Undergoing Ventricular Tachycardia Ablation Research Articles

Orthogonal high-density mapping with ventricular tachycardia isthmus analysis vs. pure substrate ventricular tachycardia ablation: A case-control study.

BackgroundSubstrate-based ablation has become a successful technique for ventricular tachycardia (VT) ablation. High-density (HD) mapping catheters provide high-resolution electroanatomical maps and better discrimination of local abnormal electrograms. The HD Grid Mapping Catheter is an HD catheter with the ability to map orthogonal signals on top of conventional bipolar signals, which could provide better discrimination of the arrhythmic substrate. On the other hand, conventional mapping techniques, such as activation mapping, when possible, help to identify the isthmus of the tachycardia.AimThe purpose of this study was to compare clinical outcomes after using two different VT ablation strategies: one based on extensive mapping with the HD Grid Mapping Catheter, including VT isthmus analysis, and the other based on pure substrate ablation.MethodsForty consecutive patients undergoing VT ablation with extensive HD mapping method in the hospital clinic (November 2018–November 2019) were included. Clinical outcomes were compared with a historical cohort of 26 consecutive patients who underwent ablation using a scar dechanneling technique before 2018.ResultsThe density of mapping points was higher in the extensive mapping group (2370.24 ± 920.78 vs. 576.45 ± 294.46; p < 0.001). After 1 year of follow-up, VT recurred in 18.4% of patients in the extensive mapping group vs. 34.6% of patients in the historical control group (p = 0.14), with a significantly greater reduction of VT burden: VT episodes (81.7 ± 7.79 vs. 43.4 ± 19.9%, p < 0.05), antitachycardia pacing (99.45 ± 2.29 vs. 33.9 ± 102.5%, p < 0.001), and implantable cardioverter defibrillator (ICD) shocks (99 ± 4.5 vs. 64.7 ± 59.9%, p = 0.02).ConclusionThe use of a method based on extensive mapping with the HD Grid Mapping Catheter and VT isthmus analysis allows better discrimination of the arrhythmic substrate and could be associated with a greater decrease in VT burden.

Comparison between Standard and High-Definition Multi-Electrode Mapping Catheter in Ventricular Tachycardia Ablation.

A high-definition mapping catheter has been introduced, allowing for bipolar recording along and across the spline with a rapid assessment of voltage, activation, and directionality of conduction. We aimed to evaluate differences in mapping density, accuracy, time, and consequently RF time between different mapping catheters used for ventricular tachycardia (VT) ablation. We enrolled consecutive patients undergoing VT ablation at our center. Patients were divided into the LiveWire 2-2-2 mm catheter (group A) and the HD Grid SE (group B). Primary endpoints were total RF delivery time, the number of points acquired in sinus rhythm and VT, and the scar area. Fifty-one patients were enrolled, 22 in group A and 29 in group B. More points were acquired in the Grid group in sinus rhythm (SR) and during VT (2060.78 ± 1600.38 vs. 3278.63 ± 3214.45, p = 0.05; 4201.13 ± 5141.61 vs. 10,569.43 ± 13,644.94, p = 0.02, respectively). The scar area was smaller in group B (Bipolar area, cm2 4.52 ± 2.72 vs. 2.89 ± 2.81, p = 0.05. Unipolar area, cm2 7.47 ± 4.55 vs. 5.56 ± 2.79, p = 0.03). Radiofrequency (RF) time was shorter in the Grid group (30.52 ± 13.94 vs. 22.16 ± 11.03, p = 0.014). LPs and LAVAs were eliminated in overall >93% of patients. No differences were found in terms of arrhythmia-free survival at follow-up. In conclusion, the use of a high-definition mapping catheter was associated with significantly shorter mapping time during VT and RF time. Significantly more points were acquired in SR and during VT. During remap, we also observed more LAVAs and LPs requiring further ablation.

Long-Term Outcomes after Catheter Ablation of Ventricular Tachycardia in Dilated vs. Ischemic Cardiomyopathy.

Ischemic (ICM) and dilated cardiomyopathy (DCM) represent the two main underlying heart diseases in patients referred for catheter ablation of ventricular tachycardia (VT). While VT ablation in ischemic cardiomyopathy is relatively well-studied, data in patients with DCM are still scarce. The study aimed to compare the acute and long-term outcomes in patients with ICM and DCM who underwent VT ablation at a high-volume center. Consecutive patients who underwent VT ablation from April 2018 to April 2021 were included retrospectively. Patients with ischemic cardiomyopathy were compared to those with dilated cardiomyopathy. The primary endpoint was rate of VT recurrences, the secondary endpoints included overall mortality, rehospitalization because of cardiac condition (VT, acute heart failure, acute myocardial infarction, heart transplantation or implantation of left ventricular assisting device), and major adverse cardiac events (MACE) at long-term follow-up. A total of 225 patients admitted for first VT ablation were included. A total of 156 patients (69%) revealed ICM and 69 (31%) DCM. After a mean follow-up of 22 months, the primary endpoint of VT recurrence occurred significantly more often in the patients with dilated cardiomyopathy (ICM n = 47; 37% vs. DCM n = 34; 64%; p = 0.001). In regard to the secondary endpoint of overall mortality, there was no difference between the two patient cohorts (DCM n = 9; 15% vs. ICM n = 22; 16%; p = 0.677); the patients with DCM showed significantly higher rehospitalization rates due to cardiac conditions (75% vs. 59%; p = 0.038) and more frequent MACE (68% vs. 52%; p= 0.036). In a Cox regression model, electrical storm at admission was shown to be a predictor for VT recurrence after successful catheter ablation (HR = 1.942: 95% CI 1.237–3.050; p = 0.004), while the ablation of every induced VT morphology during the procedure (HR = 0.522; 95% CI = 0.307–0.885; p = 0.016) contributed to a positive long-term outcome. DCM is associated with a higher risk of VT recurrence after catheter ablation compared to ICM. Furthermore, patients with DCM are more frequent re-hospitalized in the majority of cases due the VT recurrence. There is no difference in the long-term mortality between the two cohorts.

Impact of ventricular arrhythmia management on suboptimal biventricular pacing in cardiac resynchronization therapy

BackgroundReduced biventricular pacing (BiVP) is a common phenomenon in cardiac resynchronization therapy (CRT) with impact on CRT-response and patients’ prognosis. Data on treatment strategies for patients with ventricular arrhythmia and BiVP reduction is sparse. We sought to assess the effects of ventricular arrhythmia treatment on BiVP.MethodsIn this retrospective analysis, the data of CRT patients with a reduced BiVP ≤ 97% due to ventricular arrhythmia were analyzed. Catheter ablation or intensified medical therapy was performed to optimize BiVP.ResultsWe included 64 consecutive patients (73 ± 10 years, 89% male, LVEF 30 ± 7%). Of those, 22/64 patients (34%) underwent ablation of premature ventricular contractions (PVC) and 15/64 patients (23%) underwent ventricular tachycardia (VT) ablation while 27/64 patients (42%) received intensified medical treatment. Baseline BiVP was 88.1% ± 10.9%. An overall increase in BiVP percentage points of 8.8% (range − 5 to + 47.6%) at 6-month follow-up was achieved. No changes in left ventricular function were observed but improvement in BiVP led to an improvement in NYHA class in 24/64 patients (38%). PVC ablation led to a significantly better improvement in BiVP [9.9% (range 4 to 22%) vs. 3.2% (range − 5 to + 10.7%); p = < 0.001] and NYHA class (12/22 patients vs. 4/27 patients; p = 0.003) than intensified medical therapy. All patients with VT and reduced BiVP underwent VT ablation with an increase of BiVP of 16.3 ± 13.4%.ConclusionIn this evaluation of ventricular arrhythmia treatment aiming for CRT optimization, both medical therapy and catheter ablation were shown to be effective. Compared to medical therapy, a higher increase in BiVP was observed after PVC ablation, and more patients improved in NYHA class.Clinical Trial RegistrationThe study was registered at clinical trials.org in August 2019: NCT04065893.

Coagulation Response and Prothrombotic Effect of Uninterrupted Oral Anticoagulant Administration AfterCatheter Ablation for VT.

Catheter ablation for ventricular tachycardia (VT) is associated with perioperative thromboembolic risk. However, the strategy for postprocedural management remains unknown. The aim of this study was to evaluate the prothrombotic response after VT ablation in various coagulation biomarkers in patients with and without the administration of oral anticoagulation (OAC). Data from 112 patients (58 with uninterrupted OAC and 54 without) with structural heart disease who underwent endocardial VT ablation were retrospectively analyzed. We also included 41 patients who underwent ablation for premature ventricular contraction from the right ventricle and 13 patients who underwent electrophysiology study (the control group). Blood samples of coagulation markers were collected before and 3days after the procedure in all patients. The percentage of D-dimer levels≤1.0μg/mL at baseline was lower in the VT ablation groups (76% and 50% in the OAC and non-OAC groups, respectively) than in the other groups (100%). After 3days, the percentage remained at 67% in the OAC group; however, the non-OAC VT group demonstrated a remarkable decrease of 20%. Similarly, fibrin monomer complex, thrombin antithrombin, and prothrombin fragment 1+2 levels were well suppressed in the control, premature ventricular contraction, and OAC groups. However, the non-OAC group demonstrated increased coagulation markers both before and after 3days. Multivariate analysis demonstrated that OAC administration and normal coagulation markers at baseline were independent predictors of stable coagulation status after ablation. The coagulation cascade was significantly activated in patients undergoing VT ablation. Uninterrupted OAC administration suppressed the coagulation response, which might be associated with a reduction in perioperative prothrombotic risk.

Catheter Ablation for Ventricular Tachycardia in Ischaemic Versus Non-Ischaemic Cardiomyopathy: A Systematic Review and Meta-Analysis

There are differences in substrate and ablation approaches for ventricular tachycardia (VT) in ischaemic (ICM) and non-ischaemic cardiomyopathy (NICM). To perform a systematic review and meta-analysis comparing clinical and procedural characteristics/outcomes of VT ablation in ICM versus NICM. Electronic databases were searched for comparative studies reporting outcomes of VT ablation in patients with ICM and NICM. Primary outcomes were acute procedural success, VT recurrence and long-term mortality. Meta-analyses were performed using random-effects modelling. Thirty-one (31) studies (7,473 patients; 4,418 ICM and 3,055 NICM) were included. Patients with ICM were significantly older (67.0 vs 55.3 yrs), more commonly male (89% vs 79%), had lower left ventricular ejection fraction (29% vs 38%) were less likely to undergo epicardial access (11% vs 36%) and were more likely to require haemodynamic support during ablation (relative risk [RR] 1.30; 95% CI 1.01-1.69). Acute procedural success (i.e. non-inducibility of VT) was higher in the ICM cohort (RR 1.10, 95% CI 1.05-1.15). Recurrence of VT at follow-up was significantly lower in the ICM cohort (RR 0.77; 95% CI 0.70-0.84). Peri-procedural mortality, incidence of procedural complications and long-term mortality were not significantly different between the cohorts. NICM and ICM patients undergoing VT ablation are fundamentally different in their clinical characteristics, ablation approaches, acute procedural outcomes and likelihood of VA recurrence. VT ablation in NICM has a lower likelihood of procedural success with increased risk of VA recurrence, consistent with known challenging arrhythmia substrate.

A novel machine learning based algorithm to predict 1-year mortality after ventricular tachycardia ablation

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): -Project no. NVKP_16-1–2016-0017 (’National Heart Program’) has been implemented with the support provided by the Ministry of Innovation and Technology of Hungary from the National Research, Development and Innovation Fund of Hungary, financed under the NVKP_16 funding scheme. -Project no. MEC_R-141548 has been implemented with the support provided by the Ministry of Innovation and Technology of Hungary from the National Research, Development and Innovation Fund, financed under the MEC_R_21 funding scheme. Background Catheter ablation constitutes an established therapeutic option in patients with monomorphic ventricular tachycardia (VT). VT patients have high comorbidity burden and high mortality, however there is big heterogenity among individual patients. Therefore, effective postprocedural risk assessment systems, prediciting the mortality of patients undergoing VT ablation are highly needed. Purpose We aimed to develop a risk stratification algorithm predicting the 1-year all-cause mortality of patients undergoing VT ablation, and to identify the most important input factors of the model. Methods Between 2005 and 2020, 272 consecutive patients underwent VT ablation due to sustained monomorphic VT at our institution. We processed their procedural, demographic and medical history data, in addition to their laboratory and echocardiographic findings. For the training of different supervised learning models, we used 63 pre-procedural and procedural variables. We performed 5-fold cross validation and calculated the area under the receiver operating characteristic (ROC) curve (AUC), to assess the performance of the models. Finally, with calculating Shapley values we determined the most important factors of the mortality prediction for the best performing model. Results After a follow up of one year, total all-cause mortality was 22% (59). In predicting 1-year mortality, the best performance was shown by the random forest model [AUC: 0,73 (0,68-0,78)] among the machine learning models we had trained. This model significantly outperformed the traditional score systems like I-VT [AUC: 0,63 (0,55-0,70) vs. 0,73 (0,68-0,78), p&amp;lt;0,001] and PAINESD [AUC: 0,63 (0,55-0,71) vs. 0,73 (0,68-0,78), p=0,009] in our dataset. The predictive factors with the biggest effect on mortality were mitral E wave deceleration time, presence of cardiac resynchronization therapy, age, electric storm and hemoglobin concentration. Conclusion We were able to establish a supervised machine learning based system which managed to predict the 1-year mortality of VT ablation patients with high accuracy and turned out to be superior when compared to the use of existing risk scores. This enables us to identify the patients in need of a more thorough follow-up, which could reduce their mortality.

Epicardial mapping and ablation of ventricular tachycardia from the coronary venous system in post-coronary bypass patients.

Ventricular tachycardia (VT) ablation of mid- or epicardial substrate is difficult and requires a creative approach in patients with a history of coronary bypass that precludes percutaneous epicardial catheter manipulation. The coronary venous system (CVS) provides limited access to the epicardial surface of the heart. The objective of this study is to assess the feasibility, safety, and efficacy of epicardial mapping and ablation of VT substrates from the CVS in patients with history of coronary bypass. Patients undergoing VT ablation at our institution were retrospectively reviewed. Those who had basal to mid ventricular substrate based on computed tomography imaging and history of coronary bypass were included. Endocardial and CVS mapping and ablation was performed in standard fashion using 3D electroanatomic mapping. The primary endpoint was defined as VT circuit elimination, termination, non-inducibility, or perturbation of the circuit. Of 192 consecutive VT ablations from 2017 to 2020, 35 (18%) had a history of coronary bypass and basal to the mid-ventricular substrate by imaging. There were no significant characteristic differences between the endocardial only (n = 19) vs endocardial + CVS (n = 16) groups. In 14 (88%) of patients undergoing CVS mapping, the VT circuit was identified to be within access from the epicardial surface. Ablation was attempted in 8 (57%) of these patients, and the primary endpoint was reached in 88% of those undergoing CVS ablation. There were no complications related to CVS ablation. Mapping and ablation of mid- or epicardial VT circuits from the CVS branches are feasible and safe and may be helpful in the treatment of VT in patients who are otherwise not candidates for percutaneous epicardial ablation.

Meta-Analysis of Catheter Ablation Outcomes in Patients With Cardiac Sarcoidosis Refractory Ventricular Tachycardia

Cardiac sarcoidosis (CS) frequently leads to ventricular tachycardia (VT), which is often refractory to antiarrhythmic and/or immunosuppressive medications and requires catheter ablation. We conducted a systematic review and meta-analysis to evaluate the role of catheter ablation in patients with refractory VT undergoing catheter ablation. We searched PubMed, Embase, and Scopus databases from their inception to December 31, 2021 with search terms "cardiac sarcoidosis" AND "electrophysiological studies OR ablation." Fifteen studies were ultimately included for evaluation. Patient demographics, VT mapping, and acute and long-term procedural outcomes were extracted. A total of 15 studies were included in our meta-analysis, with a total of 401 patients, of whom 66% were male, with ages ranging from 39 to 64years. A total of 95% of patients were on antiarrhythmics and 79% of patients were on immunosuppressants. Left ventricular ejection fraction ranged from 35% to 49% and procedure duration ranged from 269 to 462minutes. Ablation was reported using both irrigated and nonirrigated catheter tips. A total of 25% of patients (84/339) underwent repeat ablation. Acute procedural success was achieved in 57% (161/285). Procedure complications occurred in 5.7% (17/297) procedures. VT recurrence after first ablation was 55% (confidence interval 48% to 63%, 213/401); VT recurrence after multiple ablations was 37% (81/220). The composite end point of death, heart transplant, and left ventricular assist device implantation was 21% (confidence interval 14% to 30%, 55/297). In conclusion, catheter ablation is a useful modality in patients with CS with refractory VT. However, patients with CS presenting with refractory VT after undergoing VT ablation carry a poor prognosis.

CA-531-01 FAT INFILTRATION CONFERS PROPENSITY FOR VENTRICULAR TACHYCARDIA IN THE POST-INFARCT SUBSTRATE

Infiltrating adipose tissue (inFAT) is present in the post-infarct substrate, but its role in ventricular tachycardia (VT) arrhythmogenesis is not well-established. To investigate the role of post-infarct inFAT in VT propensity. 24 post-infarct patients who underwent VT ablation were prospectively enrolled across two centers. For each patient, contrast-enhanced computed tomography (CE-CT), late gadolinium-enhanced magnetic resonance imaging (LGE-MRI), and substrate mapping during sinus rhythm were acquired. Voltage amplitude, deceleration zones (DZ) which represent regions of activation slowing, and substrate-based ablation locations were compared with the inFAT and scar distributions. To glean deeper insights into arrhythmogenic propensity, novel hybrid digital heart twins representing the patient-specific inFAT from CT and scar from MRI were reconstructed. VT circuits were then induced, assessed, and compared to mapping data (Fig.A). Combined inFAT and scar had lower voltage and exhibited stronger correlations with voltage amplitude than that of scar alone (0.76±0.56 vs. 1.19±0.47 mV, p<0.0005; r = -0.54 vs. -0.45). inFAT and scar exhibited greater isochronal crowding than scar alone (3(2) vs. 2(1) isochrones, p<0.0005). Most DZs consisted of combined inFAT and scar (71.1%) rather than scar alone. The amount of ablated inFAT was strongly correlated with ablated scar (r = 0.734, p<0.05). In the digital hearts, 140 VTs were induced. The total amount of inFAT, but not scar, was significantly associated with the number of VTs induced (p<0.05). For most VT circuits, the critical isthmus was comprised of both inFAT and scar (110/140 VTs) (Fig.B). In a multivariate regression adjusting for age, infarct age, and VT circuit tissue volume, inFAT remodeling within the VT circuit, but not scar, was a predictor of the amount of DZs (β = 0.355, p<0.05) and clinical ablations (β = 0.323, p<0.005) (Fig.B). Post-infarct inFAT remodeling creates a critical arrhythmogenic substrate for VT that needs to be prioritized during ablation.

PO-697-08 NEW ALGORITHM FOR MACHINE LEARNING-BASED PREDICTION OF 1-YEAR ALL-CAUSE MORTALITY IN PATIENTS UNDERGOING VENTRICULAR TACHYCARDIA ABLATION

Catheter ablation is an efficient therapy of patients with monomorphic ventricular tachycardia (VT). Due to their high, but heterogeneous mortality, there is a high demand for post-procedural risk assessment systems, which can predict the mortality of patients undergoing VT ablation.

Late Potential Abolition in Ventricular Tachycardia Ablation

Ventricular tachycardia (VT) substrate-based ablation has become the gold standard treatment for patients with structural heart disease-related VT. VT is linked to re-entry in relation to myocardial scarring, with areas of conduction block (core scar) and of slow conduction (border zone). Slow conduction areas can be detected in sinus rhythm as late potentials (LPs). LP abolition has been shown to be the best end point to avoid long-term recurrences. Our study aimed to analyze the challenges of LP abolition and the predictors of failure. We analyzed 169 consecutive patients with structural heart disease (61% ischemic cardiomyopathy, left ventricular ejection fraction: 37 ± 13%) who underwent VT ablation between 2013 and 2018. A preprocedural clinical evaluation, including cardiac magnetic resonance, was done in 66% of patients. Electroanatomical mapping with the identification of LPs was performed in all patients. Noninducibility was achieved in 71% (119), and complete LP abolition was achieved in 61% (103) of patients. Incomplete LP abolition was a powerful predictor of VT recurrence (67% vs 33%, hazard ratio 3.19 [2.1 to 4.7]; p <0.001). Lack of use of a high-density mapping catheter (odds ratio 6.2, 1.2 to 38.1; p=0.028), the septal substrate (odds ratio 9.34, 2.27 to 38.4; p=0.002), and larger left ventricular mass (190 ± 58 g vs 156 ± 46 g, p=0.002) were predictors of incomplete LP abolition. The main reasons that contributed to unsuccessful LP abolition were anatomic obstacles (such as the conduction system) and large extension of the LP area. In conclusion, incomplete LP abolition is related to VT recurrence. Lack of use of a high-density mapping catheter, the septal substrate, and larger left ventricular mass are related to incomplete LP abolition.

Endocardial Scar-Homogenization With vs Without Epicardial Ablation in VT Patients With Ischemic Cardiomyopathy.

In this study, the authors investigated the ablation success of scar homogenization with combined (epicardial+ endocardial) vs endocardial-only approach for ventricular tachycardia (VT) in patients with ischemic cardiomyopathy (ICM) at 5 years of follow-up. Best ablation approach to achieve long-term success rate in VT patients with ICM is not known yet. Consecutive ICM patients undergoing VT ablation at our center were classified into group 1: endocardial+ epicardial scar homogenization and group 2: endocardial scar homogenization. Patients with previousopen heart surgery were excluded. Epicardial ablation was performed despite being noninducible after endocardial ablation in all group 1 patients. All patients underwent bipolar substrate mapping with standard scar settings defined as normal tissue >1.5mV and severe scar<0.5mV. Noninducibility of monomorphic VT was the procedural endpoint in both groups. Patients were followed up every 4months for 5 years with implantable device interrogations. A total of 361 patients (group 1: n=70 and group 2: n=291) were included in the study. At 5 years, 81.4% (n=57/70) patients from group 1 and 66.3% (n=193/291) from group 2 were arrhythmia-free (P = 0.01) Of those patients, 26 of 57 (45.6%) and 172 of 193 (89.1%) from group 1 and group 2 respectively were on anti-arrhythmic drugs (AAD) (log-rank P < 0.001). After adjusting for age, sex, and obstructive sleep apnea, endo-epicardial scar homogenization was associated with a significant reduction in arrhythmia-recurrence (HR: 0.48; 95%CI: 0.27-0.86; P = 0.02). In this series of patients with ICM and VT, epicardial substrate was detected in all group 1 patients despite being noninducible after endocardial ablation. Moreover, combined endo-epicardial scar homogenization wasassociated with a significantly higher success rate at 5 years of follow-up and a substantially lower need for antiarrhythmic drugs after the procedure compared with the endocardial ablation alone.

Effect of VT Ablation on Time Between VT Storm and Heart Transplant

<h3>Purpose</h3> Ventricular arrhythmia occurs frequently in patients with advanced heart failure. The optimal treatment strategy is not well-characterized. We performed a retrospective study of patients with ventricular tachycardia (VT) storm who underwent heart transplant and compare the outcomes of those who received prior ablation to those who did not. <h3>Methods</h3> VT storm was defined as three or more episodes of sustained VT, with or without external defibrillation or appropriate implantable cardioverter-defibrillator therapy within 24 hours. Patients who underwent heart transplantation at UCSD between 2010 and 2021 (N=411) were screened for history of VT storm (n=34). Patients were then stratified by occurrence of VT ablation prior to transplant. We compared time to transplant and post-transplant survival using Chi square and Mann Whitney U tests. <h3>Results</h3> Of the 34 patients with VT storm, 14 underwent VT ablation and 20 did not. Median age was 63 years old. Patient demographics between the two groups were similar, except prevalence of chronic kidney disease stage ≥3 (70% vs 29%, p = 0.017) was higher in patients without VT ablation. Four patients expired during follow up, with no statistically significant difference between the two groups. Median time from VT storm to transplant was 206.5 days in those who underwent ablation compared to 66.5 days (p =0.046) in those who did not (Table 1). <h3>Conclusion</h3> In a single-center, retrospective study of patients with advanced heart failure and VT storm, VT ablation extended transplant-free survival without affecting mortality. Larger studies are needed to assess the optimal management strategy in this patient population.

National Trends In The Utilization Of Short-term Mechanical Circulatory Support Devices During Ventricular Tachycardia Ablation Related Hospitalizations

Background : Sparse data exists describing the characteristics of patients utilizing short term mechanical circulatory support (MCS) devices (intra-aortic balloon pumps, percutaneous ventricular assist devices, extracorporeal membrane oxygenation devices) during ventricular tachycardia (VT) ablation related hospitalizations. The purpose of this study was to characterize the demographics, in-hospital mortality, length of stay and hospital charges for MCS use. Methods : In this serial cross-sectional study, we analyzed all VT ablation related hospitalizations who received short-term MCS in the United States from 2010 to 2017 by using the Nationwide Readmission Database. Results : Among 384,742 hospitalizations with primary diagnosis of VT, 41,075 (10.7%) underwent ablation procedures (4,919 in 2010 to 5,349 in 2017). For those undergoing VT ablation procedures: mean age was 63.1 years, 22.5% were females, 56.9% Medicare insured, 31.0% private insured, 27.0% were elective admissions, unadjusted in-hospital mortality was 2.4%, mean length of stay was 6.6 days and mean hospitalization charge was $147,837. Among 41, 075 VT ablation hospitalizations, 2,479 (6.0%) required use of short term MCS and the utilization increased from 211 (4.3%) in 2010 to 364 (6.8%) in 2017, p<.05 (Figure 1). For these MCS requiring hospitalizations: mean age was 64.9 years, 9.7% were females, 67.1% Medicare insured, 22.1% private insured, 35.0% were elective admissions, unadjusted in-hospital mortality was 15.1%, mean length of stay was 12.9 days and mean hospitalization charge was $335,456. From 2010 to 2017, MCS group had following trends: mean age increased (63.4 years to 64.7 years), proportion of females decreased (14.7% to 6.6%), Medicare insured increased (64.9% to 69.0%), private insured decreased (28.6% to 22.9%) and proportion with elective admission status decreased (38.4% to 38.0%). From 2010 to 2017, unadjusted in-hospital mortality increased from 10.5% to 12.6% (p<.05), mean length of stay changed from 16.8 days to 11.2 days (p<0.05) and mean hospital charges increased from $251,637 to $386,952 (p<.05). Conclusions : Use of short-term MCS during VT ablation related hospitalizations in the United States increased rapidly and in-hospital mortality has remained high. Systematic and longitudinal collection of data in this high-risk group of patients is warranted to ensure improved outcomes in the future. : Sparse data exists describing the characteristics of patients utilizing short term mechanical circulatory support (MCS) devices (intra-aortic balloon pumps, percutaneous ventricular assist devices, extracorporeal membrane oxygenation devices) during ventricular tachycardia (VT) ablation related hospitalizations. The purpose of this study was to characterize the demographics, in-hospital mortality, length of stay and hospital charges for MCS use. : In this serial cross-sectional study, we analyzed all VT ablation related hospitalizations who received short-term MCS in the United States from 2010 to 2017 by using the Nationwide Readmission Database. : Among 384,742 hospitalizations with primary diagnosis of VT, 41,075 (10.7%) underwent ablation procedures (4,919 in 2010 to 5,349 in 2017). For those undergoing VT ablation procedures: mean age was 63.1 years, 22.5% were females, 56.9% Medicare insured, 31.0% private insured, 27.0% were elective admissions, unadjusted in-hospital mortality was 2.4%, mean length of stay was 6.6 days and mean hospitalization charge was $147,837. Among 41, 075 VT ablation hospitalizations, 2,479 (6.0%) required use of short term MCS and the utilization increased from 211 (4.3%) in 2010 to 364 (6.8%) in 2017, p<.05 (Figure 1). For these MCS requiring hospitalizations: mean age was 64.9 years, 9.7% were females, 67.1% Medicare insured, 22.1% private insured, 35.0% were elective admissions, unadjusted in-hospital mortality was 15.1%, mean length of stay was 12.9 days and mean hospitalization charge was $335,456. From 2010 to 2017, MCS group had following trends: mean age increased (63.4 years to 64.7 years), proportion of females decreased (14.7% to 6.6%), Medicare insured increased (64.9% to 69.0%), private insured decreased (28.6% to 22.9%) and proportion with elective admission status decreased (38.4% to 38.0%). From 2010 to 2017, unadjusted in-hospital mortality increased from 10.5% to 12.6% (p<.05), mean length of stay changed from 16.8 days to 11.2 days (p<0.05) and mean hospital charges increased from $251,637 to $386,952 (p<.05). : Use of short-term MCS during VT ablation related hospitalizations in the United States increased rapidly and in-hospital mortality has remained high. Systematic and longitudinal collection of data in this high-risk group of patients is warranted to ensure improved outcomes in the future.

Clinical, electroanatomic and electrophysiologic characterization and outcomes of catheter ablation for ventricular tachycardia following valvular intervention.

Ventricular tachycardia (VT) can occur following valvular interventions. There are limited data describing substrate and ablation approaches in such patients. We sought to describe the clinical, electrophysiologic, electroanatomic features and catheter ablation outcomes of patients with VT following aortic and/or mitral valve intervention. Over 12-years, consecutive patients with aortic valve replacement (AVR) and/or mitral valve replacement (MVR) or repair, undergoing VT ablation, were identified from two centers. Clinical and procedural parameters and outcomes are described. Twenty-three patients (age 66 ± 14years, 78% male, left ventricular ejection fraction 37 ± 16%), with prior AVR (mechanical n = 6, bioprosthetic n = 2, transcatheter n = 1), MVR (mechanical n = 5, bioprosthetic n = 1), mitral valve repair (n = 6) and both mechanical AVR and MVR (n = 2), underwent VT ablation. Sixteen had concurrent ischemic cardiomyopathy, 10 with prior bypass surgery. Left ventricular access was obtained in 21/23 (91%) patients (transseptal n = 14, retrograde aortic n = 5, transapical n = 2), with perivalvular scar identified in 17/21 (81%). Re-entrant VT isthmi involved the perivalvular regions in 12/23 (52%) patients, and regions remote from the valve in the remainder; 9% had nonscar-related VT. Intramural substrate was ablated from adjacent chambers in 5/23 (22%) patients and with half-normal saline irrigation in 8/23 (35%) patients. There were no instances of catheter entrapment. Following final ablation, VA-free survival was 78% at 13-months. Only half of VT circuits following valvular interventions involve the valve regions themselves, while the remainder involves unrelated regions. Catheter ablation is safe and efficacious at treating VT following valvular intervention, but novel strategies may be required.

Detailed Assessment of Low-Voltage Zones Localization by Cardiac MRIinPatients With Implantable Devices.

The purpose of this study was to assess the performance and limitations of low-voltage zones (LVZ) localization by optimized late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) scar imaging in patients with cardiac implantable electronic devices (CIEDs). Scar evaluation by LGE-CMR can assist ventricular tachycardia (VT) ablation, but challenges with electroanatomical maps coregistration and presence of imaging artefacts from CIED limit accuracy. A total of 10 patients underwent VT ablation and preprocedural LGE-CMR using wideband imaging. Scar was segmented from CMR pixel signal intensity maps using commercial software (ADAS-VT, Galgo Medical) with bespoke tools and compared with detailed electroanatomical maps (CARTO). Coregistration of EP and imaging-derived scar was performed using the aorta as a fiducial marker, and the impact of coregistration was determined by assessing intraobserver/interobserver variability and using computer simulations. Spatial smoothing was applied to assess correlation at different spatial resolutions and to reduce noise. Pixel signal intensity maps localized low-voltage zones (V<1.5mV) with area under the receiver-operating characteristic curve: 0.82 (interquartile range [IQR]: 0.76-0.83), sensitivity 74% (IQR: 71%-77%), and specificity 78% (IQR: 73%-83%) and correlated with bipolar voltage (r =-0.57 [IQR: -0.68 to-0.42]) across patients. In simulations, small random shifts and rotations worsened LVZ localization in at least some cases. The use of the full aortic geometry ensured high reproducibility of LVZ localization (r >0.86 for area under the receiver-operating characteristic curve). Spatial smoothing improved localization of LVZ. Results for LVZ with V<0.5mV were similar. In patients with CIEDs, novel wideband CMR sequences and personalized coregistration strategies canlocalize LVZ with good accuracy and may assist VT ablation procedures.

Acute and long-term outcomes of VT radiofrequency catheter ablation in patients with versus without an intramural septal substrate

IntroductionAim of this study was to evaluate efficacy and safety of ventricular tachycardia (VT) catheter ablation in patients with structural heart disease (SHD) in relation to the presence of an intramural septal substrate. MethodsConsecutive patients undergoing VT ablation between January 2019 and October 2020 were included. All patients were stratified based on the presence of relevant septal substrate and freedom from VT recurrences were analyzed. ResultsIn total, 199 consecutive patients (64.2 ± 13.0 years; 89% male; 55% ischemic cardiomyopathy (ICM)) undergoing VT ablation were included. 129/199 patients (65%) showed significant septal substrate (55/90 patients (61%) with non-ischemic cardiomyopathy (NICM) compared to 74/109 patients (68%) with ICM; p = 0.37). Acute procedural success with elimination of all inducible VTs was achieved in 66/70 patients (94%) without and in 103/129 patients (80%) with a septal substrate (p = 0.007). In the cohort including patients with a clinical FU, 15/60 patients (25%) without a septal substrate and 48/123 patients (39%) with a septal substrate experienced VT recurrence during a FU of 8.1 ± 5.9 months (p = 0.069). ConclusionPresence of septal VT substrate in patients with a structural heart disease or coronary artery disease is common. Acute success of VT catheter ablation was significantly higher and mid-term success tended to be higher in patients without a septal substrate.

Long-term outcome of endocardial-only versus combined endocardial-epicardial homogenization of the scar for treatment of ventricular tachycardia in patients with ischemic cardiomyopathy

Abstract Introduction We investigated the ablation success of scar homogenization with combined (epicardial + endocardial) versus endocardial-only approach for ventricular tachycardia (VT) in patients with ischemic cardiomyopathy (ICM) at 5 years of follow-up. Method Consecutive ICM patients undergoing VT ablation at our center were classified into group 1: endocardial scar homogenization and group 2: endocardial +epicardial scar homogenization. Patients with previous open heart surgery were excluded. All patients underwent bipolar substrate mapping with standard scar settings defined as normal tissue &amp;gt;1.5 mV and severe scar &amp;lt;0.5 mV. Non-inducibility of monomorphic VT was the procedural endpoint in both groups. Patients were followed up twice a year for 5 years with implantable device interrogations. Results A total of 361 (Group 1: 291 and group 2: 70) patients were included in the study (mean age: 67 years, male: 88.4%). At 5 years, significantly higher number of patients from group 2 remained arrhythmia-free (figure 1). Of those patients, 87 (45%) and 51 (89%) from group 1 and 2 respectively were off-anti-arrhythmic drugs (AAD) (p&amp;lt;0.001). After adjusting for age, gender, hypertension, diabetes, and obstructive sleep apnea, scar homogenization using endo-epicardial approach was associated with 51% less recurrence compared to the endocardial ablation strategy (Hazard Ratio: 0.49, 95% CI: 0.27–0.89, p: 0.02). Conclusion In this series of patients with ischemic cardiomyopathy and VT, endo-epicardial scar homogenization was associated with a lower need for AAD and a significantly lower recurrence rate at 5-years of follow-up compared to the endocardial ablation alone. Funding Acknowledgement Type of funding sources: None. Figure 1

Gender differences in patients with structural heart disease undergoing VT ablation

This study sought to examine gender differences in patients with structural heart disease (SHD) referred for ablation of ventricular tachycardia (VT). Female patients are often underrepresented in large studies. Significant differences in the clinical presentation, treatment, and prognosis of female patients have been described in previous studies. We investigated 88 female patients with SHD undergoing VT ablation (mean age 59 years, 56% nonischemic cardiomyopathy, mean left ventricular ejection fraction 35%, 82% in electrical storm). A case-control study with 88 male patients was performed and the results regarding clinical and procedural characteristics, acute and long-term results of the two groups were compared. The female patients had more arrhythmogenic substrate, as they more commonly presented with electrical storm (p = .016) and had a higher number of inducible VT morphologies during the procedure (p = .018). Moreover, the female patients were less likely to have an optimized heart failure medical treatment at baseline (p = .030) and required more time from the first manifestation of the VT to ablation referral (p = .034). Although fewer epicardial ablations were performed in female patients (p = .019), the two groups showed similar results regarding VT noninducibility as ablation endpoint (p = .844), major procedure-related complications (p = .719) and freedom from VT during follow-up (p = .268). Moreover, the overall mortality in the two groups was similar (p = .176). Advanced NYHA class was associated with worse transplant and assist-device-free survival in the female group. Female patients presenting for VT ablation had more arrhythmogenic substrate and were less likely to have an optimized heart failure medical treatment. Nevertheless, the procedural acute and long-term outcomes between the two genders were similar.