( 3D group ) . RESULTS Forty patients per group were included . Mean age was 58 ± 10 years , 64 % were male ; 55 % had paroxysmal AF , 45 % had persistent AF . There were no significant differences between groups . Complete electrical isolation was reached in all but 1 PV , which was not isolated in the PVAC group because of phrenic nerve capture . Procedure and fluoroscopy times were lower in the PVAC group : 171 ± 40 minutes vs. 224 ± 27 minutes , P < .001 ; 26 ± 8 minutes vs. 35 ± 9 minutes , P < .001 ; respectively . There were no major complications . During a mean follow-up of 254 ± 99 days , 72 % in the PVAC group and 68 % in the 3D group were free of AF recurrences irrespective of the initial AF type ( P = NS ) . CONCLUSION PVAC represents a safe alternative for PV isolation . It reduces both procedure and fluoroscopy time . The short- and middle-term efficacy is comparable to a conventional point-by-point antral ablation technique Objective : To assess the effectiveness and safety of pharmacological conversion of persistent atrial fibrillation ( AF ) with a combined propafenone plus ibutilide regimen . Methods and results : 100 consecutive patients ( 66 men , mean ( SD ) age 65 ( 10 ) years ) with persistent AF ( mean ( SD ) duration 99 ( 92 ) days ) admitted for elective pharmacological cardioversion were r and omly assigned to treatment with either intravenous ibutilide ( 1 mg plus an additional 1 mg , if required ; n = 51 ) or oral propafenone ( 600 mg ) plus intravenous ibutilide at the same dose ( n = 49 ) . Success rates were 41.1 % ( 21 of 51 patients ) for ibutilide alone and 71.4 % ( 35 of 49 patients ) for propafenone plus ibutilide ( p = 0.0044 ) . However , cardioversion occurred earlier in the ibutilide alone group ( 55 ( 20 ) minutes ) compared with the combination group ( 81 ( 32 ) minutes , p = 0.0019 ) . A comparable increase in the QTc interval was observed in both groups but one case of sustained torsade de pointes , requiring electrical cardioversion , was observed in the propafenone plus ibutilide group . No other complications were noted during the hospitalisation period . Conclusion : Concurrent administration of propafenone plus ibutilide for pharmacological cardioversion of persistent AF is safe and more effective than ibutilide alone AIMS To assess the effect of metoprolol in combination with repeated cardioversion on maintenance of sinus rhythm ( SR ) . METHODS AND RESULTS Consecutive out patients with persistent atrial fibrillation ( AF ) were r and omized to treatment with metoprolol CR or placebo in a double-blind fashion . Study treatment was started at least one week before direct current ( DC ) cardioversion . Patients were followed once a week during the first 6 weeks after cardioversion . In case of relapse during this period , a second cardioversion was performed . Total treatment time was 6 months . A total of 168 patients were r and omized to metoprolol  ( n = 83 ) or placebo ( n = 85 ) . The dose of study treatment at cardioversion was 169 + /- 47 mg in the metoprolol group and 180 + /- 40 mg in the placebo group ( P = 0.12 ) . In an intention-to-treat analysis , 46 patients ( 55 % ) in the metoprolol group and 34 patients ( 40 % ) in the placebo group ( P = 0.04 ) had SR 1 week after cardioversion , and 38 patients ( 46 % ) in the metoprolol group compared with 22 patients ( 26 % ) in the placebo group had SR after 6 months ( P < 0.01 ) . CONCLUSION A treatment strategy of metoprolol CR started before cardioversion in combination with prompt second cardioversion in case of early relapse ( 1 - 6 weeks ) significantly increases the proportion of patients in SR during six months of follow-up AIMS The AFFIRM and RACE studies showed that rate control is an acceptable treatment strategy for  atrial fibrillation ( AF ) .  We examined whether strict rate control offers benefit over more lenient rate control . METHODS AND RESULTS We compared the outcome of patients enrolled in the rate-control arms of AFFIRM and RACE , using data from patients who met a composite of overlapping inclusion and exclusion criteria . We evaluated 1091 patients , 874 from AFFIRM and 217 from RACE . In AFFIRM , the rate-control strategy aim ed for a resting heart rate < or = 80 bpm and heart rate during daily activity of < or = 110 bpm . In RACE , a more lenient approach was taken : resting heart rate < 100 bpm . Primary endpoint was a composite of mortality , cardiovascular hospitalization , and myocardial infa rct ion . Mean heart rate across all follow-up visits for patients in AF was lower in AFFIRM ( 76.1 vs. 83.4 bpm ) . Event-free survival for the occurrence of the primary endpoint did not differ ( 64 % in AFFIRM vs. 66 % in RACE ) . Patients with mean heart rates during AF within the AFFIRM ( < or = 80 ) or RACE ( < 100 ) criteria had a better outcome than patients with heart rates > or = 100 ( hazard ratios 0.69 and 0.58 , respectively , for < or = 80 and < 100 compared with > or = 100 bpm ) . CONCLUSION Stringency of the approach to rate control , based on the comparison of the AFFIRM and RACE studies , was not associated with an important difference in clinical events Background — Catheter ablation ( CA ) and minimally invasive surgical ablation ( SA ) have become accepted therapy for antiarrhythmic drug – refractory atrial fibrillation . This study describes the first r and omized clinical trial comparing their efficacy and safety during a 12-month follow-up . Methods and Results — One hundred twenty-four patients with antiarrhythmic drug – refractory atrial fibrillation with left atrial dilatation and hypertension ( 42 patients , 33 % ) or failed prior CA ( 82 patients , 67 % ) were r and omized to CA ( 63 patients ) or SA ( 61 patients ) . CA consisted of linear antral pulmonary vein isolation and optional additional lines . SA consisted of bipolar radiofrequency isolation of the bilateral pulmonary vein , ganglionated plexi ablation , and left atrial appendage excision with optional additional lines . Follow-up at 6 and 12 months was performed by ECG and 7-day Holter recording . The primary end point , freedom from left atrial arrhythmia > 30 seconds without antiarrhythmic drugs after 12 months , was 36.5 % for CA and 65.6 % for SA ( P=0.0022 ) . There was no difference in effect for subgroups , which was consistent at both sites . The primary safety end point of significant adverse events during the 12-month follow-up was significantly higher for SA than for CA ( n=21 [ 34.4 % ] versus n=10 [ 15.9 % ] ; P=0.027 ) , driven mainly by procedural complications such as pneumothorax , major bleeding , and the need for pacemaker . In the CA group , 1 patient died at 1 month of subarachnoid hemorrhage . Conclusion — In atrial fibrillation patients with dilated left atrium and hypertension or failed prior atrial fibrillation CA , SA is superior to CA in achieving freedom from left atrial arrhythmias after 12 months of follow-up , although the procedural adverse event rate is significantly higher for SA than for CA . Clinical Trial Registration — URL : http:// clinical trials.gov . Unique identifier : NCT00662701 AIMS With transthoracic cardioversion of atrial fibrillation ( AF ) , biphasic are more effective than monophasic waveforms . We sought to determine the ideal energy levels for biphasic waveforms . Methods We compared biphasic truncated exponential waveforms with monophasic damped sine waveform defibrillators , in a prospect i ve , single-centre , r and omized ( 1:1 ratio ) study . The study included 154 patients receiving concomitant amiodarone ;  77 received serial biphasic ( 50 , 100 , 150 , up to 175 J ) and 77 monophasic shocks ( 100 , 200 , 300 , up to 360 J ) , 
    Output:
    