Real-time contact force sensing for pulmonary vein isolation in the setting of paroxysmal atrial fibrillation: procedural and 1-year results. Superior efficacy of pulmonary vein isolation with online contact force measurement persists after the learning period: a prospective case control study Pulmonary vein isolation using "contact force" ablation: the effect on dormant conduction and long-term freedom from recurrent atrial fibrillation--a prospective study. Is the knowledge of contact force beneficial in pulmonary vein antrum isolation? Impact of Contact Force Monitoring in Acute Pulmonary Vein Isolation Using an Anatomic Approach. A Randomized Study. Improving procedural and one-year outcome after contact force-guided pulmonary vein isolation: the role of interlesion distance, ablation index, and contact force variability in the 'CLOSE'-protocol. EFFICAS II: optimization of catheter contact force improves outcome of pulmonary vein isolation for paroxysmal atrial fibrillation 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 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 impact of an open-irrigated radiofrequency catheter with direct force measurement on atrial fibrillation ablation. Randomized trial comparing pulmonary vein isolation using the SmartTouch catheter with or without real-time contact force data. Paroxysmal AF catheter ablation with a contact force sensing catheter: results of the prospective, multicenter SMART-AF trial. Contact force facilitates the achievement of an unexcitable ablation line during pulmonary vein 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
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 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 Atrial fibrillation ( AF ) recurrence after pulmonary vein isolation ( PVI ) is associated with PV to left atrium reconduction . Effective lesion creation necessitates adequate contact force between the ablation catheter and myocardium . OBJECTIVE The purpose of this study was to study the utility of contact force-guided ablation on immediate and long-term outcomes . METHODS Seventy-five patients with highly symptomatic paroxysmal AF underwent wide circumferential PVI using an irrigated-tip radiofrequency catheter . In 25 patients , ablation was guided by real-time contact force measurements ( CF group ; SmartTouch , Biosense Webster ) . A control group of 50 patients underwent  PVI using a st and ard nonforce sensing catheter ( st and ard group ; ThermoCool , Biosense Webster ) . After PVI , all patients underwent adenosine testing to unmask dormant conduction . Patients were followed up at 3 , 6 , and 12 months and by transtelephonic monitoring as well . RESULTS Dormant conduction was unmasked and subsequently eliminated in 4 PV pairs ( 8 % ; 16 % of patients ) in the CF group and 35 PV pairs ( 35 % ; 52 % of patients ) in the st and ard group ( P = .0004 per PV pair ; P = .0029 per patient ) . The single-procedure , off-antiarrhythmic drug freedom from recurrent atrial arrhythmias at 1 year was 88 % in the CF group vs 66 % in the st and ard group ( P = .047 ) . Procedure duration and fluoroscopy time were significantly longer in the CF group ( P = .0038 and P = .0001 , respectively ) . CONCLUSION The use of real-time contact force guidance results in a significant reduction in the prevalence of dormant conduction with improved long-term freedom from recurrent arrhythmias . The utility of a contact force-guided approach requires evaluation in a long-term prospect i ve r and omized study 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 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 Aims We have recently shown that a contact force (CF)-guided ablation protocol respecting region-specific criteria of lesion contiguity and lesion depth ( ' CLOSE ' protocol ) is associated with high incidence of acute durable pulmonary vein ( PV ) isolation ( PVI ) and a high single-procedure arrhythmia-free survival at 1 year . In the present study , we compared efficiency , safety , and efficacy of ' CLOSE'-guided PVI to conventional CF-guided PVI ( CONV-CF ) . Methods and results Fifty consecutive paroxysmal atrial fibrillation ( AF ) patients underwent PV encircling using a CF-sensing catheter  targeting an interlesion distance ( ILD ) ≤6 mm and ablation index ( AI ) ≥400 and ≥550 at posterior and anterior wall ( ' CLOSE ' group ) . Results were compared to the last 50 patients undergoing ' CONV-CF ' . All patients underwent adenosine testing after PVI .  Arrhythmia recurrence was defined as any atrial tachyarrhythmia ( ATA ) > 30 s on Holter at 3 , 6 , and 12 months . Clinical characteristics did not differ . Contact force variability was comparable in between both groups ( proportion of applications with intermittent contact 2 % in ' CLOSE ' vs. 1 % in CONV-CF , P = 0.67 ) . In the ' CLOSE ' group , procedure time and radiofrequency ( RF ) time per circle were shorter ( respectively 149 ± 33 min vs. 192 ± 42 min , P < 0.0001 and 18 ± 4 min vs 28 ± 7.5 min , P < 0.0001 ) and incidence of adenosine-proof isolation was higher ( 97 % vs. 82 % , P < 0.001 ) . No complications were observed in the ' CLOSE ' group , one tamponade in the ' CONV-CF ' group . At 12 months , single-procedure freedom from ATA was 94 % in ' CLOSE ' vs. 80 % in ' CONV-CF ' group ( P < 0.05 ) . In both groups , the majority of reconnections at repeat were associated with either ILD > 6 mm and /or AI < 400/550 ( 100 % vs. 83 % , P = 0.99 ) . Conclusion ' CLOSE'-guided PVI improves procedural and 1 year outcome in CF-guided PVI while shortening procedure time . Improvement can not be explained by differences in CF variability and is most likely due to the strict application of criteria for contiguity and ablation index . A r and omized controlled trial is needed to exclude the possible contribution of a learning curve 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 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 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 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 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 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 ) 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 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
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
Contact force ( CF ) monitoring can be useful in accomplishing circumferential pulmonary vein ( PV ) isolation for atrial fibrillation ( AF ) .
This meta- analysis aim ed to assess the efficacy and safety of a CF-sensing catheter in treating AF .