***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 
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    Input: Background  Atrial fibrillation ( AF )  is a common problem after CABG . Prevention with prophylactic drug therapy has had limited success , therefore alternative approaches are required . This study investigated the role of biatrial pacing compared with no pacing on AF incidence after isolated first-time CABG . Methods and Results During surgery , temporary pacing leads were placed in the lateral wall of the right atrium and at the roof of the left atrium in Bachmann ’s bundle to allow bipolar pacing and sensing at each site . After surgery , all patients were connected to an external pacemaker ( Chorum ELA ) that also acted as a Holter monitor . Patients were consecutively r and omized to either 4 days of biatrial pacing at a base rate of 80 bpm or to no pacing ( control group , base rate 30 bpm ) . End points included an episode of AF lasting > 1 hour on pacemaker Holter , clinical ly detected AF , intensive care unit ( ICU ) and hospital stay , and postoperative complications .  One hundred thirty patients were r and omized . Biatrial pacing significantly reduced both monitored ( 13.8 % versus 38.5 % , P = 0.001 ) and clinical ( 10.8 % versus 33.8 % , P = 0.002 ) episodes of AF . Median ICU ( 19 versus 24 hours , P = NS ) and mean hospital stay ( 7.7±6.9 versus 9.7±10 , P = NS ) did not significantly change . The number of postoperative complications was lower in the biatrial group ( 13 versus 35 , P = 0.001 ) . Conclusions Biatrial pacing after CABG significantly decreases the incidence of AF . This is associated with reduced postoperative complications and a trend toward reduced ICU and hospital stay OBJECTIVES The purpose of this study was to investigate the efficacy and safety of amiodarone and propafenone in the conversion of  chronic atrial fibrillation  in a prospect i ve , r and omized , placebo-controlled study . BACKGROUND The effectiveness of amiodarone and propafenone in the treatment of patients with chronic atrial fibrillation has not been adequately studied . METHODS One hundred one patients ( 48 men , mean age 64 + /- 9 years ) with atrial fibrillation lasting > 3 weeks participated in the study . Thirty-four patients received amiodarone ( 300 mg intravenously over 1 h , followed by 20 mg/kg over the next 24 h plus 600 mg orally , in three doses , for 1 week , then 400 mg/day orally , for three weeks ) , 32 received propafenone ( 2 mg/kg intravenously over 15 min , followed by 10 mg/kg over 24 h and then 450 mg/day orally , for one month ) and the remaining 35 served as control subjects . All patients received digoxin and anticoagulant treatment as indicated ( International Normalized Ratio 2 to 3 ) . RESULTS Conversion to sinus rhythm was achieved in 16 ( 47.05 % ) patients who received amiodarone , in 13 ( 40.62 % ) who received propafenone and in none of the control subjects ( p < 0.001 for both groups vs. control subjects ) . Those who converted had smaller atria than those who did not and atrial fibrillation of shorter duration in both the amiodarone and propafenone groups . Treatment was discontinued in one patient of the propafenone group because of significant QRS widening . CONCLUSIONS Amiodarone and propafenone appear to be safe and equally effective in the termination of chronic atrial fibrillation . Left atrial diameter and arrhythmia duration are independent predictors of conversion OBJECTIVE The purpose of this study was to determine the efficacy of atrial pacing in the prevention of atrial fibrillation following cardiovascular surgery . BACKGROUND Although pharmacologic therapy has been used to help prevent postoperative atrial fibrillation , it suffers from limited efficacy and adverse effects . In the nonoperative setting , novel pacing strategies have been shown to reduce recurrences of atrial fibrillation and prolong arrhythmia-free periods in patients with paroxysmal atrial arrhythmias . METHODS A total of 154 patients ( 115 men ; mean age , 65 + /- 10 years ; ejection fraction , 53 + /- 10 % ) undergoing cardiac surgery ( coronary artery bypass surgery , 88.3 % ; aortic valve replacement , 4.5 % ; coronary bypass + aortic valve replacement , 7.1 % ) had right and left atrial epicardial pacing electrodes placed at the time of surgery . Patients were r and omized to either no pacing , right atrial ( RAP ) , left atrial ( LAP ) or biatrial pacing ( BAP ) for 72 h after surgery . Beta-adrenergic blocking agents were administered concurrently to all patients following surgery . RESULTS There was a reduction in the incidence of postoperative atrial fibrillation from 37.5 % in patients receiving no postoperative pacing to 17 % ( p < 0.005 ) in patients assigned to one of the three pacing strategies . The length of hospital stay was reduced by 22 % from 7.8 + /- 3.7 days to 6.1 + /- 2.3 days ( p = 0.003 ) in patients assigned to postoperative atrial pacing . The incidence of atrial fibrillation was lower in each of the paced groups ( RAP , 8 % ; LAP , 20 % ; BAP , 26 % ) compared with patients who did not receive postoperative pacing ( 37.5 % ) . CONCLUSION Postoperative atrial pacing , in conjunction with beta-blockade , significantly reduced both the incidence of atrial fibrillation and the length of hospital stay following cardiovascular surgery . Additional studies are needed to determine the most effective anatomic pacing site BACKGROUND --Arrhythmias are a common cause of morbidity after cardiac surgery . This study assessed the efficacy of prophylactic amiodarone in reducing the incidence of  atrial fibrillation or flutter and ventricular arrhythmias after coronary artery surgery . METHODS --A double blind , r and omised , placebo controlled trial . 60 patients received a 24 hour intravenous infusion of  amiodarone ( 15 mg/kg started after removal of the aortic cross clamp ) followed by 200 mg orally three times daily for 5 days , and 60 patients received placebo . RESULTS --6 patients ( 10 % ) in the amiodarone group and 14 ( 23 % ) in the placebo group needed treatment for arrhythmias ( 95 % confidence interval ( 95 % CI ) for the difference between groups was 0 to 26 % , p = 0.05 ) . The incidence of supraventricular tachycardia detected clinical ly and requiring treatment was lower in the amiodarone group ( 8 % amiodarone v 20 % placebo , 95 % CI 0 to 24 % , p = 0.07 ) . The incidence detected by 24 hour Holter monitoring was similar ( 17 % amiodarone v 20 % placebo ) . Untreated arrhythmias in the amiodarone group were either clinical ly benign and undetected ( n = 3 ) or the ventricular response rate was slow ( n = 2 ) . Age > 60 years was a positive risk factor for the development of supraventricular tachycardia in the amiodarone group but not in the placebo group . Fewer patients had episodes of ventricular tachycardia or fibrillation recorded on Holter monitoring in the amiodarone group ( 15 % amiodarone v 33 % placebo , 95 % CI 3 to 33 % , p = 0.02 ) . Bradycardia ( 78 % amiodarone v 48 % placebo , 95 % CI 14 % to 46 % , p < 0.005 ) and pauses ( 7 % amiodarone v 0 % placebo ) occurred in more amiodarone treated patients . Bradycardia warranted discontinuation of treatment in one patient treated with amiodarone . CONCLUSIONS --The incidence of clinical ly significant tachycardia was reduced by amiodarone . The ventricular response rate was slowed in supraventricular tachycardia , but the induction of bradycardia may preclude the routine use of amiodarone for prophylaxis Background : Atrial fibrillation is a common complication after cardiac surgery . Postoperative atrial fibrillation is associated with increased risks of morbidity and mortality , and , therefore , preventive strategies using oral amiodarone have been developed but are often unpractical . Intravenous amiodarone administered after the induction of anesthesia and continued postoperatively for 48 h could represent an effective strategy to prevent postoperative atrial fibrillation in patients undergoing cardiac valvular surgery . Methods : Single-center , double-blinded , double-dummy , r and omized controlled trial in patients undergoing valvular surgery . Patients received either an intravenous loading dose of 300 mg of amiodarone or placebo in the operating room , followed by a perfusion of 15 mg · kg−1 · 24 h−1 for 2 days . The primary endpoint was the development of atrial fibrillation occurring at any time within the postoperative period . Results : One hundred twenty patients were r and omly assigned ( mean age was 65 ± 11 yr ) .  Overall atrial fibrillation occurred more frequently in the perioperative intravenous amiodarone group compared with the placebo group ( 59.3 vs. 40.0 % ; P = 0.035 ) . Four preoperative factors were found to be independently associated with a higher risk of developing postoperative atrial fibrillation : older age ( P = 0.0003 ) , recent myocardial infa rct ion ( < 6 months ; P = 0.026 ) , preoperative angina ( P = 0.0326 ) , and use of a calcium channel blocker preoperatively ( P = 0.0078 ) when controlling for groups . Conclusion : In patients undergoing cardiac valvular surgery , a strategy using intravenous amiodarone for 48 h is not efficacious in reducing the risk of atrial fibrillation during cardiac valvular surgery BACKGROUND Atrial fibrillation ( AF ) is common after coronary artery bypass surgery ( CABG ) and results in prolonged hospitalization . The purpose of this study was to evaluate the efficacy of biatrial pacing in preventing post-CABG AF compared with single-site atrial pacing . METHODS AND RESULTS A total of 132 patients who had no history of AF and who underwent CABG were r and omized to 1 of the following 4 groups : biatrial pacing ( BiA ) , left atrial pacing ( LA ) , right atrial pacing ( RA ) , or no pacing ( control ) in postoperative period . Overdrive atrial pacing was performed for 5 days . The incidence of AF was significantly reduced in the BiA group ( 12.5 % ) compared with the other 3 groups ( LA , 36.4 % ; RA , 33.3 % ; control , 41 . 9 % ; P<0.05 ) . The mean length of hospital stay was significantly reduced in the BiA group . At baseline , the mean P-wave duration ( P(dur ) ) and dispersion ( P(dis ) ) were not prolonged . BiA pacing result ed in the most significant percentage of reduction in P(dis ) when compared with the LA or RA groups ( BiA , 42+/-8 % ; LA , 13+/-6 % ; RA , 10+/-9 % ; P<0.05 for BiA versus LA or RA ) . No significant differences existed in mean P(dur ) and P(dis ) between patients who developed AF and those who remained in sinus rhythm at baseline . However , only those patients who remained in sinus rhythm had a significant reduction in mean P(dur ) and P(dis ) after pacing therapy . CONCLUSIONS Biatrial overdrive pacing is more effective in preventing post-CABG AF than single-site atrial pacing ; this therapy also results in a shortened hospital stay . The overall reduction in atrial activation time with BiA pacing was reflected in the reduction in P(dis ) Sotalol is a beta-adrenergic blocking drug with the additional property of lengthening the cardiac action potential . These electrophysiologic properties render the drug attractive for use in the prevention of postoperative supraventricular arrhythmias ( SVA ) , and previous studies have suggested that it was indeed effective . The hemodynamic response to sotalol and its safety early after coronary artery bypass graft ( CABG ) surgery were therefore studied . Forty-two patients undergoing CABG were r and omly assigned either to receive sotalol to prevent postoperative SVA ( 25 patients ) or to serve as controls ( 17 patients ) . Sotalol was started 6 hours after surgery if patients had a cardiac index > 2.8 L/min/m2 with a pulmonary capillary wedge pressure < 15 mmHg , and if they had no contraindications to the use of beta-blockers . The drug was given as a loading infusion of 1 mg/kg over 2 hours , followed by a maintenance infusion of 0.15 mg/kg/h for 24 hours . Three hours later , patients received the first oral dose of 80 mg to be repeated every 8 or 12 hours . Adverse effects necessitating discontinuation of the drug ( bradycardia 
    Output:
    
No significant effect on all-cause or cardiovascular mortality was demonstrated .
Prophylaxis to prevent atrial fibrillation after cardiac surgery with any of the studied pharmacological or non-pharmacological interventions may be favored because of its reduction in the rate of atrial fibrillation , decrease in the length of stay and cost of hospital treatment and a possible decrease in the rate of stroke .