Three-dimensional Electroanatomic Mapping System Research Articles

Zero-fluoroscopy catheter ablation of premature ventricular contractions: comparative outcomes from the right ventricular outflow tract and other ventricular sites.

The three-dimensional electroanatomic mapping (EAM) system allows performing catheter ablation (CA) without fluoroscopy in patients with premature ventricular contractions (PVCs). The right ventricle outflow tract (RVOT) location is favorable for performing zero-fluoroscopy CA. Non-RVOT zero-fluoroscopy CA is a challenging procedure. The study aimed to evaluate the efficacy and safety of zero-fluoroscopy CA using the EAM in patients with PVCs from RVOT and non-RVOT. Completely zero-fluoroscopy CA of PVCs guided by EAM was performed in 107 patients with PVCs. 54 patients underwent zero-fluoroscopy RVOT CA. The remaining 53 patients underwent zero-fluoroscopy non-RVOT CA. Demographic and clinical baseline characteristics, procedure parameters, and follow-up were obtained from medical records. Primary outcomes were the acute and the permanent success rate (12-month follow-up), complications, and procedure time. There were no significant differences between groups regarding baseline characteristics. Acute procedural success was achieved in 52 patients (94,44%) in the RVOT zero-fluoroscopy CA group and in 45 patients (86,54%) in the non-RVOT zero-fluoroscopy CA group (ns). A long-term success rate was achieved in 50 patients (90,74%) in the RVOT zero-fluoroscopy CA group and in 44 patients (84,62%) in the non-RVOT zero-fluoroscopy CA group (ns). The median procedure time was 80.5 minutes in the RVOT group and 90 minutes in the non-RVOT group (ns). There were two complications in the non-RVOT group (ns). There were no differences in procedure time efficacy and safety zero-fluoroscopy ablation between RVOT and non-RVOT locations. Non-fluoroscopy CA of PVCs is a feasible, safe, and efficient procedure.

Intermittent hypoxia by obstructive sleep apnea is significantly associated with electro-anatomical remodeling of the left atrium preceding structural remodeling in patients with atrial fibrillation

BackgroundObstructive sleep apnea (OSA) is one of the risk factors for atrial fibrillation (AF). However, the mechanism underlying the atrial structural and electro-anatomical remodeling by OSA has not yet been clearly elucidated. MethodsThis study was conducted in 83 patients who had undergone catheter ablation for AF (49 with OSA and 34 Controls without OSA). The left atrial (LA) maps were created in all the patients using a three-dimensional electro-anatomical mapping system. The LA with a bipolar voltage of <0.5 mV was defined as the low voltage area (LVA); %LVA was defined as the ratio of the LVA to the total surface area of the LA. ResultsThe LVA and %LVA were significantly greater in the OSA group as compared with the Control group, however, there was no difference in the LA area. The 3 % oxygen desaturation index (ODI) was significantly correlated with the %LVA (r = 0.268, P = 0.014), but not with the LA area. Multiple regression analysis with adjustments identified 3 %ODI ≥30 (3.088, 1.078–8.851, P = 0.036) as being significantly associated with the %LVA. ConclusionsIn patients with AF complicated by OSA, significant increase of the LVA, but not of the LA area, was observed. The intermittent hypoxia severity was significantly associated with the LVA. These results suggest that intermittent hypoxia by OSA might be one of the mechanisms of electro-anatomical remodeling of the LA, possibly preceding structural remodeling represented by LA enlargement, in patients with AF.

VARIPULSE: A step-by-step guide to pulmonary vein isolation.

The VARIPULSE™ variable-loop circular catheter (VLCC) is a bidirectional, multielectrode catheter that can perform electrophysiological mapping and deliver pulsed field energy through the TRUPULSE™ Generator for the treatment of atrial fibrillation. This ablation system, including the CARTO 3™ three-dimensional electroanatomical mapping system, represents a fully integrated system. Pulsed field ablation (PFA) is a novel, primarily cardiac tissue-selective ablation technology with a minimal thermal effect, potentially eliminating the collateral tissue damage associated with radiofrequency ablation or cryoablation. Integration of a mapping system may lead to shorter fluoroscopy times and improve the usability of the system, allowing tracking of energy density and placement to confirm no areas around the vein are left untreated. This step-by-step review covers patient selection, mapping, the step-by-step ablation workflow, details on catheter repositioning and ensuring contact, considerations for ablation of specific anatomical variations, and discussion of ablation without fluoroscopy based on our initial clinical experience. The VLCC is part of the fully integrated PFA system designed for pulmonary vein isolation, using mapping to guide catheter placement and lesion set creation. The current workflow, which is based on our initial clinical experience, may be further refined as the PFA system is used in real-world settings.

Procedural efficiency is enhanced combining the pentaspline pulsed field ablation catheter with three-dimensional electroanatomical mapping system for pulmonary vein isolation

Abstract Background Pulsed field ablation (PFA) offers a safe, non-thermal alternative for pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF). Currently, the pentaspline PFA-system relies heavily on fluoroscopy for catheter manipulation, which poses challenges due to the complexity of left atrium anatomy. Incorporating three-dimensional electroanatomical mapping (3D-EAM) could improve procedural efficiency reducing dependency on fluoroscopy guidance. This study aims to evaluate the effects of integration of 3D-EAM with PFA during PVI. Methods Between September 2022 and December 2023, we retrospectively enrolled 248 patients with paroxysmal or persistent AF undergoing PVI at our center using the pentaspline PFA catheter. The control group (n = 104) received conventional PFA with fluoroscopic guidance alone, while the intervention group (n = 144) underwent PVI with PFA with 3D-EAM integration. Primary outcomes were procedural time, fluoroscopy time (FT), and dose area product (DAP). Secondary endpoints included acute procedural success and incidence of periprocedural complications. Results In the 3D-EAM-PFA group, procedural time was 63.3 ± 14.3 min, compared to 65.6 ± 14.9 min in the control group (p = 0.22). The 3D-EAM group experienced significantly reduced FT (9.7 ± 4.4 min vs. 16.7 ± 5.2 min) and DAP (119.2 ± 121.7 cGycm2 vs. 338.7 ± 229.9 cGycm2) compared to the control group, respectively (p &lt; 0.001). Acute procedural success was achieved in all cases. No major complications were observed in either group. Conclusion Integration of 3D-EAM with the pentaspline PFA catheter for PVI in AF treatment offers a promising approach, with significantly reduced fluoroscopy exposure without compromising procedural time and efficacy. Graphical abstract

Intracardiac Echocardiography: An Invaluable Tool in Electrophysiological Interventions for Atrial Fibrillation and Supraventricular Tachycardia.

Researchers have investigated ways to develop optimal imaging techniques to increase the safety and effectiveness of electrophysiological (EP) procedures. Intracardiac echocardiography (ICE) is an advanced imaging tool that can directly visualize cardiac anatomical structures in high resolution, assess tissue heterogeneity and arrhythmogenic substrates, locate intracardiac catheters, monitor catheter-tissue contact and ablation injury in real-time, excluding intracardiac thrombi, and quickly detect procedural complications. Additionally, real-time imaging via ICE can be integrated with a three-dimensional (3D) electroanatomical mapping (EAM) system to reconstruct cardiac anatomy. This technique also promotes the development of zero-radiation EP procedures. Many EP studies and procedures have implemented ICE because it has several advantages over fluoroscopy and transesophageal echocardiography (TEE). ICE-guided EP procedures can be performed under conscious sedation; esophageal intubation and additional anesthesiologists are not required. Atrial fibrillation (AF) and supraventricular tachycardias (SVT) are the most common tachyarrhythmias in clinical settings. A comprehensive understanding of critical anatomical structures, such as the atrial septum, fossa ovalis (FO), and great heart vessels, is needed for the successful catheter ablation of these arrhythmias.

Intermittent hypoxia is significantly associated with low-voltage areas in patients with atrial fibrillation complicated by obstructive sleep apnea

Abstract Background Obstructive sleep apnea (OSA) is one of risk factors for atrial fibrillation (AF); however, how OSA affects the structural and electrical atrial remodeling is not well described. This study aimed to determine the association of OSA with left atrial (LA) size and LA low-voltage area (LVA), a known arrhythmogenic substrate for AF. Methods Eighty-three patients undergoing catheter ablation of AF (forty-nine with OSA [apnea–hypopnea index: AHI ≥ 5/h] and thirty-four control patients without OSA by full polysomnography or portable monitor) were studied. In all cases, LA maps were created using a three-dimensional electro-anatomical mapping system in sinus rhythm or pacing from the right atrium. LVA was defined as a bipolar voltage &amp;lt; 0.5 mV. %LVA is defined as ratio of LVA to LA area. Results LVA and %LVA were larger in OSA group as compared to Control group (6.0 ± 6.6 vs. 2.6 ± 3.2 cm2, P = 0.003 and 7.5 ± 8.5 vs. 3.5 ± 4.6 %, P = 0.008, respectively). On the other hand, there was no difference in LA size between the two groups. In addition, 3% oxygen desaturation index (ODI) was significantly correlated with %LVA (r = 0.282, P = 0.010), but not with LA size (r = 0.053, P = 0.637). Multiple regression analysis demonstrated that 3%ODI ≥ 30 (3.088, 1.078-8.851, P = 0.036) was significantly associated with %LVA after adjustment. Conclusion In patients with AF complicated by OSA, significant enlargement of the LVA was observed, but there was no evidence of enlargement in LA size. Intermittent hypoxia may be one of the mechanisms of this atrial electro-anatomical remodeling.figure 1figure 2

Catheter ablation of supraventricular tachycardia and atrial flutter with no or minimal use of fluoroscopy: the initial experience of a single Bulgarian center

Introduction: Catheter ablation (CA) is an established therapy for most arrhythmias. Non-&amp;#64258; uoroscopic three-dimensional (3D) electroanatomic mapping systems allow ablation of supraventricular tachycardia (SVT) and atrial &amp;#64258; utter (AFL) with zero or near-zero &amp;#64258; uoroscopy (ZF/NZF). The current study aims to report our initial experience with ZF/NZF in SVT or AFL CA. Material and methods: We conducted a single-center prospective registry enrolling consecutive patients referred for CA of SVT or AFL. ZF/NZF CA was attempted in all patients using a commercially available 3D mapping&amp;nbsp;system. Fluoroscopy use was allowed at any point of the procedure. Procedural characteristics and long-term outcome were analyzed. The learning curve effect was also studied. Results: Sixty-three patients (age 53.5 &amp;plusmn; 14.1, 57% males) with SVT or AFL were enrolled. According to arrhythmia type typical AVNRT was diagnosed in 36 (57.1%) cases, right atrial &amp;#64258; utter in 25 (39.7%) cases, left-sided accessory pathway in 1 (1.6%) and focal right atrial tachycardia in 1 (1.6%) case. Three patients (4.8%) had two arrhythmia substrates. The procedure was performed with ZF in 49/63 cases (77.8%), while NZF was necessary in 14 (22.2%) patients with a &amp;#64258; uoroscopy time of 220 &amp;plusmn; 169 sec and a dose-area product of 7556 &amp;plusmn; 5886 mGy*cm2. Median procedural time was 88 (IQR 25-75 percentile 71.5-116) min with 22 (IQR 25-75 percentile 16-31) min of mapping time. Acute procedural success was accomplished in all patients with no periprocedural complications. Over a follow-up of 12 &amp;plusmn; 3 months, all patients remained arrhythmia-free. There was a learning curve effect with a signi&amp;#64257; cant reduction of procedural time (P = 0.025) and a signi&amp;#64257; cant difference (P = 0.019) in the rate of &amp;#64258; uoroscopy use among different periods of the study duration. Conclusion: ZF/NZF CA of SVT and AFL is associated with high ef&amp;#64257; cacy and safety. Entirely &amp;#64258; uoroless CA can be performed in the vast majority of patients. It is a feasible approach associated with a detectable learning curve effect.&amp;nbsp;

Zero-Fluoroscopy Catheter Ablation of Supraventricular Tachycardias in the Pediatric Population.

Catheter ablation (CA) of supraventricular tachycardias (SVTs) is conventionally performed with the aid of X-ray fluoroscopy. Usage of a three-dimensional (3D) electro-anatomical mapping (EAM) system and intracardiac echocardiography (ICE) enables zero-fluoroscopy ablation, eliminating the harmful effects of radiation. We retrospectively analyzed the feasibility, effectiveness and safety of zero-fluoroscopy radiofrequency and cryoablation of various types of SVTs in pediatric patients. Overall, in 171 consecutive patients (12.5 ± 3.9 years), 175 SVTs were diagnosed and 201 procedures were performed. The procedural success rate was 98% (193/197), or more precisely, 100% (86/86) for AVNRT, 95.8% (91/95) for AVRT, 94.1% (16/17) for AT and 100% (2/2) for AFL. No complications were recorded. Follow-up was complete in 100% (171/171) of patients. During the mean follow-up period of 488.4 ± 409.5 days, 98.2% of patients were arrhythmia-free with long-term success rates of 98.7% (78/79), 97.5% (78/80), 100% (13/13) and 100% (2/2) for AVNRT, AVRT, AT and AFL, respectively. Zero-fluoroscopy CA of various types of SVTs in the pediatric population is a feasible, effective and safe treatment option.

Efficacy of Catheter Ablation Using the Electroanatomical System without the Use of Fluoroscopy in Patients with Ventricular Extrasystolic Beats.

Catheter ablation (CA) has become safe and efficient for the treatment of patients with ventricular extrasystolic beats (VEBs). The three-dimensional electroanatomic mapping (EAM) system allows the elimination of fluoroscopy time during CA procedures. Non-fluoroscopy CA is a challenging procedure requiring intimate knowledge of cardiac anatomy in patients with VEBs. The study aimed to evaluate the efficacy and safety of the non-fluoroscopy CA using the EAM system in patients with VEBs. Completely fluoroless CA of VEBs guided by EAM was performed in 86% (94 out of 109) of consecutive patients with VEBs. The remaining 15 patients underwent conventional fluoroscopy-guided CA. Demographic and clinical baseline characteristics, procedure parameters, and following complications were obtained from the medical records. Primary outcomes were the acute procedural success rate, the permanent success rate (6-month follow-up), complications, and procedure time. There were no significant differences between groups regarding baseline characteristics. Acute procedural success was achieved in 85 patients (90%) in the non-fluoroscopy group and in 14 patients (93%) in the fluoroscopy group (ns). A long-term success rate was achieved in 82 patients (87%) in the non-fluoroscopy group and in 14 (82%) patients in the fluoroscopy group (ns). The median procedure time was 85 min in the non-fluoroscopy group and 120 min in the fluoroscopy group (p = 0.029). There was only one major complication in the non-fluoroscopy group (ns). Completely fluoroless CA of VEBs guided by EAM is a feasible, safe, and efficient procedure.

Minimal Fluoroscopic Catheter Ablation for Adult Patients with Paroxysmal Supraventricular Tachycardia without the Assistance of Intracardiac Echocardiography.

Radiation exposure during fluoroscopic procedures increases the risk of cancer for both patients and operators. The aim of this study was to investigate the safety and efficacy of adopting a three-dimensional electroanatomical mapping (3D EAM) system during ablation for paroxysmal supraventricular tachycardia (PSVT), without the assistance of intracardiac echocardiography (ICE), for both right- and left-chamber cardiac procedures. We retrospectively enrolled all patients with PSVT from September 2018 to December 2020. The patients were grouped according to the use of the 3D EAM system (3D-guided group, n = 102 vs. conventional group, n = 226). The acute success rates were high in both groups (100% vs. 99.1%). The fluoroscopy time was significantly lower in the 3D-guided group than in the conventional group (2.4 ± 4.4 vs. 19.0 ± 10.8 min); the procedure time was significantly increased in the 3D-guided group (104.5 ± 29.9 vs. 94.0 ± 31.9 min), and this was associated with the post-electrophysiology test diagnosis after adjustment for multiple variables [standardized B coefficient (β) 0.188]. There was no learning curve for each electrophysiologist in terms of fluoroscopy and procedure times. The 3D EAM system, without the assistance of ICE, was safe and effective in guiding PSVT ablation in both left- and right-chamber ablation.

Wide antral circumferential vs. ostial pulmonary vein isolation using pulsed field ablation-the butterfly effect.

Wide antral circumferential ablation (WACA) in comparison to ostial pulmonary vein (PV) isolation (PVI) has been attributed with improved rhythm outcome. We investigated the feasibility, lesion formation, and rhythm outcome of WACA-PVI in comparison to ostial-PVI using pulsed field ablation (PFA). Symptomatic atrial fibrillation (AF) patients (69 years, 67% male; 67% paroxysmal AF) were prospectively enrolled into our single-center registry and underwent first-time ostial-PFA or WACA-PFA, N = 15 each. In all patients, eight pulse trains (2 kV/2.5 s, bipolar, biphasic, 4× basket/flower configuration each) were delivered to each PV. In WACA-PFA, two extra pulse trains in a flower configuration were added to the anterior and posterior antrum of the PVs. For comparison of PFA lesion size, pre- and post-ablation left atrial (LA) voltage maps were acquired using a multipolar spiral catheter together with a three-dimensional electroanatomic mapping system. WACA-PFA resulted in a significant larger lesion formation than ostial-PFA (45.5 vs. 35.1 cm2, p = 0.001) with bilateral overlapping butterfly shape-like lesions and concomitant posterior LA wall isolation in 73% of patients. This was not associated with increased procedure time, sedation dosage, or exposure to radiation. One-year freedom from AF recurrence was numerically higher after WACA-PFA than ostial-PFA (94% vs. 87%) but not statistically significant (p = 0.68). No organized atrial tachycardias (ATs) were observed. Ostial-PFA patients more often underwent re-ablation due to recurrent AF episodes. WACA-PFA is feasible and resulted in significantly wider lesion sets than ostial-PFA. Concomitant posterior LA wall isolation occurred as an epiphenomenon in the majority of patients. The WACA approach was associated with neither increased procedure and fluoroscopy times nor statistically significant differences in 1-year rhythm outcome. ATs were absent.

Zero or minimal fluoroscopy catheter ablation: feasibility, efficacy, and safety results

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Fluoroscopy has been used to guide catheter ablation since the beginning of this technique, despite its important secondary effects on both patients and operators. However, three-dimensional electroanatomic mapping systems (3D-EAMP) enable ablation of some substrates using zero or minimal fluoroscopy. The aim of this study is to explore the feasibility, efficacy and safety of a zero or minimal fluoroscopy approach in our center. Methods We performed a retrospective observational study with consecutive patients that underwent catheter ablation of atrioventricular nodal reentrant tachycardia (AVNRT), accessory pathways (AP), focal atrial tachycardia and typical atrial flutter in our center, between January 2020 and November 2022. Vascular access was obtained by ultrasound guidance. The objective was zero-fluoroscopy for all patients except those with left AP, in which minimal fluoroscopy was allowed for the transseptal access (ablations with retrograde aortic approach were excluded). Results 319 consecutive patients were included. 56% were male, mean age was 55 ± 16 years. The following substrates were included: AVNRT (43%), typical atrial flutter (41%), AP (12%) and focal atrial tachycardia (5%). We achieved zero-fluoroscopy use in 99.3% of right substrates, using fluoroscopy in just two cases to introduce catheters through femoral access. Mean fluoroscopy time in left AP was 6.1 minutes. Ablation was successful in 97% of cases, and we just experienced three complications (moderate pericardial effusion, femoral hematoma and femoral arteriovenous fistula, all of them solved without requiring intervention). After a mean follow- up of 17 ± 14 months, we noticed three recurrences, performing in all of them a successful second ablation procedure. Baseline characteristics and procedure details are shown in table 1. Conclusions Catheter ablation of simple substrates with zero or minimal fluoroscopy using 3D mapping systems is feasible, effective and safe, with high success rate and low complications rate.

Cryoablation of atrioventricular nodal reentry tachycardia with utilization of three-dimensional electroanatomic mapping system

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Catheter ablation for atrioventricular nodal reentry tachycardia (AVNRT) is usually performed with radiofrequency (RF) energy, which carries a risk of collateral conduction system injury. Cryoablation is a safer, but less effective alternative. Utilization of the three-dimensional electroanatomic mapping (3D EAM) system can potentially overcome some limitations of cryoablation and possibly improve procedural outcome. Purpose We retrospectively analyzed the feasibility, efficacy, and safety of cryoablation of AVNRT guided by 3D EAM system. Methods In this retrospective study, we analyzed consecutive patients who underwent cryoablation of AVNRT in our institution from April 2017 to May 2022. All procedures were performed with either magnetic-based or impedance-based system. A 3D model of the right atrium was created and important structures were annotated. Cryomapping was performed at the presumed slow pathway location, followed with cryoablation when appropriate. Location of cryoablation was annotated either with a dot superimposed from the distal electrode of the cryoablation catheter to the surface of the 3D model or the position of the cryoablation catheter was snapshotted. Intracardiac echocardiography (ICE) was utilized at the operator’s discretion. Procedural endpoint was AVNRT noninducibility, with up to one atrial echo beat allowed. Follow-up was performed with a visit to an outpatient clinic or with a telephone interview. Results The study included 122 consecutive patients (49/122 male; 33/122 pediatric patients, mean age 40.4 ± 22.1 years; mean BMI 25.0 ± 5.7 kg/m2). Altogether, 128 procedures were performed and 124 slow-fast AVNRT were diagnosed, 4 patients had slow-slow AVNRT. In six patients the procedure was repeated due to the recurrence of AVNRT. In two procedures, cryoablation was performed in the left atrium. Impedance-based 3D EAM system was used in 89.8% (115/128) of cases, while magnetic-based 3D EAM system was used in 10.2% (13/128) of cases. In 21.9% (28/128) of cases ICE was utilized. Median number of cryoablations was 3 (2 – 4) and median ablation time was 720 s (480 – 960 s). Cryomapping during ongoing AVNRT was possible in 52.3% (67/128) of cases, with mean time to termination of 13.4 ± 6.5 s. Mean procedural time was 80.9 ± 39.3 minutes. There were no major complications related to the procedure. Endpoint was achieved in 100% (128/128) of cases. Follow-up was completed in 96.7% (118/122) of cases, mean follow-up time was 484.7 ± 342.0 days. Arrythmia-free survival rate after first procedure was 88.1% (104/118). When all repeated procedures were included, the arrhythmia-free survival rate was 94.9% (112/118). Conclusion Cryoablation of AVNRT with utilization of the 3D EAM system is feasible, effective, and safe. Although, the success rate after first procedure is lower than expected, the procedure can be safely repeated to improve the outcome.

Wave speed guided point-by-point cavo-tricuspid isthmus ablation to reduce ablation and fluoroscopy in typical atrial flutter

Abstract Funding Acknowledgements Type of funding sources: None. Background Ablation procedures for cavo-tricuspid isthmus (CTI) dependent typical atrial flutter (AFL) have traditionally been performed with conventional electrophysiology mapping guided by fluoroscopy. Three-dimensional electroanatomical mapping (EAM) systems have routinely been used to guide ablation of more complex arrhythmias, but in recent years, have been used for simple ablations with the aim of reducing irradiation. High voltage regions in the CTI have been described as a target in order to minimize procedure times, but there is a lack of knowledge regarding the utility of slow conduction zones for this purpose. Methods In a prospective cohort of patients undergoing 3D EAM assisted AFL ablation, we evaluated a novel strategy (NS) based on omnipolar vectors, using both wave speed and voltage information to focus radiofrequency (RF) lesions (see figure), and compared with a recent retrospective cohort of patients undergoing voltage-guided ablation (VG). Results A group of 26 consecutive patients with mean age 68±12 years and 88% male, underwent NS ablation, and were compared to 23 patients undergoing VG ablation, with no differences among patient characteristics. Of the 26 patients in group NS, 16 (53.9%) were successfully ablated targeting only 2 sites, representing the 2 most confluent areas of low wave speed and high voltage. A total of 24 (92.5%) were ablated successfully with targeting all sites of low wave speed. Only a single patient in the NS group required the completion of a classic CTI line. Average fluoroscopy time and radiation dose were lower in the NS group compared to VG group (1.1±2.4 min 19.5±41.7 mGray vs 8.2±10.2 min and 64.4±76.5 mGray, p=0.0014 and p=0.013, respectively). Furthermore, RF time trended towards reduction in the NS group. Conclusions A strategy based on targeting only areas of low wave speed is effective, limiting the need to complete a traditional CTI line, and reducing fluoroscopy in patients undergoin CTI ablation.

Safety and efficacy of intracardiac echocardiography-guided zero-fluoroscopic cryoballoon ablation for atrial fibrillation: a prospective randomized controlled trial.

The development of intracardiac echocardiography (ICE) has enabled fluoroless atrial fibrillation (AF) ablation using three-dimensional electroanatomical mapping systems. However, fluoroless cryoballoon ablation (CBA) remains challenging, mainly because of the lack of a visual mapping system. Hence, this study aimed to investigate the safety and efficacy of fluoroless CBA for AF under ICE guidance. Patients (n = 100) who underwent CBA for paroxysmal AF were randomly assigned to zero-fluoroscopic (Zero-X) and conventional groups. Intracardiac echocardiography was used to guide the transseptal puncture and catheter and balloon manipulation in all enrolled patients. The patients were prospectively followed for 12 months after CBA. The mean age was 60.4 years, and the left atrial (LA) size was 39.4 mm. Pulmonary vein isolation (PVI) was achieved in all patients. In the Zero-X group, fluoroscopy was used in only one patient because of unstable phrenic nerve capture during right-sided PVI. The procedure time and LA indwelling time in the Zero-X group were not statistically different compared with that in the conventional group. Fluoroscopic time (9.0 vs. 0.008 min) and radiation exposure (29.4 vs. 0.02 mGy) were significantly shorter in the Zero-X group than in the conventional group (P < 0.001). The complication rate did not differ between the two groups. During a mean follow-up of 663.3 ± 172.3 days, the recurrence rate was similar (16.0 vs. 18.0%; P = 0.841) between the groups. Multivariate analysis revealed that LA size was the only independent predictor of clinical recurrence. Intracardiac echocardiography-guided fluoroless CBA for AF was a feasible strategy without compromising acute and long-term success or complication rates.

Coherent mapping of atrial tachycardias in patients with congenital heart disease.

Coherent mapping (CM) uses a new algorithm to identify critical conduction isthmuses of atrial tachycardias (ATs). We analysed our experience of ablation of AT in patients with congenital heart disease (CHD) with this new technology. All patients with CHD who had CM of AT using the high-density mapping PENTARAY™ catheter and three-dimensional electroanatomic mapping system Carto3 between June 2019 and June 2021 were included retrospectively (n = 27). As a control group, 27 patients with CHD and mapping of AT without CM between March 2016 and June 2019 were included. In total, 54 ablation procedures were performed in 42 patients [median age 35 (interquartile range, IQR 30-48) years] and 64 ATs were induced and mapped (thereof 50 AT intraatrial re-entrant tachycardia and 14 AT ectopic AT). The median procedure duration was 180 (120-214) min and median fluoroscopy time was 10 (5.2-14) min. Acute success was 100% (27/27) in the Coherence group and 74% (20/27) in the non-Coherence group (P = 0.01). During follow-up [median 26 (12-45) months], AT recurred in 28/54 patients, thereof 15 patients needed a re-ablation procedure. Log-rank test showed no difference in recurrence rate between the two groups (P = 0.29). Three minor complications occurred (5.5%). Mapping of AT in patients with CHD using the PENTARAY™ mapping catheter and the CM algorithm led to excellent acute success. All ATs were possible to map and no complications related to the PENTARAY™ mapping catheter were observed. Thus, the use of the CM algorithm represents a promising tool in patients with CHD and complex AT.

3D mapping of phrenic nerve course for radiofrequency pulmonary vein isolation.

Phrenic nerve (PN) injury is a rare but severe complication of radiofrequency (RF) pulmonary vein isolation (PVI). The objective of this study was to characterize the typical intracardiac course of the PN with a three-dimensional electroanatomic mapping system, to quantify the need for modification of the ablation trajectory to avoid delivering an ablation lesion on sites with PN capture, and to identify very circumscribed areas of common PNC on the routine ablation trajectory of a RF-PVI, allowing fast and effective PN screening for everyday usage. We enrolled 137 consecutive patients (63 ± 9 years, 64% men) undergoing PVI. A detailed high output (20 mA) pace-mapping protocol was performed in the right (RA) and left atrium (LA) and adjacent vasculature. The right PN was most commonly captured in the superior vena cavaat a lateral (50%) or posterolateral (23%) position before descending along the RA either straight (29%) or with a posterolateral bend (20%). In the LA, beginning deep within the right superior pulmonary vein (RSPV), the right PN is most frequently detectable anterolateral (31%), then descends to the lateral proximal RSPV (23%), and further towards the lateral antral region (15%) onto the medial LA wall (12%). To avoid delivering an ablation lesion on sites with PN capture, modification of ablation trajectory was necessary in 23% of cases, most commonly in the lateral RSPV antrum (81%). No PN injury occurred. PN mapping frequently reveals the close proximity of the PN to the ablation trajectory during PVI, particularly in the lateral RSPV antrum. Routine PN pacing should be considered during RF PVI procedures.

A Novel Wide-band Dielectric Imaging System for Electro-anatomic Mapping and Monitoring in Radiofrequency Ablation and Cryoablation.

A novel wide-band dielectric mapping system, named as KODEX-EPD (EPD Solutions, Philips, Best, the Netherlands), was effectively used in the EA mapping for atrial fibrillation (AF) ablation. To date, only a few studies have concentrated on the application of the KODEX-EPD system for ablating supraventricular tachycardia or ventricular premature beats (VPBs) in human models. This study aims to assess the applicability and efficiency of a novel three-dimensional electro-anatomic (EA) mapping system to improve the success rate of ablation. This study included 11 consecutive patients who underwent ablation after EA mapping with the KODEX-EPD system. All surgeries were successfully performed using the KODEX-EPD system, including 6 cases who underwent ablation of paroxysmal supraventricular tachycardia (PSVT), 2 cases who received ablation of VPBs from right ventricular outflow tract (RVOT), and 3 cases who underwent cryoablation of AF. For ablation of PSVT or VPBs, the operation time was 31.4 (range, 24.0-38.0) min, in which a median operation time of 2.9 min was used to create anatomic images, and the median fluoroscopic dose was 7.4 mGy. For ablation of AF, the operation time was 56.0 (range, 49.0-62.0) min, in which a median of 4.3 (range, 3.4-5.2) min was used for constructing left atrium map, and the median fluoroscopic dose was 15.0 mGy. The operation time and the fluoroscopic dose were greatly shortened for all surgeries. The KODEX-EPD system is an effective and safe tool to guide the EA mapping, leading to improvement in the success rate of ablation. It can promote the ablation process with the reduced fluoroscopic dose, and it is also a promising tool for complex surgeries.

Conventional fluorscopy-guided vs zero-fluorscopy catheter ablation of supraventricular tachycardias

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Traditionally, X-ray fluoroscopy is used during catheter ablation procedures. The utilisation of ionising radiation carries non-negligible stochastic and deterministic risks to the health of both the patient and the professional staff. These effects are cumulative and behave in a linear no-threshold manner and, as such, are especially important in paediatric populations (1). The importance of reducing ionising radiation exposure has been recognised by the American College of Cardiology, which recommends the ALARA (as low as reasonably achievable) principle in all interventional laboratories (2). In recent years, advances in three-dimensional electroanatomical mapping systems and their utilisation have enabled the near-zero and zero-fluoroscopy approaches to be studied (3). Purpose The aim of this study was to evaluate the safety and efficacy of zero-fluoroscopy catheter ablation for supraventricular tachycardias (SVT). Methods 584 consecutive patients referred to our institution for catheter ablation of SVT were analysed. Patients were categorised into two groups; zero-fluoroscopy (ZF) group and conventional fluoroscopy (CF) group. Patient characteristics, procedural information, and follow-up data were compared. Results The ZF group had a higher proportion of paediatric patients (42.2% vs 0.0 %; p &amp;lt; 0.001), resulting in a younger age (30.9 ± 20.3 years vs 52.7 ± 16.5 years; p &amp;lt; 0.001) and lower BMI (22.8 ± 5.7 kg/m2 vs 27.0 ± 5.4 kg/m2; p &amp;lt; 0.001). Procedure time was shorter in the ZF group (94.2 ± 50.4 min vs 104.0 ± 54.0 min; p = 0.002). There were no major complications and the rate of minor complications did not differ between groups (0.0% vs 0.4%; p = 0.304). Acute procedural success as well as the long-term success rate when only the index procedure was considered did not differ between groups (92.5% vs 95.4%; p = 0.155; 87.1% vs 89.2%; p = 0.422). When repeated procedures were included, the long-term success rate was higher in the ZF group (98.3% vs 93.5%; p = 0.004). The difference can be partially explained by the operators’ preferences. Conclusion The safety and efficacy of ZF procedures in adult and paediatric populations are comparable to that of CF procedures.

Zero-fluoroscopy catheter ablation of supraventricular tachycardias in pediatric population

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Catheter ablation (CA) of supraventricular tachycardias (SVTs) in pediatric patients is conventionally performed with the aid of X-ray fluoroscopy. Usage of the three-dimensional (3D) electro-anatomical mapping (EAM) system and the intracardiac echocardiography (ICE) enables zero-fluorscopy ablation, eliminating the harmful effects of the radiation (1-3). Purpose We retrospectively analyzed the feasibility, effectiveness and safety of zero-fluoroscopy radiofrequency and cryoablation of various types of SVTs in pediatric patients. Methods In this retrospective study, we analyzed consecutive pediatric patients who underwent CA procedure due to SVT in our institution from April 2014 to October 2021. All procedures were performed completely without the use of fluoroscopy. A 3D EAM system and ICE were used as the principal modes of catheter visualisation. Left-sided procedures were done with ICE guided transseptal approach. Radiofrequency was the principal energy source, while cryoablation was used for arrhythmia substrates in the proximity of the conduction system. Results The study included 174 consecutive patients (69/174 (66%) female; 12.5 ± 3.9 years; 19.2 ± 3.6 kg/m2). Altogether 176 SVTs were diagnosed and treated. Atrio-ventricular nodal reentry tachycardia (AVNRT) was diagnosed in 45% of cases (80/176), atrio-ventricular reentry tachycardia (AVRT) in 47% (82/176), focal atrial tachycardia (AT) in 7% (13/176), typical atrial flutter (AFL) was treated in only one patient, while 2 patients had multiple arrhythmias (AVNRT and AVRT). In total, 202 procedures were performed. Radiofrequency ablation was performed in 76% (154/202), cryoablation in 20% (40/202) and both in 4% (8/202) of procedures. The acute procedural success rate was 96% (195/202). Procedural success rate was 99% (79/80) for AVNRT, 94% (77/82) for AVRT, 92% (12/13) for AT, and 100% (1/1) for AFL, respectively. There were no major complications in our study group. Follow-up was complete in 99% (172/174) of patients. During the follow-up period of a median of 316 days (181 - 747), 98% of patients were arrhythmia free. On average, 1.16 procedures per patient were performed with the long-term success rate of 99% (79/80), 98% (80/82), 100% (13/13) and 100% (1) for AVNRT, AVRT, AT, and AFL, respectively. Conclusion Zero-fluoroscopy CA of various types of SVTs in pediatric population is a feasible, effective, and safe treatment option.