Number Of Radiofrequency Applications Research Articles

Feasibility of catheter ablation with zero-fluoroscopy in congenital heart disease

Abstract Background Catheter ablation (CA) with zero and near-zero fluoroscopy has been shown to be safe and effective in patients (pts) without structural heart disease, but there are limited data regarding CA in congenital heart disease (CHD). Aim Our aim was to compare the safety and outcome of zero-fluoroscopy (ZF) and fluoroscopy (non-ZF) CA of CHD pts. Methods This is a single-center retrospective study of CHD pts who underwent CA at our center between 2006-2020. The ZF and non-ZF groups were compared for the complexity of anatomy, arrhythmia substrate, difficulties of vascular access, transseptal or transbaffle puncture, intracardiac pacemaker/ICD, procedural parameters, complications, and acute outcome. Near-ZF CAs (effective dose ≤1 mSv) were assigned to the ZF group. Results The ZF group included 22 pts (age: 22±13 years) and the non-ZF group 48 pts (age: 31±12 years). The distribution of CHD anatomical complexity (mild/moderate/severe) was 18.2%-68.2%-13.6% in the ZF group and 14.6%-68.7%-16.7% in the non-ZF group. Arrhythmia diagnoses were focal atrial tachycardia (ZF: 4.6%), atrial flutter (ZF: 45.4%, non-ZF: 75.0%), atrioventricular reentry tachycardia (AVRT) via manifest accessory pathway (AP) (ZF: 31.8%, non-ZF: 10.4%), AVRT via concealed AP (ZF: 4.6%, non-ZF: 8.3%), and atrioventricular nodal reentry tachycardia (ZF: 13.6%, non-ZF: 6.3%). Difficulties in vascular access occurred in 4.5% of the ZF group and 18.8% of the non-ZF group (p=0.10). The rate of transseptal/transbaffle puncture was significantly higher in the non-ZF group (22.9% vs. 4.6%, p=0.04). In the ZF group 13.6% and in the non-ZF group 20.8% of pts had pacemaker or ICD (p=0.22). Electroanatomical mapping was used in all CAs in both groups. There was no significant difference in procedure time, ablation time and the number of radiofrequency applications (ZF group: 169±53 min, 1205±906 sec, 28±15 vs. non-ZF group: 203±74 min, 1459±940 sec, 34±16, p>0.05). The acute success rate was 100% in both groups. No complications occurred in any group. Conclusion Zero fluoroscopic CA was feasible in 1/3 of the pts with CHD and as safe and effective as fluoroscopic ablation. No significant differences were found in the non-fluroscopy related procedural data between the two groups.

Safety and feasibility of zero-fluoroscopy technique in ablation-index guided pulmonary vein isolation: a prospective, single center trial

Abstract Introduction Pulmonary vein isolation (PVI) represents the cornerstone of catheter ablation procedures in patients with symptomatic paroxysmal/persistent atrial fibrillation (AF). Conventionally, PVI is performed using fluoroscopy, but it can also be performed using the zero-fluoroscopy (ZF) technique with the assistance of electroanatomical mapping systems and intracardiac ultrasound, achieving fluoroscopy-free procedures. Purpose Our study aimed to compare procedural data of ablation-index guided point-by-point radiofrequency (RF) PVI performed with non-zero-fluoroscopy (NZF) vs. ZF approaches. Methods We enrolled 100 consecutive patients undergoing PVI for antiarrhythmic drug- refractory AF in our prospective observational study. In the first 50 cases, PVI was performed using the NZF technique, and in the other 50 cases, the ZF technique was applied. Procedural time, fluoroscopy exposure, ablation parameters, and the occurrence of complications were compared between the two groups. Results Compared to the NZF group, procedural time (59.6±10.7 min vs. 74.6±13.2 min, p<0.0001) was significantly shorter in the ZF group. This difference was mainly driven by the time from puncture to the beginning of left atrial mapping, which was significantly longer in the NZF group (17 [16; 20] min vs. 31 [23; 34.5] min, p<0.001). No differences were found between the two approaches in the number of RF applications (81 [73; 103] vs. 83 [71; 91], p=0.67), total ablation energy (54986 ± 13093 Ws vs. 55500 ± 11907 Ws, p=0.48), and the left atrial dwelling time (41.5 [36; 52.5] min vs. 40.5 [35; 46], p=0.14). No complications occurred in either group. In the ZF group, complete elimination of fluoroscopy was achieved in all cases, resulting in significant differences in fluoroscopy time (0 [0; 0] sec vs. 132 [100; 160] sec, p<0.0001] and dose (0 [0; 0] mGy vs. 4.8 [4.1; 8.2] mGy, p<0.0001) compared to the NZF technique. The acute success rate was 100% in the study population, and no complications occurred during the study period. Conclusion Ablation-index guided ZF PVI is feasible and safe. Using this technique, the procedure time can be shortened besides achieving a similar acute success rate without increasing complications.

A randomized comparison of retrograde left-sided versus anterograde right-sided ablation of the atrioventricular junction.

Catheter ablation of the atrioventricular node (AVN) is an effective treatment for patients with symptomatic atrial fibrillation. This study compares the success rate, procedure time, radiation time, and complication rates of retrograde left-sided (LSA) and anterograde right-sided (RSA) AVN ablation in a randomised controlled trial. Thirty-onepatients undergoing AVN ablation were randomized to either LSA (15 patients) or RSA (16 patients). Crossover occurred after six unsuccessful radiofrequency (RF) applications. The LSA cohort had a mean age of 77.00 ± 5.17 and the RSA cohort was 79.44 ± 6.08 (p = .0240). There were five crossovers from LSA to RSA and there was one crossover from RSA to LSA. There was no significant difference in ablation time between LSA and RSA (210.40 ± 179.77vs. 192.19 ± 130.29 seconds, p = .748). There was no significant difference in procedure time, fluoroscopy time, radiation dose, or number of RF applications between the two groups. There was 1 (6.67%) serious adverse event in the LSA group and 1 (6.25%) in the RSA group due to femoral hematomas requiring blood transfusion or intervention. There was no significant difference in patient-reported discomfort between LSA and RSA (16.43 ± 20.67 vs. 17.87 ± 28.08, p = .877). The study was stopped before full recruitment due to futility. Retrograde LSA of the AVN does not reduce RF applications, procedure time, or radiation exposure compared with conventional RSA and cannot be recommended as a first-line clinical approach.

Pulmonary vein isolation with a novel radiofrequency balloon catheter: real-world predictors of single shot isolation

Abstract Funding Acknowledgements Type of funding sources: None. Background A novel multi-electrode radiofrequency balloon (RFB) catheter has been released for pulmonary vein isolation (PVI). Objectives First multicenter real-world study to evaluate predictors of single shot PVI with the novel RFB catheter. Methods In this observational study consecutive patients with drug refractory paroxysmal or persistent atrial fibrillation (AF) undergoing first-time PVI were enrolled in two high-volume ablation centers. All procedures were conducted in conjunction with a 3D-mapping system. Clinical, procedural and ablation parameters were systematically analyzed. Results 105 patients (58% males; 52% paroxysmal AF, 68 ± 11.3 mean age, left atrial volume index 38.6 ± 14.8 ml/m2) were included. 241/412 (58.5%) pulmonary veins were successfully isolated with a single shot (SS), with a time to isolation of 11.6 ± 8 s. Total number of radio frequency applications was 892 (mean 2.2/PV), resulting in successful isolation of 408/412 (99%) PVs at the end of the procedure. Mean electrodes’ impedance drop was significantly higher in the SS-PVI compared to the non-SS applications (21.5 ± 6.6 vs. 18.6 ± 6.5 Ohm). Concordantly, higher temperature rise was observed in the SS versus non-SS applications (10.9 ± 4.9°C vs. 9.6 ± 4.7°C). Conclusion In this multicenter real-world study, mean impedance drop and temperature rise emerged as valid predictors for SS-PVI with the novel RFB catheter. These parameters may help to guide efficient usage of the new RF balloon.

Efficacy comparison of high and very high power short duration pulmonary vein isolation: the HPSD remap study

Abstract Funding Acknowledgements Type of funding sources: Other. Main funding source(s): An investigator-initiated study. Research grant received from Biosense Webster (IIS 653). Background Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation. The high power short duration ablation has shown good efficacy and safety profile. Recently, very high power short duration has been introduced, but initial efficacy results were discouraging. Purpose The goal of this study was to compare the long-term durability of PVI performed with a 90W vs. 50W power setting. Methods Patients were randomized in a 1:1 fashion to undergo PVI either with 90W or 50W power. The ablation protocol was the following: in the case of 50W, the ablation index target values were 400 on the posterior wall and 500 on the anterior wall, and the inter-lesion distance was <5 mm; while in the case of 90W, a 4 seconds application was delivered at each site, with an inter-lesion distance <5 mm (preferably <4 mm anteriorly). At the index procedure, PVI was demonstrated by entrance and exit block after a 20-minute waiting period. All patients underwent a protocol-mandated repeat electrophysiology study after 3 months, regardless of symptoms. At the repeat study, all sites of PV reconnection were identified and re-ablated. Results A total of 40 patients were included in the study (20-20 on each treatment arm). Age was 65±8 years, 19 were females, BMI was 30±3.5, and 23 patients had paroxysmal AF. The most frequent comorbidities were hypertension (n=32) and diabetes (n=14). Procedure time (75 min vs. 84 min, p=0.02), left atrial dwelling time (63 min vs. 71 min, p=0.01), and radiofrequency time (335 sec vs. 1035 sec, p<0.0001) were shorter in procedures performed with 90W compared to 50W. On the other hand, the number of radiofrequency applications was higher in the case of 90W compared to 50W (85 vs. 70, p=0.09). There was no difference in the first-pass isolation rate (80% vs. 85%, p=1.0) and in the acute reconnection rate (5% vs. 15%, p=0.6) between the 90W and 50W power settings. At the repeat electrophysiology study, PV reconnection was seen in 4 and 7 patients in the 90W and 50W groups, respectively (p=0.5). The durable isolation on a per vein basis was 92% in the 90W group and 88% in the 50W group (p=0.4). Conclusions A similarly high rate of durable PVI can be achieved both with 90W and 50W power settings if a slightly smaller inter-lesion distance is targeted on the anterior wall in case of 90W. Procedure time, left atrial dwelling time, and radiofrequency time is shorter with a 90W power setting compared to 50W.

Incidence of silent cerebral lesions after pulmonary vein isolation with a novel radiofrequency balloon

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Speaker fees by Biosense Webster (not specific to this research) Background A novel radiofrequency balloon (RFB) is currently used for pulmonary vein isolation (PVI) in selected centres. The incidence of silent cerebral lesions (SCL) detected by magnetic resonance imaging (MRI) has already been researched for common energy sources such as the cryoballoon and irrigated-tip radiofrequency catheters. Purpose We aimed to investigate the incidence of SCL after RFB ablation. Methods 105 patients were treated with RFB PVI between December 2020 and November 2022. Cerebral MRI was performed in 38 unselected patients after a median of 1 day after the procedure. Neurological symptoms as well as size and location of SCL were assessed. The RFB allows for assessment of real time isolation using a spiral catheter which can be inserted through a central lumen of the balloon. During the investigated period the procedure underwent a streamlining process. Initially a 3D high resolution map of the left atrium (LA) was obtained before and after the ablation. To create this post-ablation map, the RFB had to be exchanged for a circumferential mapping catheter. After the first 50 procedures post-ablation re-mapping was omitted. This reduced the number of necessary catheter exchanges through the transseptal sheath. Results None of the patients developed neurological symptoms after the procedure. SCLs were detected in 28,9% (11) of patients. Analysis of patient baseline characteristics (gender, age, BMI, comorbidities, LA size, LVEF) as well as procedural data (procedure length, LA dwell time, ablation time, number of radiofrequency applications, cardioversion, activated clotting time) showed no significant independent predictor for SCL. We compared procedural data and SCL incidence prior to streamlining of the procedure (non-streamlined, NSL) to those after streamlining (SL). We observed a numerical difference in incidence of SCL between the NSL group (42,1%, 8 of 20) and the SL group (16,7%, 3 of 18), but the difference did not meet criteria for statistical significance (p = 0,159). Procedure time (NSL: 69.4 ± 10.8, SL: 51.1 ± 8.6, p = 0.009) and LA dwell time (NSL: 63.8 ± 10.9, SL: 45.8 ± 8.3, p = 0.009) were significantly shorter in the SL group. Conclusion This is the first report of the incidence and possible predictors of silent cerebral lesions after PVI with a novel radiofrequency balloon. We initially observed a higher-than-expected number of SCL. After streamlining of the procedure and especially reducing the necessary catheter exchanges this incidence dropped. It is now comparable to data of SCL after PVI with other technologies in our centre. This supports our assumption that the number of left atrial catheter exchanges might be an important factor for the development of SCL. Furthermore, this data emphasize the necessity of caution during the initial learning phase with new ablation devices. Further MRI after the procedure could reveal statistically significant predictors of SCL.

Randomized trial of intracardiac echocardiography-guided slow pathway ablation.

Radiofrequency (RF) catheter ablation of the slow pathway (SP) in atrioventricular nodal reentry tachycardia (AVNRT) is highly effective; however, it may require prolonged fluoroscopy and RF time. We postulated that visualization of the SP region with intracardiac echocardiography (ICE) could decrease ablation time, minimize radiation exposure, and facilitate SP ablation compared to the standard, fluoroscopy-guided approach. In our study, we randomized 91 patients undergoing electrophysiologic study and SP ablation for AVNRT into 2 groups: fluoroscopy-only (n = 48) or ICE-guided (n = 43) group. Crossover to ICE-guidance was allowed after 8 unsuccessful RF applications. Mapping plus ablation time (mean ± standard deviation: 18.8 ± 16.1min vs 11.6 ± 15.0min, p = 0.031), fluoroscopy time (median [interquartile range]: 4.9 [2.93-8.13] min vs. 1.8 [1.2-2.8] min, p < 0.001), and total ablation time (144 [104-196] s vs. 81 [60-159] s, p = 0.001) were significantly shorter in the ICE group. ICE-guidance was associated with reduced radiation exposure (13.2 [8.2-13.4] mGy vs. 3.7 [1.5-5.8] mGy, p < 0.001). The sum of delivered RF energy (3866 [2786-5656] Ws vs. 2283 [1694-4284] Ws, p = 0.002) and number of RF applications (8 [4.25-12.75] vs. 4 [2-7], p = 0.001) were also lower with ICE-guidance. Twelve (25%) patients crossed over to the ICE-guided group. All were treated successfully thereafter with similar number, time, and cumulative energy of RF applications compared to the ICE group. No recurrence occurred during the follow-up. ICE-guidance during SP ablation significantly reduces mapping and ablation time, radiation exposure, and RF delivery in comparison to fluoroscopy-only procedures. Moreover, early switching to ICE-guided ablation seems to be an optimal choice in challenging cases.

High-sensitivity cardiac troponin and C-reactive protein dynamics after cardiac electrophysiological procedures

The catheter ablation of cardiac arrhythmias causes myocardial destruction and increase of the cardiac troponin and C-reactive protein (CRP). Data regarding dynamics of high-sensitivity troponin during irrigated ablation are scarce, and for diagnostic electrophysiological studies (EPS) are lacking. We aimed to study the periprocedural dynamics of high-sensitivity cardiac troponin I (hscTn I) and CRP, as well as their relation to different procedural parameters during EPS and ablation of various arrhythmias. Material and methods: Consecutive patients with EPS or ablation performed were studied prospectively. Clinical and procedural characteristics, and pre- and postprocedural values of hscTn I and CRP are presented at days 1, 2 and 3. Six indices were chosen as procedural markers of induced myocardial injury. P-value &amp;#60; 0.05 was accepted as statistically signifi cant for all tests performed. Results: Eight EPS and 98 ablations were performed in 103 patients (58 males, 56.3%). For ablations the baseline values of hscTn I at day 1 were 3.2 ng/L (1.7-4.93), while postprocedural values at days 2 and 3 were 500 ng/L (269-1044) and 404 ng/L (179-1017), р &amp;#60; 0.05 for all days. Postprocedural hscTn I values were moderately to strongly correlated to radiofrequency (RF) energy, time and number of RF applications. Postprocedural increase of CRP was also significant, but its magnitude was much smaller. Its correlation to procedural indices was weak. For EPS the baseline values of hscTn I were 5.95 ± 5.34 ng/L (0.6-15.9), while for the next 2 days these were 53.2 ± 43.1 ng/L (13.3-144) и 16.7 ± 9.65 ng/L (3.3-30.9), р &amp;#60; 0.05 for all days. Conclusion: Signifi cant postprocedural increase of hscTn I was detected in all electrophysiology procedures – EPS and ablations. This increase was more pronounced and prolonged to at least the next day after ablation. It was clearly correlated to the cumulative RF energy, RF time and number of RF applications. Early increase of CRP was also signifi cant, but to a lesser magnitude and in weak correlation to the procedural parameters.

B-PO05-073 THE FASTR-AF TRIAL: ASSESSING THE DIAMOND TIP TEMPERATURE-CONTROLLED RADIOFREQUENCY ABLATION CATHETER TO TREAT PATIENTS WITH ATRIAL FIBRILLATION

Catheter ablation (CA) technology evolves as practitioners look to improve treatment options for atrial fibrillation (AF). A novel diamond tip, irrigated, radiofrequency (RF) ablation system accurately measures tip-tissue temperature in real-time and modulates power to maintain a target therapeutic tissue temperature. Recently, the DiamondTemp Ablation (DTA) system demonstrated strong outcomes against a contact force-sensing RF ablation system in a paroxysmal AF (PAF) population. However, no data pertaining to persistent AF (PsAF) has been reported in literature. This study sought to characterize the performance of the DTA system for the treatment of patients with drug-refractory PAF and PsAF with the second-generation RF DTA generator. DIAMOND FASTR-AF (NCT03626649) was a prospective, single-arm, multicenter European trial. Primary effectiveness endpoint was freedom from atrial arrhythmia recurrence following a 90-day blanking period through 12 months. Primary safety endpoint was a composite of serious adverse events. In total, 60 subjects (34 PAF and 26 PsAF) underwent CA with the DTA system at three centers. Patient demographics were consistent with contemporary AF studies (male 71.7%, age 63.9 ± 10.2 yrs, AF history 3.1 ± 3.9 yrs, LA size 4.4 ± 0.8 cm). The PAF cohort showed marked procedural efficiencies, as compared to PsAF, in total procedure time (76.9 ± 21.7 min vs 108.9 ± 33.6 min, p<0.001, respectively), total RF time (10.4 ± 3.5 min vs 20.4 ± 8.0 min, p<0.001), and number of RF applications (62.1 ± 25.3 vs 109.5 ± 45.5, p<0.001). Pulmonary vein isolation only was performed in 82% of PAF and 23% of PsAF subjects. Additional left-sided lesions were performed in 69% of PsAF subjects (vs 6% of PAF subjects). Safety event rate in the PAF and PsAF groups were 5.9% (2/34) and 11.5% (3/26), respectively. Freedom from recurrence was observed in 67.6% (23/34) of PAF and 61.5% (16/26) of PsAF subjects. The DiamondTemp Ablation system demonstrated long-term safety and effectiveness through 12 months post-ablation for patients with PAF or PsAF. Procedures were demonstrated to be highly efficient, with shorter time and fewer applications seen in PAF procedures.

Benefits of catheter ablation of typical cavotricuspid isthmus-dependent atrial flutter using half-normal saline

Abstract Funding Acknowledgements Type of funding sources: None. Background Radiofrequency catheter ablation (RFA) of cavotricuspid isthmus–dependent atrial flutter (AFL) is a procedure with a high success rate and a low complication rate. The anatomical variation and irregularity of the isthmus, with the high local blood flow, can reduce the effectiveness of the lesion and consequently of the procedure. Recent data suggests that deeper ablation lesions can be created using open-irrigated catheters (CA) with half-normal saline (HNS). Purpose To assess the acute efficacy and safety of RFA of AFL with half-normal saline (HNS). Compare the results with CA irrigated with normal saline (NS). Methods Randomized, prospective, observational and single-center study. Consecutive patients with first AFL RFA between June 2019 and December 2020 were included. CA with HNS or NS were used, with a limit of 40 watts and 40° C. An RFA line was performed under fluoroscopic guidance or electroanatomic mapping. If necessary, the lesion was repeated until the arrhythmia was interrupted and the bidirectional block was achieved (success). Acute success, total radiofrequency time (RT), number of radiofrequency applications, and complications were analyzed. Results 38 patients with RFA of AFL were analyzed. 19 in the HNS and 19 in the NS group. There were no significant differences between the baseline characteristics of each group. (Table 1) The accute success rate was 100% with a median of 2 RFA applications in both groups. The mean RT in HNS was 7:10 vs 09:16 min in NS group; the t-test analysis did not show a significant difference (p = .2). A subanalysis was performed in those patients who required more than 2 lines of RFA; a mean of 4 in the HNS group vs 6 in the NS group (p = .4). In the HNS group, RT was significantly shorter; 8:17 vs 13:17 min in the NS group (p = .011). (Figure 1) There was a steam pop in the HNS group and no complications or steam pop in the NS group (p = .53). Conclusions RFA of AFL using HNS is an effective and safe procedure. In patients with unfavorable anatomy who required a greater number of applications, the radiofrequency time was significantly shorter using HNS. Baseline characteristicsHNS (19 p)NS(19 p)pAge56 ± 12.3 years61 ± 10.8 years.22Male16 p (84%)16 p (84%)1Heart Disease7 p (36.8%)5 p (26.3%).68Ejection Fraction57.1 ± 11%56 ± 14.3%.49Ejection Fraction &amp;lt; 50%2 p (10.5%)2 p (10.5%)1Electroanatomic mapping10 p (52.6%)8 p (42.1%).7Abstract Figure. Fugure 1

The role of ablation index-guided pulmonary vein isolation in high-sensitivity TrThe role of ablation index-guided pulmonary vein isolation in high-sensitivoponin I and atrial fibrillation recurrence

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Ablation Index (AI) software has been associated with better freedom from atrial arrhythmias after pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (AF). There is conflicting data regarding the relationship between high sensitivity cardiac Troponin I (Hs-cTnI) and arrhythmia recurrence. The objective was to evaluate the impact of AI on Hs-cTnI level and on ablation effectiveness quotient (AEQ) and to assess if these markers are predictors of arrhythmia recurrence. Methods Prospective observational study of consecutive patients referred for PVI for paroxysmal AF ablation from October 2017 to June 2018 according to a pre-specified AI protocol. Procedural endpoints and 2-year follow-up outcomes were assessed and compared to a retrospective cohort of conventional PVI contact-force-guided group . Results A total of 56 patients were included: 29 patients the AI group and 27 patients in the control group. The mean age was 60.5 ± 10.3 years, 48% males. Left ventricular ejection fraction (60 ± 6 % AI vs 61 ± 5 % control, P = 0.07) and left atrium diameter (43 ± 7 mm AI vs 44 ± 6 mm control, P = 0.58) were comparable between groups. First-pass isolation was shown to be higher in the AI group (79% AI vs 44%, p= 0.01). Mean number of radiofrequency applications was lower in the AI group (93 ± 24 vs 111 ± 30, P = 0.02). Average contact-force was similar between groups (17.6 ± 4.1 g vs 22.6 ± 10.7 g, P =0.166). Patients that performed PVI guided by the AI had lower Hs-cTnI (1815 ± 1146 ng/L vs 3274 ± 1696 ng/L, p &amp;lt; 0.001) and lower AEQ (1.01 ± 0.7 ng/L/s vs 1.51 ± 0.7 ng/L/s, P = 0.011) compared to patients in the control group. During a mean follow-up of 26 ± 11 months, AF recurrence was documented in 10.3% of patients in the AI group and 22.2% in the control group (P = 0.223). Neither Hs-cTnI nor AEQ levels were predictors of arrhythmia recurrence. Conclusions These data suggest that AI-guided catheter ablation is associated with reduced levels of of Hs-cTnI and AEQ. Neither Hs-cTnI and AEQ should be used to predict arrhythmia recurrence. Abstract Figure.

MANual vs. automatIC local activation time annotation for guiding Premature Ventricular Complex ablation procedures (MANIaC-PVC study)

To assess potential benefits of a local activation time (LAT) automatic acquisition protocol using wavefront annotation plus an ECG pattern matching algorithm [automatic (AUT)-arm] during premature ventricular complex (PVC) ablation procedures. Prospective, randomized, controlled, and international multicentre study (NCT03340922). One hundred consecutive patients with indication for PVC ablation were enrolled and randomized to AUT (n = 50) or manual (MAN, n = 50) annotation protocols using the CARTO3 navigation system. The primary endpoint was mapping success. Clinical success was defined as a PVC-burden reduction of ≥80% in the 24-h Holter within 6 months after the procedure. Mean age was 56 ± 14 years, 54% men. The mean baseline PVC burden was 25 ± 13%, and mean left ventricular ejection fraction (LVEF) 55 ± 11%. Baseline characteristics were similar between the groups. The most frequent PVC-site of origin were right ventricular outflow tract (41%), LV (25%), and left ventricular outflow tract (17%), without differences between groups. Radiofrequency (RF) time and number of RF applications were similar for both groups. Mapping and procedure times were significantly shorter in the AUT-arm (25.5 ± 14.3 vs. 32.8 ± 12.6 min, P = 0.009; and 54.8 ± 24.8 vs. 67.4 ± 25.2, P = 0.014, respectively), while more mapping points were acquired [136 (94-222) AUT vs. 79 (52-111) MAN; P < 0.001]. Mapping and clinical success were similar in both groups. There were no procedure-related complications. The use of a complete automatic protocol for LAT annotation during PVC ablation procedures allows to achieve similar clinical endpoints with higher procedural efficiency when compared with conventional, manual annotation carried out by expert operators.

Predictors of AVNRT Recurrence After Slow Pathway Modification.

Atrioventricular nodal reentry tachycardia (AVNRT) is the most common regular supraventricular tachycardia (SVT). Slow pathway modification (SPM) is the accepted first line treatment with reported success rates around 95%. Information regarding possible predictors of AVNRT recurrence is scarce.Out of 4170 consecutive patients with SPM in our department from 1993-2018, we identified 78 patients (1.9%) receiving > 1 SPM (69% female, median age 50 years) with a recurrence of AVNRT after a successful SPM. We matched these patients for age, gender and number of radiofrequency applications during first SPM with 78 patients who received one successful SPM in our center without AVNRT recurrence. Both groups were analyzed for possible predictors of a recurrence of AVNRT during long-term follow-up. The recurrence group contained a significantly lower proportion of patients with an occurrence of junctional beats during SPM (69% versus 89%, P = 0.006). Moreover, significantly more cases of previously diagnosed atrial fibrillation/tachycardia (AF/AT; 21% versus 5%, P = 0.007) and inducible AF/AT during electrophysiology study (23% versus 6%, P = 0.006) were present in the recurrence group. While more than half of patients had a recurrence within the first year, in 20% symptoms reappeared ≥ 4 years after ablation.In a small percentage of patients, AVNRT recurs after an initially successful ablation. Interestingly, these patients had significantly fewer junctional beats during ablation and a higher rate of other (inducible) arrhythmias. AVNRT recurrence spanned a considerable timeframe and should remain a differential diagnosis, even years after ablation.

The protective effects of radiofrequency pulmonary artery denervation on the progression of chronic thromboembolic pulmonary hypertension

Abstract This study aimed to assess the safety and efficacy of radiofrequency pulmonary artery denervation with the Simplicity system in patients with distal chronic thromboembolic pulmonary hypertension. Methods and results 60 chronic thromboembolic pulmonary hypertension patients with mean pulmonary artery pressure &amp;gt;25 mm Hg and absence of proximal artery lesion defined by pulmonary angiography were randomized into 2 groups. Group 1 included 30 patients who underwent pulmonary artery denervation procedure. The other 30 patients were assigned to the control group (only angio plus right heart catheterization). The procedure of pulmonary artery denervation was performed at the lateral wall of main pulmonary artery and ostium of the left and right pulmonary arteries using the electrode from Simplicity denervation system. The programmed ablation parameters were temperature &amp;gt;50°C and time = 120 s. Using the coronary guiding technique, the tip of electrode was applied at each spot rotating the tip with pace of 2 mm. The success was defined by decrease of mean pulmonary artery pressure &amp;gt;10%, absence of complications. The primary end point was comparison of mean pulmonary artery pressure change from baseline to 12 months in pulmonary artery denervation group compared with change from baseline to 12 months in control group. The secondary point was change in 6-min walk distance and pulmonary vascular resistance at the 12-month follow-up. There were no complications after pulmonary artery denervation. The hemodynamic success was achieved in 93% of all cases. The mean number of radiofrequency applications to achieve success was 10.3 per patient. During follow-up period 3 patients died in pulmonary artery denervation group: (1 died of gastro-intestinal bleeding, 2 – of right ventricular failure) and 3 patients in control group. The mean decreases in the mean pulmonary artery pressure were 8.7 mm Hg in the pulmonary artery denervation group and 3.1 mm Hg in control group (p&amp;lt;0.05). After pulmonary artery denervation in comparison with the control group was observed significant decrease in pulmonary vascular resistance (8.3±2.8 WU vs. 11.2±3.7). 6-min walk distance significantly increased by 81 m after pulmonary artery denervation and 29 m in control group (p&amp;lt;0.05). This improvement was associated with significant improvements in the WHO functional class. Conclusions The usage of the Simplicity denervation system in pulmonary artery denervation procedure is safe and effective. Further studies are required to determine the role of pulmonary artery denervation in the treatment of chronic thromboembolic pulmonary hypertension. The next step of pulmonary artery denervation development will be the use of this method combined with recommended treatment (medical therapy, pulmonary endarterectomy and balloon pulmonary angioplasty) as additional option, that may sufficiently improve outcomes in some patients Funding Acknowledgement Type of funding source: None

Assessment of the potential damaging effect of radiofrequency exposure in children in prospective follow-up (case report series)

Aim: To evaluate the electrical activity of the myocardium and the radiofrequency (RF) application zone resulting from radiofrequency ablation (RFA) performed at an early age.Material and Methods. A prospective follow-up study included three patients who underwent intracardiac electrophysiological study (EPS) and effective RFA of the tachycardia for the first time at an early age. A reintervention was required in one case 12 years after the procedure and in two cases six years after it due to recurrent and new-onset arrhythmias. During the reintervention, electroanatomical mapping was performed to assess the potential damaging effect of radiofrequency exposure in the area of the first ablation.Results. The intracardiac EPS and amplitude bipolar CARTO-reconstruction of primary ablation area were performed during repeated RFA procedure. The study showed that neither zones with a decrease in the amplitude of electrical signal from the myocardium nor silent electrical zones were present ruling out the cicatricial-sclerotic changes in the myocardium in children in the long-term period after RF exposure.Conclusion. The study showed that no increase in the coagulation necrosis zone in the area of primary ablation occurred during the growth of child when the sparing energy and temperature parameters of RFA and the limited number of RF applications were used. Further research in this area is required.

125Manual vs. automatic local activation time annotation for guiding premature ventricular complex ablation procedures (MANIaC - PVC study)

Abstract Funding Acknowledgements Financial support was provided in form of a research grant from Biosense Webster Introduction The use of an algorithmic method (wavefront, WF) based on automatic annotation of the maximal negative slope of the unipolar electrogram (uni-EGM) within the window demarcated by the bipolar EGM (bi-EGM) may accurately identify the earliest activation site (EAS) during premature ventricular complex (PVC) ablation procedures. Purpose To assess the potential benefits of a local activation time (LAT) automatic acquisition protocol using WF plus an automatic algorithm for ECG pattern matching recognition (AUT-arm) instead of a manual LAT annotation plus ECG visual inspection (MAN-arm) during premature ventricular complexes (PVCs) ablation procedures. Methods Prospective, randomized, controlled and international multicenter study (NCT03340922). 69 consecutive patients with indication for PVC ablation were enrolled and randomized to AUT (n = 34) or MAN (n = 35) annotation protocols using the CARTO3 navigation system. The primary endpoint was mapping success, defined as complete PVC abolition after a maximum of 2 radiofrequency (RF) applications or up to 90 seconds at the identified EAS, considered the site of origin (SOO). Complete PVC abolition was considered as the procedure success, whereas clinical success was defined as the PVC-burden reduction of &amp;gt;80% in the 24-h Holter at least 1 month after the procedure. Concordance analysis of the maps obtained with both methods was performed. Results Mean age was 69 ± 15, 58% men. The mean baseline PVC burden was 26 ± 13%, mean LVEF 55 ± 12%. Baseline characteristics were similar between groups. The most frequent PVC-SOO were RVOT (41%), LV (25%; being the summit the most frequent location), and LVOT (16%), with no MAN-AUT differences. Total mapping time, number of RF applications, RF time, and procedure time were similar for both groups. The AUT-arm had a higher number of mapping points acquired (164 vs. 61; p = 0.002). There was a delayed detection of LAT at the EAS in the AUT-arm (mean 23 ± 13 ms), being more significant in left-sided PVCs (30 ± 12 vs. 15 ± 9 ms, p &amp;lt; 0.001). The 10-ms isochronal area was significantly bigger in the MAN-arm (1.95 ± 2.7 vs. 1.0 ± 1.0; p = 0.05). The median (interquartile range) distance between AUT-EAS and MAN-EAS was 4 (0–6.8) mm. Mapping success was similar for AUT (65%) and MAN (63%) (p = 1.0). Procedure success was significantly better for the AUT-arm (100% AUT vs. 86% MAN; p = 0.04), but without differences in clinical success (87% AUT vs. 82% MAN; p = 0.7). There were no procedure-related complications. Conclusions The use of a complete automatic protocol for LAT annotation (WF + ECG pattern matching) during PVC ablation procedures is feasible and safe, allowing to achieve equivalent procedural and clinical endpoints as compared to manual procedures carried out by expert operators.

Contact-Force-Sensing-Based Radiofrequency Catheter Ablation in Paroxysmal Supraventricular Tachycardias (COBRA-PATH): a randomized controlled trial

BackgroundMultiple studies have demonstrated the importance of adequate catheter–tissue contact in the creation of effective lesions during radiofrequency catheter ablation. The development of contact force (CF)-sensing catheters has contributed significantly to improve clinical outcomes in atrial fibrillation. However, CF-sensing technology is not used in the ablation of paroxysmal supraventricular tachycardia (PSVT). The possible reason for this is that PSVT ablation with the conventional approach (i.e. nonirrigated, non-CF-sensing catheters) is considered a relatively low-risk procedure with fairly high success rates (short and long term). The aim of this study is to determine whether CF sensing can further improve the outcomes of PSVT ablation.Methods/designThe COBRA-PATH study is a single-center, two-armed, randomized controlled trial. Patients without structural heart disease being referred for electrophysiology study, because of PSVT and potential treatment with radiofrequency (RF) catheter ablation, will be randomly assigned to either manual ablation with standard nonirrigated ablation catheters or manual ablation with an open-irrigated ablation catheter equipped with CF sensing (used in a virtual nonirrigated modus). The primary study endpoint is the difference in the number of RF applications during the ablation of atrioventricular nodal re-entry tachycardia, and that of Wolff–Parkinson–White syndrome and atrioventricular re-entrant tachycardia. Secondary outcome parameters include acute and long-term procedural success rates, overall duration of RF applications, procedure/fluoroscopy durations and safety parameters.DiscussionWe expect to see a reduced number/duration of RF applications required to achieve effective lesion creation, and consequently a decrease in total procedure/fluoroscopy times. Although a significant improvement in procedural success rates (acute/long term) might not be feasible to demonstrate (given the relatively high success rate of the standard ablation method), the possible decrease in procedure duration and the consequential reduction of radiation exposure has important clinical implications for both operators and patients undergoing the procedure.Trial registrationClinicalTrials, NCT04078685. Retrospectively registered on 2 September 2019.

P1021Comparative efficacy of microfidelity technology vs standard ablation for atrioventricular nodal ablation

Abstract Background Microfidelity Cateter Technology has proven efficacy in ablating atrial arrhythmias in multiple pilot studies. Closely spaced radial microelectrodes render a focused near-field electrogram. Case series suggest that this catheter design facilitates accurate ablations with fewer radiofrequency (RF) lesions. Atrioventricular junction (AVJ) ablation is regarded as a straightforward procedure, but case records show wide variance in procedure times and number of RF lesions required. Methods Twenty-four patients scheduled for AVJ ablation were randomized to treatment with either the Microfidelity technology or standard 8mm/8 French ablation catheter. Both groups located the AVJ by fluoroscopic landmarks and His electrograms, and the MiFi group used electroanatomical mapping to create the location of his electrograms. The primary endpoints were development of Junctional Rhythm (JR) or Complete Heart Block (CHB), and time from first RF lesion until rhythm change. Secondary endpoints included number of RF applications. Results Patients were randomized one-to-one to the MiFi arm or standard ablation arm. JR or CHB was achieved in all patients. Time from first RF lesion until JR/CHB was: (Median/IQR) 325 sec/250–1270 sec. vs 287 sec/101–406 sec. Number of RF applications was 5/3–15 applications vs 4.5/1–5 applications. Total procedure time in the lab was 134 min/73.5–172.5 min vs 58 min/52–146 min. Microfidelity Technology vs Standard Conclusion Analysis suggests that the MiFi catheter is efficacious in ablating the AVJ, but requires greater RF duration and number of lesions, with wider case-by-case variability to achieve JR or CHB. Microfidelity technology and electroanatomical mapping did not result in faster time to completion than using fluoroscopic landmarks and His electrograms alone. Preoperative choice of sheath for catheter stability and contact may also play a role in a more efficient timely successful ablation of the AV node. Acknowledgement/Funding Boston Scientific

Irrigated-tip vs. conventional-tip catheters for primary ablation of posteroseptal and right free-wall accessory pathways: a prospective randomized study.

The use of irrigated-tip catheters enables elimination of almost all accessory pathways (APs) resistant to standard radiofrequency ablation (RFA). However, efficacy of irrigation catheter technology in the initial AP ablation has not been studied systematically yet. We tested whether the externally irrigated-tip catheters are more effective than the conventional-tip catheters for initial RFA of the posteroseptal and right free-wall APs, i.e., where application of the conventional RFA is expected to have a lower success rate. Fifty consecutive patients (39 +/- 12 years, 32 males), who were subjected to primary catheter-ablation of the posteroseptal or right free-wall AP were randomly assigned to RFA with an externally irrigated-tip catheter (group I, n = 25; 45 degrees C/40 W outside the coronary sinus (CS) and 45 degrees C/30 W inside the CS) or a conventional-tip catheter (group C, n = 25; 60 degrees C/60 W outside and 55 degrees C/35 W inside the CS). No significant difference was identified between groups I and C with respect to acute success rate (88% vs. 96%), number of radiofrequency applications (6.8 +/- 4.7 vs. 6.1 +/- 4.3), RFA time (373 +/- 242 sec vs 365 +/- 241 sec), energy (11,022 +/- 7833 J vs. 12,870 +/- 11,414 J), fluoroscopy time (669 +/- 443 sec vs. 789 +/- 578 sec) and recurrence rate (18.2% vs. 16.7%). The only complication was encountered in group I, manifested as AV-block I-II degree after elimination of the right posteroseptal AP. Irrigated-tip catheters are not more efficient than conventional catheters in initial RFA of the posteroseptal and right free-wall APs. Therefore, the use of irrigated-tip catheters is justifiable only for ablation of the APs resistant to previously attempted conventional RFA.

Catheter ablation of cardiac arrhythmias in pregnancy without fluoroscopy: A case control retrospective study.

Cardiac arrhythmias are common in pregnant women. In most cases, they do not require treatment other than rest, electrolyte supplementation and avoidance of strong coffee and tea. Persistent arrhythmia or the ventricular rate running at a high frequency may cause hemodynamic deterioration in the fetus or in both the fetus and the mother. The aim of this study was to assess the prevalence and characteristics of arrhythmias in pregnant women who qualified for ablation as well as the feasibility and specific features of these interventions. The study group consisted of 11 pregnant women (16-32 Hbd) aged 31 + 6. The control group consisted of 111 women aged 15-50 years (34 + 10), scheduled for ablation in 2012. The medical records of the selected study and control groups were analyzed and the following data was retrieved: age, the reason the ablation procedure was performed, the ablation duration, the number of radiofrequency applications, the total duration of radiofrequency applications, gravity, and comorbidities. In the study group, accessory pathway related arrhythmias or atrial tachycardia (AT) accounted for 62% of cases, whereas in the control group for 32% (p = 0.042). All the procedures in the study group were performed with an electroanatomical system without fluoroscopy. All of the patients, but one, had no recurrence of arrhythmia. There were no complications and no overt effects were noted in the fetus. Ablation of arrhythmias during pregnancy is rare. An experienced surgeon using electroanatomical system is usually able to ablate arrhythmic substrate without the use of X-ray fluoroscopy. The most prevalent causes of arrhythmias in pregnant women requiring ablation are accessory pathway and AT focus.