Incessant Ventricular Tachycardia Research Articles

Comparison of eplerenone and spironolactone treatment in patients with ischemic heart disease hospitalized due to ventricular tachycardia

Abstract Background The beneficial effects of mineralocorticoid receptor antagonists (MRAs) regarding sudden cardiac death (SCD) risk and cardiac remodeling are well known, moreover, they also reduce episodes of ventricular tachycardia (VT). However, superiority in effectiveness between receptor selective eplerenone and conventional spironolactone is unknown. Purpose Our aim was to assess the effect of eplerenone and spironolactone on ventricular tachycardia (VT) recurrence in patients with ischemic heart disease (IHD). Methods We collected data of 563 patients with IHD following hospitalization due to a sustained VT episode in a structured registry. Propensity score matching was performed based on age, hypertension, diabetes, history of acute myocardial infarction, left ventricular ejection fraction (LVEF) and presentation with incessant VT. The matched population consisted of 188 patients and was further analyzed. Predictors were assessed using univariate and multivariate Cox regression models. Kaplan-Meier curves were used for time-to-event analyses. Results The median age was 70 years with 81% being male. One third of the patients had an ICD implanted, while 43 (23%) had CRT. The median LVEF was 30%. Twenty-five (13%) patients presented with an electrical storm and 19 (10%) had incessant VT. In 86 cases (46%), the VT caused hemodynamic instability. Ablation was performed in 66 patients (35%), while 4 required mechanical circulatory support. During the median follow-up of 856 [399-1624] days, 69 patients had VT recurrence and 118 patients died. Eplerenone use significantly reduced the risk of VT recurrence compared to spironolactone (HR: 0.48 [0.29-0.78], log-rank p=0.003). This effect was consistent in the multivariate model as well (p=0.006). Conclusions Eplerenone use may be more beneficial in terms of VT recurrence in patients with IHD who present with a sustained VT. Further analysis is required to confirm these findings.

Unsupervised machine learning defines subgroups in ischemic heart disease patients presenting with ventricular tachycardia

Abstract Background Ventricular tachycardia (VT) in ischemic heart disease (IHD) is the leading cause of sudden cardiac death (SCD). Despite the well-defined recommendations, tailoring therapies individually is often a challenge owing to the great heterogeneity in this population. We hypothesized that unsupervised machine learning can uncover hidden patterns to identify patient subgroups with similar characteristics. Aims To use unsupervised machine learning methods on a database of patients with ischemic VT, to discover subgroups with similar characteristics and compare the survival of the identified groups. Methods We collected the data of 566 patients with IHD hospitalized for sustained monomorphic VT, excluding those with acute coronary syndrome. The 17 recorded features included medical history and echocardiography. All-cause mortality was registered with one-year follow-up. We performed dimension reduction using T-distributed Stochastic Neighbor Embedding (TSNE) to produce 3 dimensions of the data. Then, we applied spectral clustering to create three groups within the population. Each group was compared to the rest of the population for each variable. Finally, we compared the survival across the three groups using Kaplan-Meyer analysis, univariate Cox-regression, and Log-rank test. Results We identified three groups with distinct characteristics. Group 1 represented the healthiest population; patients had no previous VT hospitalizations, and none of HD instability, LBBB, SCD, diabetes, VT storm or ICD shocks; additionally, they always had a single VT episode at presentation. They showed better left ventricular ejection fraction (LVEF) (38% vs. 33%, p<0.001) and TAPSE (20 mm vs. 18 mm, p=0.01), less severe mitral and tricuspid regurgitation (MR, TR), smaller left ventricular end-systolic diameter, and longer DT. Conversely, patients in Group 2 (n=349) had more previous VT hospitalizations (30% vs. 18%, p=0,003), more often had diabetes (46% vs. 18%, p<0.001), left bundle branch block (23% vs. 13%, p=0.006), and more often presented with HD instability (47% vs. 28%, p<0.001). Group 3 contained all seriously ill patients with VT storm or incessant VT, more commonly presenting with ICD shocks (34% vs. 21%, p=0.004), SCD (24% vs. 15%, p=0.004), hemodynamic instability (50% vs. 37%, p=0.01). This group had the poorest LVEF (30% vs. 35%, <0.001) and TAPSE (17 mm vs. 19 mm p=0.001), more severe MR and TR, and the shortest DT (140 ms vs. 173 ms p<0.001). Finally, we compared survival across the three groups. Significantly better survival was found in Group 1 (HR: 0.52 CI [0.28 - 0.98]) and Group 2 (HR: 0.61 CI [0.42 - 0.88]), while Group 3 had higher mortality (HR: 2.7 CI [1.83 - 3.97]). Conclusions Using spectral clustering we identified three groups in our cohort of ischemic VT patients. This method delineates the group of ischemic VT patients with the highest risk of mortality who might need more aggressive treatment and closer follow-up.

Mid-term outcomes after stereotactic arrhythmia radioablation for refractory ventricular tachycardia

Abstract Introduction stereotactic arrhythmia radioablation (STAR) is used as a rescue treatment for refractory ventricular tachycardia (VT) originating from unreachable myocardial substrate following unsuccessful radiofrequency catheter ablation (RFCA). The mid-term outcomes of STAR, however, remain poorly known. Objective to report the mid-term efficacy and safety outcomes in our series of 21 patients (pts) treated by STAR over 6 years. Methods Inclusion of consecutive pts treated by STAR with a Cyberknife system between 2017 and 2023. 3D-electroanatomical maps (EAM) of the VT substrate during unsuccessful RFCA were used to delineate the planned target volumes (PTV) on a 4D CT scan. Patients were followed up at least every 6 months by echocardiography and ICD interrogation at the outpatient clinic. Results 21 pts [16 (76 %) male, age 66±8 years] with a mean LVEF of 40±15% were included. The underlying substrate was ischemic in 7 (33 %); non-ischemic dilated in 7 (33 %); inflammatory in 4 (19%); hypertrophic in 1 (5%); neoplasic in 1 (5%); and malignant mitral valve prolapse in 1 (5%). A dose of 21±2 Gray was delivered to the PTV (26 ml, IQR 18-43 ml). After a median follow-up of 39 [IQR, 14-48] months, 12 pts (57%) remained in stable condition, 1 (5%) underwent a heart transplantation, 1 (5%) a left ventricular assistance device, 1 (5%) was in an incessant slow VT and 6 (29%) pts died (3 from end stage heart failure). 15 (71%) pts presented VT recurrences [7 (33%) ATPs; 3 (14%) shocks; 4 (19%) VT storm and 1 (5%) with a well-tolerated slow VT (100 bpm) with an LVAD till transplantation, of whom 9 (43%) required redo RFCA. The median value of total ventricular arrhythmic burden (defined as any arrhythmia requiring ICD therapies) decreased significantly from 31 (IQR, 4-100) to 7 (IQR, 1-23) (p<0.05); for nsVT from 57 (IQR, 1.5- 1196) to 41 (IQR, 0.5-584) (p ns); or ICD shocks from 1.5 (IQR, 0-5.5) to 0 (IQR, 0-2) (p<0.05); for ATPs from 21 (IQR, 2.5-94) to 4 (IQR, 0.5-13) (p<0.05). Figure 1 shows a graphic representation of arrhythmic burden before and after STAR. Conclusion in this cohort of highly selected pts with refractory VT, STAR significantly reduced the arrhythmic burden by a factor of 4 over a 3-year follow-up. Death rate remained high (29%), mostly by terminal heart failure. Nevertheless, a high proportion of pts had VT recurrences that were successfully managed by redo RFCA.VT burden before and after STAR

Real World Data from Catheter Ablation of Ventricular Tachycardias and Premature Ventricular Complexes in a Tertiary Care Center.

Background: Catheter ablation in patients with ventricular arrhythmias (VA), such as ventricular tachycardias (VT) or frequent premature ventricular complexes (PVC), is increasingly considered an effective and safe therapy when performed in experienced centers. This study sought to determine acute success rates and complication rates of ablation procedures for patients with VA in a Swiss tertiary care center. Methods: All patients who underwent ablation therapy for VT and PVC at the University Heart Center in Zurich, Switzerland, between March 2012 and April 2017 were included in this analysis. Results: A total of 120 patients underwent catheter ablation for VT and PVC (69 and 51, respectively). Seventy percent of patients were male, and the mean age was 55.3 years. The most common indication for ablation was high PVC burden (47.5%), followed by paroxysmal VT (38.3%), ICD shocks (23.3%), incessant VT (12.5%), electrical storm (7.5%), and syncope (3.3%). Acute success rates for VT and PVC ablations were 94.2% and 92.2%, respectively. Rates for complications (including major and minor) for VT and PVC were 10.1% and 7.8%, respectively. Complications occurred only in patients with structural heart disease; no complications were noted in structurally normal hearts. Conclusions: Our results suggest that catheter ablation for VT and PVC has high acute success rates with a reasonable risk for complications in the setting of tertiary care centers, comparable to those reported in other studies.

Machine-Learning-Based Prediction of 1-Year Arrhythmia Recurrence after Ventricular Tachycardia Ablation in Patients with Structural Heart Disease.

Ventricular tachycardia (VT) recurrence after catheter ablation remains a concern, emphasizing the need for precise risk assessment. We aimed to use machine learning (ML) to predict 1-month and 1-year VT recurrence following VT ablation. For 337 patients undergoing VT ablation, we collected 31 parameters including medical history, echocardiography, and procedural data. 17 relevant features were included in the ML-based feature selection, which yielded six and five optimal features for 1-month and 1-year recurrence, respectively. We trained several supervised machine learning models using 10-fold cross-validation for each endpoint. We observed 1-month VT recurrence was observed in 60 (18%) cases and accurately predicted using our model with an area under the receiver operating curve (AUC) of 0.73. Input features used were hemodynamic instability, incessant VT, ICD shock, left ventricular ejection fraction, TAPSE, and non-inducibility of the clinical VT at the end of the procedure. A separate model was trained for 1-year VT recurrence (observed in 117 (35%) cases) with a mean AUC of 0.71. Selected features were hemodynamic instability, the number of inducible VT morphologies, left ventricular systolic diameter, mitral regurgitation, and ICD shock. For both endpoints, a random forest model displayed the highest performance. Our ML models effectively predict VT recurrence post-ablation, aiding in identifying high-risk patients and tailoring follow-up strategies.

Surgery for ventricular tachycardia originating from the left ventricular summit.

Ventricular tachycardia (VT) originating from the left ventricular summit region, the most superior region of the left ventricle surrounded by the major coronary arteries and veins, is frequently refractory to pharmacological therapies and endocardial and epicardial catheter ablation. Eleven patients with an age from 31 to 79 (median 56) years old, underwent map-guided surgery for left ventricular summit VT. All patients had undergone 1-5 unsuccessful sessions of catheter ablation for incessant VT, preoperatively. Five patients had suffered VT storm and 1 had a history of cardiopulmonary resuscitation. Four patients had implanted with a defibrillator. Epicardium to endocardium transmural cryothermia was applied at the VT origin determined by intraoperative epicardial mapping with electro-anatomical mapping system. Harmonic scalpel was used to remove the epicardial fat and cryothermia was applied directly to the myocardium, avoiding thermal or mechanical injuries to the coronary vessels. Additional endocardial cryothermia at the VT origin was performed by a cryoprobe introduced into the left ventricular cavity through an aortotomy. There was no surgical mortality or long-term mortality related to VT during a median follow-up period of 60 months (interquartile range: 34-82). Five-year freedom from preoperatively documented left ventricular summit VT and non-documented VT was 91% and 73%, respectively. All the patients with postoperative VT underwent successful catheter ablation. Other patients were free from VT during the follow-up period. Epicardial to endocardial transmural cryothermia at the VT origin guided by intraoperative electro-anatomical mapping with a close collaboration with electrophysiologists was crucial in successful surgery for left ventricular summit VT.

A Case of Life-threatening Vasospastic Angina Induced by Carteolol Eye Drops.

Vasospastic angina (VSA) can be worsened by oral nonselective beta-blockers. Ophthalmic carteolol eye drops are non-selective beta blockers and effective against glaucoma and ocular hypertension. Systemic effects of ophthalmic beta blockers on VSA have not yet been reported. We herein report a case of VSA that developed after a patient started carteolol eye drops for ocular hypertension. Even though benidipine, a calcium channel blocker. was started, a VSA attack with incessant non-sustained ventricular tachycardia occurred. Once the carteolol eyedrops were discontinued, the VSA resolved. This case demonstrates that carteolol eye drops can induce life-threatening VSA.

Incessant septal ventricular tachycardia in patient with hypertrophic cardiomyopathy after failed unipolar and bipolar ablation. Is ethanol septal ablation a solution?

Incessant septal ventricular tachycardia in patient with hypertrophic cardiomyopathy after failed unipolar and bipolar ablation. Is ethanol septal ablation a solution?

P242 CARDIOGENIC SHOCK WITH ISCHEMIC PHENOTYPE SECONDARY TO INCESSANT VENTRICULAR TACHYCARDIA: A CALL FOR IMPLEMENTATION OF HUB–AND–SPOKE MODEL

Abstract A 55–years–old patient presents to emergency room with extensive anterior STEMI, complicated by acute pulmonary edema. The ECG showed sinusal tachycardia, Q waves in V1–V3, ST elevation >2mm V2–V6. The echocardiogram showed akinesia of the apex and anterolateral wall with severe reduction of contractile function (LVEF 30%). The patient was treated with CPAP, dual antiplatelet therapy and diuretics; the urgent coronary angiography showed three–vessel disease with occlusion of the proximal LAD, treated with PCI and two drug–eluting stents implantation. 48 after admission to ICU, the patient developed "combined" shock (IC↓ RVS↓ WP↑), sustained by both severe cardiac dysfunction and a septic complication, requiring inotropes and targeted antibiotic therapy (noradrenaline 0.02 gamma/Kg/min and piperacillin/tazobactam i.v). At 96 hours there was a recovery of contractile function and haemodynamics (CI from 1.8 to 2.7). Weaned from inotropes, he began therapy with low doses of ACE inhibitor, beta blocker, antialdosteronic. On the 7th day of hospitalization, without ischemic and/or electrolyte "triggers", the patient developed "arrhythmic storm" with incessant sustained ventricular tachycardias. Arrhythmias persisted despite antiarrhythmics (magnesium sulfate, amiodarone, lidocaine), IOT, sedation, mechanical ventilation. The temporary pacemaker for overdrive pacing was placed in. After placement of IABP, the patient underwent revascularization of residual coronary artery stenosis. Despite 1 hour of assistance (ABLS), incessant ventricular tachycardia persisted; a third–level center for VA–ECMO inside support was called. After positioning VA–ECMO there was progressive clinical stabilization and –concomitantly– a progressive reduction of ventricular tachycardias. ECMO support was needed for over 7 days due to persistence of arrhythmic storm; it was slowly weaned with stabilization of the patient; an AICD was implanted. Residual function of the left ventricle was mild reduced (LVEF40%) despite protracted CPR. There wasn’t residual cognitive impairment. Implementation of multidisciplinary teams in the spoke centers would improve protocols and early treatments in patients with cardiogenic shock; spoke centers would provide early access to life–saving therapies and safe transfer to hub centers.

Single beta-blocker or combined amiodarone therapy in implantable cardioverter-defibrillator and cardiac resynchronization therapy—defibrillator patients: Insights from the German DEVICE registry

Because of its antiarrhythmic potency and due to the lack of alternatives, amiodarone is often used for antiarrhythmic therapy in patients with implantable cardioverter-defibrillator (ICD) or cardiac resynchronization therapy-defibrillator systems. To date, robust data on the safety and clinical benefit of amiodarone therapy in these patients are missing. The purpose of this study was to assess the periprocedural and postprocedural outcomes of combined therapy with beta-blockers plus amiodarone compared to treatment with single beta-blockers in the "real-life" cohort of ICD recipients of the German DEVICE registry. A total of 4499 patients who underwent ICD implantation, revision, or upgrade in 49 centers participating in the German DEVICE registry were enrolled from March 2007 to February2014. Amiodarone had no significant effect on the success of defibrillation testing. Early implantation-associated complications were similar between the groups. However, 1-year overall mortality was significantly higher in the beta-blocker plus amiodarone cohort (adjusted hazard ratio 2.09; P <.001). Interestingly, among the surviving patients, amiodarone was not associated with a significantly reduced risk of ICD discharges or syncopal events. Furthermore, the occurrence of ventricular tachycardia (VT) storm or incessant VTs and the number of patients scheduled for intracardiac ablation did not differ among both groups, whereas the rate of rehospitalization was lower in the cohort with only beta-blockers. Although amiodarone has no adverse effect on the success of defibrillation testing, our data suggest an increased all-cause mortality under amiodarone therapy, especially in the subgroups of patients with sinus rhythm or severely reduced left ventricular function. In surviving patients, rates of arrhythmic events were comparable.

Abstract 14332: Syncope, Storm, and Shock: Fulminant Myocarditis

A 46-year-old female with prediabetes and recent hysterectomy three weeks prior presented to the hospital for syncope. Patient reported no chest pain or dyspnea but complained of intermittent palpitations. The patient developed runs of non-sustained ventricular tachycardia which quickly escalated into incessant ventricular tachycardia (VT). Unresponsive to maximal medical therapy, the patient was cardioverted, intubated and sedated. Electrocardiogram was obtained which showed ST segment elevation in V1 and V2 without reciprocal changes. Bedside point-of-care ultrasound was negative for wall motion abnormalities. Laboratory results were significant for normal electrolytes, elevated troponins peaking at 7.14 ng/mL the following morning, and lactic acid of 3.2 mmol/L. Patient was initiated on vasopressor and ionotropic support for suspected shock. Left heart catheterization was negative for obstructive coronary artery disease. Right heart catheterization revealed mild pulmonary hypertension and biventricular failure. Formal echocardiogram revealed mid-range ejection fraction with a small pericardial effusion. The patient’s clinical status was deteriorating and revealed multiorgan failure. In conjunction with advanced heart failure and mechanical circulatory support teams, veno-arterial extracorporeal membrane oxygenation was initiated with subsequent implantation of intra-aortic balloon pump. High-dose steroids were given while awaiting transfer to a quaternary center. The patient is currently being evaluated for endomyocardial biopsy and evaluation of left ventricular assist device or heart transplantation due to fulminant myocarditis (FM). FM requires early recognition, intensive support, and further investigation for optimal management.

Abstract 11589: Total Artificial Heart Placement in a Case of Recurrent Ventricular Tachycardia Storm

Background: Electrical storm is defined as three or more episodes of sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) within a 24-hour period requiring termination by cardioversion, anti-tachycardia pacing (ATP) or defibrillation. It can be a particularly challenging syndrome to treat when refractory to standard of care therapies, which include antiarrhythmics, sedation, and ablation. We present a case of refractory electrical storm requiring total artificial heart placement (TAH) as a bridge to transplant. Case: A 65-year-old male with a history of idiopathic non-ischemic cardiomyopathy presented with VF arrest. After return of spontaneous circulation, he was admitted to the cardiac intensive care unit. Implantable cardioverter defibrillator (ICD) interrogation showed 38 shocks delivered over the prior two-week period. Coronary angiography showed no obstructive coronary disease and an intraaortic balloon pump (IABP) was placed for cardiogenic shock. He was intubated and sedated on fentanyl and propofol. He continued to have episodes of VT despite treatment with lidocaine, procainamide, and amiodarone drips. Further trials of paralysis and left stellate ganglion nerve block did not suppress his VT. Since the patient was refractory to all prior interventions, was deemed too unstable for VT ablation, and had a prolonged anticipated wait time for heart transplant, he underwent TAH placement as a bridge to heart transplant. He recovered well and eventually underwent successful heart transplant. Discussion: Management of electrical storm requires a stepwise approach including administration of antiarrhythmics, sedation, mechanical hemodynamic support, and catheter ablation. Our patient had incessant VT despite exhaustive medical and supportive therapies, but was too unstable to undergo VT ablation. In cases of refractory VT storm, definitive treatment with heart transplantation must be considered, but bridging patients to transplant poses a challenge. Our patient underwent TAH placement and was successfully stabilized prior to transplant. In centers with this capability, TAH should be recognized as a legitimate option in the pathway for VT, particularly with a long anticipated wait time for heart transplant.

Stereotactic Radioablation for Ventricular Tachycardia in the Setting of Electrical Storm.

Stereotactic body radiotherapy (SBRT) has been reported as a safe and efficient therapy for treating refractory ventricular tachycardia (VT) despite optimal medical treatment and catheter ablation. However, data on the use of SBRT in patients with electrical storm (ES) is lacking. The aim of this study was to assess the clinical outcomes associated with SBRT in the context of ES. This retrospective study included patients who underwent SBRT in the context of ES from March 2020 to March 2021 in one tertiary center (CHU Lille). The target volume was delineated according to a predefined workflow. The efficacy was assessed with the following end points: sustained VT recurrence, VT reduced with antitachycardia pacing, and implantable cardioverter defibrillator shock. Seventeen patients underwent SBRT to treat refractory VT in the context of ES (mean 67±12.8 age, 59% presenting ischemic heart disease, mean left ventricular ejection fraction: 33.7± 9.7%). Five patients presented with ES related to incessant VT. Among these 5 patients, the time to effectiveness ranged from 1 to 7 weeks after SBRT. In the 12 remaining patients, VT recurrences occurred in 7 patients during the first 6 weeks following SBRT. After a median 12.5 (10.5-17.8) months follow-up, a significant reduction of the VT burden was observed beyond 6 weeks (-91% [95% CI, 78-103]), P<0.0001). The incidence of implantable cardioverter defibrillator shock and antitachycardia pacing was 36% at 1 year. SBRT is associated with a significant reduction of the VT burden in the event of an ES; however, prospective randomized control trials are needed. In patients without incessant VT, recurrences are observed in half of patients during the first 6 weeks. VT tolerance and implantable cardioverter defibrillator programming adjustments should be integrated as part of an action plan defined before SBRT for each patient.

Clinical Outcomes in Patients With Dilated Cardiomyopathy and Ventricular Tachycardia

BackgroundRecurrent ventricular tachycardia (VT) due to dilated cardiomyopathy (DCM) is difficult to treat, and long-term outcome data are limited. ObjectivesThe aim of this study was to identify predictors of mortality or heart transplantation (HTx) and VT recurrence. MethodsConsecutive patients with DCM accepted for radiofrequency catheter ablation (RFCA) of VT at 9 centers were prospectively enrolled and followed. ResultsOf 281 consecutive patients (mean age 60 ± 13 years, 85% men, mean left ventricular ejection fraction [LVEF] 36% ± 12%), 35% had VT storm, 20% had incessant VT, and amiodarone was unsuccessful in 68%. During follow-up of 21 months (IQR: 6-30 months), 67 patients (24%) died or underwent HTx, and 138 (49%) had VT recurrence (45 within 30 days, defined as early); the 4-year rate of VT recurrence or mortality or HTx was 70%. Independent predictors of mortality or HTx were early VT recurrence (HR: 2.92; 95% CI: 1.37-6.21; P < 0.01), amiodarone at discharge (HR: 3.23; 95% CI: 1.43-7.33; P < 0.01), renal dysfunction (HR: 1.92; 95% CI: 1.01-3.64; P = 0.046), and LVEF (HR: 1.36; 95% CI: 1.0-1.84; P = 0.052). LVEF ≤32% identified patients at risk for mortality or HTx (area under the curve: 0.75). Mortality or HTx per 100 person-years was 40.4 events after early, compared with 14.2 events after later VT recurrence and 8.5 events with no VT recurrence after RFCA (P < 0.01 for both). Patients with early recurrence and LVEFs ≤32% had a 1-year rate of mortality or HTx of 55%. VT recurrence was predicted by prior implantable cardioverter-defibrillator shocks, basal anteroseptal VT origin, and procedural failure but not LVEF. ConclusionsPatients with DCM needing RFCA for VT are a high-risk group. Following RFCA, approximately one-half remain free of VT recurrence. Early VT recurrence with LVEF ≤32% identifies those at very high risk for mortality or HTx, and screening for mechanical support or HTx should be considered. Late VT recurrence after RFCA does not predict worse outcome.

Factors predicting repeated ablation in ventricular tachycardia patients

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Heart Program Background Catheter ablation has emerged to be the principal treatment for recurrent ventricular tachycardia (VT). Previously, several predictors of VT recurrence have been described, such as LVESD, severe MR, incessant VT, ICD shocks and elevated LDH levels. However, factors predicting an additional ablation are unknown. Purpose We aimed to establish predictors of repeat ablation and compare to the predictors of ventricular arrhythmia recurrence during 1-year follow-up in structural heart disease. Methods Baseline medical history, laboratory results, imaging parameters, clinical properties of VTs, and procedural data were gathered in a structured database. Results Out of the 272 patients, 96 (35%) experienced recurrence and 36 (13%) had repeated procedures within 1 year. Independent predictors of recurrence were left ventricular end systolic diameter (HR = 1.516, p=0.015), severe mitral regurgitation (HR = 2.446, p = 0.002), incessant VT (HR = 1.64, p = 0.02), VT inducibility (HR = 3.71, p = 0.003), ICD shocks (HR = 1.95, p = 0.002) and elevated LDH levels (HR = 1.26, p = 0.003). Regarding redo ablation, elevated LDH level (HR = 1.64, p = 0.01), incessant VT (HR = 2.94, p &amp;lt; 0.001), ICD shocks (HR = 2.38, p = 0.02), only exit point ablation (HR = 2.14, p = 0.023) were independent predictors, while hypertension (HR = 0.32, p = 0.03), longer transmitral E-wave deceleration time (HR = 0.47, p = 0.04), substrate modification (HR = 0.47, p = 0.044) were protective. Conclusion Predictors of repeat ablation overlap only partially with those of VT recurrence. Predictors implying higher risk VT episodes predict both recurrence and repeat ablation while factors associated with more severe left ventricular systolic dysfunction predict recurrence but not a redo procedure.

Non-invasive delineation of ventricular tachycardia substrates for cardiac stereotactic body radiotherapy: utility of in-silico pace-mapping

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): EPSRC Background Cardiac stereotactive body radiotherapy (CSBRT) is an emerging, non-invasive ablation modality that targets ventricular tachycardia (VT) substrates in patients with limited conventional treatment options. Success of CSBRT hinges primarily on the correct identification of VT targets, which requires non-invasive planning. Current non-invasive, pre-procedure strategies employ multi-electrode electrocardiographic imaging (ECGi). Given its significant cost and potential challenges in detecting endocardial, intramural and/or septal VT sites, there is a need to optimise VT delineation strategies for CSBRT; patient-specific simulations may show promise at guiding such planning non-invasively. Purpose We aim to perform non-invasive, in-silico pace-mapping on an image-based computational model to identify VT substrates for CSBRT. We intend to show the utility of our fast computational pipeline - relying on CT imaging data only - to provide further insights on inaccessible, scar-related VT episodes. Methods A detailed computational torso model of a CSBRT candidate with incessant VT was generated from CT imaging data. Extracellular content volumes (ECVs) were used to identify different tissue types (healthy, border zone and non-conducting), and scale model tissue conductivities accordingly. In-silico pace-mapping was performed by simulating ~360 paced beats across the LV, and computing corresponding 12-lead ECGs within a fast electrophysiological (EP) simulation environment combining reaction-eikonal and lead field methods. QRS complexes from simulated paced beats were used to construct the virtual correlation pace-map against the measured QRS of the clinically-induced VT, along with a ‘reference-less’ virtual pace-map constructed from neighbouring paced-beat QRSs (within a 20 mm radius). An epicardial activation map of the clinically-induced VT was reconstructed from ECGi measurement, and used for comparison against our virtual pace-maps. Results Correlations between simulated paced-beat QRS complexes and the clinically-induced VT QRS were higher in mid-apical, infero-septal segments - segment 9 (85.71%), 10 (87.95%) and 15 (89.58%) - identifying septal origin and pathway of the induced re-entrant circuit. A possible septal VT isthmus was also identified by a high gradient in the virtual reference-less pace-map in segment 9 (&amp;gt; 2.5%/mm). Our in-silico predictions were in agreement with the clinical regions identified for CSBRT (segment 9 and 15), and provided additional information on the 3D and septal dynamics of the VT episode. Conclusions Our in-silico pace-mapping study successfully localised VT substrates in a patient unable to receive standard ablative procedures, and provided further clinical insight on the induced VT dynamics. Our rapid in-silico pace-mapping approach may be utilised to support optimal identification of VT target volumes for CSBRT.

The outcome spectrum for Dilated Cardiomyopathy and Ventricular Tachycardia: results from the prospective, multicenter, DCM-VT ablation study

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): The study was partially supported by an investigator initiated grant from Biosense Webster (a Johnson &amp; Johnson company) Background Recurrent sustained ventricular tachycardia (VT) due to nonischemic dilated cardiomyopathy (DCM) is difficult to treat and long-term outcome data are limited. Objective We aimed to identify predictors for mortality or heart transplantation (MHT) and VT recurrence. Methods Consecutive DCM patients accepted for VT catheter ablation (RFCA) in 9 centers were prospectively enrolled and followed. Results Of 281 consecutive patients (age 60±13yrs, 85% men, LVEF 36±12%) 35% had VT storm, 20% incessant VT, and 68% failed amiodarone. During a median follow-up of 21 (IQR 6-30) months after RFCA (epicardial in 58%, no RFCA due to inaccessible target in 6.4%), 67(24%) patients died/underwent HT and 138(49%) had VT recurrence (45 within 30 days defined as early); the cumulative 4-year rate of VT or MHT was 70% and of MHT 38%. In multivariable analysis predictors of MHT were early VT recurrence (HR 2.92 (CI1.37-6.21), p&amp;lt;0.01), amiodarone at discharge (HR 3.23 (CI1.43-7.33, p&amp;lt;0.01), renal dysfunction (HR 1.92 (CI1.01-3.64), p=0.046), and LVEF (HR 1.36 (CI 1.0-1.84), p=0.052). A LVEF ≤32% was the optimal threshold to identify patients at risk for MHT (AUC 0.75). MHT per 100 person-years was 40.4 after early VT recurrence and significantly higher, compared to 14.2 after later VT recurrence and to 8.5 after RFCA with no VT recurrence (both p&amp;lt;0.01). Mortality rates for patients with VT recurrence after 30 days were not significantly higher than for patients with no VT recurrences Patients with early recurrence and LVEF≤32% had a 1-year MHT rate of 55% (figure). VT recurrence was predicted by prior ICD shocks, basal antero-septal VT origin, and procedural failure but not LVEF. Conclusion DCM patients needing RFCA for VT are a high-risk group. Following RFCA half remain free of VT recurrences. Early VT recurrence with LVEF&amp;lt;0.32 identifies those with a very high risk and screening for mechanical support/ HT should be considered. Late VT recurrence after RFCA does not predict worse outcome.

Long-term impact of activation circuit-based ventricular tachycardia ablation on ventricular arrhythmia burden

Abstract Funding Acknowledgements Type of funding sources: None. Background Ventricular arrhythmias (VA) are a major cause of morbidity and mortality in heart failure patients. Ventricular tachycardia (VT) ablation is an established treatment for the reduction of recurrent implantable cardioverter-defibrillator (ICD) therapies in this population. In patients with substrate-related VT, mapping of the entire tachycardia circuit, when feasible, may allow for more accurate targeting of the clinical VT. Purpose To assess the long-term impact of catheter ablation based on activation mapping of substrate-related VT on VA burden. Methods Consecutive patients submitted to VT ablation between January 2013 and October 2021 were included. A comprehensive review of clinical records and device monitoring was performed to assess VA burden, defined as all ICD therapies and clinically documented VTs, before and after ablation. The primary outcome was reduction in the overall burden of VA after ablation. The impact of ablation on VA burden was assessed by fixed-effects Poisson regression; comparison at fixed time intervals was performed with a paired-sample Wilcoxon signed-rank test (STATA 12, JASP). Results A total of 134 VT ablation procedures were performed during the study period. Of these, there were 21 procedures where complete mapping of the VT activation circuit was achieved, corresponding to 18 patients. Mean age was 56.7 years, 88% male sex, mean left ventricular ejection fraction 39 ± 13%, BNP 540 ± 627 pg/mL. Etiology was ischemic in 44%, non-ischemic dilated cardiomyopathy in 39%, arrhythmogenic right ventricular dysplasia in 11% and hypertrophic cardiomyopathy in 6%. Mechanical support was in situ in 3 patients (two with temporary VA ECMO and one with LVAD as destination therapy); all but one patient had an ICD. Procedural duration was 209 ± 61 minutes. One patient developed complete AV block; no other peri-procedural complications were observed. During follow-up two patients died due to heart failure, one patient died from refractory cardiogenic shock with refractory incessant VT and one patient underwent orthotopic heart transplant. The mean follow-up time after ablation was 2.2 ± 1.9 years. A significant reduction in VA burden was observed (Figure 1) at 3 months (92.5% reduction, p=0.002) and 6 months after ablation (83.3% reduction, p=0.041). After fixed-effects Poisson regression, there was an estimated long-term reduction of 75% (CI 12-93%, p=0.031) of VA burden after VT circuit ablation. Conclusion Targeted circuit ablation is feasible in a subset of patients referred to VT ablation and leads to a significant sustained decrease in VA burden and device therapies.

CA-533-02 STANDARD CARDIAC RADIOABLATION DOSE (25 GRAY) DOES NOT CAUSE MYOCYTE INJURY OR NEW FIBROSIS

Noninvasive cardiac radioablation (CRA) is an emerging therapy for refractory ventricular tachycardia (VT). Focused radiation to the heart is expected to cause local myocardial destruction with replacement fibrosis (ablation effect). The extent this effect in humans is unknown. To measure the CRA ablation effect with serial serum biomarkers and late gadolinium enhanced cardiac MRI (LGE-CMR). Single-center, IRB-approved case series of patients with refractory VT (ENCORE-VT NCT02919618). Patients without contraindication underwent LGE-CMR and blood draws at three timepoints: before treatment, 3 days, and 3 months after treatment. Left ventricle (LV) scar burden was assessed using semi-automatic contouring (Medis, Netherlands), blinded to location of radioablation. Global and segmental scar burden (%) was compared across timepoints. Segments targeted for radioablation (25 Gray) were compared to surrounding and off-target segments. Blood samples were analyzed for high-sensitivity troponin-I (Tn-I, marker of myocyte injury) and galectin-3 (Gal3, marker of fibroblast activation and fibrosis). 7 patients were included for analysis: mean age 64 years, 14% female, 57% nonischemic cardiomyopathy, 86% with history of VT storm, mean LVEF 32% (range 19-58%). Mean number of cardiac segments targeted for radioablation was 4 (range 3-8), resulting in mean cardiac treatment volume (CTV) 29 cm3 and planning treatment volume (PTV) 114 cm3. Mean scar burden at baseline was 49% (range 29-68%). Changes in scar burden at 3 days and 3 months were -0.4% (IQR = 5.5%) and 3.3% (IQR = 3%). Segment-by-segment analysis (Figure 1) showed no significant scar progression in segments targeted for radioablation (mean 68% to 68% to 71%), segments surrounding the target (43% to 44% to 47%), or off-target segments (44% to 42% to 46%). Serum Tn-I and Gal3 were not significantly changed (Figure 2). Compared to VT burden before treatment, all 7 patients had substantial reduction 6 months after treatment (4 had > 95% burden reduction, 1 had resolution of incessant slow VT). Despite improvement in VT burden, there was no appreciable cardiac injury or replacement fibrosis after CRA with 25 Gray. The mechanism of early VT control with cardiac radioablation is not myocyte injury or fibrosis.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Heart Transplant As Therapy For An Unresectable Recurrent Cardiac Fibroma

<h3>Introduction</h3> Cardiac fibromas (CF) have a reported incidence of 0.03-0.32% and have an excellent prognosis. Most cardiac tumors are found incidentally, and symptoms are related to location and size. Most CF are amenable to surgical removal, but some are deemed unresectable due to their size and/or invasion of vital cardiac structures that warrant heart transplants. <h3>Case Report</h3> 66-year-old male with a history of prior cardiac fibroma resection at age 13, followed by dual-chamber pacemaker insertion due to complete heart block and recent ventricular tachycardia ablation. He came to our facility for a second opinion regarding heart transplants because he was previously considered high-risk by another facility. Echo showed an EF of 55%, with CF noted on the anterior wall. Heart CT reported a LV anterior wall mass measuring 6 × 8.5 × 8.9 cm, markedly displacing the LAD and first diagonal with a non-hypermetabolic mass on PET scan. He was presented during our multidisciplinary team rounds; the decision was to proceed with biopsy of the left ventricular cardiac mass showing CF with abundant collagen in the stroma separating the tumor cells (Figure 1A), and the CF is composed of slender spindle cells admixed with undulant and wavy collagenized stroma. No nuclear pleomorphism or mitotic activity is present (Figure 1B). Postoperatively, the patient developed incessant VT requiring amiodarone and lidocaine. EP was consulted, and due to prior VT ablation and limited options, the patient was listed for an orthotopic heart transplant (OHT). He underwent successful OHT without complications. The explanted heart has a whorled, well-circumscribed, tan appearance mass measuring 14 × 10 × 9 cm involving the LV, the interventricular septum, and epicardium (Figure 2). <h3>Discussion</h3> Cardiac fibromas are connective tissue tumors that originate from fibroblasts, typically grossly well demarcated. CF are considered benign tumors, but they are well known to be the most common arrhythmogenic tumors than other cardiac tumors; It is essential that cardiologists be aware of CF presentation, diagnosis and treatment. Careful selection of potential candidates based on patient characteristics, type of tumor, and life-threatening complications for OHT by a multidisciplinary team is imperative in such complex cases. We report a case that required orthotopic heart transplantation due to incessant ventricular tachycardia secondary to recurrent unresectable fibroma.