title: Randomised clinical trial of cryoballoon versus irrigated radio frequency catheter ablation for atrial fibrillation—the effect of double short versus standard exposure cryoablation duration during pulmonary vein isolation (CIRCA-DOSE): methods and rationale Contact force facilitates the achievement of an unexcitable ablation line during pulmonary vein isolation Reduction in radiation dose for atrial fibrillation ablation over time: A 12-year single-center experience of 2344 patients. Randomized trial comparing pulmonary vein isolation using the SmartTouch catheter with or without real-time contact force data. Comparison of lesion formation between contact force-guided and non-guided circumferential pulmonary vein isolation: a prospective, randomized study. Comparison of contact force-guided procedure with non-contact force-guided procedure during left atrial mapping and pulmonary vein isolation: impact of contact force on recurrence of atrial fibrillation Randomized comparison of contact force-guided versus conventional circumferential pulmonary vein isolation of atrial fibrillation: prevalence, characteristics, and predictors of electrical reconnections and clinical outcomes Clinical experience with contact-force and flexible-tip ablation catheter designs Use of a contact force-sensing ablation catheter with advanced catheter location significantly reduces fluoroscopy time and radiation dose in catheter ablation of atrial fibrillation. Prospective use of Ablation Index targets improves clinical outcomes following ablation for atrial fibrillation Clinical impact of an open-irrigated radiofrequency catheter with direct force measurement on atrial fibrillation ablation. Superior efficacy of pulmonary vein isolation with online contact force measurement persists after the learning period: a prospective case control study Optimizing radiofrequency ablation of paroxysmal and persistent atrial fibrillation by direct catheter force measurement-a case-matched comparison in 198 patients. Comparison of robotic and manual persistent AF ablation using catheter contact force sensing: an international multicenter registry study. Paroxysmal AF catheter ablation with a contact force sensing catheter: results of the prospective, multicenter SMART-AF trial. Randomized, Controlled Trial of the Safety and Effectiveness of a Contact Force–Sensing Irrigated Catheter for Ablation of Paroxysmal Atrial Fibrillation: Results of the TactiCath Contact Force Ablation Catheter Study for Atrial Fibrillation (TOCCASTAR) Study Real-time contact force sensing for pulmonary vein isolation in the setting of paroxysmal atrial fibrillation: procedural and 1-year results. Impact of computed tomography image and contact force technology on catheter ablation for atrial fibrillation. A prospective study on safety of catheter ablation procedures: contact force guided ablation could reduce the risk of cardiac perforation. Impact of Contact Force Monitoring in Acute Pulmonary Vein Isolation Using an Anatomic Approach. A Randomized Study. Is the knowledge of contact force beneficial in pulmonary vein antrum isolation? Contact force sensing for ablation of persistent atrial fibrillation: A randomized, multicenter trial. Comparison of the efficacy between impedance‐guided and contact force‐guided atrial fibrillation ablation using an automated annotation system
abstract: Introduction Pulmonary vein isolation ( PVI ) is an effective therapy for paroxysmal atrial fibrillation ( AF ) , but it has limitations . The two most significant recent advances have centred on the integration of real-time quantitative assessment of catheter contact force into focal radio frequency ( RF ) ablation catheters and the development of dedicated ablation tools capable of achieving PVI with a single ablation lesion ( A rct ic Front cryoballoon , Medtronic , Minneapolis , MN , USA ) . Although each of these holds promise for improving the clinical success of catheter ablation of AF , there has not been a rigorous comparison of these advanced ablation technologies . Moreover , the optimal duration of cryoablation ( freezing time ) has not been determined . Methods and analysis Patients undergoing an initial PVI procedure for paroxysmal AF will be recruited . Patients will be r and omised 1:1:1 between contact-force irrigated RF ablation , short duration cryoballoon ablation ( 2 min applications ) and st and ard duration cryoballoon ablation ( 4 min applications ) . The primary outcome is time to first documented AF recurrence on implantable loop recorder . With a sample size of 111 per group and a two-sided 0.025 significance level ( to account for the two main comparisons ) , the study will have 80 % power ( using a log-rank test ) to detect a difference of 20 % between contact force RF catheter ablation and either of the two cryoballoon ablation groups . Factoring in a 4 % loss to follow-up , 116 patients per group should be r and omised and followed for a year ( total study population of 348 ) . Ethics and dissemination The study was approved by the University of British Columbia Office of Research ( Services ) Ethics Clinical Research Ethics Board . Results of the study will be su bmi tted for publication in a peer- review ed journal . Trial registration number NCT01913522 ; Pre- Aims Contact force ( CF ) catheters provide catheter-tissue contact information to improve outcome of  pulmonary vein isolation ( PVI ) in paroxysmal atrial fibrillation ( PAF ) . We evaluated different target-CF values for achievement of the additional endpoint of an unexcitable ablation line . Methods A total of 106 patients undergoing PVI  were r and omized into three groups ( G ) ( G1 : target-CF 15 g , G2 : target-CF 10 g , G3 : CF concealed from operator ) . The PVI encircling line was divided into predefined sections . Excitable tissue along the PVI-line identified by high output pacing ( 10 V , 2 ms ) was targeted for further ablation . Results Mean average CF was 17.4 ± 4.7 g ( G1 ) vs. 12.3 ± 6.0 g ( G2 ) vs. 11.1 ± 6.5 g ( G 3 ) ( p < 0.001 ) . Primary unexcitable ablation lines were found in 38.6 , 19.4 and 5.7 % ( G1 , G2 , G3 respectively ; G1 vs. G2 p < 0.05 , G1 vs. G3 p < 0.001 , G2 vs. G3 ns ) . Additional radiofrequency (RF)-energy to achieve unexcitability was lowest in G1 ( 3.6 ± 3.1 kJ vs. 8.6 ± 7.2 kJ ( G2 ) and 10.4 ± 6.7 ( G3 ) , p ≤ 0.001 , G2 vs. G3 ns ) with accordingly lowest additional RF applications in G1 ( 3.0 ± 2.6 vs. 7.0 ± 5.4 in G2 and 8.4 ± 4.0 in G3 ; G1 vs. G2 and G3 , p < 0.001 , G 2 vs. G 3 ns ) . Sections along ablation lines with low initial CF were most likely to reveal excitability . Single procedure success was 81.9 vs. 73.5 vs. 71.4 % ( G 1 , 2 and 3 , p = 0.6 ) during 437 ± 254 day follow-up . Conclusion Higher tip-to-tissue CF during PVI facilitates the achievement of an unexcitable ablation line , requiring less additional RF-energy BACKGROUND Pulmonary vein isolation ( PVI ) is a well-established treatment of atrial fibrillation ( AF ) , with contact force (CF)-sensing catheters joining 3-dimensional mapping systems and image integration as technological advancements over the last decade . OBJECTIVE The purpose of this study was to analyze trends in radiation exposure for AF ablation over the last 12 years at our center . METHODS We review ed prospect ively collected data of 2344 consecutive PVI procedures for either paroxysmal or persistent AF between January 2004 and December 2015 . During this period , all cases used 3-dimensional mapping systems , with 8 software and 2 hardware up grade s. Primary endpoints were fluoroscopy time , absorbed dose ( Air Kerma in mGy ) , and effective dose ( mSv ) . RESULTS In total , 1914 patients underwent initial PVI , and 430 patients underwent redo PVI using radiofrequency energy . Fluoroscopy time , and absorbed and effective doses significantly and progressively decreased over the 12-year period for initial PVI as follows : 2004 - 2006 : 61 ± 27 minutes ; 2007 - 2009 : 46 ± 14 minutes , 1365 ± 1369 mGy , 11.3 ± 12.5 mSv ; 2010 - 2012 : 31 ± 11 , 464 ± 339 mGy , 9.0 ± 10.4 mSv ; and 2013 - 2015 : 17 ± 9 minutes , 304 ± 758 mGy , 5.5 ± 6.7 mSv . CF-sensing catheters were used for 357/508 PVI only cases between 2014 and 2015 . Fluoroscopy times ( 11 ± 5 vs 21 ± 8 minutes ; P < .001 ) and absorbed dose ( 200 ± 524 vs 470 ± 1326 mGy ; P = .004 ) were significantly shorter with this catheter . CONCLUSION Radiation exposure has dramatically decreased over the last decade for PVI and is related to operator experience , annual case volume , technology evolution , and more recently CF-sensing catheters . This has significant implication s for both patient and operator long-term risk BACKGROUND Contact force ( CF ) information may improve the safety and efficacy of ablation for paroxysmal atrial fibrillation ( PAF ) . OBJECTIVE The purpose of this study was to assess the impact of CF data on ablation for PAF . METHODS Patients undergoing first-time PAF ablation were r and omized at 7 UK centers to ablation with ( CF-on ) or without ( CF-off ) CF data available to the operator , using the same ablation catheter and mapping system . An ablation CF of 5 - 40 g was targeted . Pulmonary vein ( PV ) reconnection was assessed with adenosine at 60 minutes . Follow-up for arrhythmia recurrence was for 1 year with 7-day Holter recordings at 6 and 12 months . RESULTS One hundred seventeen patients were studied ( 59 CF-on , 58 CF-off ) . In the CF-on group , a reduction in acute PV reconnection rates ( 22 % vs 32 % , P = .03 ) but no significant difference in 1-year success rates off antiarrhythmic drugs ( 49 % vs 52 % , P = .9 ) was observed . There was no difference in major complication rates : 2 of 59 ( 3 % ) CF-on , 3 of 58 ( 5 % ) CF-off ( P = .7 ) . Procedural and fluoroscopy times were not significantly different ( P>.5 ) . Overall mean CFs per ablation were not different between groups ( 13.4 [9.1 - 19.6]g CF-on , 13.4 [7.4 - 22.4]g CF-off , P = .5 ) , but a greater proportion of readings in the CF-on group were in the target range ( 80 % vs 68 % , P<.001 ) . CONCLUSION This r and omized multicenter study demonstrated that CF data availability was associated with reduced acute PV reconnection but not improved 1-year success rates , procedural and fluoroscopy times , or complication rates . There was a reduction in extremes of CF , above and below the study target range , suggesting greater CF control during ablation 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 Purpose Lesion formation is a critical determinant of technical and clinical success of  pulmonary vein isolation .  Different catheter design s aim to enhance tissue contact during ablation to enable optimized lesion formation . We analyzed procedural characteristics and predictors of clinical success in patients ablated with three different contemporary ablation catheters .  Methods Two hundred sixty-eight sequentially included patients receiving pulmonary vein isolation ( PVI ) with conventional ( n = 122 ) , contact-force ( n = 96 ) and flexible-tip ( n = 60 ) catheters  were followed for a median of 14.1 months with 7d-Holter-monitoring and TTE at 3 , 6 , 12 , and 24 months . Baseline characteristics and follow-up times were homogeneous across all groups . Results Multivariable Cox proportional hazard regression for arrhythmia recurrence demonstrated a favorable hazard ratio for contact-force and flexible-tip catheters vs. conventional open irrigation catheters .  Procedure time and fluoroscopy time were shorter for contact-force and flexible-tip catheters versus conventional catheters , but equal between . Linear lesions were applied in 58 % of contact-force and 66 % of flexible-tip cases , and CFAEs were targeted in 26 % of either . Conclusions Our non-r and omized prospect ively collected data do not show a difference in observed procedure characteristics and in clinical outcome for flexible-tip versus contact-force catheter design s , while both display improved performance against conventional open irrigated-tip catheters . Linear lesions and CFAEs ablation were not associated with improved arrhythmia-free survival 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 Aims : Late recovery of ablated tissue leading to reconnection of pulmonary veins remains common following radiofrequency catheter ablation for AF . Ablation Index ( AI ) , a novel ablation quality marker , incorporates contact force ( CF ) , time , and power in a weighted formula . We hypothesized that prospect i ve use of our previously published derived AI targets would result in better outcomes when compared to CF‐guided ablation . Methods : Eighty‐nine consecutive drug‐refractory AF patients ( 49 % paroxysmal ) underwent AI‐guided ablation ( AI‐group ) . AI targets were 550 for anterior/roof and 400 for posterior/inferior left atrial segments . Procedural and clinical outcomes of these patients were compared to 89 propensity‐matched controls who underwent CF‐guided ablation ( CF‐group ) . All 178 procedures were otherwise similar , and both groups were followed‐up for 12 months . The last 25 patients from each group underwent analysis of all VisiTags ™ for ablation duration , CF , Force‐Time Integral , and impedance drop . Results : First‐pass pulmonary vein isolation ( PVI ) was more frequent in AI‐group than in CF‐group ( 173 [ 97 % ] vs. 149 [ 84 % ] circles , P < 0.001 ) , and acute PV reconnection was lower ( 11 [ 6 % ] vs. 24 [ 13 % ] circles , P = 0.02 ) . Mean PVI ablation time was similar ( AI‐group : 42 ± 9 vs. CF‐group : 45 ± 14 minutes , P = 0.14 ) . Median impedance drop for AI‐group was significantly higher than in CF‐group ( 13.7 [ 9‐19 ] Ω vs. 8.8 [ 5.2‐13 ] Ω , P < 0.001 ) . Two major complications occurred in CF‐group and none in AI‐group . Atrial tachyarrhythmia recurrence was significantly lower in AI‐group ( 15 of 89 [ 17 % ] ) than in CF‐group ( 33 of 89 [ 37 % ] , P = 0.002 ) . Conclusion : AI‐guided ablation is associated with significant improvements in the incidence of acute PV reconnection and atrial tachyarrhythmia recurrence rate compared to CF‐guided ablation , potentially due to creation of better quality lesions as suggested by greater impedance drop 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 ± 7.0 min and 11.8 ± 5.6 vs. 11.0 ± 5.8 min in the CF+ and the CF− group , respectively ) Conclusions With the use of online CF measurement , PV isolation is more frequently complete following the first circumferential lesion set . A previous learning period with direct CF feedback is not a substitute for real-time direct CF measurement to maintain this advantage BACKGROUND Sufficient 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 and outcome of RFCA for paroxysmal and persistent atrial fibrillation ( AF ) . METHODS Ninety-nine consecutive patients ( 70 % men ) with paroxysmal ( 63.6 % ) or persistent AF underwent left atrial RFCA using a 3.5-mm open-irrigated-tip ( OIT ) catheter with contact force measurement capabilities ( group 1 ) . For comparison a case-matched cohort with st and ard OIT catheters was used ( 99 patients ; group 2 ) . Case matching included gender , type of AF , number or RFCA procedures , and type of procedure . RESULTS Procedural data showed a significant decline in radiofrequency ablation time from 52 ± 20 to 44 ± 16 minutes ( P = 0.003 ) with a remarkable mean reduction in overall procedure time of 34 minutes ( P = 0.0001 ; 225.8 ± 53.1 vs 191.9 ± 53.3 minutes ) . In parallel , the total fluoroscopy time could be significantly reduced from 28.5 ± 11.0 to 19.9 ± 9.3 minutes ( P = 0.0001 ) as well as fluoroscopy dose from 74.1 ± 58.0 to 56.7 ± 38.9 Gy/cm(2 ) ( P = 0.016 ) . Periprocedural complications were similar in both groups . CONCLUSIONS The use of contact force sensing technology is able to significantly reduce ablation , procedure , and fluoroscopy times as well as dose in RFCA of AF in a mixed case-matched group of paroxysmal and persistent AF . Energy delivery is substantially reduced by avoiding radiofrequency ablation in positions with insufficient surface contact . Additionally 12-month outcome data showed increased efficacy . Such time saving and equally safe technology may have a relevant impact on laboratory management and increased cost effectiveness BACKGROUND Catheter-based contact force sensing ( CFS ) technology gives detailed information regarding contact between the catheter tip and myocardium . This may result in more effective ablation procedures . The primary objective of this study was comparison of remote robotic navigation ( RRN ) and Manual CFS ablation . The secondary objective was to compare CFS with non-CFS ablation for both navigation modes . METHODS Prospect i ve registries of consecutive cases undergoing their first ablation for persistent atrial fibrillation ( AF ) from six hospitals in the United Kingdom and South Africa were analyzed : 50 Manual/CFS and 50 RRN/CFS cases were included . Historical control non-CFS ablation patients were matched by propensity score , giving a total 200 patient cohort . RESULTS RRN/CFS was associated with improved single procedure 1-year success rates ( 64 % vs 36 % , P = 0.01 ) and shorter fluoroscopy times ( 41 % reduction , P < 0.0005 ) than Manual/CFS ablation , without any difference in procedure times ( P = 0.8 ) . The mean contact force was higher in RRN/CFS than Manual/CFS cases ( 16 [ 15 - 18 g ] vs 13 [ 12 - 15 g ] , respectively , P = 0.003 ) . Compared with non-CFS historical controls , CFS cases had higher 1-year success rates for RRN ( 64 % vs 36 % , P = 0.01 ) , but not Manual ablation ( 36 % vs 38 % , P = 1 ) . Procedure times were reduced for CFS cases ( 20 % , P < 0.005 both navigation modes ) , as were fluoroscopy times ( Manual : 43 % , RRN 83 % , P < 0.005 for both ) . There were no differences in rates of major or minor complications for either comparison ( P > 0.5 ) . CONCLUSIONS A combination of RRN and CFS is associated with improved success rates at 1 year and fluoroscopy times for persistent AF ablation , compared with Manual ablation and non-CFS RRN ablation BACKGROUND Catheter ablation is important for treatment of paroxysmal atrial fibrillation ( PAF ) . Limited animal and human studies suggest a correlation between electrode-tissue contact and radiofrequency lesion generation . OBJECTIVES The study sought to assess the safety and effectiveness of an irrigated , contact force (CF)-sensing catheter in the treatment of drug refractory symptomatic PAF . METHODS A prospect i ve , multicenter , nonr and omized study was conducted . Enrollment criteria included : ≥3 symptomatic episodes of PAF within 6 months of enrollment and failure of ≥1 antiarrhythmic drug ( Class I to IV ) . Ablation included pulmonary vein isolation with confirmed entrance block as procedural endpoint . RESULTS A total of 172 patients were enrolled at 21 sites , where 161 patients had a study catheter inserted and 160 patients underwent radiofrequency application . Procedural-related serious adverse events occurring within 7 days of the procedure included tamponade ( n = 4 ) , pericarditis ( n = 3 ) , heart block ( n = 1 , prior to radiofrequency application ) , and vascular access complications ( n = 4 ) . By Kaplan-Meier analyses , 12-month freedom from atrial fibrillation/atrial flutter/atrial tachycardia recurrence was 72.5 % . The average CF per procedure was 17.9 ± 9.4 g. When the CF employed was between investigator selected working ranges ≥80 % of the time during therapy , outcomes were 4.25 times more likely to be successful ( p = 0.0054 ; 95 % confidence interval : 1.53 to 11.79 ) . CONCLUSIONS The SMART-AF trial demonstrated that this irrigated CF-sensing catheter is safe and effective for the treatment of drug refractory symptomatic PAF , with no unanticipated device-related adverse events . The increased percent of time within investigator-targeted CF ranges correlates with increased freedom from arrhythmia recurrence . Stable CF during radiofrequency application increases the likelihood of 12-month success . ( THERMOCOOL ® SMARTTOUCH ® Catheter for Treatment of Symptomatic Paroxysmal Atrial Fibrillation ; NCT01385202 ) Background — Contact force ( CF ) is a major determinant of lesion size and transmurality and has the potential to improve efficacy of atrial fibrillation ablation . This study sought to evaluate the safety and effectiveness of a novel irrigated radiofrequency ablation catheter that measures real-time CF in the treatment of patients with paroxysmal atrial fibrillation . Methods and Results — A total of 300 patients with symptomatic , drug-refractory , paroxysmal atrial fibrillation were enrolled in a prospect i ve , multicenter , r and omized , controlled trial and r and omized to radiofrequency ablation with either a novel CF-sensing catheter or a non-CF catheter ( control ) . The primary effectiveness end point consisted of acute electrical isolation of all pulmonary veins and freedom from recurrent symptomatic atrial arrhythmia off all antiarrhythmic drugs at 12 months . The primary safety end point included device-related serious adverse events . End points were powered to show noninferiority . All pulmonary veins were isolated in both groups . Effectiveness was achieved in 67.8 % and 69.4 % of subjects in the CF and control arms , respectively ( absolute difference , −1.6 % ; lower limit of 1-sided 95 % confidence interval , −10.7 % ; P=0.0073 for noninferiority ) . When the CF arm was stratified into optimal CF ( ≥90 % ablations with ≥10 g ) and nonoptimal CF groups , effectiveness was achieved in 75.9 % versus 58.1 % , respectively ( P=0.018 ) . The primary safety end point occurred in 1.97 % and 1.40 % of CF patients and control subjects , respectively ( absolute difference , 0.57 % ; upper limit of 1-sided 95 % confidence interval , 3.61 % ; P=0.0004 for noninferiority ) . Conclusions — The CF ablation catheter met the primary safety and effectiveness end points . Additionally , optimal CF was associated with improved effectiveness . Clinical Trial Registration — http://www . clinical trials.gov . Unique identifier : NCT01278953 INTRODUCTION The additional benefit of contact force ( CF ) technology during pulmonary vein isolation ( PVI ) for paroxysmal atrial fibrillation ( AF ) to improve mid-term clinical outcome is unclear . METHODS AND RESULTS Eligible patients with symptomatic paroxysmal AF were enrolled in this prospect i ve trial , comparing circular antral catheter ablation ( guided by Carto 3 System , Biosense Webster ) using either a new open-irrigated CF catheter ( SmartTouch Thermocool , Biosense Webster ) ( CF group ) or a non-CF open-irrigated catheter ( EZ Steer Thermocool , Biosense Webster ) ( control group ) . Overall , 30 patients were enrolled in each group , with a st and ardized 12-month follow-up , free of antiarrhythmic therapy . Demographic , cardiovascular and anatomic characteristics were similar in both groups . Though complete PVI was eventually achieved in all cases in both groups , success using an exclusive anatomic approach was 80.0 % in CF group versus 36.7 % in control group ( P < 0.0001 ) . CF use was associated with significant reductions in fluoroscopy exposure ( P < 0.01 ) and radiofrequency time ( P = 0.01 ) . The incidence rates of AF recurrence were 10.5 % ( 95 % CI , 1.38 - 22.4 ) in the CF group , and 35.9 % ( 95 % CI , 12.4 - 59.4 ) in the control group ( log rank test , P = 0.04 ) . After adjustment on potential confounders , the use of CF catheter was found to be associated with a lower AF recurrence ( OR 0.18 , 95 % CI 0.04 - 0.94 , P = 0.04 ) . CONCLUSION Our findings suggest a potential benefit of real-time CF sensing technology , in reducing AF recurrence during the first year after PVI AIM To investigate the impact of using computed tomography ( CT ) and contact force ( CF ) technology on recurrence of atrial tachyarrhythmia after atrial fibrillation ( AF ) ablation . METHODS This non-r and omized study included 2 groups of patients . All patients had symptomatic recurrent paroxysmal or persistent AF and were treated with at least 1 anti arrhythmic medication or intolerant to medication . The first group included 33 patients who underwent circumferential pulmonary veins isolation ( PVI ) for AF during 2012 and 2013 guided by CT image integration ( Cartomerge , Biosense Webster , Diamond Bar , CA , United States ) of left atrium and pulmonary veins into an electroanatomic mapping ( EAM ) system ( CT group ) using st and ard irrigated radiofrequency catheter ( ThermoCool , Carto , Biosense Webster , Diamond Bar , CA , United States ) or irrigated catheter with integrated CF sensor ( Smart Touch , Carto , Biosense Webster , Diamond Bar , CA , United States ) . The second group included immediately preceding 32 patients who had  circumferential PVI by st and ard irrigated catheter ( ThermoCool ) using only EAM ( Carto ) system ( EAM group ) . Linear lesions were performed according to the discretion of operator . RESULTS Sex , age , and persistent AF were not different between groups . PVI was achieved in all patients in both groups . Linear ablations including cavo-tricuspid isthmus and or roof line ablation were not different between groups . Free of atrial tachyarrhythmia during follow-up of 24 mo was significantly higher among CT group compared to EAM group ( 81 % vs 55 % ; respectively ; P = 0.027 ) . When 11 patients from CT group who had ablation using Smart Touch catheter were excluded , the difference between CT group and EAM became non significant ( 73 % vs 55 % ; respectively ; P = 0.16 ) . Sub analysis of CT group showed that patients who had ablation using Smart Touch catheter tend to be more free of atrial tachyarrhythmia compared to patients who had ablation using st and ard irrigated catheter during follow-up ( 100 % vs 73 % ; respectively ; P = 0.07 ) . Major complications ( pericardial effusion , cerebrovascular accident/transient ischemic attack , vascular access injury requiring intervention ) did not occurred in both groups . CONCLUSION These preliminary results suggest that CT image integration and CF technology may reduce the recurrence of atrial tachyarrhythmia after catheter ablation for AF BACKGROUND Contact force ( CF ) sensing catheters provide advantages with regard to safety and efficacy . This study aim ed to evaluate if CF catheters reduce cardiac perforations and other major complications and offer equal safety compared to the magnetic navigation system ( MNS ) . METHODS Data from 1.517 ablation procedures from our prospect i ve registry was analyzed . Ablations were performed using either CF guided catheters ( CF group , n=248 ) , non-CF catheters ( NCF group , n=813 ) , or MNS ( n=456 ) . Four subgroups were analyzed : atrial fibrillation ( AF , n=557 ) , supraventricular tachycardia ( SVT , n=715 ) , ventricular tachycardia ( VT , n=190 ) and patients with congenital heart defects ( CHD , n=55 ) . The primary endpoint of this study was incidence of cardiac perforation . Secondary endpoints were major and minor complications within 30 days of the procedure . RESULTS Complications occurred in 11.3 % ( n=172 ) of the procedures . In 2.8 % ( n=43 ) a major complication occurred , 0.9 % ( n=13 ) had a perforation , 8.5 % ( n=129 ) had a minor complication and 2 patients died ( 0.1 % ) . No cardiac perforation occurred in the CF group , which was significantly different from NCF procedures ( 0.0 % vs. 1.6 % ; relative risk 0.76 , 95 % CI 0.74 - 0.79 , P=0.031 ) and equal to MNS ( 0.0 % ) . This was also observed in the AF subgroup ( 0.0 % vs. 3.3 % ; RR 0.67 , 95 % CI 0.63 - 0.72 , P=0.021 ) , and the occurrence of major complications was lower for CF versus NCF procedures ( 2.1 % vs. 7.8 % , P=0.010 ) . CONCLUSIONS CF-guided catheter ablation is superior to NCF with regard to procedural safety and avoidance of cardiac perforation . This difference is due to a reduction of cardiac perforation and major complications in the AF subgroup BACKGROUND The impact of contact force ( CF ) monitoring in pulmonary vein ( PV ) isolation after a circumferential anatomic ablation ( CAA ) is unknown . We analyze the usefulness of CF monitoring in acute PV isolation and procedure parameters using a CAA . METHODS Fifty patients with paroxysmal atrial fibrillation were r and omized into CF-on ( CF > 10 grams ; n = 25 ) or CF-off ( CF blinded ; n = 25 ) groups . We performed a first round of CAA with a ThermoCool ( ® ) SmartTouch ( ® ) catheter blinded to the LASSO ( ® ) catheter ( Biosense Webster , Diamond Bar , CA , USA ) , with radiofrequency ( RF ) lesions tagged with the VisiTag ( ™ ) Module . After the CAA , each PV was review ed with the LASSO ( ® ) catheter recording the segments with gaps . RESULTS All the PVs were isolated with a CAA in 20 patients of the CF-on versus eight of the CF-off ( P = 0.001 ) . Of the 45 segments with gaps in the left PVs , 38 were from the CF-off ( P = 0.0001 ) . Of the eight segments with gaps in the right PVs , seven were from the CF-off ( P = 0.06 ) . The CF in the left PVs was higher in the CF-on ( 16.3 ± 3.2 grams vs 10.5 ± 4.3 grams ; P = 0.0001 ) and similar in the right PVs ( 17.6 ± 3.6 grams vs 15.2 ± 5.3 grams ; P = 0.08 ) . All of the gaps were closed with additional RF LASSO ( ® ) -guided touch-up . Procedure and fluoroscopy times were shorter in the CF-on ( 139 ± 24 minutes vs 157 ± 32 minutes and 20 ± 6 minutes vs 24 ± 7 minutes ; both P = 0.039 ) . At 12 months the patients free of AF recurrence was 84 % CF-on versus 75 % CF-off ( log-rank P = 0.4 ) [ corrected ] . CONCLUSIONS In paroxysmal atrial fibrillation , a CAA guided by CF reduces PV gaps and shortens the procedure parameters at the expense of the left PVs Abstract Objective : To investigate the effect of the operator knowing the real-time contact force ( CF ) on the efficacy of pulmonary vein antrum isolation ( PVAI ) . Methods : Fifty patients with paroxysmal atrial fibrillation ( AF ) or short lasting persistent AF were r and omized to CF guided PVAI ( n = 25 ) or conventional PVAI ( n = 25 ) . In the CF guided group , CF between 10 and 40 g was aim ed at . Efficacy of PVAI was measured as reduction in AF burden ( AFB ) and time to AF recurrence detected by implantable cardiac monitor ( ICM ) , inserted three months before PVAI . Blanking period was three months and follow-up 12 months . Results : All pulmonary veins were isolated in the CF guided group and all but one in the conventional group . Mean CF was 25 g in the CF guided group and 24 g in the conventional group ( p = 0.75 ) . Compared to pre-ablation , median [ IQR ] relative reduction in AFB 3–12 months after ablation was 100 [99–100]% in the CF guided group ( p < 0.001 ) and 99.4 [25–100]% in the conventional group ( p < 0.001 ) , not different between groups ( p = 0.09 ) . Nine patients ( 36 % ) had AF recurrence in the CF guided group and 13 ( 52 % ) in the conventional group ( p = 0.21 , log-rank test ) . CF differed between operators . When adjusted for operator by regression analysis , patients without recurrent AF had lower proportion of ablation time with CF < 10 g than recurrent patients ( p = 0.034 ) . No complications occurred . Conclusions : Operator knowledge of real-time CF had no significant effect on AFB reduction or time to AF recurrence . Larger trials should be done to study benefit of real-time CF BACKGROUND Impact of contact force sensing ( CFS ) on ablation of persistent atrial fibrillation ( PeAF ) is unknown . OBJECTIVE The purpose of the TOUCH AF ( Therapeutic Outcomes Using Contact force H and ling during Ablation of Persistent Atrial Fibrillation ) r and omized trial was to compare CFS-guided ablation to a CFS-blinded strategy . METHODS Patients ( n = 128 ) undergoing first-time ablation for persistent AF were r and omized to a CFS-guided vs CFS-blinded strategy . In the CFS-guided procedure , operators visualized real-time force data . In the blinded procedure , force data were hidden . Wide antral pulmonary vein isolation plus a roof line were performed . Patients were followed at 3 , 6 , 9 , and 12 months with clinical visit , ECG , and 48-hour Holter monitoring . The primary endpoint was cumulative radiofrequency ( RF ) time for all procedures . Atrial arrhythmia > 30 seconds after 3 months was a recurrence . RESULTS PeAF was continuous for 26 weeks ( interquartile range [ IQR ] 13 - 52 ) , and left atrial size was 45 ± 5 mm . Force in the CFS-blinded and CFS-guided arms was 12 g [ IQR 6 - 20 ] and 14 g [ IQR 9 - 20 ] ( P = .10 ) , respectively . Total RF time did not differ between CFS-guided and CFS-blinded groups ( 49 ± 14 min vs 50 ± 20 min , respectively ; P = .70 ) . Single procedure freedom from atrial arrhythmia was 60 % in the CFS-guided arm and 63 % in the CFS-blinded arm off drugs . Lesions with gaps were associated with significantly less force ( 11.4 g [ IQR 6 - 19 ] vs 13.2 g [ IQR 8 - 20 ] , respectively ; P = .0007 ) and less force-time integral ( 174 gs [ IQR 91 - 330 ] vs 210 gs [ IQR 113 - 388 ] , respectively ; P < .001 ) . CONCLUSION CFS-guided ablation result ed in no difference to RF time or 12-month outcome . Lower force/force-time integral was associated with significantly more gaps Abstract Background This study compared the efficacy of catheter ablation of atrial fibrillation ( AF )  between impedance (IMP)‐guided and contact force (CF)‐guided annotation using the automated annotation system ( VisiTag ™ ) . Methods Fifty patients undergoing pulmonary vein isolation ( PVI ) for AF were r and omized to the IMP‐guided or CF‐guided groups . The annotation criteria for VisiTag ™ were a 10 second minimum ablation time and 2 mm maximum catheter movement range . A minimum CF of 10 g was added to the criteria in the CF‐guided group . In the IMP‐guided group , a minimum IMP drop of over 5 Ω was added to the criteria . Results The rates of successful PVI after an initial ablation line were higher in the CF‐guided group ( 80 % vs 48 % , P = .018 ) . Although average CF was similar between two groups , the average force‐time integral ( FTI ) was significantly higher in the CF‐guided group ( 298.3 ± 65 . 2 g·s vs 255.1 ± 38.3 g·s , P = .007 ) . The atrial arrhythmia‐free survival at 1 year demonstrated no difference between the two groups ( 84.0 % in the IMP‐guided group vs 80.0 % in the CF‐guided group , P = .737 ) . If the use of any antiarrhythmic drug beyond the blanking period was considered as a failure , the clinical success rate at 1 year was 52.0 % for the CF‐guided group vs 56.0 % for the IMP‐guided group ( P = .813 ) . Conclusions Atrial fibrillation ablation using an automated annotation system guided by CF improved the success rate of PVI after the initial circumferential ablation . An IMP‐guided annotation combined with catheter stability criteria showed similar clinical outcomes as compared to the CF‐guided annotation
target: Conclusion Meta- analysis of r and omized data demonstrated that CF guidance does not improve the safety or efficacy of AF ablation , despite initial observational data showing dramatic improvement .
background: Aims Despite widespread adoption of contact force ( CF ) sensing technology in atrial fibrillation ( AF ) ablation , r and omized data suggests lack of improvement in clinical outcomes .
  We aim ed to assess the safety and efficacy of CF-guided vs. non CF-guided AF ablation .