Ablation Of Arrhythmias Research Articles

Comparative Efficacy and Safety of Pulsed Field Ablation Versus Radiofrequency Ablation of Idiopathic LV Arrhythmias

BackgroundComparative efficacy and safety data on radiofrequency ablation (RFA) versus pulsed field ablation (PFA) for common idiopathic left ventricular arrhythmia (LV-VAs) locations are lacking. ObjectivesThis study sough to compare RFA with PFA of common idiopathic LV-VAs locations. MethodsTen swine were randomized to PFA or RFA of LV interventricular septum, papillary muscle, LV summit via distal coronary sinus, and LV epicardium via subxiphoid approach. Ablations were delivered using an investigational dual-energy (RFA/PFA) contact force (CF) and local impedance-sensing catheter. After 1-week survival, animals were euthanized for lesion assessment. ResultsA total of 55 PFA (4 applications/site of 2.0 KV, target CF ≥10 g) and 36 RFA (CF ≥10 g, 25–50 W targeting ≥50 Ω local impedance drop, 60-second duration) were performed. LV interventricular septum: average PFA depth 7.8 mm vs RFA 7.9 mm (P = 0.78) and no adverse events. Papillary muscle: average PFA depth 8.1 mm vs RFA 4.5 mm (P < 0.01). Left ventricular summit: average PFA depth 5.6 mm vs RFA 2.7 mm (P < 0.01). Steam-pop and/or ventricular fibrillation in 4 of 12 RFA vs 0 of 12 PFA (P < 0.01), no ST-segment changes observed. Epicardium: average PFA depth 6.4 mm vs RFA 3.3 mm (P < 0.01). Transient ST-segment elevations/depressions occurred in 4 of 5 swine in the PFA arm vs 0 of 5 in the RFA arm (P < 0.01). Angiography acutely and at 7 days showed normal coronaries in all cases. ConclusionsIn this swine study, compared with RFA, PFA of common idiopathic LV-VAs locations produced deeper lesions with fewer steam pops. However, PFA was associated with higher rates of transient ST-segment elevations and depressions with direct epicardium ablation.

Imaging of Cardiac Fibrosis: An Update, From the AJR Special Series on Imaging of Fibrosis.

Myocardial fibrosis (MF) is defined as excessive production and deposition of extra-cellular matrix (ECM) proteins that result in pathologic myocardial remodeling. Three types of MF have been identified: replacement fibrosis from tissue necrosis, reactive fibrosis from myocardial stress, and infiltrative interstitial fibrosis from progressive deposition of nondegradable material such as amyloid. Although echocardiography, nuclear medicine, and CT play important roles in the assessment of MF, MRI is pivotal in the evaluation of MF, with the late gadolinium enhancement (LGE) technique used as a primary end point. The LGE technique focuses on the pattern and distribution of gadolinium accumulation in the myocardium and assists in the diagnosis and establishment of the cause of both ischemic and nonischemic cardiomyopathy. LGE MRI also aids prognostication and risk stratification. In addition, LGE MRI is used to guide the management of patients considered for ablation for arrhythmias. Parametric mapping techniques, including T1 mapping and extracellular volume measurement, allow detection and quantification of diffuse fibrosis, which may not be detected by LGE MRI. These techniques also allow monitoring of disease progression and therapy response. This review provides an update on the imaging of MF, including prognostication and risk stratification tools, electrophysiologic considerations, and disease monitoring.

Phantom study of augmented reality framework to assist epicardial punctures.

The objective of this study is to evaluate the accuracy of an augmented reality (AR) system in improving guidance, accuracy, and visualization during the subxiphoidal approach for epicardial ablation. An AR application was developed to project real-time needle trajectories and patient-specific 3D organs using the Hololens 2. Additionally, needle tracking was implemented to offer real-time feedback to the operator, facilitating needle navigation. The AR application was evaluated through three different experiments: examining overlay accuracy, assessing puncture accuracy, and performing pre-clinical evaluations on a phantom. The results of the overlay accuracy assessment for the AR system yielded . Additionally, the puncture accuracy utilizing the AR system yielded . During the pre-clinical evaluation on the phantom, needle puncture with AR guidance showed , whereas needle puncture without AR guidance showed . Overall, the AR platform has the potential to enhance the accuracy of percutaneous epicardial access for mapping and ablation of cardiac arrhythmias, thereby reducing complications and improving patient outcomes. The significance of this study lies in the potential of AR guidance to enhance the accuracy and safety of percutaneous epicardial access.

Catheter ablation of papillary muscle arrhythmias: procedural characteristics and long term outcome

Abstract Background Ventricular arrhythmias (VA) originating from the papillary muscles can occur both in patients with and without structural heart disease. Although catheter ablation is the treatment of choice, ablation success remains challenging and long-term outcomes for this origin of VA are still unsatisfactory. Methods and Results All patients undergoing catheter ablation for premature ventricular contractions or ventricular tachycardia between june 2009 and november 2022 were analyzed. 66 patients (26 female (39%), mean age 60±15 years) undergoing catheter ablation of VA originating from the papillary muscle were identified. 21/66 (32%) patients had a reduced or mildly reduced left ventricular ejection fraction at time of initial presentation. While mitral valve regurgitation was present in 32/66 (48%) patients, mitral valve prolapse was observed in only 2/66 (3%) patients. 6/66 (9%) patients presented with non-sustained ventricular tachycardia (VT) and 1/66 (2%) patient presented with sustainend VT prior to catheter ablation. 61/66 (92%) patients underwent ablation of PVCs of the left ventricular papillary muscles (22/66 (33%) patients anterolateral; 39 (59%) patients posteromedial). 5/66 patients underwent ablation of premature ventricular complex (PVC) originating from the papillary muscles of the right ventricle. In 13/66 (19.7%) patients only a retrograde approach was used, in 26/66 (39.5%) patients a retrograde and an additional transeptal approach and in only 10/66 (15.2%) patients solely a transeptal approach. Mean PVC QRS duration was 152.5 ± 3.5 msec. Ablation was acutely successful in 44/66 (67%) patients. Mean procedure time was 145.8 ± 63.7 minutes and mean number of radiofrequency applications was 21.3 ± 16.7 (25 to 55 Watts, 37764.2 ± 27824.1 Joules). Overall, procedural complications occurred in 4/66 (6%) patients Follow up data were obtained from Holter ECGs, review of medical records, patient consultation, or via structured follow-up within the prospective TRUST registry. All information was combined to assess recurrence of PVC/VT. Recurrence of VA originating from the papillary muscles occurred in 11/66 (17%) patients. 9/66 patients (14%) underwent re-ablation due to recurrence of VA originating from the papillary muscles after previous ablation procedures. Conclusion Catheter ablation of papillary muscle arrhythmias is associated with a single procedural success rate of 67% with a procedural complication rate of 6%. 14% of patients underwent re-ablation due to recurrence of papillary muscle arrhythmias.

Electrocardiographic imaging to guide ablation of ventricular arrhythmias shows a higher benefit in patients with low intraprocedural burden

Abstract Background and aims Electrocardiographic imaging (ECGI) provides a non-invasive activation map of focal ventricular arrhythmias that has shown good accuracy regardless of the type of cardiac source used. Pre-procedure diagnosis in cases that are expected to be difficult and management of infrequent or poorly tolerated or multiple arrhythmias are some situations that may benefit the most from having an ECGI performed before the procedure. This study aimed to assess the benefit of the ECGI in patients with low intraprocedural burden. Methods We performed 81 ECGI procedures in 64 consecutive patients referred for ablation of ventricular arrhythmias (VAs). Ablations were performed with remote magnetic navigation or manually. The localization of the VAs based on the ECGI and invasive electroanatomic mapping was performed using a segmental model of the ventricles. A perfect match (PM) was defined as a predicted location within the same anatomic segment, whereas a near match (NM) was defined as a predicted location within the same segment or a contiguous one. The agreement between the ECGI and the invasive map was evaluated. The benefit of the ECGI in the subgroup of patients with intraprocedural infrequent VAs, defined as less than 1 VA complex /min, was assessed in terms of the success of the procedure. Results The ECGI was performed with the AMYCARD 01 only, in 26 patients, with the VIVO only, in 21 patients, and with both systems in 17 patients. Fifty-one patients underwent ablation. 65 ECGI procedures were performed before ablation in those 51 patients, 37 with Amycard with a rate of PM of 79% and NM of 97%, and 28 ECGI procedures with VIVO with 82% of PM and 93% of NM, not significantly different, respectively, p=0.764 and 0.573. The overall success rate was 80%. The low intraprocedural burden group included 28 patients (2 examples shown in the figure). The success rate was 86%, higher than the overall success rate, and much higher than the previously reported in the literature for this group of patients. Conclusions The ECGI was useful in predicting the location of the VA in general but was especially helpful in cases that are usually challenging, like patients with intraprocedural infrequent VAs.

Coronary venous ethanol ablation of refractory left ventricular summit arrhythmias: comparison with radiofrequency ablation

Abstract Background Radiofrequency (RF) ablation of ventricular premature beats (VPBs) and ventricular tachycardia (VT) arising from the left ventricular (LV) summit is challenging and may fail due to anatomical inaccessibility of the substrate. Coronary Venous Ethanol Ablation (CVEA) has been suggested as a bailout strategy following failed RF ablation of LV Summit Arrhythmias (LVSA). Comparison with RF ablation strategies are lacking. Purpose To compare CVEA with RF ablation for the treatment of LVSA. Methods Between January and November 2023, 20 patients were treated with CVEA for LVSA. Results were compared to 36 patients that underwent RF ablation for LVSA (Panel A). Endo- and/or epicardial RF ablation was performed based on local signal precocity and pace-mapping. Coronary venogram-guided mapping of coronary sinus side-branches was performed using an angioplasty wire connected to our EP-recording system using a crocodile clamp. The target veins were specifically selected based on early presystolic potentials and confirmed by matching VPB pace-maps. For the treatment, angioplasty balloon(s) measuring 2-2.5×6-8 mm were employed to administer ethanol into the target branch of the coronary sinus. Data are reported as mean ± standard deviation, unless otherwise indicated. P-values are two-tailed. Results (Panel B): Patient characteristics were similar for both groups, except for the number of prior failed ablation procedures (75% males; mean age: 63 ± 13 y; 31 with structural heart disease; mean LVEF 39 ± 9%; VPB burden 25 ± 12%; Number of (NS)VT 72 ± 151; 65% redo in case of CVEA, 28% for RF). Mean pace-match was 97 ± 1% (99.8% max.) for CVEA versus 93 ± 8% (97% max.) for RF ablation (P = 0.002). Earliest presystolic signal was -70 ms (-49 ± 12) for CVEA versus -50 ms (-31 ± 12) for RF (P = 0.0002). Acute success, defined as elimination of VPB/VT was 95% versus 83% for CVEA and RF ablation respectively. VPB burden at Holter was 1 ± 3% 6-8 weeks after CVEA versus 8 ± 10% following RF ablation (P = 0.024). In patients with VT, number of (NS)VT decreased by 90% after CVEA (P = 0.014), while this was not significant for RF ablation. After a median follow-up of 8 months (IQR 2-10), 15% of CVEA patients showed residual non-LV summit ventricular arrhythmia as compared to 39% showing recurrence of LV summit VPB or VT following RF ablation. No patients died. One patient developed tamponade following RF ablation and one patient received PCI in the CVEA group. Conclusion Retrograde coronary venous ethanol ablation is an effective ablation strategy for the treatment of LV summit arrhythmias, also compared to conventional RF ablation.

Ablation of premature ventricle contraction arising from papillary muscle without intracardiac echo using point-by-point mapping

Abstract Background Catheter radiofrequency ablation (RFA) of ventricular arrhythmias (VAs) arising from the left ventricle's papillary muscles (PM) has been associated with inconsistent results due to difficulties in 3D reconstruction of this intraventricular structure. The use of intracardiac echo-guided ablation allows for the 2D visualisation of the PM and the guiding of ablation catheter. Cryo energy allows stable contact with the target structure during ablation. These two techniques have been shown to increase the success rate of ablation (77% reported - 1) but don’t allow the construction of the 3D map of papillary muscle with activation during PVC. Using a combination of point-by-point mapping (PbP) along with "fast anatomical mapping" (FAM) (Carto® 3 System) allows 3D reconstruction of the PM geometry with activation. These may increase the accuracy of PVC origin targeting. Aim This study aims to assess the feasibility and success rate of RFA of PVC arising from the papillary muscles of the left ventricle. Methods and results We retrospectively analysed 214 patients treated with RFA for PVCs in two institutions. PVC arose from PM in 12(5.6%) cases (65±20 years old; 42% males; 33% with ejection fraction&amp;gt;50%; 8.3% antero-lateral PM). Initial detailed FAM of the left ventricle was performed using PVC pattern matching via transaortic or transmitral approach. Then, all points with preexcitation to QRS onset were copied from FAM into the new PbP map. That automatically created the geometry of PM with an activation map inside the LV shell. Irrigated high power (50 W) RFA was performed at the site of earliest activation at the PM shell. The acute success rate was 75% (n=9) without complications. PVC recurrence at 12-month follow-up was 11% (n=1 out of 9). Conclusions RFA of PVC arising from papillary muscles using point-by-point mapping is feasible and associated with a success rate comparable to the previously reported one when intracardiac echo-guided ablation is used.

Digital health in the electrophysiological lab: Initial experience, safety and feasibility using remote support for arrhythmia ablation-Results of REMOTE-VA study

Abstract Background In most electrophysiology (EP) labs, electroanatomical mapping (EAM) systems are operated on site by qualified staff or field technical engineers (FTE). Due to lack of skilled personnel, the FTE usually must travel between different hospitals and procedures must be planned in advance. Ablation of ventricular arrhythmias (VA) represents the most complex procedure in the field. The use of remote support (RS) to guide complex EP procedures has the potential to increase flexibility, reduce travel times and maximise healthcare resources. Purpose To evaluate the safety and feasibility of RS as compared to on-site support guided catheter ablation procedures for VA. Methods All patients undergoing ventricular tachycardia (VT) or premature ventricular complex (PVC) ablation using remote support were included. The electronical system of the hospital was searched for 30 days postprocedural emergency department (ED) visits, unplanned ambulatory presentations, and readmissions. RS guided three-dimensional (3D) mapping was achieved by connecting the EAM software with an integrated audio-visual solution for remote support. Internet connection-based headphones and high-resolution cameras ensured the communication between the operator and the FTE, who worked exclusively from home office. The control group consisted of an equal number of patients matched for the type of procedure and undergoing on-site guided procedures. All ablations were performed using high density 3D mapping, as per institutional standard. Results Between October 2022 and October 2023, a total of 25 patients underwent VT (32%) or PVC ablation in our centre using RS and were compared to 25 patients undergoing the same procedures under on-site guidance. In the RS group one patient underwent epicardial VT ablation and another one bipolar ablation for VT Storm. The demographic data were similar between the groups. The median procedure time was 120 (93, 143) minutes in the RS group and 112 (95, 138) minutes in the control group (p=0.95), while the fluoroscopy time was 11.4 (7.0, 14.0) and 7.26 (5.0, 10.9) minutes respectively (p=0.08). The procedural success was achieved in 96% procedures in the RS group and in 100% in the control group. No technical issues or changes to on-site support were reported. One minor intraprocedural complication was noted among the control patients, while 24% of the patients in each group developed minor complications until discharge. Two patients in the RS group and one in the control group had ED visits, while only one patient in the control group had an unplanned ambulatory presentation. One unplanned readmission was reported in the control group (Table 1). Conclusions Even in the most complex procedures including epicardial ablation, the use of RS was feasible and safe in this single centre study. This approach has the potential to increase the feasibility in case of emergency procedures, reduce travel times, and maximise healthcare resources.

A patient-based realistic simulation platform to train future electrophysiologists to complex ablation procedures

Abstract Title An immersive catheter ablation platform based on patients’ 3D heart model for the simulation and training of future electrophysiologists. Background Arrhythmias are on the rise worldwide due to the ageing of the population. Projections urge to train the next generation of electrophysiologists (EPs) to perform catheter (CATH) ablation (CA) of arrhythmias. Training of future EPs relies mostly on a companionship, where teaching of CATH steerability is made on patients (pts) referred for procedures. While several other domains have established the utility of simulators to speed up learning process, increase safety and establish procedure road maps, dedicated simulators for EPs based on pts’ real anatomy do not exist yet. Purpose To speed up the handling of steerable CATH on MRI-based 3D heart models to optimize ablation road maps in pts referred for complex arrhythmias. Methods ARTS is an Artificial Intelligence and Augmented Reality-based platform comprising two key components: HeARTS and ARTSim. HeARTS is designed to automatically generate 3D heart models from pts’ MRI scans. ARTSim is a CA simulator that utilizes the 3D heart models of the pts for the planning and simulation of CA procedures. This simulator incorporates innovative techniques for digitizing and tracking the movements of a physical catheter in real time, and enabling its navigation within a completely virtual heart. With this technology, the CATH can be precisely steered to various heart locations, including the right and left (LA) atrium, the coronary sinus, and the right and left (LV) ventricles. Results Panel A of the figure shows the mannequin used for the simulator, where a real ablation CATH is introduced within the pt’s heart through a venous introducer. Panel B shows right anterior oblique (RAO) and modified RAO views of a pt suffering from a typical right atrial flutter. Note the presence of yellow tags positioned along the cavotricuspid isthmus (CTI) that the trainee must reach for a programmable duration using the shaft and the handle of the CATH shown in panel A. Panel C shows the virtual ablation CATH in green positioned on the target dots of the CTI. The pink color indicates that the trainee reached the desired target, which became red when the CATH remained stable at the same location for a duration of 5 sec (i.e. stability) with a force &amp;gt;5g (i.e. efficacy) and &amp;lt;20g (i.e. safety). Conclusions Herein, we present ARTS, a realistic CA simulation platform for the training of future EPs, that offers all the typical characteristics of 3D navigation including steerability, stability measurements and the force applied. Importantly, ARTS is based on the true anatomy of the pts, hence might be used to establish and discuss roadmaps to optimize procedures efficacy and safety. Version 2.0, foreseen early 2024, will include 3D late gadolinium enhancement and transseptal puncture for virtual LA and LV procedures, and later on activation times and myocardial voltage.Figure

Comparative analysis of clinical outcomes in repeat ablation for recurrent atrial tachyarrhythmia following initial pulmonary vein isolation with pulsed-field ablation and cryoballoon ablation

Abstract Background While pulsed-field ablation (PFA) holds promise for the initial catheter ablation performing pulmonary vein (PV) isolation (PVI) in patients with atrial fibrillation (AF), a repeat procedure remains necessary for those experiencing recurrent atrial tachyarrhythmia (ATA). This study aimed to evaluate the clinical outcomes of repeat procedures following the initial PFA in patients with recurrent ATA by comparing that following the initial CBA. Methods Patients who underwent a second ablation for recurrent ATA following initial PVI with pentaspline PFA or cryoballoon ablation (CBA) were included. Repeat ablation utilized radiofrequency current ablation with three-dimensional mapping guidance, involving repeat PVI combined with linear ablations when necessary. Acute data, such as documented arrhythmia before the repeat procedure, the number of reconnected PVs, procedural characteristics, and clinical follow-up, were analyzed. Results In total, 110 patients underwent initially successful PVI with PFA (N = 51) and CBA (N = 59), followed by a repeat procedure for recurrent ATA with a mean time interval of 365±299 days between the two procedures. The primary indication at the repeat procedure was atrial tachycardia (AT) in the PFA group (N = 27, 53%) and AF in the CBA group (N = 47, 80%). The overall PV reconnection rate per vein was 22.1%, with no significant difference between the two groups (19.1% in PFA vs. 24.7% in CBA, P = 0.16). Repeat PVI was successfully performed in all patients with PV reconnection (41.2% in PFA vs. 55.9% in CBA, P = 0.12). PV reconnection was most commonly found at the right inferior PV in both groups (25.5% vs. CBA; 32.2%, P = 0.44). Additional substrate modification was conducted in 76.5% of the PFA group and 74.6% in the CBA group, respectively (P = 0.82). The mean follow-up period was 349±280 days. The Kaplan-Meier curve indicated no statistical significance in the 1-year arrhythmia-free survival after the repeat procedure (62.4% in PFA vs. and 73.0% in CBA group, P = 0.54, Figure). Conclusion Comparable lesion durability between the initial PVI with PFA and CBA was unveiled during the repeat ablation. The second ablation for recurrent arrhythmia following initial PFA demonstrated a favorable clinical success rate at one year after the subsequent procedure, showing no significant difference compared to repeat ablation subsequent to CBA.arrhythmia-free survival after the repe

Novel systematic processing of cardiac magnetic resonance imaging identifies target regions associated with infarct-related ventricular tachycardia

Abstract Introduction In the clinic, complete characterization of reentrant ventricular tachycardia (VT) circuits using classical electrophysiological criteria and state-of-the-art high density mapping during VT is complex, and often cannot be completed because of hemodynamic instability. This common limitation has motivated the implementation of mapping strategies during sinus rhythm or ventricular pacing aiming to identify scar regions associated with VT isthmuses or potential arrhythmogenicity. Complementary imaging-based strategies including advanced analyses of scar tissue characteristics have been also proposed for procedure planning and identification of potential arrhythmogenic regions. However, the most recent expert consensus report on catheter ablation of ventricular arrhythmia highlights the lack of agreement on the preferable signal intensity (SI) cut-off values for assessment of tissue heterogeneity and scar areas on late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) images. The latter makes LGE-CMR imaging processing highly operator-dependent and potentially sensitive to selection bias. Purpose We aimed at developing and validating a systematic processing approach on LGE-CMR images to identify potential VT corridors that may include protected isthmuses associated with VT maintenance. Methods Translational study including 18 pigs with established myocardial infarction and inducible VT undergoing in vivo characterization of the anatomical and functional myocardial substrate associated with VT maintenance. Clinical validation was conducted in a multicenter series of 33 patients with ischemic cardiomyopathy undergoing VT ablation. Three-dimensional CMR-LGE images were processed using systematic scanning of 15 signal intensity cut-off ranges to obtain surface visualization of all potential VT corridors. Analysis and comparisons of imaging and electrophysiological data were performed in individuals with full electrophysiological characterization of the isthmus sites of at least one VT morphology. Results In both the experimental pig model and patients undergoing VT ablation, all the electrophysiologically-defined isthmus sites (n=11 and n=19, respectively) showed overlapping regions with CMR-based potential VT corridors. Such imaging-based VT corridors were less specific than electrophysiologically-guided ablation lesions at functionally relevant isthmus sites (Figure). However, in patients, decreasing from 15 to 7 the number of signal intensity cut-off ranges for systematic imaging processing significantly reduced the area of imaging-based potential VT corridors, without diminishing the capability to detect functionally relevant VT isthmus sites. Conclusions Systematic processing of 3D LGE-CMR images provides unbiased identification of imaging based potential VT corridors that contain functionally relevant protected isthmus sites.

First experiences with protected VT ablation using surgical Impella 5.5

Abstract Introduction Ablation of ventricular arrhythmias (VA) is still challenging due to the complex substrate of the underlying heart disease. Depending on specific risk factors acute hemodynamic decompensation during or after VT ablation procedures may occur and hemodynamic support may be required. Protected VA ablation with different devices has been evaluated but associated complications like bleeding, vascular closure or weaning from the device have been restrictive. We present data on a dedicated approach to patients with anticipated hemodynamic deterioration using preventive surgical Impella support. Method 5 patients (2 female) underwent protected VT ablation under our standardized protocol. Indication for Impella support was severely impaired left ventricular function and multiple medical therapy refractory ventricular arrhythmias. 4 patients had conventional VT ablation before. Mean age was 66,8 years, mean CHADSVASC 4,4, 1 patient with non-ischemic cardiomyopathy (CMP), 1 with hypertrophic non-obstructive CMP, 3 patients with ischemic CMP. Mean EF was 20%, mean mixed venous saturation was 36 %, mean PAINESD score 27. In all patients a 5.5. Impella was implanted surgically 1 day before planned VT ablation via the right subclavian artery. VT ablation procedure started with substrate mapping, VT induction and activation mapping of the inducible VT to identify the critical VT isthmus. Ablation was directed to dissection of the critical isthmus of inducible VAs and elimination of all late potentials within low voltage areas. The Impella device was explanted after weaning off the hemodynamic support. Results Implantation of Impella 5.5 was successfully performed in all patients in general anesthesia without any complication via surgical approach. Specifically, no access site vascular complications were noted. In 4 patients the VT ablation procedure was performed in analgosedation, 1 patient in GA as this patient was intubated due to recurrent VA requiring defibrillation. Mean procedure time was 125 min, radiation time 1,3 min, inducible VTs 1,3 , median 2 morphologies. In all patients all inducible VTs could be eliminated, in 1 patient polymorphic VA was still inducible at the end of the procedure. Impella was explanted after mean 5,2 days (3-11 days). No complications occurred. All patients were discharged alive on heart failure medication and in 2 patients with amiodaron. At a mean follow up of 3.5 months, all patients are alive without VA recurrence and heart failure decompensation. Conclusion Surgical Impella implantation for protected VT ablation in severe heart failure patients is feasible and allows for effective VT mapping and ablation. Access site safety and protection for heart failure decompensation in addition to the possibility of individually mobilisation and weaning after the procedure make this protocol an attractive option. Prospective evaluation of standardized indication is needed.

Remote magnetic navigation for catheter ablation of complex arrhythmias in congenital heart disease: an initial experience using a transnational telerobotic approach

Abstract Background The field of congenital electrophysiology (EP) is still in its relative infacncy with a limited number of electrophysiologists capable of performing catheter ablation in patients with congenital heart disease (CHD). As a result, patients or physicians are often required to travel great distances to performed specialised ablation procedures, something made near impossible during the COVID-19 pandemic. Objective We aimed to explore the feasibility and safety of a telerobotic approach to catheter ablation where the remote operator was situated approximately 1200km away from the patient and local team. Methods A 3D-printed 'phantom' heart was used in a pilot experiment in which no significant difference was seen between the local and remote operators in electroanatomic (EAM) mapping of the phantom heart using remote magnetic navigation (RMN). Catheter ablation was subsequently performed in patients with severe CHD using a transnational telerobotic approach to catheter ablation where the remote operator was able to view the dedicated console with live fluoroscopy, EAM and EP signals, as well as control the mapping and ablation catheters from 1200km away. As a safety precaution, radiofrequency (RF) could only be delivered by the local team. Results In total, 10 procedures were performed in 9 patients with severe CHD (mean age 38) between April and December 2021. All patients underwent an atrial ablation and one additional non-CHD patient underwent denervation of the pulmonary arteries. Median procedure duration was 335 (minutes) (IWR 230-349) with 11.5 minutes (QRS 3-15.4) of fluoroscopy exposure and 752 (IQR 674-905) seconds of RF delivery. There were no acute procedural complications. At one-year follow-up, one patient died as a result of heart failure and there were two arrhythmia recurrences. Conclusions Telerobotic catheter ablation is feasible and effective and creates the possibility of exciting new approaches to remote ablation and its use in the tele-proctoring of international fellows.

Real life experience with point by point pulsed field ablation for recurrent ventricular arrhythmias

Abstract Introduction The safety and effectiveness of electroporation/point by point pulsed field ablation (PP PFA) as emerging technoloy for catheter ablation (CA) of ventricular arrhythmias (VAs) has been described till now only in case reports. Purpose The aim of this observational retrospective study is to present real life data concerning the overall performance of PP PFA for CA of recurrent VA. Methods A total number of 13 consecutive patients (11 VTs and 2 PVCs), in whom recurrent VTs after RF ablation documented, were included. In all patients the substrate location was documented beforehand based on cardiac MRI or CT with myocardial thinning. For substrate mapping a high resolution multipoint mapping catheter was used. A complete success was defined as non inducibility of any arrhythmia at the end of procedure respectively lack of VA recurrence at follow – up. Results Excepting 2 patients, all other had a non ischemic cardiomyopathy as underlying heart disease (mean age 63 ± 8 y/o, mean LVEF 42 % ± 9 %). In every patient at least one conventional RF CA has been performed previously (mean 2 ± 1) and 38 % of patients had a previous epicardial RF VT ablation. The PP PFA VT ablation was performed endocardialy in 11 patients (84 %), respectively epicardialy in 2 patients. The ablation sites had a septal location in 53 % of patients and other localisation in 47 % of patients. The applied energy was 25 A. The overall acute complete success was achieved in 77 % patients. At medium 6 ± 3 months follow up a complete success was present in 46 % cases. Most frequently a VT recurrence after PP PFA ablation was encountered in patients with combined septal and nonseptal substrate distrubution. After PP PFA, the RF CA strategy due to recurrent VAs was endocardial in 2 patients, respectively epicardial 2 in cases and bipolar in 1 case. No PP PFA redos were undergone. Three major complications have been documented (1 tamponade, 1 AV block III° and 1 complete LBBB). Conclusion As bailout strategy in patients with failed conventional CA, PP PFA represents a safe strategy. Specific complications like temporary atrioventricular or intraventricular conduction disturbancies are extremely rare, reversible but not life threathening. The midterm success is satisfactory but still limited in patients with intramural substrate.

Neural network for automatic ICD-EGMs matching in pace-mapping and ablation of ventricular arrhythmias

Abstract Background Mapping of the ventricular arrhythmias (VA) is often not possible due to the non-inducibility of the electrophysiological study (EPS). Since twelve-lead electrocardiograms (ECG) of the clinical ventricular tachycardia (VT) are also often not available, therefore stored implantable cardioverter-defibrillator (ICD) electrograms (EGMs) of the clinical VT are often the only documentation. The pace mapping matching to the stored ICD-EGM template of the clinical VT can help to identify the VT exit site. Automatic objective computing of similarity scores between EGMs is impossible because ICD programmer devices do not have any interface allowing the export of digital EGMs. Therefore, images can only be accessed for similarity by subjective eyeballing. The MatcherNet Siamese neural network takes a pair of EGM images and predicts their similarity. Purpose This study aimed to assess the feasibility of the automatic ICD-EGMs matching by MatcherNet neural network for pace mapping of VT/premature ventricular contraction (PVC) exit site. Methods Consecutive patients undergoing VT ablation or ablation of ventricular fibrillation, triggered by PVC were included in the study, if the clinical VT/PVC was not inducible during EPS but ICD-EGMs of clinical VT/PVC were stored in the device. Electro-anatomical mapping was performed to reveal substrates (low-voltage areas, abnormal potentials, DEEP-potentials, conduction crowding). Subsequently, the low-output pacing from various locations tagged on the 3D map of LV was performed, and the paced ICD-EGM images were stored from the ICD programmer device for offline analysis and calculation of the similarity. RF ablation was conducted based on the substrate map findings, including the area of the most remarkable similarity between paced ICD-EGMs and clinical ICD-EGM templates assessed by eyeballing. The ICD-EGMs similarity scores (Manhattan similarity and Pearson correlation) were predicted by MatcherNet for each pacing site offline and transferred to the 3D map for the assessment of similarity distribution (Figure 1). Results We included 7 patients with VA episodes registered and stored by their ICD. The clinical characteristics are presented in Table1. In all patients, we were able to find the sites of highest ICD-EGM similarity to the clinical template with gradual decrementing of the similarity score at the increasingly distant pacing areas. The site of the highest similarity was collocated with VT substrate and ablation areas in all patients. Abrupt change of the similarity score at the adjacent pacing sites was detected in the 2 cases, indicating the possible protected VT isthmus. After ablation procedure only one patient with DCM experienced VA recurrence. Conclusion This technology opens new possibilities for the utilization of ICD-EGMs during the pace mapping of ventricular tachycardia, especially in the cases of non-inducibility during electrophysiological study.Figure 1Table 1

Effects of hemodynamic support on arrhythmia-free survival following catheter ablation of ventricular arrhythmias

Abstract Background Radiofrequency-guided catheter ablation is an established therapy for ventricular tachycardia (VA). Hemodynamic support (HS) is often required for patients suffering from incessant VA to guide ablation. Data on the outcome of patients receiving HS during VA ablation procedures are lacking. Purpose The aim of this observational study was to analyze the acute procedural success as well as long-term 36-month-VA-recurrence rates and mortality in patients requiring HS during VA ablation procedures. Methods Data from consecutive patients receiving HS during VA ablation procedures between 2015-2023 were analyzed. HS was defined as the use of an Impella, an extracorporeal membrane oxygenation (ECMO) or a left ventricular assist device (LVAD). HS-group patients were compared to patients that underwent VA ablation procedures without HS. All patients were continuously followed up in our outpatient clinic. Data on procedural parameters, acute success and complications as well as long-term VA-free survival and mortality were analyzed. Results A total of 95 consecutive patients (mean age 60.9 ± 11.0 years, 15% female) were included. 62 patients (65%, mean age 60.4±9.4 years, 16% female) receiving HS (ECMO or Impella: n=26, 42%; ECMO+Impella: n=7, 11%; LVAD: n=29, 47%) were compared to those without (mean age 61.7±13.5 years, 12 % female). In the HS-cohort a significantly lower left ventricular ejection fraction (LVEF) (p&amp;lt;0.001), a higher New York Heart Association (NYHA) functional class (p=0.013) and a more frequent antiarrhythmic drug use (p=0.045) was documented. Fluoroscopy times were significantly longer in the HS-group (HS: 10:22 ± 07:04 vs. no HS: 05:52 ± 02:50 minutes, p&amp;lt;0.001). Acute procedural success (HS: n=59, 95% vs. no HS: n=33, 100%, p=0.549) and major procedure complications (HS: n=4. 6% vs. no HS: n=4. 6%, p=1.000) were comparable between the two groups. Nevertheless, patients receiving HS had a significantly higher in-hospital mortality (HS: n=20, 32 % vs. no HS: n=2, 6%, p=0.004). The estimated 36-month-VA-free survival was comparable between the groups (Log-rank p=0.114). But Kaplan-Meier-plot analyses revealed a significantly higher estimated mortality in patients receiving HS (Log-rank p=0.002) (Figure 1). Between the subgroups (ECMO or Impella vs. LVAD) no statistically relevant differences were observed (Log-rank p=0.466). Multivariate analyses revealed HS as an independent predictor for mortality (Hazard ratio (HR) 3.259, Confidence Interval (CI) 1.060-10.015, p=0.039), but not for VA-recurrence. Conclusion In the specific cohort of patients receiving HS, VA ablation procedures seem to be safe and effective with comparable acute and long-term success- and complication-rates. The need for HS seems to be associated with an increased risk for mortality. Further studies are required to validate our initial observations.Kaplan-Meier-plot on 36-month survival

First experience of focal pulsed field ablation for premature ventricular contractions

Abstract Introduction Pulsed field ablation (PFA) has emerged as a novel strategy to achieve ablation of cardiac tissue. Clinical evidence suggests a remarkable lesion durability and safety profile for AF ablation. Nonetheless, a growing interest exists in broadening its field of application for catheter ablation of ventricular arrhythmias (VA). The CENTAURI system arises as a promising PFA system for targeting VA as it allows pulsed electric field (PEF) delivery via standard, commercially available focal ablation catheters and concomitant coupling with their mapping systems. Purpose To assess, for the first time, the feasibility of focal PFA via the CENTAURI system for premature ventricular complex (PVC) ablation. Methods We conducted a prospective analysis of patients with either high burden (&amp;gt;10%) or symptomatic idiopathic PVC undergoing focal PFA using CENTAURI system at our institution. Procedures were performed between December 2022 and August 2023. Acute and long-term success were defined as no PVC recurrence during a 24h in-hospital monitoring period, and ≥80% burden reduction with absence of symptoms after at least 30 days post-ablation, respectively. PVC monitoring was performed by implantable loop recorder (ILR) or surface ECG Holter monitoring. Results Fourteen patients (age range: 16-87 years; 10 females) were included. Procedures were performed via the CENTAURI system in combination with CARTO 3 system and EnSite X EP system in 4 (28.6%) and 10 cases (71.4%) respectively. Targeted ablation sites were the right ventricular outflow tract (6 cases), right moderator band (2 cases), left postero-medial papillary muscle -PM- (2 cases), and right posterior PM, tricuspid annulus, left posterior fascicle and aortomitral continuity (AMC) in one case. On average, 6.5 applications were delivered to the site of origin with a mean contact force of 11g. Procedural duration and fluoroscopy time were 102 and 8.9 minutes. Two minor complications were observed: one transitory ST depression (solved after i.v. nitrate administration) after repeated applications to AMC, and a femoral pseudoaneurysm. The remaining 12 procedures were uneventful. Although most of the procedures were performed under general anesthesia due to concerns about potential significant muscular contraction, 3 cases (21.4%) were successfully managed with light sedation, without significant muscular contraction nor map shift. Incomplete abolishment of PVC during first 24 h was observed in 2 patients (14.3%). After a median follow-up of 113 days (IQR: 83-188), recurrences were detected in one patient (7.14%). Conclusion Herein we report the feasibility and efficacy of PVC ablation using a focal PEF delivery system (CENTAURI). Furthermore, we describe the possibility of performing PVC ablation with this technology under light sedation, which might be important for minimizing anesthesia impact on PVC burden.Table of characteristicsPVC morphologies

Initial experience with ablation of ventricular arrhythmias using a pulsed-field system

Abstract Introduction Catheter ablation using radiofrequency (RF) current is a well-established method of treatment of ventricular arrhythmias (VA). However, RF ablation may fail to eliminate deeply located arrhythmogenic substrate. Pulsed-field (PF) is a novel energy source with a potential to create deeper lesions, especially in scar tissue. Purpose This study aims to present the data on safety and efficacy (acute outcome data) of VA ablation using PF. Methods The population consists of 15patients (5 women, age: 61 ± 19years) after previously failed RF ablation of VA. The underlying condition was nonischemic cardiomyopathy (53%), coronary artery disease (13%), and congenital heart disease (13%), respectively. No structural heart disease was present in 20% of cases. The mean left ventricular ejection fraction was 39 ± 13%. Eighty percent of patients had sustained VA, the remaining patients presented with frequent ventricular ectopy. Ablation was performed using a conventional irrigated 4-mm tip catheter in a combination with commercially available PF generator. Peripheral venous blood samples for the assessment of the plasmatic levels of high-sensitivity troponin T (hsTnT) were obtained the next day (usually 18-24hours) after the procedure. Results A mean of 17±12 PF applications (25A) per patient were delivered. In 5 patients (33%), an additional RF ablation (4±9 applications) was performed. Acute success as assessed by non-inducibility of VA or elimination of ectopic focus was achieved in all but one patient (93%). In 4 cases (27%), PF energy was applied within the great cardiac vein and subsequent coronary angiography did not reveal any abnormality. On the other hand, transient conduction system block occurred in 3 cases (20%) during PF application on the lateral LV wall remotely from the LV septum (complete AV block in one, LBBB in two patients). These events resolved in all cases within one hour. Ablation using PF did not result in excessive increase of hsTnT (657±482ng/l, with upper reference level of 14ng/l). Conclusion Initial experience with PF for the treatment of VA indicates high acute efficacy. The long-term effect is to be determined. PF applications in the ventricle may be associated with unexpected but transient conduction system damage, even when applications are performed remotely from the interventricular septum. The postprocedural increase in plasma troponin levels is only moderate.

Transbaffle or retrograde aortic approach for atrial arrhythmias ablation in patients with D-TGA treated with atrial switch surgery

Abstract Introduction Patients with D- transposition of the great arteries (TGA) treated with Senning or Mustard surgeries have high incidence of supraventricular tachycardias (SVTs). Accessing to the pulmonary venous atrium (PVAt) is frequently required to perform the ablation, however it can be challenging. Aim To investigate the differences between a retrograde aortic approach (Re-Aa) and transbaffle approach (TBa) for PVAt ablation in this set of patients. Methods Prospective observational study in a third level hospital since April 2018 until October 2022, with a medium-term follow-up. All consecutive patients (pt) with history of SVT and atrial switch surgery that underwent electrophysiologic study (EP) and electroanatomic mapping using a high-density Grid mapping catheter and a contact-force ablation catheter were included. Results A total of 25 EPs were performed in 20 pt (13 (52%) Female, median age 37 y.o [IQR 34-41], median follow-up time 13 month [IQR 10-37]). In 14 pt the PVAt was mapped and ablated via Re-Aa, and in 11 with TBa. Table 1 shows basal patients characteristics, note that no significant differences between groups were found. In 19 pt (76%) a CTI-dependent flutter was documented (10 (71%) in Re-Aa group and 9 (82%) in TBa, p=0.6). Furthermore, in 7 pt other tachycardia circuits were found. Accurate mapping of all the CTI walls were achieved with both strategies, however, the posterior PVAt wall and the pulmonary veins were suboptimal mapped with Re-Aa due to a lack of catheter contact. Acute ablation success was 83% in Re-Aa and 100% in TBa (p=0.5). Despite a higher recurrence rate in the Re-Aa in the first months (20% vs 0%), no significant differences in recurrences were found between groups within 1 year of follow-up (HR 1.3 [95%CI: 0,2-7], p=0.8) (FIGURE). Complication rate was 20% in Re-Aa and 0% in TBa. All complications were directly related to the arterial vascular access (1 femoral pseudoaneurysm, 1 iliac dissection, 1 mediastinal hematoma), and were successfully treated. Conclusion In D-TGA treated with atrial switch surgery, PVAt mapping and ablation is feasible with both strategies with a high acute success rate and without significant differences in recurrences at mid-term follow up. However, TBa is associated with a lower complications rate and also with a better catheter contact and accurate mapping in the PVAt posterior wall.

Real-time characterization of radiofrequency lesions by local multifrequency impedance with thermal correction

Abstract Background/Introduction Recent studies have shown that measuring local impedance (LI) at a single frequency can be useful for real-time characterization of radiofrequency (RF) lesion size during arrhythmia ablation procedures. (1) However, these systems do not take into account the effect of the increase in tissue temperature on the impedance measurement itself, which could be avoided by comparing the impedance at different frequencies. Purpose The aim of this study was to evaluate the ability of local multifrequency impedance (LMI) to characterize the size of RF lesions in real-time, while correcting for the thermal effect on the measurement. Methods Lesions were performed on the epicardium in 5 anesthetized pigs while measuring IML (from 1 to 209 kHz) before, during, and after ablations (20W/30W/40W, 60s, &amp;gt;10g) through a conventional irrigated electrocatheter connected to a cardiac navigation system and a RF generator. In these measurements, the thermal effect on the tissue was corrected by assuming that the changes in impedance at high frequency were only due to the temperature variation and not to the injury itself. Local voltage (Vuni) was also measured before and after ablations, and catheter-measured temperature and contact force were monitored. At the end of the procedure, the animals were sacrificed, and a histological study of the lesions was performed. Results A total of 43 effective lesions (11±2 per animal) were performed. The 40W lesions were deeper and wider than the 20W lesions (6,6 ± 3,3 mm vs. 5,4 ± 2,0 mm vs. 4,0 ± 1,9 mm; ANOVA p&amp;lt;0.05) and presented a significant decrease in unipolar voltage that was similar among the different lesions (40W vs. 20W: 56% vs. 40%; ANOVA p=ns; Figure). Four seconds after the start of the ablation the 40W lesions had a greater decrease in IML than the 30W and 20W lesions (73±14Ω vs. 85±4Ω vs. 100±12Ω; ANOVA p&amp;lt;0.05). After thermal adjustment, IML recorded 30 and 55 seconds after the start of the ablation correlated better with the final depth of the lesion than IL or Vuni (Table). Conclusions The measure of IML during ablation allows a better quantification of the changes in the structural characteristics of myocardial tissue than local impedance at a single frequency. The increase in tissue temperature during ablation influences the values of local impedance and should be considered when creating new impedance-based metrics to predict the chronic size of the RF lesion.Figure.Lesion quantification by LMITable.Correlation analysis