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 Contact force ( CF ) monitoring could be useful in accomplishing circumferential pulmonary vein ( PV ) isolation ( CPVI ) for atrial fibrillation ( AF ) . OBJECTIVE The purpose of this study was to compare procedure parameters and outcomes between CF-guided and non-guided CPVI . METHODS Thirty-eight consecutive AF patients ( mean age 60 ± 11 years , 28 paroxysmal AF ) undergoing CPVI were r and omized to non-CF-guided ( n = 19 ) and CF-guided ( n = 19 ) groups .  CPVI was performed with the ThermoCool SmartTouch catheter in both groups . The end-point was bidirectional block between the left atrium ( LA ) and PV . In the CF group , CF was kept between 10 and 20 g during CPVI , whereas in the non-CF group , all CF information was blanked . Radiofrequency energy at 30 W in the anterior and 25 W in the posterior LA wall was applied for 20 - 25 seconds at each point . RESULTS CPVI was successfully accomplished without any major complications in both groups . Mean CF in the non-CF and CF groups were 5.9 ± 4.5 g and 11.1 ± 4.3 g , respectively , for left-side CPVI , and 9.8 ± 6.6 g and 12.1 ± 4.8 g , respectively , for right-side CPVI ( both P < .001 ) . The procedure and fluoroscopy times  for CPVI in the non-CF and CF groups were 96 ± 39 minutes and 59 ± 16 minutes , respectively ( P < .001 ) , and 22 ± 63 seconds and 9 ± 20 seconds ( P = NS ) , respectively . Total number of residual conduction gaps was 6.3 ± 3.0 in the non-CF group and 2.8 ± 1.9 in the CF group ( P < .001 ) . During 6-month follow-up , 84.2 % of patients in the non-CF group and 94.7 % in the CF group were free from any atrial tachyarrhythmias ( P = .34 ) . CONCLUSION CF-guided CPVI  is effective in reducing procedure time and additional touch-up ablation and may improve long-term outcome Background The aim of this study was to evaluate the impact of contact force ( CF ) visualization on the incidence of low and high CF during left atrial ( LA ) mapping and pulmonary vein isolation ( PVI ) . Methods CF was assessed in 70 patients who underwent PVI .  Three highly experienced operators performed all procedures . The operators were blinded to CF in group A ( 35 patients ) , and CF was displayed in group B ( 35 patients ) . In group B , optimal CF was defined as mean CF between 10 and 39 g , and operators attempted to acquire points and ablate within this range . Results A total of 8401 mapping points were analyzed during LA mapping ( group A : 4104 , group B : 4297 ) . Low CF < 10 g and high CF ≥40 g were noted in a significantly larger number of points in group A ( 37.7 vs. 12.0 % , P < 0.001 ; 11.5 vs. 1.5 % , P < 0.001 ) . At the mitral isthmus and ridge areas , CF was significantly lower ( 7.7 vs. 12.2 g , P < 0.001 ; 5.3 vs. 11.7 g , P < 0.001 ) in group A than in group B. PVI was successfully achieved in all patients . There were significant site-dependent CF differences between the two groups . Optimal CF was achieved in significantly more applications in group B ( P < 0.001 ) . There was no significant difference in atrial fibrillation ( AF ) recurrence rates after a minimum follow-up of 1 year between the two groups in this cohort ( P = 0.24 ) . No significant peri-procedural complications occurred in either group . Conclusions CF visualization can assist in avoiding both low and high CF , which may have the potential to improve lesion formation and patient safety profile . In this study , CF-guided ablation did not affect AF recurrence Purpose We prospect ively investigated the differences in pulmonary vein reconnections ( PVRs ) and clinical outcomes between contact force (CF)-guided and conventional circumferential PV isolation ( CPVI ) of atrial fibrillation ( AF ) . Methods One hundred twenty consecutive AF patients ( 63 ± 10 years ; 88 males ) undergoing an initial CPVI were r and omized to ablation with a target CF of 20 g ( CF group ; n = 60 ) or that with operators blinded to the CF information ( blind group ; n = 60 ) . Results The CF group had fewer PVRs ( 0.67 ± 0.91/patient vs. 1.16 ± 1.16/patient ; P = 0.007 ) , a lower incidence of persistent PVRs ( 13.2 vs. 41.2 % ; P < 0.001 ) , and a shorter procedural time for the CPVI ( 50 vs. 56 min ; P = 0.019 ) than the blind group . The mean CF was higher in the CF group than the blind group ( 18.0 vs. 16.1 g ; P < 0.001 ) , with the most significant difference observed along the posterior right-sided PVs ( P-RPVs ) and anterior left-sided PVs ( A-LPVs ) . In logistic regression models , the mean CF was a negative predictor of PVRs along the P-RPVs and A-LPVs in the blind group ( odds ratios , 0.728 and 0.786 ; P < 0.001 and 0.007 ) , while no significant predictor was identified in the CF group or elsewhere in the blind group . In the Kaplan-Meier analysis , the arrhythmia-free survival rate at 12 months was 89.9 % in the CF group and 88.2 % in the blind group , respectively ( P = 0.624 ) . Conclusions CF-guided CPVI can reduce PVRs and the procedural time and be particularly beneficial along regions where a relatively low CF tends to be applied : the P-RPVs and A-LPVs . The comparable clinical outcomes may be due to the learning curve effect obtained by the CF-guided technique and repeated provocation of dormant PV conduction Aims A challenge of pulmonary vein isolation ( PVI ) in catheter ablation for paroxysmal atrial fibrillation ( PAF ) is electrical reconnection of the PV . EFFICAS I showed correlation between contact force ( CF ) parameters and PV durable isolation but no prospect i ve evaluation was made . EFFICAS II was a multicentre study to prospect ively assess the impact of CF guidance for an effective reduction of PVI gaps . Methods and results Pulmonary vein isolation using a radiofrequency ( RF ) ablation catheter with an integrated force sensor ( TactiCath ™ ) was performed in patients with PAF . Operators were provided EFFICAS I-based CF guidelines [ target 20 g , range 10–30 g , minimum 400 g s force-time integral ( FTI ) ] . Conduction gaps were assessed by remapping of PVs after 3 months , and gap rate was compared with EFFICAS I outcome . At follow up , 24 patients had 85 % of PVs remaining isolated , compared with 72 % in EFFICAS I ( P = 0.037 ) in which CF guidelines were not used . The remaining 15 % of gaps correlated to the number of catheter moves at creating the PVI line , quantified as Continuity Index . For PV lines with contiguous lesions and low catheter moves , durable isolation was 81 % in EFFICAS I and 98 % in EFFICAS II ( P = 0.005 ) . At index procedure , the number of lesions was reduced by 15 % in EFFICAS II vs. EFFICAS I. Conclusion The use of CF with the above guidelines and contiguous deployment of RF lesions in EFFICAS II study result ed in more durable PVI in catheter ablation of PAF AIMS The aim of this study was to evaluate the ' real-world ' impact of a novel contact force (CF)-sensing ( SmartTouch ™ , Biosense Webster , Diamond Bar , CA , USA ) catheter coupled with an advanced catheter location ( ACL ) system on fluoroscopy time and fluoroscopy dose during atrial fibrillation ( AF ) ablation . METHODS AND RESULTS This was a retrospective observational cohort study of prospect ively collected data of 1515 consecutive patients undergoing paroxysmal AF ( PAF ) and persistent AF ( PerAF ) ablation at a single institution between 2009 and 2014 . Patients undergoing AF ablation with the SmartTouch catheter and the ACL system ( SmartTouch group , n = 510 ) were compared with those undergoing AF ablation without this technology ( control group , n = 1005 ) . The primary outcomes were total fluoroscopy time ( min ) and fluoroscopy dose as measured by the dose-area product ( mGy cm(2 ) ) . Secondary endpoints included total procedure time , total ablation time , and major cardiac complications ( tamponade , pericardial effusion , and urgent cardiac surgery ) . The SmartTouch group had significantly lower fluoroscopy times ( 9.5 vs. 41 min , P < 0.001 ) , radiation doses ( 1044 vs. 3571 mGy cm(2 ) , P < 0.001 ) , and shorter procedural time ( 195 vs. 240 min , P < 0.001 ) when compared with the control group . This was statistically significant for both PAF and PerAF ablations and for both de novo and redo AF procedures . After a learning curve , a median fluoroscopy time of 3.5 min ( interquartile range 6 ) for all AF ablations was achieved . There was no difference in the rate of cardiac complications ( ∼ 1.5 % ) . CONCLUSION SmartTouch ™ CF-sensing catheter use with ACL ™ during AF ablation significantly reduces fluoroscopy times by 77 % , radiation dose by 71 % , and procedural time by 19 % but does not improve overall safety or the risk of cardiac complications BACKGROUND Electrode-tissue contact is crucial for adequate lesion formation in radiofrequency catheter ablation ( RFCA ) . OBJECTIVE We assessed the impact of direct catheter force measurement on acute procedural parameters during RFCA of atrial fibrillation ( AF ) . METHODS Fifty consecutive patients ( 28 male ) with paroxysmal AF who underwent their first procedure of circumferential pulmonary vein ( PV ) isolation ( PVI ) were assigned to either RFCA using ( 1 ) a st and ard 3.5-mm open-irrigated-tip catheter or ( 2 ) a catheter with contact force measurement capabilities . Using the endpoint of PVI with entry and exit block , acute procedural parameters were assessed . RESULTS Procedural data showed a remarkable decline in ablation time ( radiofrequency time needed for PVI ) from 50.5 ± 15.9 to 39.0 ± 11.0 minutes ( P = 0.007 ) with a reduction in overall procedure duration from 185 ± 46 to 154 ± 39 minutes ( P = 0.022 ) . In parallel , the total energy delivered could be significantly reduced from 70,926 ± 19,470 to 58,511 ± 14,655 Ws ( P = 0.019 ) . The number of acute PV reconnections declined from 36 % to 12 % ( P = 0.095 ) . CONCLUSIONS The use of contact force sensing technology is able to significantly reduce ablation and procedure times in PVI . In addition , energy delivery is substantially reduced by avoiding radiofrequency ablation in positions with insufficient surface contact . Procedural efficacy and safety of this new feature have to be evaluated in larger cohorts Purpose Use of online contact force ( CF ) measurement during circumferential pulmonary vein  ( PV )  isolation ( CPVI ) for atrial fibrillation ( AF ) has demonstrated improvements in procedural parameters and mid-term clinical outcome . However , it is unknown if experience gained with CF measuring catheters improves the efficacy of subsequent CPVI procedures performed without CF measurement . Methods This prospect i ve trial compared procedural results of CPVI performed without a CF measuring catheter to a control group performed with a CF measuring catheter , by an operator with prior experience with CF technology .. Results Thirty-six eligible paroxysmal ( n = 27 ) or persistent ( n = 9 ) AF patients were consecutively enrolled . Twelve patients underwent CPVI  with the non-CF catheter ( CF− group ) in a recall period and 24 with the CF catheter ( CF+ group ) . After the first circumferential lesion set , the number of PV pairs requiring additional touch-up lesions to achieve electrical isolation was significantly less in the CF+ group ( 2 of 48 ( 4.2 % ) vs. 7 of 24 ( 29.2 % ) in the CF+ and CF− groups , respectively , p = 0.005 ) . The procedure time was significantly lower in the CF+ group ( 117.9 ± 23.3 vs. 134.1 ± 25.3 min , p = 0.033 ) . Radiofrequency ( RF ) and fluoroscopy time did not differ between groups ( 31.5 ± 7.1 vs. 31.8 ± 
    Output:
    
agent
CF-sensing catheter ablation of AF can reduce the incidence of major complications and generate better outcomes compared with NCF-sensing catheters during the 12-month follow-up period
***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 Contact force ( CF ) monitoring could be useful in accomplishing circumferential pulmonary vein ( PV ) isolation ( CPVI ) for atrial fibrillation ( AF ) . OBJECTIVE The purpose of this study was to compare procedure parameters and outcomes between CF-guided and non-guided CPVI . METHODS Thirty-eight consecutive AF patients ( mean age 60 ± 11 years , 28 paroxysmal AF ) undergoing CPVI were r and omized to non-CF-guided ( n = 19 ) and CF-guided ( n = 19 ) groups .  CPVI was performed with the ThermoCool SmartTouch catheter in both groups . The end-point was bidirectional block between the left atrium ( LA ) and PV . In the CF group , CF was kept between 10 and 20 g during CPVI , whereas in the non-CF group , all CF information was blanked . Radiofrequency energy at 30 W in the anterior and 25 W in the posterior LA wall was applied for 20 - 25 seconds at each point . RESULTS CPVI was successfully accomplished without any major complications in both groups . Mean CF in the non-CF and CF groups were 5.9 ± 4.5 g and 11.1 ± 4.3 g , respectively , for left-side CPVI , and 9.8 ± 6.6 g and 12.1 ± 4.8 g , respectively , for right-side CPVI ( both P < .001 ) . The procedure and fluoroscopy times  for CPVI in the non-CF and CF groups were 96 ± 39 minutes and 59 ± 16 minutes , respectively ( P < .001 ) , and 22 ± 63 seconds and 9 ± 20 seconds ( P = NS ) , respectively . Total number of residual conduction gaps was 6.3 ± 3.0 in the non-CF group and 2.8 ± 1.9 in the CF group ( P < .001 ) . During 6-month follow-up , 84.2 % of patients in the non-CF group and 94.7 % in the CF group were free from any atrial tachyarrhythmias ( P = .34 ) . CONCLUSION CF-guided CPVI  is effective in reducing procedure time and additional touch-up ablation and may improve long-term outcome Background The aim of this study was to evaluate the impact of contact force ( CF ) visualization on the incidence of low and high CF during left atrial ( LA ) mapping and pulmonary vein isolation ( PVI ) . Methods CF was assessed in 70 patients who underwent PVI .  Three highly experienced operators performed all procedures . The operators were blinded to CF in group A ( 35 patients ) , and CF was displayed in group B ( 35 patients ) . In group B , optimal CF was defined as mean CF between 10 and 39 g , and operators attempted to acquire points and ablate within this range . Results A total of 8401 mapping points were analyzed during LA mapping ( group A : 4104 , group B : 4297 ) . Low CF < 10 g and high CF ≥40 g were noted in a significantly larger number of points in group A ( 37.7 vs. 12.0 % , P < 0.001 ; 11.5 vs. 1.5 % , P < 0.001 ) . At the mitral isthmus and ridge areas , CF was significantly lower ( 7.7 vs. 12.2 g , P < 0.001 ; 5.3 vs. 11.7 g , P < 0.001 ) in group A than in group B. PVI was successfully achieved in all patients . There were significant site-dependent CF differences between the two groups . Optimal CF was achieved in significantly more applications in group B ( P < 0.001 ) . There was no significant difference in atrial fibrillation ( AF ) recurrence rates after a minimum follow-up of 1 year between the two groups in this cohort ( P = 0.24 ) . No significant peri-procedural complications occurred in either group . Conclusions CF visualization can assist in avoiding both low and high CF , which may have the potential to improve lesion formation and patient safety profile . In this study , CF-guided ablation did not affect AF recurrence Purpose We prospect ively investigated the differences in pulmonary vein reconnections ( PVRs ) and clinical outcomes between contact force (CF)-guided and conventional circumferential PV isolation ( CPVI ) of atrial fibrillation ( AF ) . Methods One hundred twenty consecutive AF patients ( 63 ± 10 years ; 88 males ) undergoing an initial CPVI were r and omized to ablation with a target CF of 20 g ( CF group ; n = 60 ) or that with operators blinded to the CF information ( blind group ; n = 60 ) . Results The CF group had fewer PVRs ( 0.67 ± 0.91/patient vs. 1.16 ± 1.16/patient ; P = 0.007 ) , a lower incidence of persistent PVRs ( 13.2 vs. 41.2 % ; P < 0.001 ) , and a shorter procedural time for the CPVI ( 50 vs. 56 min ; P = 0.019 ) than the blind group . The mean CF was higher in the CF group than the blind group ( 18.0 vs. 16.1 g ; P < 0.001 ) , with the most significant difference observed along the posterior right-sided PVs ( P-RPVs ) and anterior left-sided PVs ( A-LPVs ) . In logistic regression models , the mean CF was a negative predictor of PVRs along the P-RPVs and A-LPVs in the blind group ( odds ratios , 0.728 and 0.786 ; P < 0.001 and 0.007 ) , while no significant predictor was identified in the CF group or elsewhere in the blind group . In the Kaplan-Meier analysis , the arrhythmia-free survival rate at 12 months was 89.9 % in the CF group and 88.2 % in the blind group , respectively ( P = 0.624 ) . Conclusions CF-guided CPVI can reduce PVRs and the procedural time and be particularly beneficial along regions where a relatively low CF tends to be applied : the P-RPVs and A-LPVs . The comparable clinical outcomes may be due to the learning curve effect obtained by the CF-guided technique and repeated provocation of dormant PV conduction Aims A challenge of pulmonary vein isolation ( PVI ) in catheter ablation for paroxysmal atrial fibrillation ( PAF ) is electrical reconnection of the PV . EFFICAS I showed correlation between contact force ( CF ) parameters and PV durable isolation but no prospect i ve evaluation was made . EFFICAS II was a multicentre study to prospect ively assess the impact of CF guidance for an effective reduction of PVI gaps . Methods and results Pulmonary vein isolation using a radiofrequency ( RF ) ablation catheter with an integrated force sensor ( TactiCath ™ ) was performed in patients with PAF . Operators were provided EFFICAS I-based CF guidelines [ target 20 g , range 10–30 g , minimum 400 g s force-time integral ( FTI ) ] . Conduction gaps were assessed by remapping of PVs after 3 months , and gap rate was compared with EFFICAS I outcome . At follow up , 24 patients had 85 % of PVs remaining isolated , compared with 72 % in EFFICAS I ( P = 0.037 ) in which CF guidelines were not used . The remaining 15 % of gaps correlated to the number of catheter moves at creating the PVI line , quantified as Continuity Index . For PV lines with contiguous lesions and low catheter moves , durable isolation was 81 % in EFFICAS I and 98 % in EFFICAS II ( P = 0.005 ) . At index procedure , the number of lesions was reduced by 15 % in EFFICAS II vs. EFFICAS I. Conclusion The use of CF with the above guidelines and contiguous deployment of RF lesions in EFFICAS II study result ed in more durable PVI in catheter ablation of PAF AIMS The aim of this study was to evaluate the ' real-world ' impact of a novel contact force (CF)-sensing ( SmartTouch ™ , Biosense Webster , Diamond Bar , CA , USA ) catheter coupled with an advanced catheter location ( ACL ) system on fluoroscopy time and fluoroscopy dose during atrial fibrillation ( AF ) ablation . METHODS AND RESULTS This was a retrospective observational cohort study of prospect ively collected data of 1515 consecutive patients undergoing paroxysmal AF ( PAF ) and persistent AF ( PerAF ) ablation at a single institution between 2009 and 2014 . Patients undergoing AF ablation with the SmartTouch catheter and the ACL system ( SmartTouch group , n = 510 ) were compared with those undergoing AF ablation without this technology ( control group , n = 1005 ) . The primary outcomes were total fluoroscopy time ( min ) and fluoroscopy dose as measured by the dose-area product ( mGy cm(2 ) ) . Secondary endpoints included total procedure time , total ablation time , and major cardiac complications ( tamponade , pericardial effusion , and urgent cardiac surgery ) . The SmartTouch group had significantly lower fluoroscopy times ( 9.5 vs. 41 min , P < 0.001 ) , radiation doses ( 1044 vs. 3571 mGy cm(2 ) , P < 0.001 ) , and shorter procedural time ( 195 vs. 240 min , P < 0.001 ) when compared with the control group . This was statistically significant for both PAF and PerAF ablations and for both de novo and redo AF procedures . After a learning curve , a median fluoroscopy time of 3.5 min ( interquartile range 6 ) for all AF ablations was achieved . There was no difference in the rate of cardiac complications ( ∼ 1.5 % ) . CONCLUSION SmartTouch ™ CF-sensing catheter use with ACL ™ during AF ablation significantly reduces fluoroscopy times by 77 % , radiation dose by 71 % , and procedural time by 19 % but does not improve overall safety or the risk of cardiac complications BACKGROUND Electrode-tissue contact is crucial for adequate lesion formation in radiofrequency catheter ablation ( RFCA ) . OBJECTIVE We assessed the impact of direct catheter force measurement on acute procedural parameters during RFCA of atrial fibrillation ( AF ) . METHODS Fifty consecutive patients ( 28 male ) with paroxysmal AF who underwent their first procedure of circumferential pulmonary vein ( PV ) isolation ( PVI ) were assigned to either RFCA using ( 1 ) a st and ard 3.5-mm open-irrigated-tip catheter or ( 2 ) a catheter with contact force measurement capabilities . Using the endpoint of PVI with entry and exit block , acute procedural parameters were assessed . RESULTS Procedural data showed a remarkable decline in ablation time ( radiofrequency time needed for PVI ) from 50.5 ± 15.9 to 39.0 ± 11.0 minutes ( P = 0.007 ) with a reduction in overall procedure duration from 185 ± 46 to 154 ± 39 minutes ( P = 0.022 ) . In parallel , the total energy delivered could be significantly reduced from 70,926 ± 19,470 to 58,511 ± 14,655 Ws ( P = 0.019 ) . The number of acute PV reconnections declined from 36 % to 12 % ( P = 0.095 ) . CONCLUSIONS The use of contact force sensing technology is able to significantly reduce ablation and procedure times in PVI . In addition , energy delivery is substantially reduced by avoiding radiofrequency ablation in positions with insufficient surface contact . Procedural efficacy and safety of this new feature have to be evaluated in larger cohorts Purpose Use of online contact force ( CF ) measurement during circumferential pulmonary vein  ( PV )  isolation ( CPVI ) for atrial fibrillation ( AF ) has demonstrated improvements in procedural parameters and mid-term clinical outcome . However , it is unknown if experience gained with CF measuring catheters improves the efficacy of subsequent CPVI procedures performed without CF measurement . Methods This prospect i ve trial compared procedural results of CPVI performed without a CF measuring catheter to a control group performed with a CF measuring catheter , by an operator with prior experience with CF technology .. Results Thirty-six eligible paroxysmal ( n = 27 ) or persistent ( n = 9 ) AF patients were consecutively enrolled . Twelve patients underwent CPVI  with the non-CF catheter ( CF− group ) in a recall period and 24 with the CF catheter ( CF+ group ) . After the first circumferential lesion set , the number of PV pairs requiring additional touch-up lesions to achieve electrical isolation was significantly less in the CF+ group ( 2 of 48 ( 4.2 % ) vs. 7 of 24 ( 29.2 % ) in the CF+ and CF− groups , respectively , p = 0.005 ) . The procedure time was significantly lower in the CF+ group ( 117.9 ± 23.3 vs. 134.1 ± 25.3 min , p = 0.033 ) . Radiofrequency ( RF ) and fluoroscopy time did not differ between groups ( 31.5 ± 7.1 vs. 31.8 ± 
    Output:
    