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 — The purpose of this study was to reevaluate the ECG features of arrhythmogenic right ventricular dysplasia ( ARVD ) . The second objective was to evaluate the sensitivity and specificity of the st and ard and newly proposed diagnostic ECG markers in the presence of a right bundle-branch block ( RBBB ) . Methods and Results — One hundred patients with ARVD ( 57 men ; aged 39±15 years ) and 57 controls ( 21 men ; aged 40±17 years ) were included . Among the 100 patients with ARVD , a complete RBBB was present in 17 patients , and 15 patients had an incomplete RBBB . T-wave inversion through V3 demonstrated optimal sensitivity and specificity in both ARVD patients without a complete RBBB or incomplete RBBB ( 71 % [ 95 % confidence interval , 58 % to 81 % ] and 96 % [ 95 % confidence interval , 81 % to 100 % ] , respectively ) and in ARVD patients with incomplete RBBB ( 73 % [ 95 % confidence interval , 45 % to 92 % ] and 95 % [ 95 % confidence interval , 77 % to 100 % ] , respectively ) . Between ARVD patients and controls with a complete RBBB , the only 2 parameters that differed were the prevalence of T-wave inversion through V4 ( 59 % versus 12 % , respectively ; P<0.05 ) and an r′/s ratio in V1 < 1 ( 88 % versus 14 % , respectively ; P<0.005 ) . In ARVD patients with complete RBBB , the most sensitive and specific parameter was an r′/s ratio < 1 . Conclusions — We evaluated comprehensively the diagnostic value of ECG markers for ARVD . On the basis of the findings , we propose an algorithm , with examination of QRS morphology being the first step , for ECG evaluation of ARVD patients . Definite criteria are then applied on the basis of the presence of no RBBB , incomplete RBBB , and complete RBBB to obtain the best diagnostic utility of the ECG Background —Left atrioesophageal fistula is a rare but devastating complication that may occur after  catheter ablation of atrial fibrillation . We used capsule endoscopy to assess esophageal injury after catheter ablation for atrial fibrillation in a population r and omized to undergo general anesthesia or conscious sedation . Methods and Results —Fifty patients undergoing atrial fibrillation ablation for paroxysmal symptomatic atrial fibrillation refractory to antiarrhythmic drugs were enrolled and r and omized , including those undergoing the procedure under general anesthesia ( 25 patients , group 1 ) and those receiving conscious sedation with fentanyl or midazolam ( 25 patients , group 2 ) . All patients underwent esophageal temperature monitoring during the procedure . The day after ablation , all patients had capsule endoscopy to assess the presence of endoluminal tissue damage of the esophagus . We observed esophageal tissue damage in 12 ( 48 % ) patients of group 1 and 1 esophageal tissue damage in a single patient ( 4 % ) of group 2 ( P<0.001 ) . The maximal esophageal temperature was significantly higher in patients undergoing general anesthesia ( group 1 ) versus patients undergoing conscious sedation ( group 2 ) ( 40.6±1 ° C versus 39.6±0.8 ° C ; P < 0.003 ) . The time to peak temperature was 9±7 seconds in group 1 and 21±9 seconds in group 2 , and this difference was statistically significant ( P<0.001 ) . No complication occurred during or after the administration of the pill cam or during the procedures . All esophageal lesions normalized at the 2-month repeat endoscopic examination . Conclusion —The use of general anesthesia increases the risk of esophageal damage detected by capsule endoscopy Background — Tecarfarin ( ATI-5923 ) is a novel oral vitamin K antagonist . Unlike warfarin , it is metabolized by esterases , escaping metabolism by the cytochrome P450 system and thereby avoiding cytochrome P450–mediated drug-drug or drug-food interactions as well as genetic variations found in the cytochrome P450 system . Both tecarfarin and warfarin can be monitored with the international normalized ratio . We hypothesized that the time in therapeutic range for tecarfarin will exceed values usually experienced with warfarin . Methods and Results — This was a 6- to 12-week open-label , multicenter , phase IIA study of 66 atrial fibrillation patients with a mild to moderate risk of stroke to determine the safety and tolerability of tecarfarin and to ascertain an optimal tecarfarin dosing regimen . Sixty-four subjects ( 97 % ) were taking warfarin at enrollment and were switched to tecarfarin . After the initial 3 weeks of tecarfarin treatment , the mean interpolated time in therapeutic range was 71.4 % . Only 10.9 % of patients had time in therapeutic range of < 45 % . Times in extreme international normalized ratio ranges of < 1.5 and > 4.0 were 1.2 % and 1.2 % , respectively . The median daily dose ( for an individual patient ) to maintain an international normalized ratio between 2 and 3 was 15.6 mg ( range , 6 to 29 mg ) . Conclusions — This is the first study of tecarfarin in patients with atrial fibrillation . It appears that tecarfarin may possess advantages over the currently available st and ard of care , warfarin , by improving time in therapeutic range . Adequately powered prospect i ve trials are warranted to definitively compare tecarfarin with warfarin in clinical setting s for which warfarin is indicated Background — Atrial arrhythmias are common early after atrial fibrillation ( AF ) ablation . We hypothesized that empirical antiarrhythmic drug ( AAD ) therapy for 6 weeks after AF ablation would reduce the occurrence of atrial arrhythmias . Methods and Results — We r and omized consecutive patients with paroxysmal AF undergoing ablation to empirical antiarrhythmic therapy ( AAD group ) or no antiarrhythmic therapy ( no-AAD group ) for the first 6 weeks after ablation . In the no-AAD group , only atrioventricular nodal blocking agents were prescribed . All patients wore a transtelephonic monitor for 4 weeks after discharge and were reevaluated at 6 weeks . The primary end point of the study was a composite of ( 1 ) atrial arrhythmias lasting more than 24 hours ; ( 2 ) atrial arrhythmias associated with severe symptoms requiring hospital admission , cardioversion , or initiation/change of antiarrhythmic drug therapy ; and ( 3 ) intolerance to antiarrhythmic agent requiring drug cessation .  Of 110 enrolled patients ( age 55±9 years , 71 % male ) , 53 were r and omized to AAD and 57 to no-AAD . There was no difference in baseline characteristics between groups . During the 6 weeks after ablation , fewer patients reached the primary end point in the AAD compared with the no-AAD group ( 19 % versus 42 % ; P=0.005 ) . There remained fewer events in the AAD group ( 13 % versus 28 % ; P=0.05 ) when only end points of AF > 24 hours , arrhythmia-related hospitalization , or electrical cardioversion were compared . Conclusions — AAD treatment during the first 6 weeks after AF ablation is well tolerated and reduces the incidence of clinical ly significant atrial arrhythmias and need for cardioversion/hospitalization for arrhythmia management Background — Postural tachycardia syndrome ( POTS ) induces disabling chronic orthostatic intolerance with an excessive increase in heart rate on st and ing . β-Blockade is an appealing treatment approach , but conflicting preliminary reports are conflicting . We tested the hypothesis that propranolol will attenuate the tachycardia and improve symptom burden in patients with POTS . In protocol 1 , a low dose ( 20 mg ) was compared with placebo , and the dose response was assessed in protocol 2 . Methods and Results — In protocol 1 , patients with POTS ( n=54 ) underwent acute drug trials of propranolol 20 mg orally and placebo , on separate mornings , in a r and omized crossover design . Blood pressure , heart rate , and symptoms were assessed while the patients were seated and after st and ing for up to 10 minutes before and hourly after the study drug . Supine ( P<0.001 ) and st and ing ( P<0.001 ) heart rates were significantly lower after propranolol compared with placebo . The symptom burden improvement from baseline to 2 hours was greater with propranolol than placebo ( median , −4.5 versus 0 arbitrary units ; P=0.044 ) . In protocol 2 , 18 patients with POTS underwent similar trials of high-dose ( 80 mg ) versus low-dose ( 20 mg ) propranolol . Although the high dose elicited a greater decrease than the low dose in st and ing heart rate ( P<0.001 ) and orthostatic tachycardia ( P<0.001 ) , the improvement in symptoms at 2 hours was greater with low-dose propranolol ( −6 versus −2 arbitrary units ; P=0.041 ) . Conclusions — Low-dose oral propranolol significantly attenuated tachycardia and improved symptoms in POTS . Higher-dose propranolol did not further improve , and may worsen , symptoms Background — Many patients with atrial fibrillation are at high risk for stroke and require antithrombotic therapy . Antiarrhythmic drugs have not previously been shown to reduce the risk of stroke in atrial fibrillation . The effect of dronedarone , a new multichannel-blocking antiarrhythmic drug , on stroke has been evaluated in a r and omized , double-blind clinical trial , ATHENA ( A placebo-controlled , double-blind , parallel-arm Trial to assess the efficacy of dronedarone 400 mg BID for the prevention of cardiovascular Hospitalization or death from any cause in patiENts with Atrial fibrillation/atrial flutter ) . Methods and Results — Patients with persistent or paroxysmal atrial fibrillation and at least 1 risk factor for cardiovascular hospitalization were r and omized to receive dronedarone ( 400 mg BID ) or double-blind matching placebo and followed up for a minimum of 1 year to a common termination at 30 months . All strokes that occurred during the study were included in the present post hoc analysis . There were 4628 patients r and omized to placebo or dronedarone .  The baseline risk factors for stroke were well balanced between the 2 groups , and the baseline mean CHADS2 score was 2 . The baseline use of either oral anticoagulant therapy or antiplatelet agent alone was 60 % . Dronedarone reduced the risk of stroke from 1.8 % per year to 1.2 % per year ( hazard ratio 0.66 , 95 % confidence interval 0.46 to 0.96 , P=0.027 ) . The effect of  dronedarone  was similar whether or not patients were receiving oral anticoagulant therapy , and there was a significantly greater effect of  dronedarone  in patients with higher CHADS2 scores . Conclusions — In this post hoc analysis , a reduction in stroke was observed in patients with atrial fibrillation who were receiving usual care , which included antithrombotic therapy and heart rate control , who were r and omized to dronedarone . Further studies to investigate the effect of dronedarone and other antiarrhythmic agents on stroke are indicated Background — The Sudden Cardiac Death in Heart Failure Trial ( SCD-HeFT ) demonstrated that implantable cardioverter-defibrillator ( ICD ) therapy reduces all-cause mortality in patients with New York Heart Association class II/III heart failure and a left ventricular ejection fraction ≤35 % on optimal medical therapy . Whether ICD therapy reduced sudden death caused by ventricular tachyarrhythmias without affecting heart failure deaths in this population is unknown . Methods and Results — SCD-HeFT r and omized 2521 subjects to placebo , amiodarone , or shock-only , single-lead ICD therapy .  Over a median follow-up of 45.5 months , a total of 666 deaths occurred , which were review ed by an Events Committee and initially categorized as cardiac or noncardiac . Cardiac deaths were further adjudicated as result ing from sudden death presumed to be ventricular tachyarrhythmic , bradyarrhythmia , heart failure , or other cardiac causes . ICD therapy significantly reduced cardiac mortality compared with placebo ( adjusted hazard ratio , 0.76 ; 95 % confidence interval , 0.60 to 0.95 ) and tachyarrhythmia mortality ( adjusted hazard ratio , 0.40 ; 95 % confidence interval , 0.27 to 0.59 ) and had no impact on mortality result ing from heart failure or noncardiac causes . The cardiac and tachyarrhythmia mortality reductions were evident in subjects with New York Heart Association class II but not in subjects with class III heart failure . The reduction in tachyarrhythmia mortality with ICD therapy was similar in subjects with ischemic and nonischemic disease . Compared with placebo , amiodarone had no significant effect on any mode of death . Conclusions — ICD ther 
    Output:
    
agent
Studies of RFA for treatment of atrial fibrillation report higher efficacy rates than do studies of AAD therapy and a lower rate of complications
***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 — The purpose of this study was to reevaluate the ECG features of arrhythmogenic right ventricular dysplasia ( ARVD ) . The second objective was to evaluate the sensitivity and specificity of the st and ard and newly proposed diagnostic ECG markers in the presence of a right bundle-branch block ( RBBB ) . Methods and Results — One hundred patients with ARVD ( 57 men ; aged 39±15 years ) and 57 controls ( 21 men ; aged 40±17 years ) were included . Among the 100 patients with ARVD , a complete RBBB was present in 17 patients , and 15 patients had an incomplete RBBB . T-wave inversion through V3 demonstrated optimal sensitivity and specificity in both ARVD patients without a complete RBBB or incomplete RBBB ( 71 % [ 95 % confidence interval , 58 % to 81 % ] and 96 % [ 95 % confidence interval , 81 % to 100 % ] , respectively ) and in ARVD patients with incomplete RBBB ( 73 % [ 95 % confidence interval , 45 % to 92 % ] and 95 % [ 95 % confidence interval , 77 % to 100 % ] , respectively ) . Between ARVD patients and controls with a complete RBBB , the only 2 parameters that differed were the prevalence of T-wave inversion through V4 ( 59 % versus 12 % , respectively ; P<0.05 ) and an r′/s ratio in V1 < 1 ( 88 % versus 14 % , respectively ; P<0.005 ) . In ARVD patients with complete RBBB , the most sensitive and specific parameter was an r′/s ratio < 1 . Conclusions — We evaluated comprehensively the diagnostic value of ECG markers for ARVD . On the basis of the findings , we propose an algorithm , with examination of QRS morphology being the first step , for ECG evaluation of ARVD patients . Definite criteria are then applied on the basis of the presence of no RBBB , incomplete RBBB , and complete RBBB to obtain the best diagnostic utility of the ECG Background —Left atrioesophageal fistula is a rare but devastating complication that may occur after  catheter ablation of atrial fibrillation . We used capsule endoscopy to assess esophageal injury after catheter ablation for atrial fibrillation in a population r and omized to undergo general anesthesia or conscious sedation . Methods and Results —Fifty patients undergoing atrial fibrillation ablation for paroxysmal symptomatic atrial fibrillation refractory to antiarrhythmic drugs were enrolled and r and omized , including those undergoing the procedure under general anesthesia ( 25 patients , group 1 ) and those receiving conscious sedation with fentanyl or midazolam ( 25 patients , group 2 ) . All patients underwent esophageal temperature monitoring during the procedure . The day after ablation , all patients had capsule endoscopy to assess the presence of endoluminal tissue damage of the esophagus . We observed esophageal tissue damage in 12 ( 48 % ) patients of group 1 and 1 esophageal tissue damage in a single patient ( 4 % ) of group 2 ( P<0.001 ) . The maximal esophageal temperature was significantly higher in patients undergoing general anesthesia ( group 1 ) versus patients undergoing conscious sedation ( group 2 ) ( 40.6±1 ° C versus 39.6±0.8 ° C ; P < 0.003 ) . The time to peak temperature was 9±7 seconds in group 1 and 21±9 seconds in group 2 , and this difference was statistically significant ( P<0.001 ) . No complication occurred during or after the administration of the pill cam or during the procedures . All esophageal lesions normalized at the 2-month repeat endoscopic examination . Conclusion —The use of general anesthesia increases the risk of esophageal damage detected by capsule endoscopy Background — Tecarfarin ( ATI-5923 ) is a novel oral vitamin K antagonist . Unlike warfarin , it is metabolized by esterases , escaping metabolism by the cytochrome P450 system and thereby avoiding cytochrome P450–mediated drug-drug or drug-food interactions as well as genetic variations found in the cytochrome P450 system . Both tecarfarin and warfarin can be monitored with the international normalized ratio . We hypothesized that the time in therapeutic range for tecarfarin will exceed values usually experienced with warfarin . Methods and Results — This was a 6- to 12-week open-label , multicenter , phase IIA study of 66 atrial fibrillation patients with a mild to moderate risk of stroke to determine the safety and tolerability of tecarfarin and to ascertain an optimal tecarfarin dosing regimen . Sixty-four subjects ( 97 % ) were taking warfarin at enrollment and were switched to tecarfarin . After the initial 3 weeks of tecarfarin treatment , the mean interpolated time in therapeutic range was 71.4 % . Only 10.9 % of patients had time in therapeutic range of < 45 % . Times in extreme international normalized ratio ranges of < 1.5 and > 4.0 were 1.2 % and 1.2 % , respectively . The median daily dose ( for an individual patient ) to maintain an international normalized ratio between 2 and 3 was 15.6 mg ( range , 6 to 29 mg ) . Conclusions — This is the first study of tecarfarin in patients with atrial fibrillation . It appears that tecarfarin may possess advantages over the currently available st and ard of care , warfarin , by improving time in therapeutic range . Adequately powered prospect i ve trials are warranted to definitively compare tecarfarin with warfarin in clinical setting s for which warfarin is indicated Background — Atrial arrhythmias are common early after atrial fibrillation ( AF ) ablation . We hypothesized that empirical antiarrhythmic drug ( AAD ) therapy for 6 weeks after AF ablation would reduce the occurrence of atrial arrhythmias . Methods and Results — We r and omized consecutive patients with paroxysmal AF undergoing ablation to empirical antiarrhythmic therapy ( AAD group ) or no antiarrhythmic therapy ( no-AAD group ) for the first 6 weeks after ablation . In the no-AAD group , only atrioventricular nodal blocking agents were prescribed . All patients wore a transtelephonic monitor for 4 weeks after discharge and were reevaluated at 6 weeks . The primary end point of the study was a composite of ( 1 ) atrial arrhythmias lasting more than 24 hours ; ( 2 ) atrial arrhythmias associated with severe symptoms requiring hospital admission , cardioversion , or initiation/change of antiarrhythmic drug therapy ; and ( 3 ) intolerance to antiarrhythmic agent requiring drug cessation .  Of 110 enrolled patients ( age 55±9 years , 71 % male ) , 53 were r and omized to AAD and 57 to no-AAD . There was no difference in baseline characteristics between groups . During the 6 weeks after ablation , fewer patients reached the primary end point in the AAD compared with the no-AAD group ( 19 % versus 42 % ; P=0.005 ) . There remained fewer events in the AAD group ( 13 % versus 28 % ; P=0.05 ) when only end points of AF > 24 hours , arrhythmia-related hospitalization , or electrical cardioversion were compared . Conclusions — AAD treatment during the first 6 weeks after AF ablation is well tolerated and reduces the incidence of clinical ly significant atrial arrhythmias and need for cardioversion/hospitalization for arrhythmia management Background — Postural tachycardia syndrome ( POTS ) induces disabling chronic orthostatic intolerance with an excessive increase in heart rate on st and ing . β-Blockade is an appealing treatment approach , but conflicting preliminary reports are conflicting . We tested the hypothesis that propranolol will attenuate the tachycardia and improve symptom burden in patients with POTS . In protocol 1 , a low dose ( 20 mg ) was compared with placebo , and the dose response was assessed in protocol 2 . Methods and Results — In protocol 1 , patients with POTS ( n=54 ) underwent acute drug trials of propranolol 20 mg orally and placebo , on separate mornings , in a r and omized crossover design . Blood pressure , heart rate , and symptoms were assessed while the patients were seated and after st and ing for up to 10 minutes before and hourly after the study drug . Supine ( P<0.001 ) and st and ing ( P<0.001 ) heart rates were significantly lower after propranolol compared with placebo . The symptom burden improvement from baseline to 2 hours was greater with propranolol than placebo ( median , −4.5 versus 0 arbitrary units ; P=0.044 ) . In protocol 2 , 18 patients with POTS underwent similar trials of high-dose ( 80 mg ) versus low-dose ( 20 mg ) propranolol . Although the high dose elicited a greater decrease than the low dose in st and ing heart rate ( P<0.001 ) and orthostatic tachycardia ( P<0.001 ) , the improvement in symptoms at 2 hours was greater with low-dose propranolol ( −6 versus −2 arbitrary units ; P=0.041 ) . Conclusions — Low-dose oral propranolol significantly attenuated tachycardia and improved symptoms in POTS . Higher-dose propranolol did not further improve , and may worsen , symptoms Background — Many patients with atrial fibrillation are at high risk for stroke and require antithrombotic therapy . Antiarrhythmic drugs have not previously been shown to reduce the risk of stroke in atrial fibrillation . The effect of dronedarone , a new multichannel-blocking antiarrhythmic drug , on stroke has been evaluated in a r and omized , double-blind clinical trial , ATHENA ( A placebo-controlled , double-blind , parallel-arm Trial to assess the efficacy of dronedarone 400 mg BID for the prevention of cardiovascular Hospitalization or death from any cause in patiENts with Atrial fibrillation/atrial flutter ) . Methods and Results — Patients with persistent or paroxysmal atrial fibrillation and at least 1 risk factor for cardiovascular hospitalization were r and omized to receive dronedarone ( 400 mg BID ) or double-blind matching placebo and followed up for a minimum of 1 year to a common termination at 30 months . All strokes that occurred during the study were included in the present post hoc analysis . There were 4628 patients r and omized to placebo or dronedarone .  The baseline risk factors for stroke were well balanced between the 2 groups , and the baseline mean CHADS2 score was 2 . The baseline use of either oral anticoagulant therapy or antiplatelet agent alone was 60 % . Dronedarone reduced the risk of stroke from 1.8 % per year to 1.2 % per year ( hazard ratio 0.66 , 95 % confidence interval 0.46 to 0.96 , P=0.027 ) . The effect of  dronedarone  was similar whether or not patients were receiving oral anticoagulant therapy , and there was a significantly greater effect of  dronedarone  in patients with higher CHADS2 scores . Conclusions — In this post hoc analysis , a reduction in stroke was observed in patients with atrial fibrillation who were receiving usual care , which included antithrombotic therapy and heart rate control , who were r and omized to dronedarone . Further studies to investigate the effect of dronedarone and other antiarrhythmic agents on stroke are indicated Background — The Sudden Cardiac Death in Heart Failure Trial ( SCD-HeFT ) demonstrated that implantable cardioverter-defibrillator ( ICD ) therapy reduces all-cause mortality in patients with New York Heart Association class II/III heart failure and a left ventricular ejection fraction ≤35 % on optimal medical therapy . Whether ICD therapy reduced sudden death caused by ventricular tachyarrhythmias without affecting heart failure deaths in this population is unknown . Methods and Results — SCD-HeFT r and omized 2521 subjects to placebo , amiodarone , or shock-only , single-lead ICD therapy .  Over a median follow-up of 45.5 months , a total of 666 deaths occurred , which were review ed by an Events Committee and initially categorized as cardiac or noncardiac . Cardiac deaths were further adjudicated as result ing from sudden death presumed to be ventricular tachyarrhythmic , bradyarrhythmia , heart failure , or other cardiac causes . ICD therapy significantly reduced cardiac mortality compared with placebo ( adjusted hazard ratio , 0.76 ; 95 % confidence interval , 0.60 to 0.95 ) and tachyarrhythmia mortality ( adjusted hazard ratio , 0.40 ; 95 % confidence interval , 0.27 to 0.59 ) and had no impact on mortality result ing from heart failure or noncardiac causes . The cardiac and tachyarrhythmia mortality reductions were evident in subjects with New York Heart Association class II but not in subjects with class III heart failure . The reduction in tachyarrhythmia mortality with ICD therapy was similar in subjects with ischemic and nonischemic disease . Compared with placebo , amiodarone had no significant effect on any mode of death . Conclusions — ICD ther 
    Output:
    