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: Despite the widespread use of amiodarone in non-surgical patients , its role in the management of supraventricular tachyarrhythmias after cardiac surgery is not clear . We set out to compare the relative efficacy of amiodarone and digoxin in the management of  atrial fibrillation and flutter in the early postoperative period . This prospect i ve r and omised trial comprised 30 patients , previously in sinus rhythm , who developed sustained atrial fibrillation or flutter following myocardial revascularisation , valve surgery or combined procedures .  Amiodarone was administered as an intravenous loading dose followed by a continuous infusion . Digoxin was given as an intravenous loading dose followed by oral maintenance therapy . Electrocardiographic and haemodynamic monitoring  was continued for 24 h after the commencement of treatment . There was a marked reduction in heart rate in both groups , mainly in the first 6 h , from 146 to 89 beats per minute in the amiodarone group and from 144 to 95 in the digoxin group . At the end of the 24 h , one of the 15 patients in the amiodarone group and 3 of the 15 patients in the digoxin group remained in atrial fibrillation . No patient in either group developed adverse reactions . We conclude that intravenous amiodarone therapy is safe and at least as effective as digoxin in the initial management of arrhythmias after cardiac surgery 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 Objective : We sought to assess the efficacy and safety of amiodarone for restoration and maintenance of sinus rhythm in patients with chronic atrial fibrillation in a prospect i ve , r and omized , double blind trial . Background : Restoration and preservation of sinus rhythm is difficult in patients with chronic atrial fibrillation . The efficacy of oral amiodarone has not been conclusively established . Methods : Ninety-five patients with chronic atrial fibrillation , lasting an average of 35.6 months , were r and omized to either amiodarone ( 600 mg/d ) ( 47 patients ) or placebo ( 48 patients ) during four weeks . Nonresponders underwent electric cardioversion , and those who reverted continued with amiodarone ( 200 mg/d ) or placebo . End-points were successful cardioversion and sinus rhythm maintenance . Results : Sixteen patients ( 34.04 % ) in the amiodarone group reverted within 27.28 ± 8.85 days in comparison with 0 % in the placebo group ( P < 0.000009 ) . The conversion rate rose to 51.72 % in patients with chronic atrial fibrillation lasting less than 12 months . Twenty-eight patients in the amiodarone group and 39 in the placebo group underwent electric cardioversion , which was successful in 19 patients ( 67.8 % ) of the amiodarone group and in 15 ( 38.46 % ) of the placebo group ( P = 0.017 ) . Altogether , conversion was obtained in 79.54 % of the amiodarone group patients and in 38.46 % of the placebo group patients ( P < 0.0001 ) . During follow-up , atrial fibrillation relapsed in 13 ( 37.14 % ) of 35 patients of the amiodarone group within 8.84 + 8.57 months and in 12 ( 80 % ; P = 0.009 ) of 15 patients of the placebo group within 2.74 ± 3.41 months . Conclusions : Oral amiodarone  restored sinus rhythm in one third of patients with chronic atrial fibrillation , increased the success rate of electric cardioversion , decreased the number of relapses and delayed their occurrence AIMS This study compared the efficacy and safety of intravenous dofetilide with amiodarone and placebo in converting atrial fibrillation or flutter to sinus rhythm . METHODS AND RESULTS One hundred and fifty patients with atrial fibrillation or flutter ( duration range 2 h-6 months ) were given 15-min intravenous infusions of 8 microg . kg(-1)of dofetilide ( n=48 ) , 5 mg . kg(-1)of amiodarone ( n=50 ) , or placebo ( n=52 ) and monitored continuously for 3 h. Sinus rhythm was restored in 35 % , 4 % , and 4 % of patients , respectively ( P<0.001 , dofetilide vs placebo;P = ns , amiodarone versus placebo ) . Dofetilide was more effective in atrial flutter than in atrial fibrillation ( cardioversion rates 75 % and 22 % , respectively;P=0.004 ) . The mean time to conversion with dofetilide was 55+/-15 min . Dofetilide prolonged the QTc interval ( + 16 % at 20 min ) . Amiodarone substantially decreased the ventricular rate in non-converters ( -18 beats . min(-1)at 30 min ) . Two patients given dofetilide ( 4 % ) had non-sustained ventricular tachycardias , and four ( 8 % ) had torsade de pointes , in one case requiring electrical cardioversion . CONCLUSION Intravenous dofetilide is significantly more effective than amiodarone or placebo in restoring sinus rhythm in patients with atrial fibrillation or flutter . However , when infused intravenously at this dose and rate , dofetilide causes a significant incidence of torsade de pointes A 24 h intravenous dosing regimen of amiodarone was design ed to reach a peak plasma concentration at 1 h and to maintain the concentration above a certain level during the infusion period . A r and omized , open-label , digoxin-controlled study was undertaken to observe the efficacy and safety of the dosing regimen of amiodarone in treating recent-onset , persistent , atrial fibrillation and flutter with ventricular rates above 130 beats.min-1 . Fifty patients with a mean age of 70 + /- 7 ( SD ) years were enrolled and r and omly assigned to receive either amiodarone intravenously ( n = 26 ) or digoxin ( n = 24 ) . Amiodarone HCl was infused over 24 h according to the following regimen : 5 mg.min-1 , 3 mg.min-1 , 1 mg.min-1 and 0.5 mg.min-1 for 1 , 3 , 6 and 14 h , respectively , for a 70-kg subject . Digoxin ( 0.013 mg.kg-1 ) was infused in three divided doses , each dose 2 h apart and infused over 30 min . The mean heart rates in the amiodarone group decreased significantly from 157 + /- 20 beats.min-1 to 122 + /- 25 beats.min-1 after 1 h ( P < 0.05 vs baseline ) , and then decreased further to stabilize at 96 + /- 25 beats.min-1 after 6 h ( P < 0.05 ) . The digoxin group had fewer dramatic alterations in heart rates , compared to the amiodarone group , in the first 8 h ( P < 0.05 , respectively ) . Maximum reduction was reached only after 8 h. The amiodarone infusion was prematurely aborted in two patients due to severe bradycardia and death after conversion in one patient and aggravation of heart failure in the other . ( ABSTRACT TRUNCATED AT 250 WORDS BACKGROUND Spontaneous conversion of recent onset paroxysmal atrial fibrillation  to  normal sinus rhythm  occurs commonly and is not affected by low-dose amiodarone treatment . METHODS In a r and omized , placebo-controlled trial of 100 patients with paroxysmal atrial fibrillation of recent onset ( < 48 h ) we compared the effects of treatment with continuous intravenous amiodarone 125 mg per hour ( total 3 g ) and intravenous placebo .  Patients in the placebo group who did not convert to normal sinus rhythm within 24 h were started on amiodarone therapy . RESULTS Conversion to normal sinus rhythm occurred within 24 h in 32 of 50 patients ( 64 % ) in the placebo group , most of whom converted within 8 h. Lower conversion rates were observed in patients with hypertension , ischaemic heart disease or congestive heart failure and in patients with echocardiographic findings of left atrial diameter above 45 mm , ejection fraction below 45 % or significant mitral regurgitation . However , in most patients these clinical or echocardiographic risk factors of decreases in conversion rate were not present . In such patients the spontaneous conversion rate was approximately 90 % . The conversion rate during 24 h of treatment in the amiodarone group was 92 % ( P=0.0017 , compared to the placebo group ) . In this group , the conversion rate was largely unaffected by baseline characteristics . Of the 18 patients who did not convert with placebo , 15 ( 85 % ) converted after being crossed over to amiodarone . All patients not responding to high-dose amiodarone were in chronic atrial fibrillation within 1 month . In patients still in atrial fibrillation after 8 h of treatment , the pulse rate decreased significantly more in the amiodarone as compared to the placebo group ( 83+/-15 vs 114+/-20 beats . min(-1 ) , P=0.0014 ) . CONCLUSION The spontaneous conversion of recent onset paroxysmal atrial fibrillation is high and approaches 90 % in specific clinical and echocardiographically defined subgroups . Intravenous high-dose amiodarone safely facilitates conversion of paroxysmal atrial fibrillation . However , such treatment should be reserved for patients with unfavourable risk factor profiles , not converting during 8 h of observation or requiring rate control Abstract Purpose : Atrial fibrillation ( AF ) is a fairly common complication of acute myocardial infa rct ion ( AMI ) . The aim of this study was to examine the safety and efficacy of intravenous amiodarone in converting AF associated with AMI . Methods : Seventy patients with AMI complicated with AF were prospect ively divided into 3 groups : a ) In group D ( n = 26 ) , 0.75 mg digoxin was administered intravenously and thereafter as needed , b ) In group AM ( n = 16 ) , 300 mg of amiodarone was infused over 2 hours followed by 44 mg/hour for up to 60 hours or until sinus rhythm was restored , c ) In group D + AM ( n = 28 ) , 0.75 mg of digoxin was administered ( as in group D ) for the initial 2 hours followed by amiodarone infusion as in group AM . Results : Sinus rhythm was restored : a ) by the end of the 2nd hour in 9/26 patients from group D , 4/16 from group AM , and 10/28 from group D + AM ( p = NS ) , b ) by the end of the 96th hour , in 18/26 patients from group D , and in all patients from group AM and groupd D + AM . The corresponding duration of AF was 51 ± 34 hours , 17 ± 15 hours and 9 ± 13 hours , respectively ( F = 15.4 , p < 0.001 ) . AF recurred in 9/26 , 5/16 and 1/28 patients of groups D , AM and D + AM , respectively ( p = 0.026 ) . The required dosage of amiodarone  was lower in the D + AM group than in the AM group 
    Output:
    
agent
We found that the size of the left atrium , presence of cardiovascular disease , and protocol s of amiodarone administration did not influence the magnitude of effect .
Serious adverse events were infrequent .
Amiodarone is effective for converting AF to sinus rhythm in a wide range of 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: Despite the widespread use of amiodarone in non-surgical patients , its role in the management of supraventricular tachyarrhythmias after cardiac surgery is not clear . We set out to compare the relative efficacy of amiodarone and digoxin in the management of  atrial fibrillation and flutter in the early postoperative period . This prospect i ve r and omised trial comprised 30 patients , previously in sinus rhythm , who developed sustained atrial fibrillation or flutter following myocardial revascularisation , valve surgery or combined procedures .  Amiodarone was administered as an intravenous loading dose followed by a continuous infusion . Digoxin was given as an intravenous loading dose followed by oral maintenance therapy . Electrocardiographic and haemodynamic monitoring  was continued for 24 h after the commencement of treatment . There was a marked reduction in heart rate in both groups , mainly in the first 6 h , from 146 to 89 beats per minute in the amiodarone group and from 144 to 95 in the digoxin group . At the end of the 24 h , one of the 15 patients in the amiodarone group and 3 of the 15 patients in the digoxin group remained in atrial fibrillation . No patient in either group developed adverse reactions . We conclude that intravenous amiodarone therapy is safe and at least as effective as digoxin in the initial management of arrhythmias after cardiac surgery 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 Objective : We sought to assess the efficacy and safety of amiodarone for restoration and maintenance of sinus rhythm in patients with chronic atrial fibrillation in a prospect i ve , r and omized , double blind trial . Background : Restoration and preservation of sinus rhythm is difficult in patients with chronic atrial fibrillation . The efficacy of oral amiodarone has not been conclusively established . Methods : Ninety-five patients with chronic atrial fibrillation , lasting an average of 35.6 months , were r and omized to either amiodarone ( 600 mg/d ) ( 47 patients ) or placebo ( 48 patients ) during four weeks . Nonresponders underwent electric cardioversion , and those who reverted continued with amiodarone ( 200 mg/d ) or placebo . End-points were successful cardioversion and sinus rhythm maintenance . Results : Sixteen patients ( 34.04 % ) in the amiodarone group reverted within 27.28 ± 8.85 days in comparison with 0 % in the placebo group ( P < 0.000009 ) . The conversion rate rose to 51.72 % in patients with chronic atrial fibrillation lasting less than 12 months . Twenty-eight patients in the amiodarone group and 39 in the placebo group underwent electric cardioversion , which was successful in 19 patients ( 67.8 % ) of the amiodarone group and in 15 ( 38.46 % ) of the placebo group ( P = 0.017 ) . Altogether , conversion was obtained in 79.54 % of the amiodarone group patients and in 38.46 % of the placebo group patients ( P < 0.0001 ) . During follow-up , atrial fibrillation relapsed in 13 ( 37.14 % ) of 35 patients of the amiodarone group within 8.84 + 8.57 months and in 12 ( 80 % ; P = 0.009 ) of 15 patients of the placebo group within 2.74 ± 3.41 months . Conclusions : Oral amiodarone  restored sinus rhythm in one third of patients with chronic atrial fibrillation , increased the success rate of electric cardioversion , decreased the number of relapses and delayed their occurrence AIMS This study compared the efficacy and safety of intravenous dofetilide with amiodarone and placebo in converting atrial fibrillation or flutter to sinus rhythm . METHODS AND RESULTS One hundred and fifty patients with atrial fibrillation or flutter ( duration range 2 h-6 months ) were given 15-min intravenous infusions of 8 microg . kg(-1)of dofetilide ( n=48 ) , 5 mg . kg(-1)of amiodarone ( n=50 ) , or placebo ( n=52 ) and monitored continuously for 3 h. Sinus rhythm was restored in 35 % , 4 % , and 4 % of patients , respectively ( P<0.001 , dofetilide vs placebo;P = ns , amiodarone versus placebo ) . Dofetilide was more effective in atrial flutter than in atrial fibrillation ( cardioversion rates 75 % and 22 % , respectively;P=0.004 ) . The mean time to conversion with dofetilide was 55+/-15 min . Dofetilide prolonged the QTc interval ( + 16 % at 20 min ) . Amiodarone substantially decreased the ventricular rate in non-converters ( -18 beats . min(-1)at 30 min ) . Two patients given dofetilide ( 4 % ) had non-sustained ventricular tachycardias , and four ( 8 % ) had torsade de pointes , in one case requiring electrical cardioversion . CONCLUSION Intravenous dofetilide is significantly more effective than amiodarone or placebo in restoring sinus rhythm in patients with atrial fibrillation or flutter . However , when infused intravenously at this dose and rate , dofetilide causes a significant incidence of torsade de pointes A 24 h intravenous dosing regimen of amiodarone was design ed to reach a peak plasma concentration at 1 h and to maintain the concentration above a certain level during the infusion period . A r and omized , open-label , digoxin-controlled study was undertaken to observe the efficacy and safety of the dosing regimen of amiodarone in treating recent-onset , persistent , atrial fibrillation and flutter with ventricular rates above 130 beats.min-1 . Fifty patients with a mean age of 70 + /- 7 ( SD ) years were enrolled and r and omly assigned to receive either amiodarone intravenously ( n = 26 ) or digoxin ( n = 24 ) . Amiodarone HCl was infused over 24 h according to the following regimen : 5 mg.min-1 , 3 mg.min-1 , 1 mg.min-1 and 0.5 mg.min-1 for 1 , 3 , 6 and 14 h , respectively , for a 70-kg subject . Digoxin ( 0.013 mg.kg-1 ) was infused in three divided doses , each dose 2 h apart and infused over 30 min . The mean heart rates in the amiodarone group decreased significantly from 157 + /- 20 beats.min-1 to 122 + /- 25 beats.min-1 after 1 h ( P < 0.05 vs baseline ) , and then decreased further to stabilize at 96 + /- 25 beats.min-1 after 6 h ( P < 0.05 ) . The digoxin group had fewer dramatic alterations in heart rates , compared to the amiodarone group , in the first 8 h ( P < 0.05 , respectively ) . Maximum reduction was reached only after 8 h. The amiodarone infusion was prematurely aborted in two patients due to severe bradycardia and death after conversion in one patient and aggravation of heart failure in the other . ( ABSTRACT TRUNCATED AT 250 WORDS BACKGROUND Spontaneous conversion of recent onset paroxysmal atrial fibrillation  to  normal sinus rhythm  occurs commonly and is not affected by low-dose amiodarone treatment . METHODS In a r and omized , placebo-controlled trial of 100 patients with paroxysmal atrial fibrillation of recent onset ( < 48 h ) we compared the effects of treatment with continuous intravenous amiodarone 125 mg per hour ( total 3 g ) and intravenous placebo .  Patients in the placebo group who did not convert to normal sinus rhythm within 24 h were started on amiodarone therapy . RESULTS Conversion to normal sinus rhythm occurred within 24 h in 32 of 50 patients ( 64 % ) in the placebo group , most of whom converted within 8 h. Lower conversion rates were observed in patients with hypertension , ischaemic heart disease or congestive heart failure and in patients with echocardiographic findings of left atrial diameter above 45 mm , ejection fraction below 45 % or significant mitral regurgitation . However , in most patients these clinical or echocardiographic risk factors of decreases in conversion rate were not present . In such patients the spontaneous conversion rate was approximately 90 % . The conversion rate during 24 h of treatment in the amiodarone group was 92 % ( P=0.0017 , compared to the placebo group ) . In this group , the conversion rate was largely unaffected by baseline characteristics . Of the 18 patients who did not convert with placebo , 15 ( 85 % ) converted after being crossed over to amiodarone . All patients not responding to high-dose amiodarone were in chronic atrial fibrillation within 1 month . In patients still in atrial fibrillation after 8 h of treatment , the pulse rate decreased significantly more in the amiodarone as compared to the placebo group ( 83+/-15 vs 114+/-20 beats . min(-1 ) , P=0.0014 ) . CONCLUSION The spontaneous conversion of recent onset paroxysmal atrial fibrillation is high and approaches 90 % in specific clinical and echocardiographically defined subgroups . Intravenous high-dose amiodarone safely facilitates conversion of paroxysmal atrial fibrillation . However , such treatment should be reserved for patients with unfavourable risk factor profiles , not converting during 8 h of observation or requiring rate control Abstract Purpose : Atrial fibrillation ( AF ) is a fairly common complication of acute myocardial infa rct ion ( AMI ) . The aim of this study was to examine the safety and efficacy of intravenous amiodarone in converting AF associated with AMI . Methods : Seventy patients with AMI complicated with AF were prospect ively divided into 3 groups : a ) In group D ( n = 26 ) , 0.75 mg digoxin was administered intravenously and thereafter as needed , b ) In group AM ( n = 16 ) , 300 mg of amiodarone was infused over 2 hours followed by 44 mg/hour for up to 60 hours or until sinus rhythm was restored , c ) In group D + AM ( n = 28 ) , 0.75 mg of digoxin was administered ( as in group D ) for the initial 2 hours followed by amiodarone infusion as in group AM . Results : Sinus rhythm was restored : a ) by the end of the 2nd hour in 9/26 patients from group D , 4/16 from group AM , and 10/28 from group D + AM ( p = NS ) , b ) by the end of the 96th hour , in 18/26 patients from group D , and in all patients from group AM and groupd D + AM . The corresponding duration of AF was 51 ± 34 hours , 17 ± 15 hours and 9 ± 13 hours , respectively ( F = 15.4 , p < 0.001 ) . AF recurred in 9/26 , 5/16 and 1/28 patients of groups D , AM and D + AM , respectively ( p = 0.026 ) . The required dosage of amiodarone  was lower in the D + AM group than in the AM group 
    Output:
    