Linear Lesions Research Articles

MR imaging differences between Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorders: A single institutional study in a tertiary referral centre in Sri Lanka.

Background and objectives- Multiple Sclerosis (MS) and Neuromyelitis Optica Spectrum Disorders (NMOSD) are the commonest demyelinating diseases of the central nervous system with overlapping clinical and radiological features, leading to frequent misinterpretation. This study aimed to describe neuroimaging features for differentiating MS and NMOSD and also comparing NMOSD subcategories.Methods- A cross sectional study was conducted at a single tertiary referral center in Sri Lanka. The magnetic resonance imaging (MRI) characteristics of 82 MS and 36 NMOSD patients were prospectively evaluated by a fourth-year resident under the supervision of consultant radiologists and were analyzed using standard descriptive statistical tests. Results- Statistical analyses indicated significance (p<0.05) in distinguishing both entities (MS and 36 NMOSD) across lesions in periventricular, subcortical, intracortical, inferior temporal, corpus callosum, and infratentorial locations by MRI. Dawson finger lesions, U fibers, calloso-septal interface involvement and T1 black holes indicated MS, whereas linear ependymal lesions suggested NMOSD. In the spinal cord, peripherally located short-segment lesions were significant for MS (p=0.000) and longitudinally extensive lesions involving central grey matter (p=0.000) pointed towards NMOSD. There was only a slight variation in lesion distribution between cervical and thoracic cord. MS showed more brain parenchymal volume loss while spinal cord atrophy was higher in NMOSD. Symmetry and location of the optic pathway lesions reinforced the differentiation.Conclusion- Comprehensive analyses support the use of neuroimaging in distinguishing between NMOSD and MS. However, further multicentric longitudinal studies are required to differentiate NMOSD phenotypes.

Manifestations and distribution rules of jingjin lesions in neck-type cervical spondylosis

To explore the manifestations of jingjin (sinews/fascia) lesions and summarize their distribution rules in the patients with neck-type cervical spondylosis so as to provide the evidences for the development of clinical diagnosis and treatment scheme of acupuncture for cervical spondylosis. A total of 120 patients with neck-type cervical spondylosis were collected. The meridian diagnostic method was used to examine the upper back of each patient, the manifestation category of jingjin lesions, locations and the affected muscle regions of twelve meridians were recorded. (1) The punctate lesions of jingjin were detected in 15 regions, and the highest frequency of lesion occurred in the region from the inner upper corner of the scapula to Quyuan (SI 13) (113 cases, 94.2% of lesion frequency). The lesion frequency of 10 regions was ≥50.0%. The punctate lesions were mainly distributed in the muscle regions of hand-shaoyang (349 cases) and foot-taiyang (333 cases). (2) The linear lesions of jingjin were detected in 10 regions, and the highest frequency of lesion occurred in the region from the inner upper corner of the scapula to Quyuan (SI 13) (77 cases, 64.2% of lesion frequency). The lesion frequency of 2 regions was ≥50.0%. The linear lesions occurred mainly in the muscle region of foot-taiyang (251 cases). (3) Eight regions were examined to be the planar lesions of jingjin, and the highest frequency of lesion was found in the site of Jianjing (GB 21) (84 cases, 70.0% of lesion frequency). The lesion frequency of 3 regions was ≥50.0%. The muscle region of foot-taiyang (260 cases) was predominated in the planar lesions. (4) The distribution of all of the punctate, linear and planar lesions of jingjin was analyzed statistically. It was found that 25 regions were involved and those with the high lesion frequency were distributed in the area from the inner upper corner of the scapula to Quyuan (SI 13), the sites of Jianjing (GB 21) and Dazhui (GV 14), transverse processes of C3 to C5 and the area from the lateral border of the scapula to the teres minor, separately. The muscle regions of foot-taiyang, hand-shaoyang and hand-yangming were involved in various kinds of jingjin lesions. Jingjin lesions in patients with neck-type cervical spondylosis can be divided into three categories, namely, punctate, linear and planar lesions; of which, the punctate lesions are dominated. A majority of jingjin lesions is related to the muscle region of foot-taiyang, and the lesion frequency is higher compared with the lesions to the muscle regions of hand-shaoyang and hand-yangming. Jingjin lesions are commonly distributed in the area from the inner upper corner of the scapula to Quyuan (SI 13).

Catheter navigation by intracardiac echocardiography enables zero-fluoroscopy linear lesion formation and bidirectional cavotricuspid isthmus block in patients with typical atrial flutter

IntroductionOne of the most helpful aspects of intracardiac echocardiography (ICE) implementation in electrophysiological studies (EPS) is the real-time visualisation of catheters and cardiac structures. In this prospective study, we investigated ICE-guided zero-fluoroscopy catheter navigation during radiofrequency (RF) ablation of the cavotricuspid isthmus (CTI) in patients with typical atrial flutter (AFL).Methods and resultsThirty consecutive patients (mean age 72.9 ± 11.4 years, 23 male) with ongoing (n = 23) or recent CTI-dependent AFL underwent an EPS, solely utilizing ICE for catheter navigation. Zero-fluoroscopy EPS could be successfully accomplished in all patients. Mean EPS duration was 41.4 ± 19.9 min, and mean ablation procedure duration was 20.8 ± 17.1 min. RF ablation was applied for 6.0 ± 3.1 min (50W, irrigated RF ablation). Echocardiographic parameters, such as CTI length, prominence of the Eustachian ridge (ER), and depth of the CTI pouch on the ablation plane, were assessed to analyse their correlation with EPS- or ablation procedure duration. The CTI pouch was shallower in patients with an ablation procedure duration above the median (4.8 ± 1.1 mm vs. 6.4 ± 0.9 mm, p = 0.04), suggesting a more lateral ablation plane in these patients, where the CTI musculature is stronger. CTI length or ER prominence above the respective median did not correlate with longer EPS duration.ConclusionsZero-fluoroscopy CTI ablation guided solely by intracardiac echocardiography in patients with CTI-dependent AFL is feasible and safe. ICE visualisation may help to localise the optimal ablation plane, detect and correct poor tissue contact of the catheter tip, and recognise early potential complications during the ablation procedure.Graphical

Linear epicardial cryoablation effects in a porcine model: Lesion characteristics and vascular risk.

Cryoablation in open-chest surgical interventions for ventricular arrhythmias has been reported with reasonable procedural outcomes. However, the characteristics of cryoablation lesions on the ventricular myocardium are not well defined. The purpose of the present study was to determine the tissue and vascular effects of a linear epicardial cryoablation probe in a porcine animal model. Five adult Yorkshire swine underwent median sternotomy and application of linear cryoablation lesions using a malleable aluminum linear cryoablation probe of varying duration (2, 3, 4, and 5 min), including one lesion placed intentionally over the left anterior descending coronary (LAD) artery. Histological analysis was performed. Maximum lesion depth was approximately 1.0 cm with 3 min freezes, with no significant increase in depth achieved with longer lesions. No transmural lesions were achieved. No large vessel epicardial coronary artery injuries were seen to the LAD; however, surprisingly, remote isolated interventricular septal injury was seen in all animals, suggestive of possible compromise of smaller coronary arterial vessels. Single application freezes with an aluminum linear cryoablation probe can create homogeneous ablative lesions over the ventricular myocardium with a maximum depth of approximately 1.0 cm. No large vessel injury occurred with direct lesion application of the LAD; however, small coronary vessels may be at risk.

Intraoperative monitoring of intraesophageal temperature during radiofrequency ablation of the posterior wall of the left atrium in atrial fibrillation (literature review)

Currently catheter radiofrequency ablation (RFA) has become the standard treatment for patients with atrial fibrillation (AF). During RFA, additional linear lesions are performed along the posterior wall of the left atrium, which can cause damage to the esophagus. The manuscript considers the methods introduced into practice to prevent damage to the esophagus during RFA, the pros and cons of the techniques.

Delineation of conduction gaps of linear lesions during atrial fibrillation ablation using ultra-high-density mapping.

Linear lesions are routinely created by radiofrequency catheter ablation. Unwanted electrical conduction gaps can be produced and are often difficult to ablate. This study aimed to clarify the characteristics of conduction gaps during atrial fibrillation ablation by analysing bidirectional activation maps using a high-density mapping system (RHYTHMIA). This retrospective study included 31 patients who had conduction gaps along pulmonary vein (PV) isolation or box ablation lesions. Activation maps were sequentially created during pacing from the coronary sinus and PV to reveal the earliest activation site, defined by the entrance and exit. The locations, length between the entrance and exit (gap length), and direction were analysed. Thirty-four bidirectional activation maps were drawn: 21 were box isolation lesions (box group), and 13 were PV isolation lesions (PVI group). Among the box group, nine conduction gaps were present in the roof region and 12 in the bottom region, while nine in right PV and four in left PV among the PVI group. Gap lengths in the roof region were longer than those in the bottom region (26.8 ± 11.8 vs. 14.5 ± 9.8 mm; P = 0.022), while those in right PV tended to longer than those in left PV (28.0 ± 15.3 vs. 16.8 ± 8.0 mm, P = 0.201). The entrances and exits of electrical conduction gaps were separated, especially in the roof region, indicating that epicardial conduction might contribute to gap formation. Identifying the bidirectional conduction gap might indicate the location and direction of epicardial conduction.

Bilateral en coup de sabre morphea in a male child: A rare presentation.

En coup de sabre is a rare subtype of morphea. Only a few bilateral cases have been reported to date. We report a case of a 12-year-old male child with two linear brownish depressed asymptomatic lesions over the forehead with hair loss on the scalp. After thorough clinical, ultrasonography and brain imaging, a diagnosis of bilateral en coup de sabre morphea was made and the patient was treated with oral steroids and weekly methotrexate.

A new skin laxity scale for the buttocks: the Skin Laxity Visual Scale (SLVS).

The Skin Laxity Severity Scale for the buttocks was previously developed to separately assess buttock ptosis, a scalloped appearance of the skin, infragluteal fold, localized fat on the lower third of the buttocks, and linear depressed lesions. A more objective, faster and shorter version of this scale, to be evaluated visually, would be more feasible to apply in daily practice. To present a new skin laxity scale for the buttocks: the Skin Laxity Visual Scale (SLVS). To establish the scale, investigators chose, by consensus, the most representative cases of each skin laxity grade. The images were graphically edited to better represent the degree of skin laxity identified in a previous study. Scale validity and reliability were assessed in two validation cycles, performed by eight dermatologists assessing 50 clinical cases. Overall, Kendall's, weighted-kappa, and intraclass correlation coefficients indicated very good reliability and consistent inter- and intra-rater agreement (p<0.001). The scale validity was confirmed by criteria validity tests (rs: 0.76, p<0.05). The SLVS for the buttocks is a reliable, reproducible, accurate and valid scale to identify skin laxity severity and its different features. It will very likely be an easy-to-use and convenient tool to appropriately assess improvement obtained with treatment and follow patients.

The novel left atrial anterior 'seatbelt' line reduces sustained atrial arrhythmia by 72% compared to pulmonary vein isolation alone in a cohort of 400 virtual atria models

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No.860974. Background The success-rate of pulmonary vein isolation (PVI) is modest in persistent atrial fibrillation (AF), but additional empirical ablation, such as posterior wall isolation (PWI), has not been shown to reduce the rate of AF recurrence. The "seatbelt", an anterior linear ablation lesion connecting the right superior pulmonary vein to the mitral annulus, is a novel substrate modification approach that is yet to be tested in a large-scale randomised clinical trial. Purpose To use in-silico trials with human-based modelling and simulation to compare the efficacy of (i) PVI alone, (ii) PVI and PWI (PVI+PWI), or (iii) PVI and seatbelt (PVI+SB) for the prevention of atrial arrhythmia in large populations of virtual patient models. Methods AF was simulated in a cohort of 400 virtual atrial models with anatomical and electrophysiological variability, with AF persisting for &amp;gt;7 seconds defined as sustained. Models which sustained AF were each independently subjected to all three ablation approaches before repeating the AF induction protocol. Results Three hundred forty-four (86%) atrial models developed sustained AF at baseline. After applying the ablation lesions, substantially fewer models sustained atrial arrhythmias in the PVI+SB group (50 [14%] vs. 134 [39%] with PVI+PWI vs. 172 [50%] with PVI). PVI+SB was more effective than PVI and PVI+PWI in preventing both AF and atrial flutter (i.e., presence of a single rotor), since PVI and PVI+PWI led to the formation of anatomical re-entries around the rings of the pulmonary veins and the posterior wall of the left atrium, respectively (Figure). Therefore, PVI+SB restricted atrial flutter mainly to the right atrium (either anatomical, around the inferior cava vein, or functional, meandering throughout the venous portion of the right atrium, Figure). Importantly, in all three ablation strategies, the likelihood of AF recurrence was directly proportional to the surface area of the right atrium (AF probability increased 0.95%/cm², 0.88%/cm² and 0.56%/cm² after PVI+SB, PVI+PWI and PVI, respectively). The role of the right atrial size was less accentuated for PVI alone, since after the ablation the entire left atrial body was still available for rotor anchoring. Moreover, an enlarged left atrium enabled the appearance of micro-re-entries in the anterior and inferior wall of the left atrium, even after applying floor and roof lines. One atrial model additionally presented a rotor in the posterior wall of the left atrium after completely isolating it from the left atrial body. Conclusion(s) In a cohort of 400 virtual atrial models, PVI+SB reduced sustained atrial arrhythmias by 72% compared to PVI alone and by 64% to PVI+PWI, but AF could still originate in an enlarged right atrium.

Arrhythmogenic Right Ventricular Cardiomyopathy With Extensive Abnormal Substrate: Is Isolation Possible?

BackgroundIn arrhythmogenic right ventricular cardiomyopathy (ARVC) patients with extensive right ventricular free wall (RVFW) abnormal substrate, large-area homogenization with combined epicardial and endocardial approach is time consuming and often inadequate for modification. ObjectivesThis study aimed to explore the feasibility and efficacy of RVFW abnormal substrate isolation in such patients to control ventricular tachycardia (VT). MethodsEight consecutive ARVC patients with VT who had extensive abnormal RVFW substrate were included. VT induction was performed before substrate mapping and modification. Detailed voltage mapping was done during sinus rhythm. A circumferential linear lesion was deployed along the border zone of low-voltage area on the RVFW to achieve electrical isolation. Other small areas with fractionated or late potentials were further homogenized. ResultsAll 8 patients had RVFW endocardial low-voltage area. The entire RV low-voltage area was 113.8 ± 84.1 cm2 (49.6% ± 29.8%) and the dense scar was 59.6 ± 39.8 cm2 (25.0% ± 14.1%). Electrical isolation of abnormal substrate was achieved in 5 of 8 (62.5%) patients via endocardial approach alone and 3 of 8 (37.5%) patients via a combination of endocardial and epicardial approach. Electrical isolation was verified by slow automaticity (5 of 8, 62.5%) or RV noncapture (3 of 8, 37.5%) during high-output pacing inside the encircled area. VTs were induced in 6 patients before ablation, and all patients were rendered noninducible after ablation. During a median follow-up of 43 months (range: 24-53 months), 7 of 8 (87.5%) patients remained free of sustained VT. ConclusionsElectrical isolation of RVFW is feasible and can be the option in ARVC patients with extensive abnormal substrate.

A novel stepwise approach incorporating ethanol infusion in the vein of Marshall for the ablation of persistent atrial fibrillation.

Apart from pulmonary vein isolation (PVI), several step-by-step procedures that aim to modify left atrial substrate have been proposed for the ablation of persistent atrial fibrillation (AF), yet the optimal strategy remains elusive. There are cumulative data suggesting an incremental benefit of adding vein of Marshall (VOM) ethanol infusion to PVI in patients with persistent AF. We sought to evaluate the feasibility and efficacy of a novel stepwise ablation approach, incorporating a VOM alcoholization step, for persistent AF. In this single-center study, we prospectively enrolled 66 consecutive patients with symptomatic persistent AF and failure of at least one antiarrhythmic drug (ADD). The ablation procedure consisted of (i) PVI, (ii) left atrial segmentation with VOM ethanol infusion and the deployment of linear radiofrequency lesions across the roof and the mitral isthmus and (iii) electrogram-based ablation of dispersion zones. The first two steps were performed in all patients, whereas the third step was carried out only in those still in AF at the end of the second step. Atrial tachycardias during the procedure were mapped and ablated. At the end of the procedure, cavotricuspid isthmus ablation was additionally performed in all patients. The primary endpoint was 12-month freedom from AF and atrial tachycardia after a single procedure and an initial three-month blanking period. Total procedure time was 153 ± 38.5 min. Fluoroscopy time was 16 ± 6.5 min and the radiofrequency ablation time was 26.14 ± 0.26 min. The primary endpoint occurred in 54 patients (82%). At 12 months, 65% of patients were off any AAD. In the univariate Cox regression analysis, left ventricular ejection fraction < 40% was the only predictor of arrhythmia recurrence (HR 3.56; 95% CI, 1.04-12.19; p = 0.04). One patient developed a pericardial tamponade and another a minor groin hematoma. A novel stepwise approach, including a step of ethanol infusion in the VOM, is feasible, safe and provides a high rate of sinus rhythm maintenance at 12 months in patients with persistent AF.

PO-04-071 PULSE FIELD ABLATION AND LESION FORMATION USING A UNIQUE INTEGRATED MULTIELECTRODE FOCAL, LINEAR, AND LOOP ABLATION CATHETER

Pulse field ablation (PFA) is a promising energy modality for cardiac ablation due to its speed, tissue selectivity, and potential ability to create consistent transmural lesions Evaluate PFA lesions created using an innovative catheter design combining focal, linear and pulmonary vein (PV) ablation PEF ablation was performed using an 8F bidirectional linear catheter with a 2mm tip and 4 ring electrodes through which a 3.5F loop catheter (6 to 9 rings, 3mm length on 19mm diameter) can be inserted and deployed beyond the tip (Figure, A). In 8 swine, R-wave gated biphasic pulse trains of voltage between 600 and 700V were delivered sequentially and simultaneously to the loop or linear catheter electrode pairs. The linear catheter is compatible with any commercially available 8.5F transseptal sheath. Porcine intracardiac tissue was ablated in vivo targeting the superior vena cava (SVC), right atrium (RA), RA appendage (RAA), cavotricuspid isthmus, left atrium, PVs, and right ventricle. Electrogram (EGM) amplitudes/morphology and pre- and post-ablation pacing thresholds were assessed. Triphenyl tetrazolium chloride (infused 20 minutes before euthanasia) or tetrazolium blue stain was used to demarcate and measure the lesions. Histopathologic analysis of all cardiac tissues was performed, esophageal pre and post ablation phrenic nerve stimulation were done. EGM attenuation and pacing thresholds increase were documented (see Table). Focal: PFA was delivered from the distal electrode pair of the linear catheter. Lesion measured 10.3±2.6 mm diameter, 3.15±1.56 mm depth (Figure, B). Linear: PFA was delivered to 5 electrodes of the linear catheter (Figure, C). Lesion dimension range: width: 4 - 20mm, length: 12 to 20mm. Loop: PFA was delivered sequentially via loop catheter electrode pairs to PVs resulting in transmural lesions with 2.02 ± 0.94mm depth measured at the thickest area of affected myocardium (Figure, D). Simultaneous biphasic PEF was delivered by loop electrode pairs to the RAA and SVC, resulting in transmural lesions. RAA lesion measured 132mm2 surface area with average EGM attenuation 87% ± 2% and pacing thresholds increased post ablation (p=0.00), 4.0 ± 2.1 mA pre, 18.5 ± 4.2 mA post (Figure, E) No esophageal or phrenic injuries were documented. The combined linear, focal, and circular PFA ablation device demonstrated acute lesion success and each configuration has the potential to create effective transmural lesions in the atrium.Tabled 1TableEGM % Reduction*Pacing Threshold (mA)*Lesion DimensionsFocal lesion in atrial tissue88% ± 3.8% (N=7)Pre-ablation: 2.23 ± 1.83 mAPost-ablation: 19.3 ± 2.23 mA (N=9)Diameter: 10.3 ± 2.6 mm (N=15)Surface area: 87.6 ± 41.8 mm2 (N=15)Depth: 3.15 ± 1.56 mm (N=11)**10/11 lesions transmural (1 lesion was not assessed).Linear lesions in RA and LA95% ± 5% (N=7)Pre-ablation: 2.02 ± 1.78 mAPost-ablation: 15.1 ± 5.92 mA (N=29)Width: 8.86 ± 4.93 mm (N=9)Length: 17.17 ± 3.71 mm (N=9)Surface area: 156 ± 103 mm2 (N=9)Loop lesions in SVC and PV88% ± 5% (N=53)Pre-ablation: 3.5 ± 2.8 mAPost-ablation: 18.3 ± 3.2 mA (N=80)Transmural lesions,Depth: 2.02 ± 0.94mm (N=10) Open table in a new tab

PO-04-004 UTILITY OF OPEN-WINDOW MAPPING FOR CATHETER ABLATION OF ACCESSORY PATHWAY

Open window mapping (OWM) is a novel automated mapping methods for catheter ablation of an accessory pathway (AP), in which the local signal is annotated with the windows of interest parameters set to analyze both atrial and ventricular signals. We sought to determine the utility of the OWM to identify the location of APs in patients with APs. In this two-center study, 28 patients (20 male, 55 years old: IQR 22-67) who underwent high-density OWM with extended early-meets-late (EEML) algorithm (CARTO 3, Biosense Webstar, USA) using a 20-electrode, 5-spline catheter (Pentaray, Biosense Webster) were enrolled. The lower threshold of the EEML was set to adjust the EEML gap to match propagation mapping (Figure A) and the EEML gap of > 1cm was defined as a wide AP (Figure B). The median mapping points, mapping time, and lower threshold of EEML were 2399 points (1736-3798), 24 minutes (16-30), and 22 (18-25), respectively. APs were successfully eliminated in all 28 patients (22 APs in mitral annulus and six APs in tricuspid annulus), in 19 of which were eliminated by the first radiofrequency (RF) application (68%). OWM revealed wide or multiple APs in 10 patients (36%), in all of whom multiple RF applications were required to eliminate the APs. OWM facilitates to visualize the location and width of APs, which is particularly useful to predict whether linear or cluster ablation lesion sets are required for wide APs.

PO-03-069 COHERENT SINE BURST ELECTROPORATION (CSE) FOR PULSED FIELD ABLATION: PRELIMINARY CLINICAL OUTCOMES FOR TREATMENT OF PAROXYSMAL AND PERSISTENT AF IN THE BURST-AF TRIAL

Pulsed field ablation (PFA) has a promising safety profile for treatment of atrial fibrillation. PFA is currently implemented using square waves and varying circular, multi-spline, focal, or basket catheter designs. Coherent Sine Burst Electroporation (CSE) is a novel PFA platform that uses phased sine waves delivered via a configurable catheter to produce linear, circular, or focal lesions. Investigate the acute safety and efficacy of CSE for pulmonary vein isolation (PVI), posterior wall isolation (PWI), and cavo-tricuspid isthmus (CTI) ablation in patients with paroxysmal (PAF) and persistent AF (PersAF). BURST-AF is a first-in-human, non-randomized, multicenter, single-arm trial of PAF and PersAF ablation (NCT05572047). CSE was delivered with sine waves of amplitude 2400–2900V (standard-energy) and 3000–3500V (high-energy) using a multi-configurable 7F ablation catheter (Arga MedTech Inc, San Diego, CA, USA). After informed consent and under general anesthesia, ICE-guided transseptal puncture was performed. An 8.5F deflectable sheath guided the ablation catheter into the left atrium (LA). Electro-anatomic anatomy and voltage maps were created. A minimum of 3 applications of ablation per vein including rotation were applied at each PV ostium to achieve PVI. In patients (pts) with PersAF, the linear configuration was used for PWI and CTI. PV entrance and exit block was assessed after 20-min waiting period. ICE was used to assess microbubble formation. Re-map will be performed 60-days post procedure to evaluate lesion durability. The first 5 pts were enrolled in Oct 2022. Acute safety was observed for all pts (age 62.6 ± 7.56 yrs, F/M = 80/20%, BMI 32 ± 5.7). No serious adverse events occurred. First-pass acute electrical isolation was achieved in 100% of PVs (n=20) and also in the PersAF pt for PWI and CTI. PVI duration (from 1st to last lesion) was 46.6 ± 28.5min (range 28 - 95). PVI LA dwell time was 58.6 ± 37.7min and fluoro time was 20.4 ± 6.8 min. Initial findings of CSE PFA demonstrated acute first-pass efficacy for PVI, PWI, and CTI. Additional pts and re-map data for durability assessment will be available at time of presentation. CSE allows application of high energy protocols (up to 3500V) with no microbubble formation and minimal to no muscle stimulation. The CSE Ablation Catheter facilitates focal, linear, and circular ablations, comprising a highly versatile tool for cardiac arrhythmias.

PO-01-005 GANGLIONATED PLEXI MEDIATED BRADYCARDIA RESPONSES: A PRE-CLINICAL STUDY OF DIFFERENCES BETWEEN PULSED FIELD AND RADIOFREQUENCY ABLATION IN THE LEFT ATRIUM

During left atrial catheter ablation procedures, the peri-atrial neural network of ganglionated plexi (GP) can be affected by the ablative energy. Bradycardic responses (BR) from GP stimulation have been reported during both radiofrequency (RF) and pulsed field (PF) ablation procedures. To assess differences in BR between RF and PF during canine left atrial ablation. Healthy canines (n=14) underwent transeptal access under general anesthesia. A multielectrode spherical array catheter (Globe PF System; Kardium Inc., Canada) capable of both cardiac mapping and ablation with either RF or PF was deployed in the left atrium. For each application, electroanatomic maps with ostial tags, contact maps based on blood flow detection, and animated voltage maps were created to help verify isolation. Either temperature-controlled RF ablation (63°C for 3 minutes) or PF ablation (1.7-1.8 kV) was used to circumferentially isolate two PVs/animal and create a linear and focal lesion along the posterior wall and roof of the left atrium. GP stimulation as evidenced by BR was recorded if either sinus bradycardia or AV block was noted during and/or immediately after the pulse train (Figure). A total of 11 and 3 animals underwent PF and RF ablation, respectively. All ablations were successfully delivered to all locations without adverse events. Of the animals treated with RF, none (0 of 3) displayed any evidence of GP stimulation at any locations. All animals treated with PF showed evidence of GP stimulation: all animals (11 of 11,100%) exhibited BR during ablation at the inferior common vein, with 6 of 10 (60%) animals demonstrating BR at the roof and posterior wall (Table). BR of less severity was noted during subsequent pulse trains but remained most frequent at the inferior common vein. Ganglionated plexi-mediated bradycardic responses occur with PF ablation, with evidence of some degree of stunning when repeated pulse trains are delivered. This pre-clinical model with ablation at this location will serve as a good model to further our understanding of this phenomenon. The lack of any bradycardic responses with RF either represents a lack of stimulation (perhaps because of the inability of the RF energy to reach the epicardial GPs, unlike the volumetric nature of the pulsed electrical fields) or, complete ablation without stimulation. Further work is needed to explore these differences.

PO-05-002 ARRHYTHMOGENIC RIGHT VENTRICULAR CARDIOMYOPATHY WITH EXTENSIVE ABNORMAL SUBSTRATE: IS ISOLATION POSSIBLE?

In arrhythmogenic right ventricular cardiomyopathy (ARVC) patients with extensive right ventricular free wall (RVFW) abnormal substrate, large area homogenization with combined epicardial and endocardial approach is time consuming and often inadequate for modification. We aim to explore the feasibility and efficacy of RVFW abnormal substrate isolation in such patients to control ventricular tachycardia (VT). Eight consecutive ARVC patients with VT who had extensive abnormal RVFW substrate were included. VT induction was performed before substrate mapping and modification. Detailed voltage mapping was done during sinus rhythm. A circumferential linear lesion was deployed along the border zone of low-voltage-area on the RVFW to achieve electrical isolation. Other small areas with fractionated or late potentials were further homogenized. All eight patients had extensive RV endocardial low-voltage-area (113.8 ± 84.1 cm2, 49.6 ± 29.8%) and dense scar (59.6 ± 39.8 cm2, 25.0 ± 14.1%). Electrical isolation of abnormal substrate was achieved in 5/8 (62.5%) patients via endocardial approach alone and 3/8 (37.5%) patients via a combination of endocardial and epicardial approach. Electrical isolation was verified by slow automaticity (5/8, 62.5%) or RV non-capture (3/8, 37.5%) during high output pacing inside the encircled area. VTs were induced in 6 patients before ablation and all patients rendered non-inducible after ablation. During a median follow-up of 43 months (range 24-53), 7/8 (87. 5%) patients remained free of sustained VT. Electrical isolation of RVFW is feasible and effective in ARVC patients with extensive abnormal substrate and is associated with excellent long-term rhythm control.

PO-04-081 ISOLATION OF PERSISTENT LEFT SIDED SUPERIOR VENA CAVA USING PULSED FIELD ABLATION

Pulmonary vein foci account for more than 90% of triggers for atrial fibrillation, most commonly treated with complete pulmonary vein isolation. Non–pulmonary vein triggers are the drivers of atrial fibrillation in a subgroup of patients. One such trigger is a persistent left superior vena cava (SVC), which may contain remnant muscular and pacemaker tissue carried over from embryonic life. However, reported complications of radiofrequency ablation of this structure are significant, including vein stenosis, tamponade and phrenic nerve injury. Pulsed field ablation is a promising new technology that may be uniquely suited to avoid such a complications. This case illustrates the first known application of pulsed field ablation of a left sided SVC. N/A The patient is a fifty-two year old male with a history of coronary artery disease and persistent atrial fibrillation refractory to medical therapy including rate and rhythm control strategies. He is status post multiple cardioversions with restoration to normal sinus rhythm for a relatively short period of time. The patient underwent an ablation procedure at which time it was discovered that he had an isolated persistent left sided SVC. Pulmonary vein isolation was performed using a combined radiofrequency and pulsed field ablation lattice tip catheter (Affera inc., Watertown, MA). Accordingly to study protocol, lesions were placed using radiofrequency anteriorly and pulsed field lesions posteriorly in the left atrium around the pulmonary veins resulting in complete isolation. The patient also developed a counterclockwise typical atrial flutter which was ablated. Given the propensity for triggers from the SVC, pulsed field ablation was performed by creating a circumferential lesion set superiorly beyond the left superior pulmonary vein region and inferiorly near the mid coronary sinus below the left inferior pulmonary vein. A linear lesion set connecting these two regions was also performed along the atrial portion of the coronary sinus, with subsequent confirmation of exit block and elimination of all local electrograms. In patients with persistent left SVC, pulsed field ablation is feasible without the risk of phrenic nerve injury or tamponade from excessive contact force. Further studies are necessary to examine whether the complications associated with LSVC isolation can be minimized.

PO-01-192 USE OF A LARGE-FOOTPRINT FOCAL LATTICE CATHETER FOR MAPPING AND ABLATION OF ATRIAL FLUTTERS

Catheter ablation of atrial flutters (AFL), in particular atypical (ie non-cavotricupid isthmus dependent) AFL, can be eliminated with high-density electroanatomical mapping using multielectrode catheters used in concert with radiofrequency ablation (RFA). However, this requires 2 separate complex catheters: for mapping and for ablation. Further challenges include difficulties in establishing durable block across the isthmus of identified circuits, in particular (but not exclusively) the mitral isthmus. Recently, a large footprint lattice-tip catheter (Sphere-9, Affera-Medtronic Inc.) has been developed capable of both delivering either pulsed field (PF) energy or high-power RF energy, and performing high-density mapping using mini-electrodes located throughout the lattice-tip. To determine the feasibility and efficacy, both acute and chronic, of mapping and ablation of AFL using the lattice-tip catheter. As part of a 3-center, single-arm, first-in-human study of AF ablation with the lattice-tip catheter (NCT04141007, NCT04194307), spontaneous or induced AFLs were mapped and ablated using the lattice-tip catheter, in conjunction with a compatible mapping-system. The 7Fr lattice-tip catheter has a compressible 9-mm nitinol tip with 9 embedded mini-electrodes, and is able to deliver either RF or PF energy (each lesion 2-5 sec). During AF ablation in the 178-pt cohort (39% paroxysmal, 61% persistent), AFL was identified in 47 (26%) pts. This included typical AFL in 22 (12%) pts, peri-mitral AFL in 17 (10%) and other AFLs in 26 (15%). Mapping of the AFL circuits was performed exclusively using the lattice catheter. Cavo-tricuspid isthmus (CTI), LA roof, and mitral isthmus lines were targeted in 94%, 83%, and 70% of patients in whom AFLs were identified (some flutters were not targeted flutters if not considered clinically-relevant). Bidirectional conduction block was achieved in all (100%) of attempted lines. Over a 12-month follow-up, 37 of 47 pts (79%) were free from AFL recurrence. Atrial flutters are noted in a substantial number of patients undergoing catheter ablation of atrial fibrillation. The flexibility of a large-tip focal lattice catheter allows for facile post-PVI mapping and ablation of such flutters, while minimizing the need for additional equipment and catheter exchanges. Ablation using either RF or PF energy resulted in successful block across attempted linear lesions and excellent long-term success.

Cryoglobulinemia and Neuromyelitis optica: a case of progressive weakness and neurocognitive decline (P10-5.026)

<h3>Objective:</h3> Describe a case of a woman with mixed cryoglobulinemia who presented with progressive weakness and biopsy proven systemic vasculitis in the setting of Hepatitis C virus (HCV) negative serology. <h3>Background:</h3> The disease expression of mixed cryoglobulinemia vasculitis caused by HCV infection triggers the downstream B-cell arm of autoimmunity. <h3>Design/Methods:</h3> A 61 year old woman with a history of HCV infection, mixed cryoglobulinemia, mononeuritis multiplex secondary to nervous system vasculitis affecting peripheral nerves and hypertension presented with weakness that progressed to quadriparesis and neurocognitive decline over a period of eight months. <h3>Results:</h3> MRI examination of the brain showed bilateral ventral pontine lesions extending into the middle cerebellar peduncles, ventrolateral midbrain and cerebral peduncles as well as bilateral cortical frontal lobe lesions. Also present were intrinsic mixed intensity DWI/ADC lesions of undetermined etiology and extensive subcortical and periventricular white matter hyperintensities. CT angiography of her head and neck showed large vessel intracranial vasculopathy involving the bilateral MCA branches. Conventional angiogram, however, did not show any evidence of angiographic vasculitis. MRI spectroscopy was non-diagnostic. MRI of the neuroaxis showed a small focus of linear non-enhancing hyperintense lesion at the level of C3. EMG demonstrated severe generalized sensory-motor polyneuropathy with severe axonal loss. EEG showed mild to moderate diffuse slowing. CSF evaluation was negative, HCV viral load was undetectable, connective tissue markers (Anti-dsDNA, Anti-SCL70, Anti-CENTR, Anti-RNP, Anti-Smith, Anti-SSA/SSB, ANCA) were negative and the remaining serology was significant for elevated ESR, CRP, low C4 complements, positive anti-AQP4 antibodies titers (1:2560) and positive myelin basic protein. Brain biopsy showed perivascular lymphocytic inflammation, confirming vasculitis. Our patient completed courses of high dose steroids, IVIG and Rituximab with mild improvement in motor strength. <h3>Conclusions:</h3> Although an atypical feature of NMO, cryoglobulinemia with production of anti-AQP4 antibodies may, in part, contribute to development of a demyelinating process. <b>Disclosure:</b> Dr. Esechie has nothing to disclose. Dr. Harazeen has nothing to disclose. Dr. Rivera Vega has nothing to disclose. Dr. Thottempudi has nothing to disclose. Dr. Chhabra has stock in Pfizer. Dr. Chhabra has stock in Biogen. Dr. Chhabra has stock in Johnson and Johnson. Dr. Chhabra has stock in Medtronic. Dr. Shaltoni has nothing to disclose. Muhammad Zeeshan Memon, MD has nothing to disclose. Dr. Patel has nothing to disclose. Dr. Wu has nothing to disclose.

Focal laser and intravitreal bevacizumab for choroidal neovascularization secondary to Grönblad–Strandberg syndrome

Introduction: Pseudoxanthoma elasticum is a rare genetic disorder. It has several ocular features including angioid streaks and choroidal neovascularization which can significantly affect vision. Case Report: A 50-year-old man presented with nine months history of poor vision affecting both distant and near vision. His best corrected visual acuities were 6/18 right eye and 1/60 left eye. His anterior segments were normal. Funduscopy revealed linear hyperpigmented irregular branching peripapillary lesions; angioid streaks both eyes. He had bilateral speckled retina pigment epithelial hyperpigmented lesions interspaced with dot hemorrhages in the macula region suggestive of likely choroidal neovascularization. He had “peau d’orange” skin appearance around his neck. Fundus fluorescein angiography showed features of occult subfoveal choroidal neovascularization. He was referred to a physician and had a skin biopsy which revealed histologic features of Pseudoxanthoma elasticum. He was treated with bilateral focal argon laser. However he had right intravitreal Bevacizumab after a large ipsilateral subfoveal hemorrhage. His visual acuities remained stable afterward. Conclusion: Patients with Pseudoxanthoma elasticum have to be closely monitored for ocular manifestations. Choroidal neovascularization should be detected early and promptly treated. Antivascular endothelial growth factor injections have become the preferred treatment option for choroidal neovascularization in these patients.