Contact Force Catheter Research Articles

Early recurrence of atrial fibrillation after pulmonary vein isolation: a comparative analysis between cryogenic and contact force radiofrequency ablation.

Early recurrence (ER) of atrial fibrillation (AF) within 90 days post-ablation is observed in up to 50% of patients and has been attributed to transient inflammation. The importance of ER in current era of pulmonary vein isolation (PVI) with cryoballoon ablation (CBA) and contact-force catheter radiofrequency ablation (cfRFA) has not been clearly reported. In addition, it is not known whether there are differences between types of ablation energy used during PVI. Study population was drawn from a prospective multicenter database of AF ablation. Consecutive patients undergoing first-time ablation with PVI alone, using either second-generation CBA or cfRFA catheters were included. Patients were followed at 0.5, 3, 6, and 12 months to assess recurrence. Predictors of late recurrence (LR), defined as recurrence outside the blanking period, were assessed by Cox proportional hazards regression models. Freedom from LR was calculated and compared between two groups using the Kaplan-Meier method and log-rank test. Study cohort included 300 patients (1:1 CBA:RFA, age 63.6 ± 10.3 years, 67% male). There were no baseline characteristic differences between the CBA and cfRFA groups. ER occurred in 23.3% and 16.7% of patients in the CBA and cfRFA groups, respectively (p = 0.149). One-year freedom from LR was similar for both groups (72.7% CBA vs. 78% cfRFA, p = 0.287). Fifty-two patients (25 CBA and 27 cfRFA) underwent repeat ablation and no difference in durability of PVI was found. ER was the only common independent predictor of LR for either group and for the entire cohort (HR 2.3). In our series of AF ablation using second-generation cryoballoon and contact-force RFA catheters, recurrence in the "blanking period" is seen in 20% and remains predictive of late recurrence irrespective of the energy used.

P1863Establishing safe working parameters for radio frequency catheterization along with acoustic sensing

Abstract Background Studies comparing angles of application in Radio Frequency (RF) catheter ablation other than 0 and 90 degrees are absent from the literature. Likewise, using acoustics to predict steam pop occurrences and prevent a catastrophic rupture of the myocardium has not been examined previously. Purpose Evaluate the effect of various parameters on the ablated volume and the probability of creating a boiling pop. Methods A low-cost testing and educational platform to work with generic RF catheters was set up. The in-vitro system allows controlling the blood flow surrogate over the cardiac tissue, the catheter contact force, electric power, and ablation time. Acoustic transducers have been employed with the setup to detect preliminary acoustic signals. Results Obtained results show a positive correlation between variations of the ablated surface geometry and power intensity changes. Generated figures provide percentages of a boiling pops for any given set of parameters fig1 (Top left: Probability of popping vs power and time). The probability of a boiling pop occurring increased if the ovine specimen is non-irrigated. The ratio of the burn correlates with the power and the angle of the catheter (30°, 45°, 60°, and 90°). However, the probability of the popping mostly depends on the power fig1 (Top right: Burn ratio vs power for 30°, 45°, 60°, and 90°) and fig1 (Bottom right: Cross sectional view of the corresponding lesions -same scale used for all images). Benign precursory bubbles detected by acoustics preceded the occurrence of catastrophic boiling pops fig1 (Bottom left: Acoustic signal showing a precursory pop before the major cavitation). Figure 1 Conclusion The established parameters for power intensity and exposure time should be respected to maintain a safe procedure. Acoustics can be further implemented to provide a warning for electrophysiologists before the occurrence of a boiling pop. Acknowledgement/Funding The funding for this project was provided from the URB and the MPP at the AUBMC and the AUB.

P2862Complementary use of contact force and local catheter impedance during RF ablation reduces ablation time in an in vivo swine model

Abstract Catheter-tissue coupling is crucial for effective delivery of radiofrequency (RF) energy during catheter ablation. Force sensing catheters provide a metric of mechanical tissue contact and catheter stability, while local impedance has been shown to provide sensitive information on real-time tissue heating. The complementary use of force and local impedance during RF ablation procedures could provide an advantage over the use of one metric alone. This study evaluates a prototype ablation catheter that measures both contact force (CF) using inductive sensors and local catheter impedance (LI) using only catheter electrodes. The complementary nature was assessed with discrete lesions in vitro and an intercaval line in vivo. A force-sensing catheter with LI was evaluated in explanted swine hearts (n=14) in an in vivo swine model (n=9, 50–70kg) using investigational electroanatomical mapping software. In vitro, discrete lesions were created in ventricular tissue at a range of forces (0–40g) controlled externally. RF energy was applied at a range of powers (20W, 30W, and 40W), durations (10s-60s), and catheter orientations (0°, 45°, and 90°). Lesions were stained with TTC and measured. LI drop relative to baseline during RF in the bench studies was used to inform the in vivo study. In a separate subset of animals in vivo, an intercaval line was created in three experimental groups: LI blinded, 20Ω ΔLI, and 30Ω ΔLI. CF was maintained between 15 and 25g in all groups. All ablations were performed with a power of 30W. In the LI blinded group, all lesions were delivered for 30s. In the 20Ω ΔLI group, the investigator ablated until a 20Ω drop or 30 seconds was achieved. Likewise, in the 30Ω ΔLI, the investigator ablated until a 30Ω drop or 30 seconds was achieved. In vitro, 137 discrete ventricular lesions were created. LI drop during ablation correlated strongly with lesion depth using a monoexponential fit (R=0.84) while force time integral (FTI) did not correlate as strongly (R=0.56). In the intercaval LI blinded group, starting LI ranged from 126–163Ω with a median of 138Ω. LI drops ranged from 13Ω-44Ω, with a median of 26Ω. In the 20Ω ΔLI group, starting LI ranged from 137–211Ω with a median of 161Ω and LI drop ranged from 7Ω-35Ω, with a median of 22Ω. In the 30Ω ΔLI group, starting LI ranged from 130–256Ω with a median of 171Ω and LI drop ranged from 20Ω-52Ω, with a median of 31Ω. Notably, RF time for the LI blinded group was 13±0.1 minutes while RF time in the 20Ω ΔLI group was 6.4±1.9 minutes and 7.5±0.7 minutes in the 30Ω ΔLI group. A catheter incorporating CF-sensing and LI capabilities provides a powerful tool for RF ablation. Bench studies demonstrate a strong correlation between LI drop and lesion dimensions, which guided the use of LI in vivo. In vivo, the confirmation of stable mechanical contact and viewing of real-time LI drops enabled a significant reduction in RF time while creating a continuous intercaval line. Acknowledgement/Funding This study was funded by Boston Scientific.

P1896Single-procedure success-rate of pulmonary vein isolation using point-by-point tagging lesions algorithm based on contact force technology: preliminary results of the multicentric SMOP study

Abstract Background Pulmonary veins isolation (PVI)is an effective therapy for atrial fibrillation (AF), recommended by current guidelines. However, recurrences after first radio-frequency (RF) catheter ablation (CA) are still high. PV reconnection could be due to ineffective transmural lesions; automated ablation lesion tags (the VisiTag algorithm) based on predefined parameters of catheter stability and contact force (CF) have been developed to allow the detection of ineffective ablation lesion, nevertheless there is a lack of multicenter studies exploring this technology. Objective the aim of our study was to assess the rate of recurrence after a first PVI procedure in a large, multicentric Italian population and to explore the efficacy of Visitag algorithm (CARTO 3) used to guide RF ablation of AF. Methods we analyzed 214 patients of the SMOP-AF study (Substrate Mapping as Outcome Predictor in Atrial Fibrillation Ablation), a prospective multi-centric study enrolling patients with paroxysmal and persistent AF undergoing a first PVI procedure after an high-density mapping during sinus rhythm. During the procedure, ablation was guided by an automated annotation system in which tag based on predefined parameters were displayed real-time in each lesion site on the electroanatomical map. Visitag settings for the catheter position stability were a 2,5 mm distance limit for at least 7 sec and a minimum CF of 5 g over 30% of the ablation and a FTI>400 g*s. Where available (n=106, 49.5%), Ablation Index (AI), which also incorporates information on delivered RF power, was used instead of FTI to guide RF ablation with a threshold range of 400–550 for anterior/roof and 330–420 for posterior/inferior segments. Minimum and mean contact force, time and power values for each RF-lesion were recorded while both FTI and AI values were calculated automatically by the CARTO system. Comparison between groups were made by cross-tables, Mann-Whitney or Student T test as appropriated. Results the mean age of the enrolled population was 59±9 years, left ventricular ejection fraction was 59±9%. AF was paroxysmal in 89.7%, persistent in 10.3% of the patients and refractory to at least one anti-arrhythmic drug in 86.4% of the population. At 3 months follow-up 85% of the patients were free from AF recurrences and the success rate increased to 90.8% at 3–6 months, and 86.3% at 3–12 months follow-up. The mean ablation time was shorter in AI-guided vs. FTI-guided procedures (31±9 vs 46±29 min; p<0.001). There was a trend toward a reduction in AF recurrences when AI vs. FTI was used, both at 6 and 12 months (respectively 5,4% vs 13.6%; p 0.06 and 9.6% vs 18.5%; p 0.08). Conclusion PVI isolation using dedicated algorithms developed to guide the effectiveness of RFCA leads to a very high success-rate after a single procedure. The use of AI, which integrates contact force information with delivered power, reduces the procedural time and increases the overall success-rate

P2835Feasibility and safety of same day discharge after radiofrequency catheter ablation for paroxysmal atrial fibrillation

Abstract Background Atrial fibrillation catheter ablation (CA) is the most frequent arrhythmia ablation and accounts for a significant proportion of treatment cost. Same day discharge (SDD) after paroxysmal atrial fibrillation (PAF) ablation is an attractive strategy for both patients and hospitals. Objective To understand the eligibility criteria and outcomes for PAF patients who can safely undergo same day discharge after radiofrequency catheter ablation. Methods Patients undergoing CA for PAF were evaluated for SDD at a pre-procedure visit to assess the risk of groin, respiratory, cardiac or bleeding complications. Eligibility criteria for SDD were stable anticoagulation and absence of bleeding history, systolic/diastolic heart failure, or interventional procedures within 60 days, with recommended BMI <35. Patient proximity to the hospital was also considered. Anesthesia included propofol with endotracheal intubation and all patients were ablated with a porous tip contact force catheter (STSF). Patients were on bed rest for 6 hours post-procedure, then ambulated intermittently for 1–2 hours. Discharge followed if they were stable with no evidence of vascular access complications or bleeding. A dedicated RN telephoned patients the following morning to ask a series of standard questions designed to elicit evidence of any complications. Results 52 procedures were identified for SDD, with 7 patients declining. 45 planned SDD procedures for 43 patients occurred 4/17–6/18. Average age was 57±11 years and CHA2DS2-VASc was 1.5±1.1 at procedure. Procedure time was 69±26 min (IQR: 49 - 84 min) with maximum fluoroscopy usage of 0.2 min and 508±149 mL of fluid infused through the catheter. Two patients stayed overnight due a groin bleed and atelectasis with fever, and one chose to stay for comfort. The remaining 42 discharges occurred after 7.2±1.0 hours in recovery, with no SDD-related complications and no required return visits after the follow-up call. There were 3 AF recurrences (6.7%) as of the 10 week visit. Conclusion Appropriate low risk patients identified by simple clinical criteria can be safely discharged the same day after CA of PAF. Further evaluation is required for higher risk patients. Acknowledgement/Funding The study was funded by Biosense Webster Inc.

Comparison of high‐power short‐duration (HPSD) ablation of atrial fibrillation using a contact force‐sensing catheter and conventional technique: Initial results

Atrial fibrillation (AFib) ablation is alternative treatment to drugs. Literature suggests that use of contact force (CF) catheter with higher power for short periods is effective and safe. Retrospectively analyzed 76 patients undergoing the first ablation. Third five patients-group A: 27 (77%) paroxysmal AFib (PAFib) and 8 (23%) persistent AFib (PersAFib) who underwent ablation at the power of 30 W-17 mL/minute flow with a CF of 10-30 g for 30 seconds. Fourty one patients-group B: 28 (68.3%) PAFib and 13 (31.70%) PersAFib underwent ablation using 45 W on posterior wall with CF of 8/15 g, as well as 50-W anterior wall with CF of 10/20 g-35 mL/minute flow for 6 seconds. Pulmonary vein isolation in both groups and ablated. For patients not in the sinus, we performed cardioversion before ablation. No complications. Group A: Left atrial time 110 ± 29 minutes, total 148 ± 33.6 minutes, radiofrequency time (RF) 4558 ± 1998 seconds, X-ray 8.5 ± 3.5 minutes, and elevation of esophageal temperature (ET) in 26 (74.3%). group B: Left atrial time 70.7 ± 18.5 minutes ( P < .00001), total 106 ± 23 minutes ( P < .00001), RF 1909 ± 675.8 seconds ( P < .00001), X-ray 8.8 ± 6.6 minutes ( P = .221) and elevation of ET in 21 (51.20% - P = .0578). In 6 and 12 months follow-up, we had 9 (25.71%) and 11 (31.42%) recurrences in group A and 5 (12.19%) and 7 (17.07%) in group B ( P = .231 at 6 and P = .14 at 12 months), respectively. HPSD was safe, useful, and efficient compared with CT, and reduced procedural time and total RF time. HPSD may reduce esophageal injury because of lower heating rate and it may reduce the recurrence of atrial tachyarrythmias.

Atrial fibrillation ablation with a spring sensor-irrigated contact force-sensing catheter compared with other ablation catheters: systematic literature review and meta-analysis

ObjectivesThe objective of our review was to systematically assess available evidence on the effectiveness, safety and efficiency of a spring sensor-irrigated contact force (CF) catheter (THERMOCOOL SMARTTOUCH Catheter (ST)) for...

PCV39 RADIOFREQUENCY CATHETER ABLATION WITH WARFARIN VERSUS ANTIARRHYTHMIC DRUGS WITH NEW ORAL ANTICOAGULANTS FOR THE TREATMENT OF PAROXYSMAL ATRIAL FIBRILLATION IN CHINA: A COST- EFFECTIVENESS ANALYSIS

To evaluate the cost-effectiveness of radiofrequency catheter ablation (RFCA) using contact-force catheter (Thermocool SmartTouch®) + warfarin versus antiarrhythmic drugs (AAD) + new oral anticoagulants (NOAC) in paroxysmal atrial fibrillation (PAF) patients from third-party payer's perspective in China. A two-part model was developed to estimate the cost-effectiveness of these two treatments. The short-term part was a decision-tree (1 year) including surgery-related complications and drug toxicity. The long-term was a Markov chain (lifetime) including the health states of normal sinus rhythms, AF recurrence, heart failure, stroke, post stroke, intracranial hemorrhages (ICH), post ICH, myocardial Infarction (MI), post MI, gastrointestinal bleeding and dead. Clinical efficacy, utility and cost data were obtained from published literature. The model calculated quality-adjusted life-years (QALYs) and total costs per patient. One-way and probabilistic sensitivity analyses were conducted. Captured by lifetime Markov model plus 1-year decision tree model, the total costs per patient for RFCA vs. AAD groups were ¥107,497 vs. ¥149,764; QALYs 8.16 vs. 7.58. From the 7th year, RFCA + warfarin became cost-effective (the incremental cost-effectiveness ratios at 7th year was ¥98,579/QALY, lower than the recommended threshold, 3xGDP/capita in China, ¥178,980). Furthermore, RFCA became cost-saving from the 9th year till lifetime with better effectiveness and lower overall costs compared with AAD. Both one-way and probabilistic sensitivity analyses confirmed the robustness of the results. Compared with AAD + NOAC, RFCA using contact force catheter + warfarin is cost-saving in long term for the treatment of PAF in China.

Contact Forces Required to Record Monophasic Action Potentials: A Complement to Catheter Contact Force Measurement.

The ability to monitor catheter contact force (CF) plays a major role in assessing radiofrequency ablation, impacting lesion size and arrhythmia recurrence, and dictating ablation duration and/or overall patient safety. Our study sought to determine the relative CFs required to elicit reproducible monophasic action potential (MAP) recordings. The study utilized four swine in which: first, median sternotomies were performed and MAPs were collected from seven ventricular locations on the epicardial surface of each heart; and second, a subset of endocardial signals was recorded from a reanimated heart. In these studies, the initial elicitation and then loss of stable MAP waveforms were recorded, as were their associated catheter CFs (n = 371). Mean CF at the onset of stable MAP recordings was 14.2 ± 2.9 g for epicardial and 16.6 ± 2.5g for endocardial locations. Across epicardial locations, no significant differences in CF were required to elicit MAPs. Additionally, endocardial and epicardial CFs for MAPs did not significantly differ for respective locations, i.e., right ventricular septum endocardial versus epicardial. In our study, the catheter CFs required to elicit MAPs were within optimal ranges previously reported for eliciting clinically viable radiofrequency ablations. We believe that MAP recordings could complement CF measurements with electrical data, providing additional clinical feedback for physicians performing cardiac ablation. If applied clinically, MAP recordings could potentially improve ablation outcomes in patients with cardiac arrhythmias.

Clinical and Procedural Effects of Transitioning to Contact Force Guided Ablation for Atrial Fibrillation.

A major innovation in atrial fibrillation (AF) ablation has been the introduction of contact force (CF) sensing catheters. To evaluate procedural and clinical effects of transitioning to CF-guided AF ablation. Consecutive AF ablation patients were studiedduring the period of time of transitioning from a non-CF to CF sensing catheter. Procedural data recorded was total radiofrequency time, time to isolate the left pulmonary veins (LPVs), and time to isolate the right pulmonary veins (RPVs). Clinically, the 3 and 12-month maintenance of sinus rhythm was noted and compared by: paroxysmal vs. persistent AF; CT scan LA volume more or less than 150 cc; CHA2DS2VASC more or less than 2; and LVEF more or less than 55%. Safety data was recorded as well. Total ablation times were shorter (113 vs.146 min, p=0.011)when using the CF catheters compared to non-CF ablations. This was driven by a decrease in both LPV (46 vs.72 min, p<0.001) and RPV time (54 vs. 75 min, p=0.002).The use of CF catheter did not change the overall percentage of patients in sinus rhythm at 3 and 12-months of follow up. However, sinus rhythm was more frequent at 12 months with CF ablation inpatients with an LA volume of more than 150 cc when compared to non-CF ablation (84.6% and 52.4%, p=0.03). There was no difference in outcomes with stratification by CHA2DS2VASC score or LVEF. No significant difference in complications was noted. For AF ablation, the initial use of CF-sensing technology reduced procedure times with similar overall sinus rhythm maintenance at 3 and 12 months. CF improved 12-month outcomes in patients with an enlarged LA.

Gains in Paroxysmal Atrial Fibrillation Ablation Using a Standardized Workflow to Optimize Contact Force Technologies

Catheter ablation technology has evolved rapidly in recent years. There is a need to understand the impact of these advances on efficiency, safety, and effectiveness in real-world populations. The objective of this study was to evaluate a standardized workflow that integrates a contact force (CF) catheter and stability module in an attempt to optimize efficiency and clinical outcomes of paroxysmal atrial fibrillation (PAF) ablation, and to compare the outcomes of this workflow with existing ablation technologies at a high-volume center. Consecutive ablations for PAF from July 2013 - June 2016 were included. Radiofrequency (RF) ablations were performed with the ThermocoolSF Catheter (SF) through April 2014, after which a change was made to the ThermocoolSmarttouchCatheter (ST)with a standardized workflow. Cryoballoon ablations (CA) were performed with theArctic FrontAdvancebetween July 2013 and March 2016. Systematic collection of 12-month effectiveness data began in July 2014. Prior to that time, only acute outcomes and reablations were captured. Procedural data for 32 SF, 232 ST, and 59 CA procedures for PAF were available. Mean procedure times were similar across SF and CA, and moderately shorter with ST (p=0.0201). Fluoroscopy times were substantially reduced with ST (p<0.0001). Complication rates were low and similar across all cohorts (p=0.4744), whereas reablation rates were lowest in the ST cohort (p=0.0194). PAF ablation using integrated CF and catheter stability technology with a systematic ablation workflow maylead to improvements in both procedural efficiency and reablation rates, without compromising patient safety.

Corrigendum to: Safety and efficiency of porous-tip contact-force catheter for drug-refractory symptomatic paroxysmal atrial fibrillation ablation: results from the SMART SF trial.

Corrigendum to: Safety and efficiency of porous-tip contact-force catheter for drug-refractory symptomatic paroxysmal atrial fibrillation ablation: results from the SMART SF trial.

Contact force-sensing catheters: performance in an ex vivo porcine heart model.

Contact force (CF) catheters are useful to address proper contact during ablation. However, interactions between the ablation process, or its associated irrigation flow changes, with the CF sensing may translate into unexpected CF value fluctuations. We aimed to test for unintentional CF value variations during radiofrequency applications at a fixed applied force, with two commercially available catheters (TactiCath™ and SmartTouch™), and to evaluate its theoretical clinical significance by correlating CF-derived automatic ablation algorithms (force-time integral and lesion index) and actual lesion size at two standard CF values. Four series of 20 perpendicular epicardial ablations (20W, 60s, 17ml/min) were performed on porcine left ventricle submerged in 37°C saline. Catheters were mechanically fixed at a constant position and evaluated at 10 and 20g. CF values were digitally analysed before each application changing irrigation rate (2-17-30ml/min), and during ablation. Finally, lesions were quantified. Increasing irrigation before ablation led to a slight but significant CF decrease. During ablation, CF showed a reproducible pattern: fast initial decrease, subsequent increase until higher-than-initial values and final plateau phase (CF variation up to 69% at 10g). CF variability was significantly higher at 10g and using TactiCath™. There were no major differences in lesion size between catheters at the same initial CF. CF only correlated mildly to lesion measures, and automatic algorithms globally failed to predict lesion size. CF measured values spontaneously vary during ablation following a predictable pattern (initial decrease, subsequent increase and final plateau). This is especially remarkable applying lower CF.

466Fiber optic contact force catheter efficiency and effectiveness in paroxysmal AF ablation from a large, multi-national, prospective registry (ABLATOR)

466Fiber optic contact force catheter efficiency and effectiveness in paroxysmal AF ablation from a large, multi-national, prospective registry (ABLATOR)

Two Year, Single Center Clinical Outcome After Catheter Ablation For Paroxysmal Atrial Fibrillation Guided by Lesion Index.

This study describes the use of lesion index (LSI) as a direct measure to assess the adequacy of ablation lesion formation with force-sensing catheters in ablation of paroxysmal atrial fibrillation (PAF). LSI is calculated by the formula:LSI = CF (g) ×Current (mA) ×Time (sec). Fifty consecutive patients with PAF underwent pulmonary vein (PV) isolation using a catheter dragging technique and targeting different LSI values in different anatomical areas.A force-sensing ablation catheter was used to continuously measure contact force (CF) and guide radiofrequency ablation (RF) lesion formation. Ablation lesions were delivered to achieve an LSI value of 5.0 in posterior locations, 5.5 in anterior locations and 6.0 in the regionbetween the left atrial appendage and left superiorpulmonary vein ridge. Force-time Integral (FTI) was not used to evaluate lesion formation. A single center, retrospective analysis was performed with 196/198 (99%) PVs acutely isolated. The mean procedure time was 134 ± 34 mins and the mean fluoroscopy time was 7.8 ± 3.2 mins. At a mean follow up of two years, 43/50 (86%) of patients were in normal sinus rhythm with no documented recurrences of atrial fibrillation. LSI can be used to guide the placement of durable lesion formation with RF ablation using CF catheters in patients with PAF.

The best of two worlds? Pulmonary vein isolation using a novel radiofrequency ablation catheter incorporating contact force sensing technology and 56-hole porous tip irrigation.

This study aimed to evaluate feasibility and safety as well as 1-year clinical outcome of pulmonary vein isolation (PVI) using a unique radiofrequency ablation catheter ("Thermocool SmartTouch SurroundFlow"; STSF) incorporating both, contact force (CF) sensing technology and enhanced tip irrigation with 56 holes, in one device. A total of 110 patients suffering from drug-refractory atrial fibrillation underwent wide area circumferential PVI using either the STSF ablation catheter (75 consecutive patients, study group) or a CF catheter with conventional tip irrigation ("Thermocool SmartTouch", 35 consecutive patients, control group). For each ablation lesion, a target CF of ≥ 10-39g and a force time integral (FTI) of > 400 gs was targeted. Acute PVI was achieved in all patients with target CF obtained in > 85% of ablation points when using either device. Mean procedure time (131.3 ± 33.7min in the study group vs. 133.0 ± 42.0min in the control group; p = 0.99), mean fluoroscopy time (14.0 ± 6 vs. 13.5 ± 6.6min; p = 0.56) and total ablation time were not significantly different (1751.0 ± 394.0 vs. 1604.6 ± 287.8s; p = 0.2). However, there was a marked reduction in total irrigation fluid delivery by 51.7% (265.52 ± 64.4 vs. 539.6 ± 118.2ml; p < 0.01). The Kaplan-Meier estimate 12-month arrhythmia-free survival after the index procedure following a 3-month blanking period was 79.9% (95% CI 70.4%, 90.4%) for the study group and 66.7% for the control group (95% CI 50.2%, 88.5%). This finding did not reach statistical significance (p = 0.18). Major complications occurred in 2/75 patients (2.7%; one pericardial tamponade and one transient ischemic attack) in the study group and no patient in the control group (p = 18). PVI using the STSF catheter is safe and effective and results in beneficial 1-year clinical outcome. The improved tip irrigation leads to a significant reduction in procedural fluid burden.

Lesion Index-Guided Ablation Facilitates Continuous, Transmural, and Durable Lesions in a Porcine Recovery Model.

The Lesion Index (LSI) is a proprietary algorithm from Abbott Medical combining contact force, radiofrequency application duration, and radiofrequency current. It can be displayed during ablation with the TactiCath contact force catheter. The LSI Index was designed to provide real-time lesion formation feedback and is hypothesized to estimate the lesion diameter. Before ablation, animals underwent cardiac computed tomography to assess atrial tissue thickness. Ablation lines (n=2-3 per animal) were created in the right atrium of 7 Göttingen mini pigs with point lesions (25 W). Within each line of ablation, the catheter tip was moved a prescribed distance (D/mm) according to 1 of 3 strategies: D=LSI+0 mm; D=LSI+2 mm; or D=LSI+4 mm. Two weeks after ablation, serial sections of targeted atrial tissue were examined histologically to identify gaps in transmural ablation. LSI-guided lines had a lower incidence of histological gaps (4 gaps in 69 catheter moves, 5.8%) than LSI+2 mm lines (7 gaps in 33 catheter moves, 21.2%) and LSI+4 mm lines (15 gaps in 23 catheter moves, 65.2%, P<0.05 versus D=LSI). ΔLSI was calculated retrospectively as the distance between 2 adjacent lesions above the mean LSI of the 2 lesions. ΔLSI values of ≤1.5 were associated with no gaps in transmural ablation. In this model of chronic atrial ablation, delivery of uninterrupted transmural linear lesions may be facilitated by using LSI to guide catheter movement. When ΔLSI between adjacent lesions is ≤1.5 mm, no gaps in atrial linear lesions should be expected.

Contact force facilitates the achievement of an unexcitable ablation line during pulmonary vein isolation.

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. A total of 106 patients undergoing PVI were randomized into three groups (G) (G1: target-CF 15g, G2: target-CF 10g, 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 (10V, 2ms) was targeted for further ablation. Mean average CF was 17.4 ± 4.7g (G1) vs. 12.3 ± 6.0g (G2) vs. 11.1 ± 6.5g (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 ± 3.1kJ vs. 8.6 ± 7.2kJ (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 3ns). 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 ± 254day follow-up. Higher tip-to-tissue CF during PVI facilitates the achievement of an unexcitable ablation line, requiring less additional RF-energy.

Atrial fibrillation ablation: 1-year “real-life” outcome with contact force catheter after a single procedure

Atrial fibrillation ablation success rate has improved over the years. Data regarding success rate with contact force catheter are only available in clinical trials. The aim of our study was to assess the “real-life” success rate of atrial fibrillation ablation at 1 year using the Smarttouch catheter (Biosense Webster). Patients who underwent first procedure of atrial fibrillation ablation between January 2014 and December 2015 were prospectively enrolled. Patients with paroxysmal atrial fibrillation (PAF) underwent pulmonary vein isolation. Patients with persistent atrial fibrillation (PeAF) had pulmonary vein isolation with linear ablation and/or atrial defragmentation to obtain sinus rhythm. Procedure success rate was defined as free from any arrhythmia during the first year of follow-up. Overall, 246 patients (62.6 ± 11 year, 68% males) were enrolled in our study. One hundred and forty eight patients underwent PAF ablation and 99 patients underwent PeAF ablation. Among the PAF patients, 26 had atrial arrhythmias during follow-up (success rate 82.4%). Among the PeAF patients, 33 had atrial arrhythmias during follow-up (success rate 66,6%). Interestingly, 29.79% of patients with no arrhythmia recurrence were still on antiarrhythmic drugs despite our recommendations to stop them at 3 months after the procedure. After a single atrial fibrillation ablation with contact force catheter (Smarttouch, Biosense webster), real-life success rate is consistent with clinical trials. Some patients without arrhythmia recurrence were still on antiarrhythmic drugs despite electrophysiologists recommendations.

Contact Force-Sensing Catheters in Atrial Fibrillation Ablation: A Meta-Analysis of Randomised Controlled Studies

Background: Atrial fibrillation (AF) is typically treated through pulmonary vein isolation (PVI). The patient is susceptible to AF recurrence if the PVI treatment is incomplete. Contact-force catheters are an alternative treatment with potential to cause more effective ablation lesions, producing improved results.