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. Contact force sensing for ablation of persistent atrial fibrillation: A randomized, multicenter trial. Contact force and force-time integral in atrial radiofrequency ablation predict transmurality of lesions. Paroxysmal AF catheter ablation with a contact force sensing catheter: results of the prospective, multicenter SMART-AF trial. Pulmonary vein isolation using "contact force" ablation: the effect on dormant conduction and long-term freedom from recurrent atrial fibrillation--a prospective study.
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 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 AIMS During radiofrequency ( RF ) delivery , lesion volume is highly dependent on contact force ( CF ) . It has recently been shown that changes of bipolar electrogram ( EGM ) predict transmurality . We hypothesized that there is a correlation between CF and EGM criteria of transmural lesion ( TL ) during RF . METHODS AND RESULTS We prospect ively studied consecutive 512 RF applications from atrial fibrillation ablation procedures .  A force-sensing ablation catheter ( Tacticath ( ® ) , Endosense ) was used to continuously measure CF and force-time integral ( FTI ) during each RF application . Distal bipolar EGM was analysed before , during , and after each RF application . Depending on initial EGM morphology , transmurality of lesions was defined by : ( i ) disappearance of the positivity after RF when there was QR morphology , ( ii ) diminution > 75 % of the positivity when there was QRS morphology , or ( iii ) disappearance of the R ' positivity when there was RSR ' morphology . Electrogram criteria were vali date d by electrophysiologists blinded to force measurements . Force-time integral was higher in TL than in non-transmural lesions ( NTLs ) : 652 ± 248 vs. 212 ± 140 gs ( P < 0.001 ) . Mean CF per RF pulse was higher in TL than in NTL : 26.3 ± 12.5 vs. 11.3 ± 10.3 g ( P < 0.001 ) . The best cut-off to predict TL was an FTI ≥ 392 gs [ sensitivity 0.89 , specificity ( Sp ) 0.93 , positive predictive value ( PPV ) 0.98 , and negative predictive value 0.67 ] and a higher FTI ( > 700 gs ) warrants transmurality of RF atrial lesions ( 100 % Sp and PPV ) . CONCLUSION Contact force and FTI during RF are correlated with TL . During RF delivery , a target FTI > 392 gs can be used as an endpoint 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 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
In conclusion , this meta- analysis shows that the use of CF technology decreases AF recurrence at a median follow-up of 12 months and also led to decreased use of RF during ablation .
There was no difference in total procedure length and fluoroscopy exposure
The suboptimal outcomes of atrial fibrillation ( AF ) ablation have been attributed to lack of transmural lesions during pulmonary vein isolation .
The advent of contact force ( CF ) sensing technology enables real-time assessment of the applied force at the catheter-tissue interface and increases the chances of transmural lesions .
We sought to perform a meta- analysis of data from eligible studies to delineate the true impact of CF technology .