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 This double-blind , multicenter , placebo-controlled study determined the efficacy and safety of dofetilide in converting  atrial fibrillation ( AF ) or atrial flutter ( AFl )  to  sinus rhythm ( SR ) and maintaining SR for 1 year . Methods and Results Patients with AF or AFl ( n=325 ) were r and omized to 125 , 250 , or 500 & mgr;g dofetilide or placebo twice daily . Dosages were adjusted for QTc response and , after 105 patients were enrolled , for calculated creatinine clearance ( ClCr ) . Pharmacological cardioversion rates for 125 , 250 , and 500 & mgr;g dofetilide were 6.1 % , 9.8 % , and 29.9 % , respectively , versus 1.2 % for placebo ( 250 and 500 & mgr;g versus placebo;P = 0.015 and P < 0.001 , respectively ) . Seventy percent of pharmacological cardioversions with dofetilide were achieved in 24 hours and 91 % in 36 hours . For the 250 patients who successfully cardioverted pharmacologically or electrically , the probability of remaining in SR at 1 year was 0.40 , 0.37 , 0.58 for 125 , 250 , and 500 & mgr;g dofetilide , respectively , and 0.25 for placebo ( 500 & mgr;g versus placebo , P = 0.001 ) . Two cases of torsade de pointes occurred , 1 on day 2 and the other on day 3 ( 0.8 % of all patients given active drug ) ; 1 sudden cardiac death , classified as proarrhythmic , occurred on day 8 ( 0.4 % of all patients given active drug ) . Conclusions Dofetilide , a new class III antiarrhythmic agent , is moderately effective in cardioverting AF or AFl to SR and significantly effective in maintaining SR for 1 year . In-hospital initiation and dosage adjustment based on QTc and ClCr are necessary to minimize a small but nonnegligible proarrhythmic risk CONTEXT Treatment with antiarrhythmic drugs and anticoagulation is considered first-line therapy in patients with symptomatic atrial fibrillation ( AF ) .  Pulmonary vein isolation ( PVI ) with radiofrequency ablation may cure AF , obviating the need for antiarrhythmic drugs and anticoagulation . OBJECTIVE To determine whether PVI is feasible as first-line therapy for treating patients with symptomatic AF . DESIGN , SETTING , AND PARTICIPANTS A multicenter prospect i ve r and omized study conducted from December 31 , 2001 , to July 1 , 2002 , of 70 patients aged 18 to 75 years who experienced monthly symptomatic AF episodes for at least 3 months and had not been treated with antiarrhythmic drugs . INTERVENTION Patients were r and omized to receive either PVI using radiofrequency ablation ( n=33 ) or antiarrhythmic drug treatment ( n=37 ) , with a 1-year follow-up . MAIN OUTCOME MEASURES Recurrence of AF , hospitalization , and quality of life assessment . RESULTS Two patients in the antiarrhythmic drug treatment group and 1 patient in the PVI group were lost to follow-up . At the end of 1-year follow-up , 22 ( 63 % ) of 35 patients who received antiarrhythmic drugs had at least 1 recurrence of symptomatic AF compared with 4 ( 13 % ) of 32 patients who received PVI ( P<.001 ) . Hospitalization during 1-year follow-up occurred in 19 ( 54 % ) of 35 patients in the antiarrhythmic drug group compared with 3 ( 9 % ) of 32 in the PVI group ( P<.001 ) . In the antiarrhythmic drug group , the mean ( SD ) number of AF episodes decreased from 12 ( 7 ) to 6 ( 4 ) , after initiating therapy ( P = .01 ) . At 6-month follow-up , the improvement in quality of life of patients in the PVI group was significantly better than the improvement in the antiarrhythmic drug group in 5 subclasses of the Short-Form 36 health survey . There were no thromboembolic events in either group . Asymptomatic mild or moderate pulmonary vein stenosis was documented in 2 ( 6 % ) of 32 patients in the PVI group . CONCLUSION Pulmonary vein isolation appears to be a feasible first-line approach for treating patients with symptomatic AF . Larger studies are needed to confirm its safety and efficacy In order to compare the efficacy and long-term tolerability of flecainide acetate versus quinidine , 239 patients with paroxysmal atrial fibrillation were prospect ively treated with flecainide ( n = 122 ) or quinidine ( n = 117 ) in an open-label , r and omized trial . All patients were followed for 1 year after initiation of therapy unless their antiarrhythmic drug was discontinued due to an inadequate therapeutic response or intolerable side effects . Although both drugs were equally effective in adequately controlling recurrences of atrial fibrillation ( difference , p = 0.282 ; not significant ) , fewer flecainide patients had to have their therapy discontinued due to adverse experiences ( p = 0.012 ) . Based on both endpoints ( efficacy and tolerability ) , an estimated 70.5 % of flecainide versus 55.4 % of quinidine patients would remain effectively treated at the end of 1 year on therapy ( p < or = 0.007 ) . The findings of this prospect i ve study suggest that in the treatment of paroxysmal atrial fibrillation ( 1 ) flecainide and quinidine are equally effective in the acceptable suppression of symptomatic paroxysmal atrial fibrillation ; ( 2 ) flecainide is better tolerated than quinidine and is less likely to be discontinued due to adverse effects ; and ( 3 ) given the overall endpoint of efficacy and tolerability , more patients are likely to continue long-term therapy with flecainide than with quinidine STUDY OBJECTIVES To compare the efficacy and safety of amiodarone and propafenone when used for the prevention of  atrial fibrillation ( AF ) and maintenance of normal sinus rhythm in patients with refractory AF . DESIGN Prospect i ve , r and omized , single-blind trial . SETTING Tertiary cardiac referral center . PATIENTS One hundred forty-six consecutive patients ( 72 men ; mean age , 63 + /- 10 years [ + /- SD ] ) with recurrent symptomatic AF . INTERVENTIONS We studied 146 patients after restoration of sinus rhythm ; patients were r and omized to amiodarone , 200 mg/d , or propafenone , 450 mg/d . Follow-up clinical evaluations were conducted at the first , second , fourth , and sixth months , and at 3-month intervals thereafter . The proportion of patients relapsing to AF and /or experiencing side effects was calculated for each group using the Kaplan-Meier method . End point of the study was recurrence of AF or occurrence of side effects necessitating discontinuation of medication . MEASUREMENTS AND RESULTS Of 146 patients , 72 received amiodarone and 74 received propafenone . The two groups were clinical ly similar . Of the 72 patients receiving amiodarone , AF developed in 25 patients , after an average of 9.8 months , compared to 33 of the 74 patients receiving propafenone after an average of 3.8 months . Twelve patients receiving amiodarone and 2 patients receiving propafenone had side effects necessitating withdrawal of medication while still in sinus rhythm . CONCLUSIONS Amiodarone tends to be more effective than propafenone in maintaining sinus rhythm in patients with AF , but this advantage is offset by a higher incidence of side effects BACKGROUND In-hospital administration of flecainide and propafenone in a single oral loading dose has been shown to be effective and superior to placebo in terminating atrial fibrillation . We evaluated the feasibility and the safety of self-administered oral loading of flecainide and propafenone in terminating atrial fibrillation of recent onset outside the hospital . METHODS We administered either flecainide or propafenone orally to restore sinus rhythm in 268 patients with mild heart disease or none who came to the emergency room with atrial fibrillation of recent onset that was hemodynamically well tolerated . Of these patients , 58 ( 22 percent ) were excluded from the study because of treatment failure or side effects . Out-of-hospital self-administration of flecainide or propafenone -- the " pill-in-the-pocket " approach -- after the onset of heart palpitations was evaluated in the remaining 210 patients ( mean age [ + /-SD ] , 59+/-11 years ) . RESULTS During a mean follow-up of 15+/-5 months , 165 patients ( 79 percent ) had a total of 618 episodes of arrhythmia ; of those episodes , 569 ( 92 percent ) were treated 36+/-93 minutes after the onset of symptoms . Treatment was successful in 534 episodes ( 94 percent ) ; the time to resolution of symptoms was 113+/-84 minutes . Among the 165 patients with recurrences , the drug was effective during all the arrhythmic episodes in 139 patients ( 84 percent ) . Adverse effects were reported during one or more arrhythmic episodes by 12 patients ( 7 percent ) , including atrial flutter at a rapid ventricular rate in 1 patient and noncardiac side effects in 11 patients . The numbers of monthly visits to the emergency room and hospitalizations were significantly lower during follow-up than during the year before the target episode ( P<0.001 for both comparisons ) . CONCLUSIONS In a selected , risk-stratified population of patients with recurrent atrial fibrillation , pill-in-the-pocket treatment is feasible and safe , with a high rate of compliance by patients , a low rate of adverse events , and a marked reduction in emergency room visits and hospital admissions OBJECTIVE To assess and compare the safety and efficacy of amiodarone and sotalol in the treatment of patients with recurrent symptomatic atrial fibrillation . DESIGN Prospect i ve , r and omised , single blind , placebo controlled study . SETTING Tertiary cardiac referral centre . PATIENTS 186 consecutive patients ( 97 men , 89 women ; mean ( SD ) age , 63 ( 10 ) years ) with recurrent , symptomatic atrial fibrillation . INTERVENTIONS 65 patients were r and omised to amiodarone , 61 to sotalol , and 60 to placebo . Patients receiving amiodarone were maintained at a dose of 200 mg/day after a 30 day loading phase . The sotalol dose was 160 - 480 mg daily , as tolerated . MAIN OUTCOME MEASURES Recurrence of atrial fibrillation or side effects . RESULTS In the amiodarone group , 31 of the 65 patients developed atrial fibrillation after an average of six months , while 15 ( 11 in sinus rhythm and four in atrial fibrillation ) experienced significant side effects after an average of 16 months . In the sotalol group , relapse to atrial fibrillation occurred in 47 of the 61 patients after an average of eight months ; three experienced side effects during the titration phase . In the placebo group , 53 of the 60 patients developed atrial fibrillation after an average of four months ( p < 0.001 for amiodarone and sotalol v placebo ; p < 0.001 for amiodarone v sotalol ) . CONCLUSIONS Both amiodarone and sotalol can be used for the maintenance of normal sinus rhythm in patients with symptomatic atrial fibrillation .  Amiodarone is more effective but causes more side effects This prospect i ve , r and omized , single-blinded , placebo-controlled study compared the efficacy and safety of sotalol and propafenone when used for long-term prevention of  atrial fibrillation .  For the long-term maintenance of normal sinus rhythm , propafenone seems to be more effective than sotalol The objective of this r and omized , double-blind , placebo-controlled clinical trial was to test the efficacy and safety of a new sustained-release preparation of the antiarrhythmic drug propafenone ( propafenone SR ) in reducing the frequency of symptomatic arrhythmia recurrences in patients with atrial fibrillation ( AF ) . Patients with a history of symptomatic AF who were in sinus rhythm were r and omly assigned to receive placebo or propafenone SR 425 , 325 , or 225 mg , all twice daily . Recurrent symptomatic arrhythmias were documented using  transtelephone electrocardiographic monitoring . Electrocardiograms were review ed by an event committee that was blinded to treatment assignment . In the primary efficacy analysis , propafenone SR significantly lengthened the time to first symptomatic atrial arrhythmia recurrence at all 3 doses compared with placebo as assessed by log-rank test : propafenone SR 425 mg twice daily versus placebo twice daily , p < 0.001 ; 325 mg twice daily versus placebo twice daily , p < 0.001 ; and 225 mg twice daily versus placebo twice daily , p 
    Output:
    
agent
No other antiarrhythmic showed a significant effect on mortality compared with controls .
Class IA , IC , and III drugs are effective in maintaining sinus rhythm but increase adverse effects , and class IA drugs may increase mortality
***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 This double-blind , multicenter , placebo-controlled study determined the efficacy and safety of dofetilide in converting  atrial fibrillation ( AF ) or atrial flutter ( AFl )  to  sinus rhythm ( SR ) and maintaining SR for 1 year . Methods and Results Patients with AF or AFl ( n=325 ) were r and omized to 125 , 250 , or 500 & mgr;g dofetilide or placebo twice daily . Dosages were adjusted for QTc response and , after 105 patients were enrolled , for calculated creatinine clearance ( ClCr ) . Pharmacological cardioversion rates for 125 , 250 , and 500 & mgr;g dofetilide were 6.1 % , 9.8 % , and 29.9 % , respectively , versus 1.2 % for placebo ( 250 and 500 & mgr;g versus placebo;P = 0.015 and P < 0.001 , respectively ) . Seventy percent of pharmacological cardioversions with dofetilide were achieved in 24 hours and 91 % in 36 hours . For the 250 patients who successfully cardioverted pharmacologically or electrically , the probability of remaining in SR at 1 year was 0.40 , 0.37 , 0.58 for 125 , 250 , and 500 & mgr;g dofetilide , respectively , and 0.25 for placebo ( 500 & mgr;g versus placebo , P = 0.001 ) . Two cases of torsade de pointes occurred , 1 on day 2 and the other on day 3 ( 0.8 % of all patients given active drug ) ; 1 sudden cardiac death , classified as proarrhythmic , occurred on day 8 ( 0.4 % of all patients given active drug ) . Conclusions Dofetilide , a new class III antiarrhythmic agent , is moderately effective in cardioverting AF or AFl to SR and significantly effective in maintaining SR for 1 year . In-hospital initiation and dosage adjustment based on QTc and ClCr are necessary to minimize a small but nonnegligible proarrhythmic risk CONTEXT Treatment with antiarrhythmic drugs and anticoagulation is considered first-line therapy in patients with symptomatic atrial fibrillation ( AF ) .  Pulmonary vein isolation ( PVI ) with radiofrequency ablation may cure AF , obviating the need for antiarrhythmic drugs and anticoagulation . OBJECTIVE To determine whether PVI is feasible as first-line therapy for treating patients with symptomatic AF . DESIGN , SETTING , AND PARTICIPANTS A multicenter prospect i ve r and omized study conducted from December 31 , 2001 , to July 1 , 2002 , of 70 patients aged 18 to 75 years who experienced monthly symptomatic AF episodes for at least 3 months and had not been treated with antiarrhythmic drugs . INTERVENTION Patients were r and omized to receive either PVI using radiofrequency ablation ( n=33 ) or antiarrhythmic drug treatment ( n=37 ) , with a 1-year follow-up . MAIN OUTCOME MEASURES Recurrence of AF , hospitalization , and quality of life assessment . RESULTS Two patients in the antiarrhythmic drug treatment group and 1 patient in the PVI group were lost to follow-up . At the end of 1-year follow-up , 22 ( 63 % ) of 35 patients who received antiarrhythmic drugs had at least 1 recurrence of symptomatic AF compared with 4 ( 13 % ) of 32 patients who received PVI ( P<.001 ) . Hospitalization during 1-year follow-up occurred in 19 ( 54 % ) of 35 patients in the antiarrhythmic drug group compared with 3 ( 9 % ) of 32 in the PVI group ( P<.001 ) . In the antiarrhythmic drug group , the mean ( SD ) number of AF episodes decreased from 12 ( 7 ) to 6 ( 4 ) , after initiating therapy ( P = .01 ) . At 6-month follow-up , the improvement in quality of life of patients in the PVI group was significantly better than the improvement in the antiarrhythmic drug group in 5 subclasses of the Short-Form 36 health survey . There were no thromboembolic events in either group . Asymptomatic mild or moderate pulmonary vein stenosis was documented in 2 ( 6 % ) of 32 patients in the PVI group . CONCLUSION Pulmonary vein isolation appears to be a feasible first-line approach for treating patients with symptomatic AF . Larger studies are needed to confirm its safety and efficacy In order to compare the efficacy and long-term tolerability of flecainide acetate versus quinidine , 239 patients with paroxysmal atrial fibrillation were prospect ively treated with flecainide ( n = 122 ) or quinidine ( n = 117 ) in an open-label , r and omized trial . All patients were followed for 1 year after initiation of therapy unless their antiarrhythmic drug was discontinued due to an inadequate therapeutic response or intolerable side effects . Although both drugs were equally effective in adequately controlling recurrences of atrial fibrillation ( difference , p = 0.282 ; not significant ) , fewer flecainide patients had to have their therapy discontinued due to adverse experiences ( p = 0.012 ) . Based on both endpoints ( efficacy and tolerability ) , an estimated 70.5 % of flecainide versus 55.4 % of quinidine patients would remain effectively treated at the end of 1 year on therapy ( p < or = 0.007 ) . The findings of this prospect i ve study suggest that in the treatment of paroxysmal atrial fibrillation ( 1 ) flecainide and quinidine are equally effective in the acceptable suppression of symptomatic paroxysmal atrial fibrillation ; ( 2 ) flecainide is better tolerated than quinidine and is less likely to be discontinued due to adverse effects ; and ( 3 ) given the overall endpoint of efficacy and tolerability , more patients are likely to continue long-term therapy with flecainide than with quinidine STUDY OBJECTIVES To compare the efficacy and safety of amiodarone and propafenone when used for the prevention of  atrial fibrillation ( AF ) and maintenance of normal sinus rhythm in patients with refractory AF . DESIGN Prospect i ve , r and omized , single-blind trial . SETTING Tertiary cardiac referral center . PATIENTS One hundred forty-six consecutive patients ( 72 men ; mean age , 63 + /- 10 years [ + /- SD ] ) with recurrent symptomatic AF . INTERVENTIONS We studied 146 patients after restoration of sinus rhythm ; patients were r and omized to amiodarone , 200 mg/d , or propafenone , 450 mg/d . Follow-up clinical evaluations were conducted at the first , second , fourth , and sixth months , and at 3-month intervals thereafter . The proportion of patients relapsing to AF and /or experiencing side effects was calculated for each group using the Kaplan-Meier method . End point of the study was recurrence of AF or occurrence of side effects necessitating discontinuation of medication . MEASUREMENTS AND RESULTS Of 146 patients , 72 received amiodarone and 74 received propafenone . The two groups were clinical ly similar . Of the 72 patients receiving amiodarone , AF developed in 25 patients , after an average of 9.8 months , compared to 33 of the 74 patients receiving propafenone after an average of 3.8 months . Twelve patients receiving amiodarone and 2 patients receiving propafenone had side effects necessitating withdrawal of medication while still in sinus rhythm . CONCLUSIONS Amiodarone tends to be more effective than propafenone in maintaining sinus rhythm in patients with AF , but this advantage is offset by a higher incidence of side effects BACKGROUND In-hospital administration of flecainide and propafenone in a single oral loading dose has been shown to be effective and superior to placebo in terminating atrial fibrillation . We evaluated the feasibility and the safety of self-administered oral loading of flecainide and propafenone in terminating atrial fibrillation of recent onset outside the hospital . METHODS We administered either flecainide or propafenone orally to restore sinus rhythm in 268 patients with mild heart disease or none who came to the emergency room with atrial fibrillation of recent onset that was hemodynamically well tolerated . Of these patients , 58 ( 22 percent ) were excluded from the study because of treatment failure or side effects . Out-of-hospital self-administration of flecainide or propafenone -- the " pill-in-the-pocket " approach -- after the onset of heart palpitations was evaluated in the remaining 210 patients ( mean age [ + /-SD ] , 59+/-11 years ) . RESULTS During a mean follow-up of 15+/-5 months , 165 patients ( 79 percent ) had a total of 618 episodes of arrhythmia ; of those episodes , 569 ( 92 percent ) were treated 36+/-93 minutes after the onset of symptoms . Treatment was successful in 534 episodes ( 94 percent ) ; the time to resolution of symptoms was 113+/-84 minutes . Among the 165 patients with recurrences , the drug was effective during all the arrhythmic episodes in 139 patients ( 84 percent ) . Adverse effects were reported during one or more arrhythmic episodes by 12 patients ( 7 percent ) , including atrial flutter at a rapid ventricular rate in 1 patient and noncardiac side effects in 11 patients . The numbers of monthly visits to the emergency room and hospitalizations were significantly lower during follow-up than during the year before the target episode ( P<0.001 for both comparisons ) . CONCLUSIONS In a selected , risk-stratified population of patients with recurrent atrial fibrillation , pill-in-the-pocket treatment is feasible and safe , with a high rate of compliance by patients , a low rate of adverse events , and a marked reduction in emergency room visits and hospital admissions OBJECTIVE To assess and compare the safety and efficacy of amiodarone and sotalol in the treatment of patients with recurrent symptomatic atrial fibrillation . DESIGN Prospect i ve , r and omised , single blind , placebo controlled study . SETTING Tertiary cardiac referral centre . PATIENTS 186 consecutive patients ( 97 men , 89 women ; mean ( SD ) age , 63 ( 10 ) years ) with recurrent , symptomatic atrial fibrillation . INTERVENTIONS 65 patients were r and omised to amiodarone , 61 to sotalol , and 60 to placebo . Patients receiving amiodarone were maintained at a dose of 200 mg/day after a 30 day loading phase . The sotalol dose was 160 - 480 mg daily , as tolerated . MAIN OUTCOME MEASURES Recurrence of atrial fibrillation or side effects . RESULTS In the amiodarone group , 31 of the 65 patients developed atrial fibrillation after an average of six months , while 15 ( 11 in sinus rhythm and four in atrial fibrillation ) experienced significant side effects after an average of 16 months . In the sotalol group , relapse to atrial fibrillation occurred in 47 of the 61 patients after an average of eight months ; three experienced side effects during the titration phase . In the placebo group , 53 of the 60 patients developed atrial fibrillation after an average of four months ( p < 0.001 for amiodarone and sotalol v placebo ; p < 0.001 for amiodarone v sotalol ) . CONCLUSIONS Both amiodarone and sotalol can be used for the maintenance of normal sinus rhythm in patients with symptomatic atrial fibrillation .  Amiodarone is more effective but causes more side effects This prospect i ve , r and omized , single-blinded , placebo-controlled study compared the efficacy and safety of sotalol and propafenone when used for long-term prevention of  atrial fibrillation .  For the long-term maintenance of normal sinus rhythm , propafenone seems to be more effective than sotalol The objective of this r and omized , double-blind , placebo-controlled clinical trial was to test the efficacy and safety of a new sustained-release preparation of the antiarrhythmic drug propafenone ( propafenone SR ) in reducing the frequency of symptomatic arrhythmia recurrences in patients with atrial fibrillation ( AF ) . Patients with a history of symptomatic AF who were in sinus rhythm were r and omly assigned to receive placebo or propafenone SR 425 , 325 , or 225 mg , all twice daily . Recurrent symptomatic arrhythmias were documented using  transtelephone electrocardiographic monitoring . Electrocardiograms were review ed by an event committee that was blinded to treatment assignment . In the primary efficacy analysis , propafenone SR significantly lengthened the time to first symptomatic atrial arrhythmia recurrence at all 3 doses compared with placebo as assessed by log-rank test : propafenone SR 425 mg twice daily versus placebo twice daily , p < 0.001 ; 325 mg twice daily versus placebo twice daily , p < 0.001 ; and 225 mg twice daily versus placebo twice daily , p 
    Output:
    