Electroanatomic Mapping System Research Articles

P102 DIFFERENCES IN HIGH–DENSITY MAPPING OF KOCH‘S TRIANGLE DURING TYPICAL AV NODAL REENTRANT TACHYCARDIA INTEGRATED AND NOT INTEGRATED WITH DIRECT RECORDING OF ATRIOVENTRICULAR NODE STRUCTURES POTENTIAL: A MULTICENTER NON–RANDOMIZED STUDY

Abstract Background Despite the sustained efforts and advances in the fields of anatomy, histology, immunohistochemistry and cardiac mapping, the definition of the AVNRT circuit in humans is still incomplete. This discouraging result can be explained by many reasons, but the most important one has been the impossibility to map the AVNRT circuit without recording the electrical activity of the AVN and its extensions, which represent the diastolic interval in the tachycardia cycle. The aim of this study was to compare high density activation mapping integrated and not integrated with AV node potential recordings to establish the importance of annotation of AV nodal structure electrical activity in defining Koch’s triangle activation during AVNRT. Methods Electroanatomic 3–D reconstruction and propagation automated mapping of atrial activation during both sinus rhythm and tachycardia was performed using a basket catheter (64 electrodes of 0.4–mm2 area; 2.5–mm spacing, Orion, Boston Scientific, Natick, MA) and the Rhythmia electroanatomic mapping system in group 1 patients (X). In group 2 patients (45) the AV node potential (a very low frequency signal distinct from atrial, His bundle or ventricular activations, recorded from electrodes overlying the region of the compact AV node and its extensions by using a non–conventional bipolar electrogram filtering of [0.05/1 – 250] Hz) were also recorded both during slow fast AVNRT. Results The integrated map showed that during AVNRT, the activation wavefront descends from the Tendon of Todaro region (fast pathway area) and rises along the septal leaflet of the tricuspid valve through the RINE and reaches the AV bundle probably via the LNB bypassing the compact AV node almost completely. This kind of activation of the Koch’s triangle was not reconstructed by the non–integrated map. Moreover, the recording of the potentials of the AV node structures makes it possible to obtain a 100% coverage of the tachycardia cycle which was only 32% in the non–integrated maps (p < 0.0001). Conclusion The recording of the electrical activity of AV nodal structures allows a better definition of the circuit of typical slow–fast AVNRT which, in the majority of the cases, is completely localised in the right atrium.

PO-05-068 MAJOR VASCULAR COMPLICATIONS IN A LARGE COHORT OF PATIENTS UNDERGOING CATHETER ABLATION FOR VPB/VT IN A HIGH-VOLUME, TERTIARY EP CENTER

Catheter ablation is an established treatment method both in patients with idiopathic premature ventricular complexes (PVC) or ventricular tachycardia (VT) and in structural heart disease (SHD) VT. Major vascular complications (MVCs) are the most frequent in these populations. A retrospective study investigating the incidence of MVCs in large-volume, specialized VT center and analyzing their predictors. We included PVC/VT patients who had their first ablation procedure between August 2006 - December 2020. The procedures were performed under conscious sedation except for patients who were on mechanical ventilation because of hemodynamical or electrical instabilit. Activation mapping supported by an electroanatomic mapping system was used in idiopathic cases. In SHD, substrate mapping using an electroanatomic mapping system and pacemapping was employed as a prerequisite for complete substrate modification during spontaneous rhythm or pacing. Activation and entrainment mapping for well-tolerated VTs were rarely used. The goal of ablation was to abolish all inducible VTs. A specific institutional tracking system for complications of invasive procedures was used to collect all periprocedural complications that were subsequently adjudicated. MVCs were defined as those that result in permanent injury or death, require intervention or treatment, prolong hospitalization (>48 hrs) or require new hospitalization. Idiopathic PVC/VT ablation was performed in 656 pts (males: 50%, age: 51 ± 17 years, re-ablations: 15%). SHD VT was ablated in 1637 pts (males: 88%, age: 63 ± 13 years, re-ablations: 30%, ischemic cardiomyopathy: 65%, left ventricular ejection fraction: 34 ± 13%, electrical storm: 24%). In idiopathic PVC/VT, MVCs were observed in 2.4 % (4.0% in males vs. 0.9% in females, P <0.01). In SHD, the rate of MVCs reached 3.5 % (2.8% in males vs. 9.4% in females, P <0.00001). Based on the multivariable regression model, the composite risk score to predict MVCs was proposed that was calculated as a sum of risk points for age (0, 1, 2, and 3 points for <50, 50–59, 60–69, and ≥70 years, respectively), female gender (2 points), and serum creatinine >1.3mg/dL (2 points), range 0–7 (Figure). While in an idiopathic setting, MVCs were more frequent in males, which may reflect a higher proportion of more complex LV ablations and arterial access, there was a significant female predominance in MVCs in SHD. The composite risk score predicts the risk of MVCs independently of VT cause.

PO-02-201 OUTCOMES OF RADIOFREQUENCY ABLATION OF ATRIAL FIBRILLATION IN OCTOGENARIANS IN A MULTICENTER REGISTRY (REAL-AF)

Catheter ablation for atrial fibrillation (AF) has significantly increased in prevalence, including in an elderly population. However, some studies suggest that outcomes of AF ablation may be inferior in elderly patients. Real-world, multi-center data is minimal and may provide more insight on this possibility. To compare the outcomes of octogenarians versus non-octogenarians undergoing catheter ablation of AF in high volume centers. Patients undergoing radiofrequency ablation of AF were prospectively enrolled in a multi-center registry (REAL-AF) from January 2018 to May 2021. The cohort was divided into 2 groups, patients ≥ 80 years old (octogenarians) and patients < 80 years old (non-octogenarians). Baseline characteristics and procedural data were collected prospectively on all patients. Routine ambulatory monitoring was performed at 6- and 12-months and additionally as needed based on symptoms. Efficacy was assessed at 12 months. The primary outcome was freedom from symptomatic atrial arrhythmias lasting greater than 30 seconds after a 90-day blanking period. 71 patients were included in the octogenarian group and 1,134 patients in the non-octogenarian group. The proportion of patients with persistent AF was similar between the groups. Octogenarians were more likely to have lower BMI, hypertension, prior bleeding, and left atrial scar as assessed by electro-anatomic mapping system (EAM). Left ventricular ejection fraction and left atrial volume as measured on EAM were also similar among the groups. There was a trend towards increased recurrence of atrial arrhythmias in octogenarians (table 1). At 12 months, octogenarians were more likely to be on anti-arrhythmic drugs as well. However, there was no difference in procedure-related complications between the groups. When controlled for left atrial scar burden, there was no difference in outcomes between the two groups. Octogenarians undergoing ablation of atrial fibrillation are more likely to have recurrent atrial arrhythmias than younger patient; this difference seems to be associated with an increased likelihood of abnormal left atrial voltage in the elderly patients. Although octogenarians are considered a frail population, AF ablation maintained similar safety profiles and arrhythmia related healthcare utilization rates when compared to a younger population.

MP-453088-7 PROOF-OF-CONCEPT FORWARD-SOLUTION MAPPING OF A FOCAL ATRIAL TACHYCARDIA ORIGIN USING THE OUTPATIENT 12-LEAD ELECTROCARDIOGRAM

Arrhythmia source mapping is essential to the delivery of targeted catheter ablation for cardiac arrhythmias. Whether mapping may be performed using outpatient 12-lead electrocardiogram (ECG) data was unknown. The objective of this proof-of-concept study was to evaluate the feasibility, temporal efficiency, and accuracy for forward-solution mapping using clinical ECG data obtained outside the electrophysiology laboratory. The patient is a 24-year-old female with recurrent, symptomatic focal atrial tachycardia (focal AT) diagnosed by 12-lead ECG in the outpatient clinic. After unsuccessful medical therapy, she elected to proceed with catheter ablation at Kaiser Santa Clara Medical Center. 12-lead ECG data from the clinical ECG database (Muse, GE Medical) was exported and transferred to the forward-solution mapping system (vMap, Vektor Medical). After data upload and system confirmation of acceptable data quality, a selection window was placed around the focal AT P-wave of interest (Figure A). The mapping process was initiated and the probabilistic source locations for the focal AT were displayed by the system. These results were then compared to the results of invasive activation mapping. Results from the forward-solution analysis demonstrated a highest probability focal AT source at the anterior base of the left atrial appendage (Figure B). Total processing time following upload of the ECG data into the clinical system was less than 3 minutes. Invasive activation mapping using the electroanatomic mapping system (Carto, Biosense-Webster) also demonstrated the site of early activation at the anterior base of the left atrial appendage (Figure C). Center-to-center spatial error between the forward-solution result and the site of early activation by invasive mapping was 8.8 mm. Forward-solution arrhythmia source mapping using data from a commercial ECG system obtained outside the electrophysiology laboratory is feasible, time-efficient, and demonstrates excellent agreement with invasive electroanatomic mapping. Future studies are required to determine whether this process may facilitate the delivery of targeted arrhythmia therapy in larger populations.

PO-01-187 FEASIBILITY OF FLUOROLESS PULMONARY VEIN ISOLATION USING A SINGLE-SHOT CONFORMABLE PULSED FIELD ABLATION CATHETER

Fluoroless pulmonary vein isolation (PVI) using point-by-point ablation catheters guided by electroanatomical mapping (EAM) systems is standard practice in many operators’ practice. While “single-shot” PVI tools have a streamlined procedural workflow, and with a safety profile enhanced by the emergence of pulsed field ablation (PFA) technology, these catheters have not been able to support a completely fluoroless workflow. A novel 8-Fr single-shot large lattice catheter with integrated magnetically-tracked EAM and PFA capabilities has been developed. To report for the first time the feasibility of performing single-shot PVI using a completely fluoroless approach. This 8 Fr PFA catheter (SpherePVI; Affera-Medtronic Inc) has a conformable large lattice framework that is expandable to 34 mm in diameter to permit “customization” to varying pulmonary vein anatomies (see Figure). It was delivered using an 8.5 Fr deflectable sheath (Agilis, Abbott Inc), and used with a custom EAM system (Prism-1; Affera-Medtronic Inc.) to render PV and left atrial anatomy. The PFA generator (HexaPULSE; Affera-Medtronic Inc) delivered biphasic waveforms (5 sec per application; 1.3-2.0 kV[±]); goal of 1-3 lesions per PV) from six elements situated circumferentially around the equatorial plane of the lattice. These cases conducted at a single center as part of a first-in-human study (NCT05115214): under general anesthesia, ICE was used to guide transeptal puncture and catheter positioning; fluoroscopy was initially used, followed by completely fluoroless ablation (using only ICE and EAM). The fluoroless cohort (n = 4 AF pts) was well matched with the control cohort (n = 5 AF pts) with similar baseline characteristics except for having more male patients (see Table). PVI was 100% successful in both groups. For PVI, both the number of PFA lesions delivered (16.3±0.5 vs 16.6±0.9 in the fluoroless and control groups, respectively) and the PVI ablation times (time only during lesion application; 1.6±0.0 min vs 1.6±0.1 min), and transpired time (defined as time transpiring between first to last lesion application; 8.3±1.1 min vs 9.6±2.2 min) were comparable. The total fluoroscopy time in the control group was 5.5±2.7 min. There were no serious adverse events in either group. This case series provides the proof-of-principle that fluoroless single-short PVI is feasible, safe and effective using a conformable large lattice PFA catheter.

PO-01-119 CATHETER STABILITY ANALYSIS IN ABLATION OF PAROXYSMAL ATRIAL FIBRILLATION: IMPACT OF A NOVEL FLEXIBLE ELECTRODE TIP

Catheter electrode stability is a key factor of a successful radiofrequency (RF) ablation lesion formation. Current techniques to enhance or monitor catheter stability include the use of steerable introducers, high-frequency jet ventilation, and the incorporation of objective lesion marker placement via Electroanatomic Mapping (EAM) Systems. In addition to automatic lesion marker placement, the EnSite™ AutoMark Module records catheter location during RF energy delivery, providing insight into catheter electrode stability during ablation. To demonstrate improved stability during ablation with a flexible laser cut tip electrode vs. a solid-6-hole electrode tip during de novo PVI ablation for the treatment of PAF and concomitant CTI-lines for the treatment of typical AFL. AutoMark™ ablation data gathered during the TactiFlex AF IDE NCT04356040 (flex tip catheter) and TactiSense IDE NCT03354663 (solid tip catheter) trials was analyzed (FIGURE). Both trials were prospective, non-randomized multicenter clinical studies which enrolled 355 and 150 subjects worldwide, respectively. PVI and CTI lesions from point-by-point ablation style operators with discrete lesions were included. Anatomic region assignment of each RF episode was accomplished using machine learning. Average distance and standard deviations of the ablation electrode movement from the mean positional centroid were calculated for each RF episode. Stability was evaluated as the percent of time during an RF episode where the ablation electrode remained within 2.5mm of the ablation lesion centroid. A total of 10285 flexible tip and 2141 solid tip RF episodes were analyzed from 112 and 21 cases, respectively. The average RF episode duration for the flexible tip and solid tip lesions, was 10.6 ± 4.8 and 17.1 ± 9.8 seconds, respectively. The flexible tip and solid tip catheters remained positionally stable within a 2.5 mm sphere for 85.3% ± 22.7 and 79.9% ± 26.1 of the RF episode duration, respectively, (p <0.001) (FIGURE). In the subset of lesions <10 seconds, the difference in stability was even more pronounced (TABLE). A flexible tip ablation catheter (TactiFlex™ SE) demonstrated greater stability than a solid tip ablation catheter (TactiCath™ SE) during ablation of atrial fibrillation and CTI-dependent atrial flutter. Greater stability during lesion formation may result in more durable lesions and better patient outcomes.Tabled 1Catheter# RF EpisodesRF Episode Duration, sec (SD)Mean (SD)Median [Q1, Q3]p-valueAll RF EpisodesFlexible Tip1028510.6 (4.8)85.3% (22.7)96.9% [79.9, 100]< 0.001Solid Tip214817.1 (9.8)79.9% (26.1)92.6% [66.7, 100]< 0.001RF Episodes < 10 secFlexible Tip43406.4 (2.8)85.0% (24.2)98.7% [80.7, 100]< 0.001Solid Tip5427.3 (2.3)73.6% (32.9)89.8% [51.7, 100]< 0.001Stability of a solid tip (TactiCath™ Contact Force Ablation Catheter, Sensor Enabled™) versus flexible tip (TactiFlex™ Contact Force Ablation Catheter, Sensor Enabled™), reported as the percent time the catheter tip remained within a 2.5 mm radius sphere. Open table in a new tab

PO-04-054 FIRST REPORTED HUMAN CASE OF ELECTRICAL STORM TREATED WITH THE NEW HIGH-POWER-SHORT-DURATION TACTIFLEXTMABLATION CATHETER.

In the last decade, standard-power-long-duration radiofrequency delivery systems were the standard care to treat ventricular arrhythmias. Recently, high-power-short-duration radiofrequency delivery systems are available and TactiFlexTM Ablation Catheter is the most recent one. we present the first worldwide case of electrical storm catheter ablation using the new TactiFlexTM. N/A A 78 years old female was admitted to the emergency department because of arrhythmic storm. Thirty days earlier she had been hospitalized for acute coronary syndrome. On initial assessment, she appeared soporous, arterial blood pressure was 80/50 mmHg and ECG revealed sustained monomorphic ventricular tachycardia, regular cycle length, left bundle branch morphology, negative concordance in precordial lead. Patient therapy included metoprolol, mexiletine and cordarone; intravenous lidocaine and procainamide were added, with poor results in controlling arrhythmia; then, we decide to perform VT catheter ablation. Left ventricle mapping was performed with TactiFlexTM and AdvisorTM HDGrid Mapping Catether supported by the new EnsiteX V2 electro-anatomical mapping system and Omnipolar Technology. During voltage substrate mapping we found a central necrotic core area surrounded by a low voltage area in the mild-apical posterior-lateral wall. During late potential mapping the same area showed late and multi-fragmented potentials. Clinical tachycardia was easily induced during programmed ventricular pacing. VT activation map was performed and no meso-diastolic potentials or "early meets late" areas were found, probably signifying a possible epicardial regions involvement in the VT circuitry: it was not possible to reconstruct the entire arrhythmia circuit. Activation velocity map was performed and VT slowed in the same regions of low voltage and fragmented potentials. High-power radiofrequency energy (35W-25seconds or 40W-20seconds pulses) was delivered in the mid-basal posterior-septal wall obtaining VT termination. Subsequently, substrate homogenization, which include late and fragmented potentials elimination, was performed. No ventricle arrhythmias were inducible during programmed ventricular pacing. No procedure-related complications occurred. TactiFlexTM appears safe and effective to control left VT. Further reports and studies are needed to evaluate the most appropriate Watts and seconds to perform effective and safe human left ventricle injuries.

PO-05-092 BIPOLAR ELECTROGRAM PEAK FREQUENCY VALUE DERIVED FROM HIGH-DENSITY ELECTROANATOMIC MAPPING EFFICIENTLY IDENTIFIES THE CRITICAL ISTHMUS IN SCAR-RELATED VENTRICULAR TACHYCARDIA

It is of challenges to differentiate local activities from far-field potentials, especially the multicomponent electrograms of diastolic potentials in scar-related reentrant ventricular tachycardia (VT). The peak frequency (PF) of each electrogram has the potential to discriminate near-field from far-field potentials. The study aimed to identify the VT isthmus by applying PF criteria on VT activation maps. The study consisted of 10 patients with scar-related VT (ischemic/nonischemic cardiomyopathy 6/4). The characteristics of the VT circuits were assessed using high-density multielectrode catheters. VT isthmuses were identified based on activation maps, entrainment, and ablation results. The accuracy of applying PF value over the activation map in detecting VT isthmus was assessed. 12 VT isthmuses were identified. The mean bipolar voltage and PF of the VT isthmuses were 0.26 ± 0.13 mV and 319.3 ± 58.6 Hz respectively. All isthmuses were within areas of bipolar voltage less than 0.5 mV and PF of more than 250 Hz. With the automated -dv/dtmax annotation during VT, the isthmus could be identified in 5 of 12 (41.7%) VT circuits without manual annotation. By automated PF annotation, the VT isthmus could be identified in 9 of 12 (75.0%) VT circuits without the need for manual adjustment. VT isthmus was always located in the electrogram with bipolar LVZ (<0.5 mV) with a PF value over 250Hz during VT. Moreover, the VT isthmus could be more intuitively identified by the automated peak frequency annotation than -dv/dtmax annotation in the current daily practice using high-density 3D electroanatomic mapping system.

PO-05-232 SAFETY AND EFFICACY OF ATRIOVENTRICULAR NODAL REENTRY TACHYCARDIA ABLATION USING AN IRRIGATED CONTACT FORCE CATHETER

Atrioventricular Nodal Reentry Tachycardia (AVNRT) ablation is a common procedure in contemporary electrophysiology practice. Traditionally ablation for AVNRT has been performed with non-irrigated catheters, guided by fluoroscopy and intracardiac electrograms. Increasingly electroanatomic mapping systems are utilized to allow for low or zero fluoroscopy procedures. Contact force catheters can provide information on tissue contact and stability that can be helpful in patients with challenging anatomy. Available contact force catheters are irrigated and concern has existed for using irrigated tip ablation catheters for AVNRT ablation due to the potential to create lesions that are too deep and could increase the risk for AV block. To describe the safety and efficacy for the use of irrigated contact force catheters for ablation of AVNRT Review of procedural data from patients undergoing radiofrequency ablation for AVNRT using electroanatomical mapping combined with irrigated contact force catheter. Fifty patients from 4 regions across Australia were included. Procedures were performed by 9 experienced electrophysiologists. No periprocedural complications occurred. Procedural success was achieved in 96%. Median lesion contact force (25-75 centile) was 4.0(2-6)g. Peak power was set at 50W, median baseline irrigation was at 2ml/min and 6ml/min during ablation. Median number of lesions was 9(4.5-17.5); with total ablation time of 203(95-366) seconds. 60% of the cases were performed without fluoroscopy. Ablation of AVNRT using an irrigated contact force catheter on low irrigation setting is safe and effective. Contact force catheters using low irrigation settings may safely improve success rates in AVNRT with challenging anatomy or ablation of other substrate in close proximity to vital structures.

PO-01-074 USE OF ELECTRO-ANATOMIC MAPPING TO REDUCE THE NUMBER OF LEAD DEPLOYMENT ATTEMPTS FOR OPTIMAL LEFT BUNDLE AREA PACING: A CASE SERIES

Left bundle area pacing (LBP) often requires multiple lead deployments into the interventricular septum to find an ideal site with left bundle capture. Evaluate the use of 3-dimensional electro-anatomical mapping system (3D map) to aid in the identification of the correct implant site to achieve optimal left bundle branch capture. Three consecutive patients requiring pacing for AV block with LVEF 40-45% are included in this case series. After ultrasound-guided axillary vein access, a decapolar catheter was advanced and visualized using Carto (DecaNav, Biosense Webster). Intracardiac anatomy was defined using fast activation mapping in the region of the bundle of His and right ventricular septum. High- and low-output pacing was delivered from each of the electrode pairs of the decapolar catheter while it abutted the septum. Ideal deployment site was chosen from among the electrode pair sites based on W-pattern in V1, R wave axis in inferior leads, and aVL/aVR relationship. After this site was marked on the 3D map, the catheter was removed and the pacing lead (Biotronik Solia S60) was advanced under 3D mapping guidance and deployed. Please see Table 1 for patient characteristics and procedure details. Please see figure for EAM Utilization of 3D mapping to select the ideal site of LBP capture can allow for (1) improved procedural efficiency, (2) decreased fluoroscopy usage, and (3) successful LBP capture with a single deployment.Tabled 1Patient characteristics and Procedure detailsPatient 1Patient 2Patient 3Age (years)645577GenderMaleMaleFemaleBody Mass Index (Kg/m2)273421Number of implant attempts111Fluoroscopy time2 minutes 25 secs1 min 47 secs2 minutes 50 secsComplicationsNoneNoneNone Open table in a new tab

PO-02-121 IMPACT OF PULMONARY VEIN OVALITY AND OCCLUSION STATUS MEASURED BY THE NOVEL DIELECTRIC-BASED MAPPING SYSTEM ON ACUTE VEIN ISOLATION DURING CRYOBALLOON ABLATION

Cryoballoon ablation (CBA) has been widely accepted as a major technic for pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF). PV anatomy is an important factor to obtain circumferential balloon adhesion that results in vein occlusion to achieve acute PVI. The KODEX-EPD (Philips, Amsterdam, Netherlands) is a dielectric-based electroanatomic mapping system that can display a panoramic (PANO) view of the left atrium and evaluate PV occlusion without other imaging modalities. Prior studies demonstrated that high PV ovality is the potential mechanism of impeding the formation of durable lesion. However, the accuracy of PV ovality assessed by KODEX-EPD system and how it influences the performance of the PV occlusion tool and acute PVI are still unknown. To assess the PV occlusion and PV ovality using the KODEX-EPD system, and to evaluate the accuracy of them and their impact on acute PVI. We enrolled 10 patients who underwent primary CBA for paroxysmal AF using KODEX-EPD system, all of them had a pre-procedural cardiac CT or MRI. Ovality index (OI) was defined as the ratio of the PV maximum diameter divided by PV minimum diameter which was measured by KODEX-EPD system under PANO view and on CT/MRI images under sagittal view. An evaluation of PV occlusion was obtained using the KODEX-EPD Occlusion Viewer and intracardiac echography on each CB-PV engagement. Single shot PVI was defined as the isolation of PV at the first freezing attempt after complete occlusion of the PV. Fifty-eight balloon-PV engagements in 39 PVs were analyzed. Consistent occlusion status between KODEX and ICE were obtained in 50 (86%) engagements [complete occlusion: 30/34 (88%), incomplete occlusion 20/24 (83%)]. The OI of PV with incomplete occlusion by KODEX is significantly larger than that with complete occlusion (2.0±0.5 vs 1.6 ±0.4. p=0.03). Representative cases are shown in Figure1A and B. Single shot PV isolation was achieved in 33 of 39 PVs (84%). All of them showed complete occlusion status in KODEX, and OI of PV with single shot isolation was significantly smaller than that without single shot isolation (1.6±0.4 vs 2.1±0.4, p=0.003). A positive correlation was found between the OI measured by KODEX and CT/MRI (Figure1C). The evaluation of PV anatomy and occlusion status using the novel dielectric-based mapping system is feasible and may facilitate CB ablation of AF. Higher PV ovality is associated with incomplete PV occlusion and lower acute PVI rate.

Radiofrequency catheter ablation of ventricular tachycardia using combined endocardial techniques in patients with structural heart disease improves procedural effectiveness and reduces arrhythmia episodes.

Evidence indicates that radiofrequency catheter ablation (RFCA) of ventricular tachycardia (VT) in patients with structural heart disease (SHD) is safe and effective. However, arrhythmia recurrence is still relatively high, and the optimal procedural strategy is unclear. In clinical practice, several combinations of mapping and ablation techniques are used to improve VT ablation efficacy. The study aimed to evaluate and provide evidence on the efficiency and safety of a systematized combination of VT ablation (mapping) techniques in patients with SHD. From 2016 to 2019, 47 patients (54 procedures) with SHD (89% heart failure, 94% ischemic heart disease, 37% VT storm) who underwent RFCA of VT were retrospectively analyzed from a group of 58 consecutive patients. During RFCA of VT, different combinations of three techniques, activation mapping (AM), pace mapping (PM), and substrate-based mapping (SbM), were used. The procedures were performed using the CARTO® 3 (Biosense Webster Inc., Diamond Bar, CA, US) electro-anatomical mapping system. During a median (interquartile range [IQR]) follow-up of 25.5 months (11.75-52.25), VT-free survival after ablation was 68.5% (n = 37/54 procedures). Acute procedural success was achieved in 85% (n = 46/54 procedures). The number of induced VT morphologies, induction of non-clinical or non-sustained VT after ablation, and fewer VT mapping techniques used during the procedure were related to decreasing VT-free survival. VT ablation strategy based on systemic use of combined techniques is effective and safe in long-term follow-up of patients with SHD.

High-density and high coverage composite mapping of repetitive atrial activation patterns

BackgroundRepetitive atrial activation patterns (RAAPs) during atrial fibrillation (AF) may be associated with localized mechanisms that maintain AF. Current electro-anatomical mapping systems are unsuitable for analyzing RAAPs due to the trade-off between spatial coverage and electrode density in clinical catheters. This work proposes a technique to overcome this trade-off by constructing composite maps from spatially overlapping sequential recordings. MethodsHigh-density epicardial contact mapping was performed during open-chest surgery in goats (n=16, left and right atria) with 3 or 22 weeks of sustained AF (249-electrode array, electrode distance 2.4 mm). A dataset mimicking sequential recordings was generated by segmenting the grid into four spatially overlapping regions (each region 6.5 cm2, 48±10% overlap) without temporal overlap. RAAPs were detected in each region using recurrence plots of activation times. RAAPs in two different regions were joined in case of RAAP cross-recurrence between overlapping electrodes. We quantified the reconstruction success rate and quality of the composite maps. ResultsOf 1021 RAAPs found in the full mapping array (32±13 per recording), 328 spatiotemporally stable RAAPs were analyzed. 247 composite maps were generated (75% success) with a quality of 0.86±0.21 (Pearson correlation). Success was significantly affected by the RAAP area. Quality was weakly correlated with the number of repetitions of RAAPs (r=0.13, p<0.05) and not affected by the atrial side (left or right) or AF duration (3 or 22 weeks of AF). ConclusionsConstructing composite maps by combining spatially overlapping sequential recordings is feasible. Interpretation of these maps can play a central role in ablation planning.

Compatibility assessment of a temperature-controlled radiofrequency catheter with a novel electroanatomical mapping system.

The novel DiamondTemp ablation system (DTA) and EnSiteX mapping System (EAM) are both CE-Marked and FDA approved medical devices. The DTA has been validated by its manufacturer only in combination with previous version of EnSite System-EnSite Precision. The aim of this study was to evaluate compatibility of DTA with EnSite X with a previously developed protocol. Three configurations were tested: 3.1. Medtronic Generator connection Box (GCB) and AmpereConnect cable; 3.2. the Medtronic GCB-E and electrogram out cable from GCB to EAM; 3.3. Direct connection of DTA to EAM using intracardiac out cable with no GCB. The previously developed universal method for compatibility assessment of ablation catheters and navigation systems was used with success for assessing DTA and EnSite X EAM compatibility, with reproducible results. Accuracy of DTA visualization with different setups was evaluated with a phantom model measuring distances between DTA and reference points. DTA is compatible with EnSiteX EAM with a safety and reliability profile guaranteed, if within the described specifications. In particular, careful setup is mandatory to achieve good clinical outcomes as only setup 3.2 is viable for both NavX and Voxel Mode and demonstrated satisfactory results and accuracy. Setup 3.3 showed a significant shift immediately after catheter insertion. Catheter position was away from baseline points and the dislocation increased during the radiofrequency delivery. Previously developed method for compatibility assessment of ablation catheters and navigation systems has been used for a new EAM. DTA is compatible with EnSiteX EAM with proper configuration.

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.

Efficacy and Safety of Nonfluoroscopic Approach During Catheter Ablation of Ventricular Tachycardias

Aim To evaluate a possibility of using radiofrequency catheter ablation guided by intracardiac echocardiography (ICE), its efficacy and safety for treatment of ventricular tachycardia (VT) of various etiology.Material and methods Catheter intervention was performed for 20 enrolled patients with symptomatic VT. Ablation procedures were guided by a 3D electroanatomical mapping system and ICE.Results Mean duration of the procedure was 201.2±62.5 min. The procedure was successful (non-inducibility of VT) in 100% of cases. None of the patients had postoperative complications.Conclusion Ablation of VT arrhythmogenic substrate guided by 3D electroanatomical navigational mapping and ICE without X-ray is feasible and safe.

Utility of cardiac imaging in patients with ventricular tachycardia

Ventricular tachycardia (VT) is a life-threatening arrhythmia that may be idiopathic or result from structural heart disease. Cardiac imaging is critical in the diagnostic workup and risk stratification of patients with VT. Data gained from cardiac imaging provides information on likely mechanisms and sites of origin, as well as risk of intervention. Pre-procedural imaging can be used to plan access route(s) and identify patients where post-procedural intensive care may be required. Integration of cardiac imaging into electroanatomical mapping systems during catheter ablation procedures can facilitate the optimal approach, reduce radiation dose, and may improve clinical outcomes. Intraprocedural imaging helps guide catheter position, target substrate, and identify complications early. This review summarises the contemporary imaging modalities used in patients with VT, and their uses both pre-procedurally and intra-procedurally.

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.

A Data-Driven Preprocessing Framework for Atrial Fibrillation Intracardiac Electrocardiogram Analysis

Atrial Fibrillation (AF) is the most common cardiac arrhythmia. Signal-processing approaches are widely used for the analysis of intracardiac electrograms (iEGMs), which are collected during catheter ablation from patients with AF. In order to identify possible targets for ablation therapy, dominant frequency (DF) is widely used and incorporated in electroanatomical mapping systems. Recently, a more robust measure, multiscale frequency (MSF), for iEGM data analysis was adopted and validated. However, before completing any iEGM analysis, a suitable bandpass (BP) filter must be applied to remove noise. Currently, no clear guidelines for BP filter characteristics exist. The lower bound of the BP filter is usually set to 3-5 Hz, while the upper bound (BP¯th) of the BP filter varies from 15 Hz to 50 Hz according to many researchers. This large range of BP¯th subsequently affects the efficiency of further analysis. In this paper, we aimed to develop a data-driven preprocessing framework for iEGM analysis, and validate it based on DF and MSF techniques. To achieve this goal, we optimized the BP¯th using a data-driven approach (DBSCAN clustering) and demonstrated the effects of different BP¯th on subsequent DF and MSF analysis of clinically recorded iEGMs from patients with AF. Our results demonstrated that our preprocessing framework with BP¯th = 15 Hz has the best performance in terms of the highest Dunn index. We further demonstrated that the removal of noisy and contact-loss leads is necessary for performing correct data iEGMs data analysis.

Non-invasive electrocardiographic mapping on the ward to guide ablation of premature ventricular contractions

Premature ventricular contracts (PVCs) are commonly encountered in clinical practice, but their ablation can prove difficult. In 15 patients with idiopathic PVCs, non-invasive mapping system View Into Ventricular Onset ™ (VIVO) in combination with 12‑lead Holter monitoring on the ward accurately guided catheter ablation via the creation of ‘electrical roadmaps’ of ventricular activation. This allowed for better discussions of risks and benefits with the patient prior to the procedure, and is likely to have particular advantages for patients with a low PVC burden, multiple morphologies, or difficult to reach origins. Clinical perspectivePERSONALISED APPROACH: A novel non-invasive mapping tool in combination with technology, such as 12 lead Holter monitoring, allows for individualised, accurate prediction of PVC origin outside the electrophysiology (EP) lab. Non-invasive mappingAn “electrical road map” can be implemented into 3D electroanatomical mapping systems, shortening procedure times and resulting in excellent clinical outcomes. Potential benefitsVIVO could be used to improve catheter ablation outcomes for patients with infrequent PVCs, multiple morphologies and/or difficult to reach origins.