Ventricular Tachycardia Ablation Procedures Research Articles

Road-Map to Epicardial Approach for Catheter Ablation of Ventricular Tachycardia in Structural Heart Disease: Results From a 10-Year Tertiary-Center Experience.

Epicardial approach in ventricular tachycardia (VT) ablation is still regarded as a second-step strategy, due to the risk of complications. We evaluated the frequency that epicardial ablation targets were identified and ablation performed following pericardial access compared with unnecessary pericardial access for different VT causes and potential markers of epicardial VT. All VT ablation procedures including epicardial approach over a 10-year period were included. First-line epicardial approach was indicated in arrhythmogenic right ventricular cardiomyopathy (ARVC) and postmyocarditis VT; in patients with idiopathic dilated cardiomyopathy (IDCM) and postmyocardial infarction, indications resulted from available imaging techniques or 12-lead VT morphology. The epicardial approach was considered useful if epicardial ablation was performed after epicardial mapping. Feasibility, complications, and long-term outcome were reported. Four hundred and eighty-eight subjects with a median age of 60 years (interquartile range, 47-65) and of left ventricle ejection fraction 41% (interquartile range, 30-55) underwent 626 epicardial VT ablations. Percutaneous access had a success rate of 92.2% and a complication rate of 3.6%. Overall, epicardial approach was, respectively, indicated to 11.8% of postmyocardial infarction patients, 49.5% in IDCM, 94% in myocarditis, and 90.7% in ARVC. Epicardial ablation at the first ablation attempt was performed in 9.3% of postmyocardial infarction patients, 28.8% in IDCM, 86.5% in myocarditis, and 81.3% in patients with ARVC. In first-line epicardial group, ARVC and myocarditis showed the highest odds for epicardial ablation (OR, 4.057 [95% CI, 1.299-8.937]; P=0.007; OR, 3.971 [95% CI, 1.376-11.465]; P=0.005, respectively). IDCM independently predicted unnecessary epicardial approach (OR, 2.7 [95% CI, 1.7-4.3]; P<0.001). After a follow-up of 41 months (interquartile range, 19-64), patients with IDCM experienced higher rate of recurrences and mortality compared with other causes. Epicardial approach is integral part of ablation armamentarium regardless of the VT cause, with high feasibility and low complication rate in experienced centers. Our data support its use at first ablation attempt in VTs related to ARVC and myocarditis.

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

Role of mechanical circulatory support in VT ablation procedures: data from the German PROTECT VT registry

Abstract Introduction Ventricular tachycardia (VT) ablation in patients with progressed heart failure (HF) is known to be complex and associated with a high periprocedural risk and mortality, in part due due to hemodynamic instability during ongoingVTs. Use of mechanical circulatory support (MCS) systems has been already implemented in complex high-risk percutaneous coronary intervention (CHIP-PCI) workflows. Use and benefit of MCS in VT ablation is still under debate. MCS protected VT ablation (proVT-A) might be associated with improved clinical outcomebut potentially comes along with an increased risk of periprocedural complications. Based on data of four German high-volume centers we aimed to analyze retrospective data on patient characteristics and impact of proVT-A with respect to safety and mid-term efficacy. Methods All patients undergoing proVT-A as a primary approach from four German EP centers were included in the analysis. Use of MCS in bailout scenariosin VT ablation were not included. Patient characteristics, procedural parameters and clinical outcome were evaluated. The primary endpoint was a combined endpoint of VT/VF recurrence and all-cause death. Results 41 patients who underwent proVT-A were included. Mean age was 64±11a, 92% of patients were male (38/41), 65% (27/41) suffered from ischemic cardiomyopathy, mean left ventricular ejection fraction was 33±13%,76% (31/41) of patients presented with a documented hemodynamically not tolerated VT, mean PAAIN-ESD score was 13±7, and 46% (19/41) had a history of a previous VT ablation w/o MCS. During proVT-A procedure at least one VT was inducible and mappable in 35 patients (85%). Acute procedural success was 85%, with only n=6 patients remaining inducible for VT. Mean procedure duration was 245±46min. With respect to periprocedural safety (30days)a total of n=12 relevant procedural complications were reported in 8 patients. This included n=5 vascular access complications, of which n=3 requiring transfusion or surgery. One case of periprocedural death was reported 6h post proVT-A due to PEA. Three patients developed pericardial effusion, one requiring drainage. Freedom from VT/VF was 78% (n=9 VT/VF recurrences) after a mean follow-up (FU) of 15±14 months (figure 1A). Death of any cause occurred in n=9 patients (figure 1B). In summary, after a mean FU of 15±14 months n=16 patients (39%) met the combined endpoint of VT/VF recurrence and all-cause death (figure 1C). Conclusion Patients enrolled in the German PROTECT VT Registry had significant cardiovascular comorbidities and therefore represent a high-risk population for VT ablation. Use of MCS was feasible, comparably safe, associated with high procedural and promising long-term success rate. These results highlight the need for larger registries and future prospective trials evaluating the potential benefit of proVT-A in selected patients. Further, it should be aimed for optimization of periprocedural vascular access site management.

Epicardial catheter ablation of ventricular tachycardia in patients of acm - from a university hospital report in switzerland

Abstract Background Arrhythmogenic left ventricular cardiomyopathy (ALVC) as a subtype of arrhythmogenic cardiomyopathy (ACM) is increasingly being recognized. Cardiac magnetic resonance (CMR) has emerged as the primary imaging modality for the diagnosis of ACM. In patients with right-dominant ACM (ARVC) and recurrent sustained ventricular tachycardia (VT), endocardial +/-epicardial ablation yields good clinical outcomes in the long-term. However, studies on VT ablation in ACM with LV involvement are scarce. Purpose We sought to investigate clinical outcomes of VT ablation in ACM patients with LV involvement. Methods The study included patients from the Zurich ACM Registry who met 2020 "Padua Criteria" for ACM and underwent VT ablation between January 2018 and July 2023. Epicardial ablation was performed in patients with recurrent sustained VT despite endocardial ablation, those lacking and endocardial substrate or if the ECG of the VT / substrate on CMR was suggestive of an epicardial origin. Catheter ablation was guided by activation/entrainment mapping for mappable VT, and pace mapping/voltage mapping during sinus rhythm for unmappable VT. Consecutive follow-up of all patients was performed according to our protocol. Results Twenty-one ACM patients underwent n=24 VT ablation procedures. Of those 20 patients, 6 patients (30%) had LV involvement on CMR. Eight (33%) patients underwent epicardial +/- endocardial ablation. Among patients receiving epicardial ablation, 3 patients (38%) had LV involvement. These three underwent a single ablation procedure, which was epicardial only. Total follow-up was 30 months (range 4-43). Three-month sustained VT/VF recurrence rates were 12% in the ACM group with LV involvement vs 25% in ACM without LV involvement. All patients with sustained VT/VF recurrence underwent repeat ablation via an epicardial approach within 3 months and were free of sustained VT/VF thereafter during a median follow-up of 12 months. One-year recurrence rate did not differ between ACM patients with LV involvement vs. without LV involvement (7.7% vs 8.3%, P＝0.117). Seven out of eight epicardial ablations achieved freedom from VT/VF after one-year follow-up. One ARVC patient with previous endocardial ablation had recurrent VT one month after epicardial ablation, which was free of VT after Flecainide combined with beta-blocker. No significant differences were found in the use of beta-blockers and antiarrhythmic drugs between both groups (ACM with LV involvement vs. without LV involvement) at baseline and during one-year follow-up. Conclusions Single or adjuvant epicardial substrate ablation of VT in arrhythmogenic cardiomyopathy is promising in terms of postprocedural VT free survival, especially in patients with left ventricular involvement demonstrated by CMR.Figure 1Figure 2

Non-invasive detection of slow conduction with cardiac magnetic resonance imaging for ventricular tachycardia ablation.

Non-invasive myocardial scar characterization with cardiac magnetic resonance (CMR) has been shown to accurately identify conduction channels and can be an important aid for ventricular tachycardia (VT) ablation. A new mapping method based on targeting deceleration zones (DZs) has become one of the most commonly used strategies for VT ablation procedures. The aim of the study was to analyse the capability of CMR to identify DZs and to find predictors of arrhythmogenicity in CMR channels. Forty-four consecutive patients with structural heart disease and VT undergoing ablation after CMR at a single centre (October 2018 to July 2021) were included (mean age, 64.8 ± 11.6 years; 95.5% male; 70.5% with ischaemic heart disease; a mean ejection fraction of 32.3 ± 7.8%). The characteristics of CMR channels were analysed, and correlations with DZs detected during isochronal late activation mapping in both baseline maps and remaps were determined. Overall, 109 automatically detected CMR channels were analysed (2.48 ± 1.15 per patient; length, 57.91 ± 63.07 mm; conducting channel mass, 2.06 ± 2.67 g; protectedness, 21.44 ± 25.39 mm). Overall, 76.1% of CMR channels were associated with a DZ. A univariate analysis showed that channels associated with DZs were longer [67.81 ± 68.45 vs. 26.31 ± 21.25 mm, odds ratio (OR) 1.03, P = 0.010], with a higher border zone (BZ) mass (2.41 ± 2.91 vs. 0.87 ± 0.86 g, OR 2.46, P = 0.011) and greater protectedness (24.97 ± 27.72 vs. 10.19 ± 9.52 mm, OR 1.08, P = 0.021). Non-invasive detection of targets for VT ablation is possible with CMR. Deceleration zones found during electroanatomical mapping accurately correlate with CMR channels, especially those with increased length, BZ mass, and protectedness.

Ventricular Tachycardia Ablation in Patients With Desmoplakin Cardiomyopathy

BackgroundDesmoplakin (DSP) pathogenic variants are rare causes of arrhythmogenic cardiomyopathy and often involve the right and left ventricles. Ventricular tachycardia (VT) ablations may be required in these patients, but procedural characteristics have not been reported. ObjectivesIn this study, the authors sought to report a multicenter experience of VT ablation in patients with DSP pathogenic variants. MethodsVT ablations performed in patients with known DSP pathogenic variants were analyzed across 6 centers in 3 countries. Patient characteristics and acute and long-term procedural outcomes were reported. ResultsA total of 20 patients (13 men, median age 43 years [Q1-Q3: 41.5-53.0 years], left ventricular ejection fraction 43.0% [Q1-Q3: 41.5%-53.0%], 11 previous failed ablations) were referred for VT ablation procedures. All patients had symptomatic VTs, with ICD therapy in 19 patients. Epicardial procedures were performed in 16 of the 20 patients. VT target sites were located in the right ventricular (RV) endocardium (n = 11), the RV epicardium (n = 4), the left ventricular (LV) endocardium (n = 2) and the LV epicardium (n = 7). In 3 patients, the VT target sites were in close proximity to coronary arteries, limiting ablation. During follow-up, VTs recurred in 11 patients, and repeated ablations were performed in 9 patients. Allowing for multiple procedures, 19 of the 20 patients remained free of VT recurrence after a median follow-up of 18 months [Q1-Q3: 5-60 months]. ConclusionsPatients with DSP cardiomyopathy often have biventricular involvement, and ablation procedures often require ablation in both ventricles and the epicardium. Recurrences are not uncommon, and the pathologic substrate can be located in close proximity to epicardial coronary arteries, limiting the success rate of ablations.

VT ablation based on CT imaging substrate visualization: results from a large cohort of ischemic and non-ischemic cardiomyopathy patients.

The eradication of ventricular tachycardia (VT) isthmus sites constitutes the minimal procedural endpoint for VT ablation procedures. Contemporary high-resolution computed tomography (CT) imaging, in combination with computer-assisted analysis and segmentation of CT data, facilitates targeted elimination of VT isthmi. In this context, inHEART offers digitally rendered three-dimensional (3D) cardiac models which allow preoperative planning for VT ablations in ischemic and non-ischemic cardiomyopathies. To date, almost no data have been collected to compare the outcomes of VT ablations utilizing inHEART with those of traditional ablation approaches. The presented data are derived from a retrospective analysis of n = 108 patients, with one cohort undergoing VT ablation aided by late-enhancement CT and subsequent analysis and segmentation by inHEART, while the other cohort received ablation through conventional methods like substrate mapping and activation mapping. The ablations were executed utilizing a 3D mapping system (Carto3), with the mapping generated via the CARTO® PENTARAY™ NAV catheter and subsequently merged with the inHEART model, if available. Results showed more successful outcome of ablations for the inHEART group with lower VT recurrence (27% vs. 42%, p < 0.06). Subsequent analyses revealed that patients with ischemic cardiomyopathies appeared to derive a significant benefit from inHEART-assisted VT ablation procedures, with a higher rate of successful ablation (p = 0.05). Our findings indicate that inHEART-guided ablation is associated with reduced VT recurrence compared to conventional procedures. This suggests that employing advanced imaging and computational modeling in VT ablation may be valuable for VT recurrences.

A comparison of general anesthesia versus monitored anesthesia care during catheter ablation for ventricular tachycardia

Abstract Background Catheter ablation of ventricular tachycardia (VT) may be performed under general anesthesia (GA) or monitored anesthesia care (MAC). There is a paucity of data studying these two sedation strategies with respect to intraprocedural characteristics, and outcomes of VT ablation. Purpose The purpose of this study was to assess the effects of anesthesia techniques on VT inducibility and outcomes. Methods A single-center, retrospective study of patients undergoing catheter ablation for scar-related VT, from 2016-2022, was conducted. Data collected included demographics, comorbidities, medications, relevant laboratory abnormalities, electrocardiograms, echocardiograms, detailed procedural characteristics, and outcomes. Results One hundred sixty-eight patients who underwent a total of 200 VT ablation procedures were included. The patients undergoing GA had a greater burden of comorbidities including congestive heart failure (77.2% vs. 60.9%), hypertension (66.9% vs. 60.0%), atrial arrhythmias (50.7% vs. 43.8%), diabetes mellitus (21.3% vs. 9.4%), chronic kidney disease (44.1% vs. 31.3%), prior stroke (11.8% vs. 10.9%), myocardial infarction (31.6% vs. 29.7%), pre-existing implantable cardioverter-defibrillator (86.8% vs. 71.9%) and had a higher median number of antiarrhythmic drugs at baseline (2 vs. 1) [Figure 1]. There was a greater percentage of patients with non-ischemic cardiomyopathy (58.1% vs. 51.6%) in the GA cohort. The mean left ventricular ejection fraction was not different among the two groups (39.3 ± 13.9 vs. 42.5 ± 15.3). The GA group had more hemodynamic instability at baseline (p &amp;lt; 0.01), and during VT induction (p &amp;lt; 0.01). There was no significant difference in the number of VT induced, or tachycardia cycle length, in each group. Despite higher radiofrequency energy delivery time in the GA group as compared to the MAC group, the GA group had higher VT inducibility post-procedure and were more likely to be discharged on antiarrhythmic drugs. Even though the recurrence of VT was higher in the GA group compared to the MAC group (41.9% vs. 31.3%), the VT-free survival curves were not significantly different by Kaplan-Meier analysis (p=0.19) [Figure 2]. In a multivariate regression analysis, the sedation strategy was not an independent predictor of VT recurrence (p=NS). However, baseline hemodynamic instability was an independent predictor of VT recurrence after accounting for all intraprocedural characteristics (p=0.008). Conclusion Patients undergoing VT ablation under GA have more comorbidities and tend to be on more antiarrhythmic drugs. The GA group had more hemodynamic instability during the procedure and had greater overall VT recurrence, however, not significant in a time-based analysis. The greater overall recurrence in the GA group could be because they represent a sicker population, or the hemodynamics during the procedure preclude adequate ablation of the VT circuit elements.Figure 1Figure 2

Abstract 17014: Differences in the Outcomes of Catheter Ablation for Ventricular Tachycardia in Patients With Ischemic versus Non-Ischemic Cardiomyopathy

Background: Catheter ablation is an effective tool to reduce ventricular tachycardia (VT) burden. There is a lack of robust data studying the characteristics and outcomes of VT ablation in patients with ischemic (ICM) versus non-ischemic cardiomyopathy (NICM). Aims: The aim of this study was to assess the impact of ICM vs NICM on outcomes of VT ablation. Methods: A single-center, retrospective study of patients undergoing catheter ablation for VT was conducted. Results: A total of 168 patients, undergoing 200 VT ablation procedures, were included in this study. NICM group (112 procedures) was compared to ICM group (88 procedures). Patients in the ICM group were older (66.6 ± 13.4 vs 58.9 ± 14.4 years) and had higher rates of prior myocardial infarction (65.9% vs 3.6) and coronary artery bypass graft surgery (40.9% vs 1.8%). Overall, ICM group had more comorbidities like hypertension (80.7% vs 52.7%), diabetes mellitus (23.9% vs 12.5%), chronic kidney disease (45.5% vs 35.7%), stroke (17% vs 7.1%), and lower left ventricular ejection fraction (36.8 ± 13.2% vs 43.1 ± 14.7%). The ICM group had lower incidence of prior cardiac valvular surgery (9.1% vs 29.5%). The inducibility of VT (93% vs 93.5%; p= 1.0) and the number of different VT morphologies induced during the case (1.9 ± 1.5 vs 2.3 ± 2.5; p=0.19) was similar between the two groups. There was no acute mortality in either group. There was a non-significant trend towards greater VT recurrence in the NICM group (43.2% vs 33.3%, p= 0.19). However, patients with NICM had a lower VT-free survival as determined by Kaplan-Meier analysis (p=0.05) [Figure]. Long term mortality was higher in ICM group when compared to NICM group (18.2% vs 8.9%, p&lt;0.01). Conclusion: Patients undergoing VT ablation in the NICM group when compared to the ICM group were noted to be younger, had fewer comorbidities, and lower long-term mortality. However, they had significantly less VT-free survival, likely owing to more challenging substrate responsible for VT.

Abstract 16093: Hemodynamic Implications of Transseptal Access for Ventricular Tachycardia Ablation in Patients With Left Ventricular Assist Devices

Introduction: Ventricular tachycardia (VT) is common in patients with left ventricular assist devices (LVAD), and catheter ablation can be an effective treatment strategy. Although transseptal approach for LV mapping and ablation is often preferred, iatrogenic atrial septal defect (ASD) after transseptal access may theoretically result in clinically significant right-to-left shunting. The short- and long-term implications of transseptal puncture, including hemodynamic changes in LVAD patients, remain uncertain. Methods and Results: From 2013-2023, 15 LVAD patients (age 68.5±12 years; 2 women) underwent 18 VT ablation procedures with single transseptal access for LV ablation without ASD closure afterwards. Clinical VT was eliminated in 83%. No patients had prior PFO/ASD; Mean RVSP was 45mmHg, 6 (40%) had pulmonary hypertension, and 8 (53.3%) had moderate or severe RV dysfunction. All patients had previously failed at least 1 antiarrhythmic drug (amiodarone 100%; sotalol 33%; mexiletine 94%). Procedural complications occurred in 3 procedures (all related to vascular access, none directly related to transseptal access; 1 patient with interrupted IVC requiring transhepatic access had bleeding due to transection of intercostal artery requiring arterial embolization). Post-procedure echocardiograms (n=14; mean time to echo 90±116 days) showed no intra-cardiac shunting or persistent ASD. Right heart catheterization (pre: n=12; post: n=8, at mean follow-up 187±243 days) showed similar pre- and post-ablation RA pressures (11.6 vs 14.9 mmHg, p =0.24) and wedge pressures (14.9 vs 20.4 mmHg, p =0.8) with absence of significant shunting based on pre- and post-ablation arterial (95.2% vs 97.7%, p =0.06) and PA oxygen saturations (56.5% vs 51.3%, p =0.29). No episodes of clinically significant hypoxia occurred after ablation. Conclusion: Transseptal access for VT ablation can be safely performed in LVAD patients and is unlikely to result in clinically or hemodynamically significant residual shunting over long-term follow-up. Therefore, empiric ASD closure after transseptal access in all LVAD patients is likely unnecessary.

Abstract 12814: Impact of Obesity on Catheter Ablation of Ventricular Tachycardia in the United States: In-Hospital and 30-day Outcomes

Background: Catheter ablation for ventricular tachycardia (VT) has been increasingly performed. While it is estimated that 42% of adults in the United States are obese, the impact of obesity on VT ablation procedures remains unclear. Objective: This study aimed to evaluate the procedural outcomes and 30-day readmission among non-obese and obese patients who underwent catheter ablation of VT. Method: Using the Nationwide Readmissions Database, our study included patients aged 18 years or older who underwent catheter ablation for VT between 2017 and 2020. The study cohort was stratified into non-obese (BMI &lt; 30kg/m 2 ) and obese (BMI ≥ 30kg/m 2 ). The in-hospital procedural outcome and 30-day readmission were analyzed between these groups. Results: Our study included a total of 835 obese patients (19.7%) and 3393 non-obese patients (80.3%). Obese group had a higher rate of prolonged length of stay (&gt;7 days) (37.6% vs 31.2%, p&lt;0.01) and a higher cost of hospitalization ($39 983 vs $37 015, p&lt;0.01). Overall, there were no significant differences in early mortality (4.5% vs 3.8%, p=0.45). Apart from increased vascular complications in the obese group (1.8% vs 0.9%, p=0.03), there were no significant differences in other procedural complications between both groups. There were no significant differences in 30-day readmission rates between obese and non-obese groups (15.5% vs 14.1%, p=0.38). Additional analysis performed in the obese group revealed a non-significant decreasing trend in early mortality rate post-procedurally (5.4% to 4.8%, P trend = 0.66). On multivariable analysis, heart failure was associated with a higher risk of 30-day readmission in obese patients (OR: 2.00; 95% CI: 1.01-3.99; p=0.05). Conclusion: Our study suggests that catheter ablation for VT can be performed relatively safely in obese patients without significant differences in 30-day mortality and readmission outcomes. Patients should not be excluded from VT ablation on the basis of obesity.

Systematic use of half normal saline during ablation of ventricular tachycardia in structural heart disease.

Efficiency and safety of ablation using half normal saline (HNS) has been shown in refractory ventricular tachycardia (VT), but no evaluation in unselected larger populations has been made. To evaluate the efficiency and safety of systematic HNS ablation in VT ablation. All successive VT ablations in patients with structural heart disease from 2018 to 2021 used HNS in our center and were retrospectively included. One hundred seventy-seven successive VT ablation procedures using HNS have been performed in 148 patients (91% males, mean 64±12 years, ischemic cardiomyopathy 64%, left ventricular ejection fraction 38±13%). A mean of 19±7.5 min of RF was delivered, with a mean power of 44±7W. Relevant complications happened in 9% (strokes 2%, tamponades 3%, atrioventricular block during septal ablations 5%). Over a mean follow-up of 15±9 months, VT recurred in 46%. Final recurrence rate after one or several procedures was 36% (18 months follow-up). Number of VT episodes decreased from 14±35 before to 2.5±10 after ablation (p<.0001) and number of ICD shocks decreased from 4.8±6.8 to 1.5±0.8 (p=.027). Systematic use of HNS during VT ablations in patients with structural heart disease leads to long-term recurrences rates and complications in the range of what is reported using normal saline. Although controlled studies are needed for demonstrating the superiority of such attitude, the use of HNS in every scar-related VT ablation seems safe for standard cases and may be furthermore useful in case of refractory arrhythmias due to difficult-to-ablate substrates.

Value of genotyping and scar-phenotyping for VT ablation procedures in patients with nonischemic left ventricular cardiomyopathies.

Variants of cardiomyopathy genes in patients with nonischemic cardiomyopathy (NICM) generate various phenotypes of cardiac scar and delayed enhancement cardiac magnetic resonance (DE-CMR) imaging which may impact ventricular tachycardia (VT) management. The objective was to compare the findings of cardiomyopathy genetic testing on DE-CMR imaging and long-term outcomes among patients with NICM undergoing VT ablation procedures. Image phenotyping and genotyping were performed in a consecutive series of patients referred for VT ablation and correlated to survival free of VT. Scar depth index (SDI) (% of scar at 0-3 mm, 3-5 mm and >5 mm projected on the closest endocardial surface) was determined. Forty-three patients were included (11 women, 55 ± 14 years, ejection fraction (EF) 45 ± 16%) and were followed for 3.4 ± 2.9 years. Pathogenic variants (PV) were identified in 16 patients (37%) in the following genes: LMNA (n = 5), TTN (n = 5), DSP (n = 2), AMLS1 (n = 1), MYBPC3 (n = 1), PLN (n = 1), and SCN5A (n = 1). A ring-like septal scar (RLSS) pattern was more often seen in patients with pathogenic variants (66% vs 15%, p = .001). RLSS was associated with deeper seated scars (SDI >5 mm 30.6 ± 22.6% vs 12.4 ± 16.2%, p = .005), and increased VT recurrence (HR 5.7 95% CI[1.8-18.4], p = .003). After adjustment for age, sex, EF, and total scar burden, the presence of a PV remained independently associated with worse outcomes (HR 4.7 95% CI[1.22-18.0], p = .02). Preprocedural genotyping and scar phenotyping is beneficial to identify patients with a favorable procedural outcome. Some PVs are associated with an intramural, deeper seated scar phenotype and have an increase of VT recurrence after ablation.

Thirty-day readmission after catheter ablation for ventricular tachycardia: associated factors and outcomes.

Patients with ventricular tachycardia (VT) who require VT ablation are at high risk for readmission. This study aimed to identify the causes and outcomes of 30-day readmission after VT ablation and to analyze the predictors of recurrent VT that required rehospitalization. Using the Nationwide Readmission Database, our study included patients aged ≥ 18years who underwent VT catheter ablation between 2017 and 2020. Based on the International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM), we identified the causes of 30-day readmission by organ systems and analyzed their outcomes. Additional analysis was performed to determine the independent predictors of 30-day readmission for recurrent VT. Of the 4228 patients who underwent VT ablation, 14.2% were readmitted within 30days of the procedure. The most common cause of readmission was cardiac events (73.6%). Among the cardiac-related readmissions, recurrent VT (47.7%) and congestive heart failure (CHF) (12.9%) were the most common etiologies. Among the readmissions, patients readmitted for CHF had the highest rate of readmission mortality (9.2%). Of the patients readmitted within 30days of the procedure, 278 patients (6.8%) were readmitted for recurrent VT. Via multivariable analysis, CHF (OR: 1.97; 95% CI: 1.12-3.47; P = 0.02) and non-elective index admissions (OR: 1.63; 95% CI: 1.04-2.55; P = 0.03) were identified as the independent predictors predictive of 30-day readmissions for recurrent VT. Recurrent VT was the most common cause of readmission after the VT ablation procedure, and CHF and non-elective index admissions were the significant predictors of these early readmissions. Readmission due to CHF had the highest mortality rate during readmission.

A new workflow including Coherent algorithm in sinus rhythm for the treatment of Ventricular Tachycardia in patients with scar related heart disease

Abstract Funding Acknowledgements Type of funding sources: None. Background Catheter ablation is a well establish therapy in patients with structural heart disease (SHD) and sustain ventricular tachycardia (VT). Scar substrate modification is one of the two endpoint of a VT ablation procedure. Dechanneling is one of the described successful techniques that shown to be effective for substrate modification Aim This is a pilot study aiming to evaluate the feasibility and the acute efficacy of a new mapping approach for VT ablation with the combination of high density (HD) mapping and Coherent mapping algorithm. Methods All enrolled patients underwent radio frequency catheter ablation (RFCA) for drug-refractory VT or VT storm. Before mapping, programmed ventricular stimulation was performed in all patients for the induction of clinical VT or any other ventricular arrhythmias (VA), if VA was inducible, then electrical cardioversion was conducted to restore sinus rhythm. After transseptal puncture, left ventricular (LV) HD mapping was conducted using a 3D mapping system aiming &amp;gt;5000 mapping points during sinus rhythm, intrinsic atrial rhythm, or ventricular pacing with a multielectrode catheter. During HD mapping, all late potentials (LPs) were tagged as double potentials (DP) and all potentials below 0,2 mV were tagged as scar. Then, Coherent mapping was used to visualize electrical propagation through the LV, based on velocity vector identification, highlighting how the electrical signal enters the scar and identifying the "entrance points" (EP). RFCA was delivered in a power-controlled mode on all the individuated EPs using an open, irrigated-tip ablation catheter with contact force sensor. After RFCA, a second remap was conducted to evaluate the LPs abolition. Then, a programmed ventricular stimulation was performed to validate non inducibility of any VAs. Results 10 consecutive patients (age 71,25±10,32 years, 100% male) undergoing RFCA for drug-refractory VT or VT storm (50%). Acute procedural end-point were: abolition of the LPs and non-inducibility of any VA at the end of the procedure. Abolition of LPs was reached in all cases while non inducibility was reached in 9 patients (90%). Mean procedural time was 214±33,81 min, mean mapping time was 89±15,40 min with mean number of acquired points of 5218±359,56. Mean fluoroscopy time and dose were 15±33,81 min and 5218±7149,8 µGm2, respectively. Mean entrance points identified was 2,6±0,84. In 5 patents (50%), after ablation a modification in the refractory period of the left ventricular myocardium was observed. Mean RF time was 1216±565,46 seconds, with mean number of Visitag of 33±29,98. No acute complication were reported. Conclusion High-density mapping in sinus rhythm combined with Coherent algorithm facilitates the understanding of the substrate and provides targets for effective ablation. This approach has been proven safe and with high acute success rates.

A method to identify which patients will have VT substrate ablation targets prior to ablation procedure

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): Dr Nanthakumar is a recipient of the Mid-career Investigator Award from the Heart &amp; Stroke Foundation of Ontario Background Recent trials in ventricular tachycardia (VT) ablation suggest that early ablation could reduce VT burden. A method to predict which patients will have substrate ablation targets based on non-invasive testing prior to the procedure does not exist and could be of value in selecting ideal patients for early VT substrate ablation. Decrement-evoked potential (DeEP) mapping is used to identify VT substrate ablation targets.1 A method for predicting which patients would have DeEP targets on a pre-ablation 12-lead ECG has not yet been developed. Objective To develop a metric to predict the presence of physiological substrate VT ablation targets from the 12-lead ECG. Method 22 electrophysiology (EP) lab VT cases that had undergone DeEP mapping were extracted from the CARTO® 3 system and were analysed retrospectively. For each case, DeEP was calculated by subtracting last component of the nearfield evoked response in the pacing train (S1) from the latest component of the nearfield evoked decremented response of the extra stimulus (S2). By inference, 12-lead ECG prediction was calculated by subtracting the width of the 12-lead surface ECG envelope of S1 from the width of the 12-lead ECG envelope of S2. Cases were divided into three categories: - Cases displaying intracardiac DeEP between 0-10ms – no ablation targets - Cases displaying intracardiac DeEP between 10-50ms – DeEP positive - Cases displaying intracardiac DeEP &amp;gt;50ms – prominent DeEP present Results Out of the 22 cases, 8 were characterised as no ablation targets, 12 as DeEP positive, and 2 as prominent DeEP present. The 12-lead surface ECG measurement means were 3.5±4.6ms for the no ablation target group, 23.2±9.1ms for positive DeEP group, and 80.9±8.1ms for prominent DeEP group. The surface ECG decrement was significantly different P&amp;lt;0.0001 between the three groups. Consequently, we propose that ECG QRS widening of envelope width of 20ms or more may indicate the presence of DeEP targets during invasive mapping. Conclusion It may be possible to detect which patients will have substrate ablation targets based on 12-lead ECG, prior to the VT ablation procedure. Additionally, this prediction rule, based on its association with arrhythmogenic potentials, may be able to predict which ambulatory patients who have not had manifest VT, may be prone to develop VT thus help identify early VT ablation candidates. This concept should be validated in larger data sets and is ideal for training and testing using surface ECG envelopes with artificial intelligence algorithms.

PO-05-004 CAUSES AND OUTCOMES OF EARLY READMISSIONS AFTER VENTRICULAR TACHYCARDIA ABLATION

Patients with ventricular tachycardia (VT) who require VT catheter ablation are a population at high risk for readmissions. The contemporary causes and outcomes of readmission after VT ablation are not well-established. This study aimed to identify the causes and outcomes of readmission within 30 days after VT ablation procedure. Using the all-payer, nationally representative Nationwide Readmissions Database, our study included patients aged 18 years or older who underwent VT catheter ablation between 2017 and 2019. On the basis of the International Classification of Diseases, Tenth Revision, Clinical Modification, we identified and categorized the causes of readmissions by organ systems and analyzed their outcomes. Out of 3,170 patients who underwent VT ablation, 446 (14.1%) patients were readmitted within 30 days of the procedure. The most common cause of readmission was cardiac (n=326, 73.1%), followed by infectious (n=31, 7.0%), neurological (n=15, 3.4%), renal (n=13, 2.9%), gastrointestinal (n=9, 2.0%), respiratory (n=9, 2.0%), vascular (n=9, 2.0%), endocrinological (n=5, 1.1%) and hematological (n=5, 1.1%) events. Among the cardiac causes-related readmission, recurrent VT (65.0%), and congestive heart failure (CHF) (18.1%) were the most common etiologies. Among these causes of readmissions, patients readmitted due to CHF had the highest rate in readmission mortality (8.47%), prolonged length of hospital stay for more than 7 days (42.37%), non-home discharge (33.9%), and the highest cost of hospitalization. Recurrent VT was the most common cause of early readmission after VT ablation procedure. However, early readmission due to CHF had the poorest outcome with the highest mortality rate during the readmission.

PO-05-034 CLINICAL CHARACTERISTICS AND OUTCOMES AFTER VENTRICULAR TACHYCARDIA ABLATION USING ULTRALOW TEMPERATURE CRYOABLATION IN PATIENTS WITH PRIOR CATHETER ABLATION

Ablation of scar mediated Ventricular Tachycardia (VT), especially when the location of circuit is intramural can be quite challenging with the use of radiofrequency (RF) ablation. Preclinical data with the use of Ultralow temperature Cryoablation has shown that it can create deep, transmural lesions and can generate temperature as low as -196° C. To present a series of patients who had recurrent VT despite prior RF ablation and then underwent VT ablation with Ultralow temperature cryoablation system (Adagio) as part of the FDA compassionate use authorization. We performed retrospective analysis of patients who had undergone VT ablation using the Adagio system. Follow up data on clinical outcomes and recurrence of VT episodes were collected based on clinic visits, device interrogations and remote transmissions from Implantable Cardioverter Defibrillators (ICDs). A total of 5 patients underwent Ultralow temperature cryoablation for VT between 10/2021 and 05/2022 at our institution. The average age of patients in our case-series was 72 +/- 8.6 years and 3 (60%) of patients had h/o ischemic cardiomyopathy. The median number of prior VT ablations performed per patient was 2, and 40% of patients had presented in electric storm. During the VT ablation procedure using the Adagio system, the average number of inducible VT episodes was 2.6 +/- 1.8. All 5 patients were non-inducible at the end of VT ablation. At an average follow up period of 207.6 +/- 77.7 days, after having undergone VT ablation using the Adagio system, all 5 patients remained free of ICD shocks or electric storm during the follow up period and only 2 patients were maintained on anti-arrhythmic therapy. One patient underwent cardiac transplant because of recurrence of relatively slow VT episodes and advanced congestive heart failure. It is also worthwhile to note that in this patient, given the inaccessible location of VT circuit (peri-mitral region after prior cardiac surgery for cardiac aneurysm), ablation lesions could not be optimally delivered. Another patient experienced 1 episode of slow monomorphic VT, which was ATP terminable. Although our experience is based on a small sample size, the follow up outcomes using Ultralow temperature Cryoablation system for VT ablation in a challenging patient subset with limited options seems promising. Future studies would yield data on efficacy and safety of this system in high-risk subset of patients.

Comparison of warfarin with direct oral anticoagulants for thromboembolic prophylaxis after catheter ablation of ventricular tachycardia.

Thromboembolic events after catheter ablation of ventricular tachycardia (VT) can result in significant morbidity. Thromboembolic prophylaxis after catheter ablation can be achieved by the use of antiplatelet agents, vitamin K antagonists, or direct oral anticoagulants (DOACs). The relative safety and efficacy of these modes of prophylaxis are uncertain. We sought to compare the outcomes of patients who received warfarin or DOACs for thromboembolic prophylaxis after catheter ablation of VT. Anticoagulation with DOACS was started after left ventricular VT ablation in a series of 42 consecutive patients with structural heart disease (67 ± 11 years, 3 women, ejection fraction 32 ± 14%). Duration of hospital stay, bleeding episodes, and thromboembolic events were compared to a historic consecutive group of patients (n = 38, 65 ± 13 years, 14 women, ejection fraction 36 ± 13%) in whom anticoagulation with a formerly described protocol of heparin and vitamin K antagonist was used after VT ablation procedures. Hospital stay was significantly shorter in the group where DOACs were used as compared to vitamin K antagonists (3.3 ± 1.8 vs. 5.0 ± 2.5 days postablation; p = 0.001) without an increase of bleeding or thromboembolic events. Anticoagulation with DOACs is safe and shortens hospital stay in patients with structural heart disease undergoing left ventricular VT ablation procedures.

The value of functional substrate mapping in ventricular tachycardia ablation.

In the setting of structural heart disease, ventricular tachycardia (VT) is typically associated with a re-entrant mechanism. In patients with hemodynamically tolerated VTs, activation and entrainment mapping remain the gold standard for the identification of the critical parts of the circuit. However, this is rarely accomplished, as most VTs are not hemodynamically tolerated to permit mapping during tachycardia. Other limitations include noninducibility of arrhythmia or nonsustained VT. This has led to the development of substrate mapping techniques during sinus rhythm, eliminating the need for prolonged periods of mapping during tachycardia. Recurrence rates following VT ablation are high; therefore, new mapping techniques for substrate characterization are required. Advances in catheter technology and especially multielectrode mapping of abnormal electrograms has increased the ability to identify the mechanism of scar-related VT. Several substrate-guided approaches have been developed to overcome this, including scar homogenization and late potential mapping. Dynamic substrate changes are mainly identified within regions of myocardial scar and can be identified as local abnormal ventricular activities. Furthermore, mapping strategies incorporating ventricular extrastimulation, including from different directions and coupling intervals, have been shown to increase the accuracy of substrate mapping. The implementation of extrastimulus substrate mapping and automated annotation require less extensive ablation and would make VT ablation procedures less cumbersome and accessible to more patients.