Catheter Ablation Of Ventricular Tachycardia Research Articles

Trans-apical catheter ablation of ventricular tachycardia in a patient with metallic aortic and mitral valves

We present a patient with a history of heart failure and metallic aortic and mitral valves surgeries, who required ablation for a drug-refractory left ventricular tachycardia. But the metallic valves prohibited the insertion of catheters via retrograde or via trans-septal approaches. Therefore, we decided to perform catheter ablation by direct left ventricle puncture through a minithoracotomy. The arrhythmia was successfully ablated via of trans-apical approach and did not recur at six months follow-up.

A case of left middle cerebral artery occlusion during catheter ablation for paroxysmal ventricular tachycardia

A case of left middle cerebral artery occlusion during catheter ablation for paroxysmal ventricular tachycardia

Major in-hospital complications after catheter ablation of cardiac arrhythmias: individual case analysis of 43 031 procedures.

In-hospital complications of catheter ablation for atrial fibrillation (AF), atrial flutter (AFL), and ventricular tachycardia (VT) may be overestimated by analyses of administrative data. We determined the incidences of in-hospital mortality, major bleeding, and stroke around AF, AFL, and VT ablations in four German tertiary centres between 2005 and 2020. All cases were coded by the G-DRG- and OPS-systems. Uniform code search terms were applied defining both the types of ablations for AF, AFL, and VT and the occurrence of major adverse events including femoral vascular complications, iatrogenic tamponade, stroke, and in-hospital death. Importantly, all complications were individually reviewed based on patient-level source records. Overall, 43 031 ablations were analysed (30 361 AF; 9364 AFL; 3306 VT). The number of ablations/year more than doubled from 2005 (n = 1569) to 2020 (n = 3317) with 3 times and 2.5 times more AF and VT ablations in 2020 (n = 2404 and n = 301, respectively) as compared to 2005 (n = 817 and n = 120, respectively), but a rather stable number of AFL ablations (n = 554 vs. n = 612). Major peri-procedural complications occurred in 594 (1.4%) patients. Complication rates were 1.1% (n = 325) for AF, 1.0% (n = 95) for AFL, and 5.3% (n = 175) for VT. With an increase in complex AF/VT procedures, the overall complication rate significantly increased (0.76% in 2005 vs. 1.81% in 2020; P = 0.004); but remained low over time. Following patient-adjudication, all in-hospital cardiac tamponades (0.7%) and strokes (0.2%) were related to ablation. Major femoral vascular complications requiring surgical intervention occurred in 0.4% of all patients. The in-hospital mortality rate adjudicated to be ablation-related was lower than the coded mortality rate: AF: 0.03% vs. 0.04%; AFL: 0.04% vs. 0.14%; VT: 0.42% vs. 1.48%. Major adverse events are low and comparable after catheter ablation for AFL and AF (∼1.0%), whereas they are five times higher for VT ablations. In the presence of an increase in complex ablation procedures, a moderate but significant increase in overall complications from 2005-20 was observed. Individual case analysis demonstrated a lower than coded ablation-related in-hospital mortality. This highlights the importance of individual case adjudication when analysing administrative data.

Catheter Ablation of Ventricular Tachycardia in the Presence of Mechanical Aortic and Mitral Valve Replacement

Catheter Ablation of Ventricular Tachycardia in the Presence of Mechanical Aortic and Mitral Valve Replacement

Technological advances in ventricular tachycardia catheter ablation: the relentless quest for novel solutions to old problems.

Several novel technologies allowing catheter ablation (CA) with a favorable safety/efficacy profile have been recently developed, but not yet extensively clinically tested in the setting of ventricular tachycardia CA. In this technical report, we overview technical aspects and preclinical/clinical information concerning the application of three novel CA technologies in the ventricular milieu: a pulsed field ablation (PFA) generator (CENTAURI™, Galaxy Medical) to be used with linear, contact force-sensing radiofrequency ablation catheters; a contact force-sensing radiofrequency ablation catheter equipped with six thermocouples and three microelectrodes (QDOT Micro™, Biosense-Webster), allowing high-resolution mapping and temperature-controlled CA; and a flexible and mesh-shaped irrigation tip, contact force-sensing radiofrequency ablation catheter (Tactiflex, Abbott). We also report three challenging VT cases in which CA was performed using these technologies. The CENTAURI system was used with the Tacticath™ (Abbott) ablation catheter to perform ventricular PFA in a patient with advanced heart failure, electrical storm, and a deep intramural septal substrate. Microelectrode mapping using QDOT Micro™ helped to refine substrate assessment in a VT patient with congenitally corrected transposition of the great arteries, and allowed the identification of the critical components of the VT circuit, which were successfully ablated. Tactiflex™ was used in two challenging CA cases (one endocardial and one epicardial), allowing acute and mid-term control of VT episodes without adverse events. The ideation and development of novel technologies initially intended to treat atrial arrhythmias and successfully implemented in the ventricular milieu is contributing to the progressive improvement in the clinical benefits derived from VT CA, making this procedure key for successful management of increasingly complex patients.

Outcomes of catheter ablation for ventricular tachycardia in the geriatric population

Abstract Background Catheter ablation has emerged as the first-line therapy for management of ventricular tachycardia (VT) over the last decade. There is a reluctance for older patients to be referred for catheter ablation with concerns for complications and poor outcomes. Purpose The purpose of the study was to assess the safety and outcomes of catheter ablation for VT in patients more than 74 years of age in comparison to younger patients. Methods A single-center retrospective study of 200 procedures in 168 patients undergoing catheter ablation for scar-related VT was conducted. Data collected included demographics, comorbidities, medications, relevant laboratory abnormalities, electrocardiograms, Holter, device electrograms, structural data including echocardiograms and cardiac magnetic resonance imaging, detailed procedural characteristics, and outcomes. Results The mean age in the older cohort was 77.7 ± 3.7 years compared to 57.6 ± 13.1 years in the younger group (p < 0.01) [Figure 1]. The geriatric patients had more males (93.6% vs. 75.8%) and had greater proportion of comorbidities including congestive heart failure (89.4% vs. 66.7%), hypertension (91.5% & 56.9%), atrial arrhythmias (66.0% vs. 43.1%), chronic kidney disease (68.1% vs. 31.4%), prior myocardial infarction (53.2% vs. 24.2%), and stroke (21.3% vs. 8.5%). The older patients were on more antiarrhythmic drugs at baseline. During the procedure, the number of cases with VT induction and hemodynamic stability was similar in older and younger groups. In cases where VT was induced, the older patients had a greater number of VTs induced (2.7 ± 3.0 vs. 1.9 ± 1.8), with slower cycle lengths (454.9 ± 122.6 vs. 379.3 ± 108.1 milliseconds). There was no difference noted in the procedural complications between the two groups. Older patients were more likely to be discharged on antiarrhythmic medications (87.2% vs. 71.2%) and had higher long-term mortality (29.8% vs. 7.8%). The older group was less likely to have a repeat ablation procedure (8.5% vs 24.2%). There was no difference in long-term VT-free survival rates among the two groups [Figure 2]. Conclusion Patients more than 74 years of age undergoing catheter ablation for structural VT have a greater comorbidity burden but demonstrate similar procedural complications and VT-free survival rates, when compared to the younger cohort.Figure 1Figure 2

Differences in the outcomes of catheter ablation for ventricular tachycardia by sex

Abstract Background Catheter ablation of ventricular tachycardia (VT) has emerged as the mainstay of management for these sick patients. There is a lack of long-term data studying the characteristics and outcomes of VT ablation in females and the comparison with males. Purpose The purpose of the study was to assess the impact of sex on outcomes of catheter ablation for ventricular tachycardia. Methods A single-center retrospective study of 200 procedures in 168 patients undergoing catheter ablation for scar-related VT under GA or MAC sedation was conducted. Data collected included demographics, comorbidities, medications, relevant laboratory abnormalities, electrocardiograms, structural data including echocardiograms and cardiac magnetic resonance imaging, detailed procedural characteristics, and outcomes. Results Females undergoing VT ablation were younger (49.4 ± 15.6 vs. 65.5 ± 12.2 years) [Figure 1]. Females had a lower burden of comorbidities, including congestive heart failure (30.0 % vs. 82.5%), hypertension (27.5% vs. 74.4%), atrial arrhythmias (20.0% vs. 55.6%), chronic kidney disease (25.0% vs. 43.8%), prior myocardial infarction (15.0% & 35.0%), and coronary artery bypass graft surgery (0.0% & 23.8%). Females were on fewer antiarrhythmic drugs at baseline. During the procedure, males had a greater likelihood of undergoing general anesthesia (72.5% vs. 50.0%) and associated hemodynamic instability at baseline (30.0% vs. 12.5%). It was more likely for VT to be induced in males, and females required more induction medications. There was no difference in complication rates between males and females. A greater proportion of males were discharged and maintained on antiarrhythmic drugs after the procedure. There was no significant difference in VT recurrence or long-term mortality. Using Kaplan-Meier analysis, no difference was seen in long-term VT-free survival by sex (p=0.20) [Figure 2]. In a multivariate regression model, female sex had no bearing on the VT-free survival. Conclusion Females undergoing catheter ablation for VT are younger and have fewer comorbidities. They tend to be on fewer antiarrhythmic drugs at baseline, and after ablation. Interestingly, despite a healthier baseline profile, females do not experience less VT recurrence or mortality compared to males. Further study would be needed to investigate this association.Figure 1Figure 2

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 < 0.01), and during VT induction (p < 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

Catheter ablation for ventricular tachycardia after myocardial infarction: meta-analysis of randomised controlled trials

Abstract Background The prognostic impact of ventricular tachycardia (VT) catheter ablation is an important outstanding research question. Purpose We undertook a reconstructed individual patient data meta-analysis of randomised controlled trials comparing ablation to medical therapy in patients developing VT after myocardial infarction (MI). Methods We systematically identified all trials comparing catheter ablation to medical therapy in patients with VT and prior MI. The pre-specified primary endpoint was all-cause mortality assessed using reconstructed individual patient data obtained by digitisation of published Kaplan-Meier curves and subsequent construction of Cox proportional hazards regression models. Pre-specified secondary endpoints included trial-level assessment by random effects meta-analysis of all-cause mortality, VT recurrence, defibrillator shocks and all-cause hospitalisations. Meta-regression was performed to evaluate the effect of VT mapping in addition to substrate modification. Sensitivity analyses were performed depending on the proportion of patients with prior MI included. (PROSPERO ID CRD42023390799) Results Eight trials, recruiting a total of 874 patients, were included. 430 patients were randomised to catheter ablation and 444 to medical therapy. Catheter ablation reduced all-cause mortality compared to medical therapy when synthesising reconstructed individual patient data (hazard ratio 0.57, 95% confidence interval (CI) 0.38 to 0.85, p=0.007), but not in trial-level analysis (relative risk 0.91, 95%CI 0.67 to 1.23, p=0.53, I2=0%). Catheter ablation significantly reduced VT recurrence, defibrillator shocks and hospitalisations compared to medical therapy. Sensitivity analyses were consistent with the primary analyses. Conclusion In patients with post-infarct ventricular tachycardia, catheter ablation reduces mortality.

Optimal pixel signal intensity threshold for the assessment of endocardial left-ventricular scar by 3D dark blood MRI compared to bipolar voltage electro-anatomical mapping

Abstract Background Late gadolinium enhancement (LGE) MRI is considered the standard for noninvasive assessment of 3D scar architecture. Intraprocedural integration of 3D scar models improve the outcome of catheter ablation for ventricular tachycardia (VT). A pixel signal intensity (PSI) cut-off of 40 to 60% has been widely used for conventional bright-blood LGE MRI. Novel 3D MRI acquisitions with dark-blood (DB) nulling with higher spatial resolution and superior detection of (subendocardial) scar patterns are increasingly available, but the optimal pixel signal intensity (PSI) value remains unknown. Purpose To compare the accuracy of the 3D DB MRI-derived endocardial scar reconstructions at three different PSI cut-offs with endocardial electro-anatomical contact mapping in patients with scar-related VT. Methods Preprocedural 3D DB LGE MRIs were retrospectively compared to high-density endocardial left-ventricular (LV) bipolar voltage mapping (cut-off 0.5-1.5mV) obtained during endocardial mapping at sinus rhythm using the ADAS3D software. The LV scar models were aligned using the mitral valve, left ventricular apex and aorta cusps. Points with a Euclidean node-to-node distance of ≥10 mm were excluded. Variable upper PSI thresholds were set at 50%, 60% and 70%; the lower threshold at two-thirds of the upper limit. The 10% LV layer from the 3D MRI was used. The pairs of points were checked for agreement for scar or healthy (%). The Pearson correlation was used to analyze the agreement between core scar, border zone and healthy tissue area (in %) at three thresholds. Results Ten patients (90% male, mean age 65±11 year, 8 ischemic/2 nonischemic, LV ejection fraction 41±6%) were analyzed. A mean of 2024 (range 385-6810) pairs were analyzed per patient at three PSI thresholds. A correct correlation for scar or healthy was present in 67%, 69% and 69% for the upper PSI thresholds of 50%, 60% and 70% respectively. The optimal match was obtained for an upper PSI cutoff value of 70%, for healthy (r2=0.57; P=0.01), border zone (r2=0.73; P=0.01), 50% for core (r2=0.09; P=0.39). Using a 60% PSI cutoff the scar core % increased significantly compared to the 70% cutoff (12.8 ±13.8 versus 4.9±7.3, P=0.001). Conclusion The optimal depiction of the boundary between healthy and border zone scar by 3D DB MRI is best depicted at an upper PSI threshold of 70%.

Catheter ablation of ventricular arrhythmias in arrhythmogenic cardiomyopathy - comparison of different approaches and results of genetic testing

Abstract Introduction Arrhythmogenic cardiomyopathy (ACM) is a disease characterized by fatty-fibrous remodeling of the myocardium and a high risk of ventricular tachycardia (VT). Catheter ablation is an effective method that prevents VT recurrences. Although the arrhythmogenic substrate in ACM is located dominantly in the epicardium, in some patients VT can be effectively suppressed only by endocardial ablation. Purpose Retrospective analysis of catheter ablation results of VT in patients with ACM and right ventricular involvement. Methods Between 2001-2021, catheter ablation of VT was performed in 51 patients (mean age 43±18 years, 9 women) with a clinical diagnosis of ACM and right ventricular involvement. Pathogenic/likely pathogenic mutation was detected during the genetic testing in 80% of patients. Repeated ablation procedures were necessary to suppress VT (a total of 1.9±1.3 procedures/patient). According to the approach, patients were divided into three groups: A - endocardial ablation only (n=20); B - endocardial ablation first, followed by epicardial approach (n=15); C- primary epicardial approach (n=16). Results The primary epicardial approach (group C) compared to the endocardial approach (group A+B) was associated with better VT free survival (Figure 1, p<0.02) and significantly fewer procedures needed to suppress arrhythmia recurrences (1.1±0.2 vs 2.3±1.5 procedures/patient; p<0.005). Patients in whom an endocardial approach (group A) was sufficient to control arrhythmias were significantly older than patients in whom an epicardial approach (group B) had to be used (52.9±15.1 vs 36.0±16.0 years; p<0.001). The frequency of pathogenic mutations did not differ among groups (A - 83% vs B - 71% vs C - 86%; p=n.s.). The most commonly found mutation was in the gene for plakophilin 2 (51% of all patients). Conclusion Epicardial VT ablation in ACM patients with right ventricular involvement leads to the most effective control of arrhythmias. Endocardial ablation alone may be sufficient to control VT in older patients. The identification of a pathogenic/likely pathogenic mutation does not seem to be relevant for choice of ablation approach.Figure 1

Abstract 12037: Impact of Age on Hospital Outcomes After Catheter Ablation for Ventricular Tachycardia

Background: Catheter ablation for ventricular tachycardia (VT) has been increasingly performed over the past decades. However, the real-world data on the safety profile of this procedure among elderly patients is limited. Objective: This study aimed to evaluate the procedural outcomes and 30-day readmission among those aged 18-64 years versus those aged ≥65 years who underwent catheter ablation of VT. Method: 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 2020. We divided the patients into non-elderly (18-64 years old) and elderly age groups (≥65 years old). We then analyzed the in-hospital procedural outcome and 30-day readmission between these groups. Results: Our study included 2075 (49.1%) non-elderly patients and 2153 (50.9%) elderly patients who underwent VT ablation. Following the procedure, elderly patients had significantly higher rates of prolonged index hospitalization (≥7 days) (35.5% vs 29.3%, p<0.01), non-home discharge (13.4% vs 6.0%, p<0.01), 30-day readmission (17.0% vs 11.4%, p<0.01), and early mortality (5.5% v 2.4%, p<0.01). The median cumulative cost of hospitalization was significantly higher in the elder groups ($40,230 vs. $37,612, p ≤0.01). There was no significant difference in the procedural complications between the two groups. Through multivariable analysis, the elderly group was associated with significantly higher odds of early mortality (OR: 7.50; CI 1.86 - 30.31, p=0.01), non-home discharge (OR: 2.41; CI: 1.93 - 3.00, p<0.01) and 30-day readmissions (OR: 1.58; CI 1.32 - 1.89, p<0.01). Conclusion: Our study suggests that elderly patients have poorer in-hospital outcome in early mortality, non-home discharge and 30-day readmissions following catheter ablation for VT. There was no significant difference between elderly and non-elderly groups in the procedural complications.

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<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 12679: Thirty-Day Readmissions for Recurrent Ventricular Tachycardia Following Catheter Ablation of Ventricular Tachycardia: Predictors and Outcomes

Background: Despite the optimal efficacy of catheter ablation for ventricular tachycardia (VT), recurrence of VT can occur post-procedurally. However, data on the high-risk population for VT recurrence and the in-hospital outcomes remain scarce. Objective: This study aimed to determine the predictors of 30-day readmission for recurrent VT after catheter ablation of VT and assess the in-hospital outcomes. Method: Using the all-payer, nationally representative Nationwide Readmissions Database, we identified the patients aged ≥18 years who underwent catheter ablation for VT and were readmitted within 30 days because of recurrent VT from 2017 to 2020. We performed unweighted univariable and multivariable analyses to determine the outcomes and to identify the patient and hospital variables that were predictive of 30-day readmissions for recurrent VT. A p-value of <0.05 is considered statistically significant. Results: In our analysis, a total of 4,102 patients were discharged alive after VT ablation, of which 278 (6.8%) were readmitted within 30 days for recurrent VT. Recurrent VT was also the most common cause of 30-day readmission (47.7%, n=278/583). Compared to non-recurrent VT readmission, readmission due to recurrent VT had higher mortality during rehospitalization (7.55% vs 3.72%, p<0.01) and higher cumulative hospitalization cost ($57584 vs $37846, p<0.01). Via multivariable analysis, congestive heart failure (aOR: 1.84; 95% CI: 1.07-3.17; P=0.03) and non-elective index admissions (aOR: 1.88; 95% CI: 1.32-2.68; P<0.01) were the independent predictors of 30-day readmission for recurrent VT. Conclusion: Recurrent VT was the most common cause of 30-day readmission following VT ablation. Congestive heart failure and non-elective index admissions were the independent predictors of 30-day readmissions for recurrent VT. These highlight the importance of further research in ablation strategies to improve the efficacy of VT ablation.

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 < 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 (>7 days) (37.6% vs 31.2%, p<0.01) and a higher cost of hospitalization ($39 983 vs $37 015, p<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.

Abstract 17188: Electrocardiographic Algorithms for Localization Ventricular Ectopy From the Ventricular Outflow Tracts Demonstrate Poor Accuracy and Agreement

Background: Premature ventricular contractions (PVCs) and ventricular tachycardia (VT) commonly arise from the outflow tracts of the left and right ventricles and can be treated with catheter ablation when symptomatic or associated with cardiomyopathy. Accurate localization of these ectopic sources aids procedural planning. Several different electrocardiographic (ECG) algorithms have been published, but their relative performance has not been assessed. Objective: Compare the accuracy and agreement of three ECG algorithms for PVC localization. Methods: ECGs from patients who underwent catheter ablation for PVCs or VT originating the outflow tract region were analyzed using three published PVC localization algorithms. The predictions from these algorithms were then compared to the site of successful catheter ablation (right ventricular outflow tract [RVOT], left ventricular outflow tract [LVOT], or epicardium). The accuracy and agreement of the three algorithms were compared. Results: A total of 43 patients were evaluated and ectopy was suppressed via ablation from a single chamber in 37 (86%) of patients. VT/PVCs originated from the RVOT (N=10), LVOT (N=26), and epicardium (N=1). The three studied algorithms demonstrated accuracy rates of 46-70%. The algorithms disagreed on the predicted ectopy location for 19 (51%) patients. When all algorithms agreed (N=18), the prediction was accurate for only 11 patients (61%). Conclusion: Rules-based ECG algorithms demonstrate poor performance and use of different published algorithms frequently result in disparate results. More accurate and consistent methods incorporating individualized electroanatomic variation may improve accuracy and periprocedural management for PVC and VT ablation.

Intramyocardial Hematoma During Catheter Ablation for Scar-Related Ventricular Tachycardia.

Intramural hematoma during ablation for scar-related ventricular tachycardia (VT) is a rare but life-threatening complication. The goal of this study was to describe the features and outcomes of intramural hematoma during ablation for scar-related VT. From 2010 to 2022, >3,514 ablations for ventricular arrhythmias were performed at 2 institutions. Four cases of intramural hematoma complicating VT ablation for scar-related VT were identified. Intraprocedural details, imaging data, and surgical notes were reviewed to create a recognizable pattern of events highlighting this complication. In 3 of 4 cases, intramural hematoma occurred during catheter ablation with an open irrigated 3.5mm tipped catheter using normal saline for irrigation. In one case, hematoma was noted after ablation using an investigational needle electrode catheter. The occurrence of a steam pop preceded detection of an expanding intramural hematoma in 3 cases. ST-segment elevation on electrocardiography was evident in 3 cases; intracardiac echocardiographic imaging detected the hematoma in all cases. Epicardial rupture and pericardial effusion requiring drainage occurred in 3 cases, whereas 1 hematoma was self-contained and did not require intervention. Surgical intervention was performed in 2 cases, with successful outcomes. One patient who was deemed not a surgical candidate died of progressive cardiogenic shock. Intramural hematoma during ablation for scar-related VT is a rare but potentially catastrophic complication that requires prompt recognition. Steam pops during ablation frequently precede the hematoma formation. Surgical intervention may be life-saving, although contained hematomas can occasionally be managed conservatively.

A Comparison of Statistical Analysis Between "Real" Patients Reported in Kaplan-Meier Curves and "Reconstructed" Patients Estimated Through the IPDfromKM Method: Analysis of Eight Trials Evaluating Catheter Ablation of Ventricular Tachycardia.

Time-to-event endpoints are most widely used in oncology and, to a lesser extent, in cardiology. Typical statistical parameters employed in this context include overall survival,progression-free survival,and recurrence-free survival. The graphical presentation of the results is based on the Kaplan-Meier plot. When Kaplan-Meier curves are included in a meta-analysis, the typical methodological approach is a simplified onebecause the results of each trial (as well as those of the meta-analysis itself) are expressed through a 2x2 contingency;the methodological simplification is that the follow-up is left out from the analysis and, consequently, the Kaplan-Meier curves are omitted as well. The IPDfromKM method, developed in 2021,is an artificial intelligence algorithm designed to be used in these situations. According to this method, to keep the Kaplan-Meier curves in the meta-analysis, each curve is converted into a database of individual patients (which are denoted as "reconstructed" individual patients). In this way, for the purposes of the meta-analysis, the statistical methods are based on individual patients (like those of clinical trials) so that the Kaplan-Meier curves must not be excluded, and the effect of the follow-up can, therefore, be investigated. This technical report describes the IPDfromKM method in all of its operational details. To present the method, a meta-analysis investigating the effects of catheter ablation to prevent ventricular tachyarrhythmia (VT) hasbeen taken as an example. The original meta-analysis, which included nine controlled trials, waspublished in February 2023 and adopted the simplified approach based on 2x2 contingency tables. We have reanalyzed these trials by using the IPDfromKM method. Overall, both the standard binary meta-analysis and the IPDfromKM method showedthat ablation significantly reducesVT recurrence (hazard ratio, 0.820for binary meta-analysis vs 0.728 for the IPDfromKMmethod). By contrast, while no heterogeneity was found by the binary method, the IPDfromKM foundsignificant heterogeneity, which was confirmed by visual inspection of the Kaplan-Meier curves. This suggests that the results of the IPDfromKM method are more accurate because they include the effect of the follow-up on patients' outcomes. In conclusion, our reanalysis confirms the significant benefit determined by ablation, but a more pronounced degree of between-trial heterogeneity has been found. Finally, it should be stressed that, outside the field of meta-analysis, the IPDfromKM method is also applicable to carry out an indirect comparison between treatments that have never been compared in real clinical trials. In this case, reconstructed patients are analyzed by conducting a simulated comparative trial.

Experience in applied veno-arterial extracorporeal membrane oxygenation to support catheter ablation of malignant ventricular tachycardia

BackgroundAn electrical storm due to malignant ventricular tachycardia (VT) is a life-threatening condition that requires catheter ablation (CA). Most VT arrhythmias evolve over time after acute myocardial infarction, coronary artery bypass grafting, or chronic heart failure. Clinically, only radiofrequency ablation can identify and block all arrhythmia origin points. The procedure necessitates continuous VT induction in patients, resulting in hemodynamic instability; therefore, extracorporeal membrane oxygenation (ECMO) support is required. Earlier studies have reported substantial mortality rates; however, our results are significantly more favorable. In this study, we combined the minimally invasive extracorporeal circulation (MiECC) approach with ECMO to preserve an appropriate ECMO flow rate, thus reducing intraoperative left heart afterload. We report 21 cases illustrating the usefulness of modified veno-arterial (VA)-ECMO in this scenario. MethodsData of 21 patients supported by the modified VA-ECMO system (MiECC approach combined with the ECMO system) during VT CA in the Wuhan Asia Heart Hospital between June 2020 and July 2021 were reviewed retrospectively. ResultsSuccessful ablation was achieved in 20 out of 21 patients (95%). The median time for ECMO implantation was 206 min. Only two patients experienced complications post-treatment. All patients made complete recovery and were discharged. All patients were alive at the 1-year-follow-up. ConclusionsOur modified VA-ECMO system helped restore systemic circulation in patients experiencing an electrical storm, thus achieving greater electrical stability during VT CA. Pre-insertion of VA-ECMO can achieve even better results.

Long-term results of catheter ablation of idiopathic and structural ventricular tachycardia

Catheter ablation of ventricular tachycardia (VTs) has emerged as an effective treatment modality. Ablation procedures for idiopathic VTs depends on the anatomical origin of the arrhythmias, is highly effective in certain cases, and has been implemented as afirst-line therapy in recent European guidelines. In contrast, catheter ablation of VTs in patients with structural heart disease has asignificant risk of arrhythmia recurrence. Interventional treatment for patients with ischemic cardiomyopathy was studied in multiple randomized multicenter trials and it was shown that catheter ablation was more effective in arrhythmia suppression compared to conservative treatment modalities. Catheter ablation of nonischemic cardiomyopathy suffers from far higher rates of arrhythmia recurrences as documented in several long-term studies and often needs complex procedures with or without epicardial mapping and ablation. There is still no clear proof of amortality benefit from catheter ablation of VTs in patients with or without structural heart disease. Nevertheless, recent guidelines recommend catheter ablation as an alternative to implantation of cardioverter-defibrillators (ICD) in selected cases.