Ventricular Tachycardia In Patients Research Articles

Impact of substrate-based ablation for ventricular tachycardia in patients with frequent appropriate implantable cardioverter-defibrillator therapy and dilated cardiomyopathy: Long-term experience with high-density mapping

IntroductionRecurrent ventricular tachycardia (VT) episodes have a negative impact on the clinical outcome of implantable cardioverter-defibrillator (ICD) patients. Modification of the arrhythmogenic substrate has been used as a promising approach for treating recurrent VTs. However, there are limited data on long-term follow-up. AimTo analyze long-term results of VT substrate-based ablation using high-density mapping in patients with severe left ventricular (LV) dysfunction and recurrent appropriate ICD therapy. MethodsWe analyzed 20 patients (15 men, 55% with non-ischemic cardiomyopathy, age 58±15 years, LV ejection fraction 32±5%) and repeated appropriate shocks or arrhythmic storm (>2 shocks/24 h) despite antiarrhythmic drug therapy and optimal heart failure medication. All patients underwent ventricular programmed stimulation (600 ms/S3) to document VT. A sinus rhythm (SR) voltage map was created with a three-dimensional electroanatomic mapping system (CARTO, Biosense Webster, CA) using a PentaRay® high-density mapping catheter (Biosense Webster, CA) to delineate areas of scarred myocardium (ventricular bipolar voltage ≤0.5 mV – dense scar; 0.5-1.5 mV – border zone; ≥1.5 mV – healthy tissue) and to provide high-resolution electrophysiological mapping. Substrate modification included elimination of local abnormal ventricular activities (LAVAs) during SR (fractionated, split, low-amplitude/long-lasting, late potentials, pre-systolic), and linear ablation to obtain scar homogenization and dechanneling. Pace-mapping techniques were used when capture was possible. The LV approach was retrograde in nine cases, transseptal in five and epi-endocardial in four. In two patients ablation was performed inside the right ventricle. ResultsLAVAs and scar areas were modified in all patients. Mean procedure duration was 149 min (105-220 min), with radiofrequency ranging from 18 to 70 min (mean 33 min) and mean fluoroscopy time of 15 min. Non-inducibility was achieved in 75% of cases (in four patients with hemodynamic deterioration and an LV assist device, VT inducibility was not performed). There were two cases of pericardial tamponade, drained successfully. During a follow-up of 50±24 months, 65% had no VT recurrences. Among the seven patients with recurrences, three underwent redo ablation and four, with fewer VT episodes, received appropriate ICD therapy. There were five hospital readmissions due to heart failure decompensation, one patient died in the first week after unsuccessful ablation of a VT storm and three died (stroke and pneumonia) >1 year after ablation. ConclusionCatheter ablation based on substrate modification is feasible and safe in patients with frequent VTs and severe LV dysfunction. This approach may be of clinical relevance, with potential long-term benefits in reducing VT burden.

Early Antiarrhythmic Efficacy of Noninvasive Cardiac Radioablation for Ventricular Tachycardia

<h3>Purpose/Objective(s)</h3> Noninvasive cardiac radioablation has been reported to be effective and relatively safe for ventricular tachycardia (VT) in preclinical and clinical studies. However, previous studies implementing cardiac radioablation set a 6-12 weeks of "blanking period" and focused on long-term effects rather than reporting the early changes. In this prospective trial, we focused on the early antiarrhythmic effects within one month after cardiac radioablation. Especially, we tried to seek the differences in response according to the cause of VT. <h3>Materials/Methods</h3> From September 2019 to December 2020, 6 patients (3 ischemic VTs and 3 non-ischemic VTs) were included in this trial and treated with stereotactic body radiotherapy (SBRT) with a single fraction of 25 Gy for intractable VT. A synthesis of imaging studies, 12-lead ECG, and electrophysiological mapping were used to localize the treatment target. The internal target volume was delineated on either maximal intensity projection of 4D-CT or deep inspiration breath hold CT. A 24-hour Holter monitoring was performed for all patients one month before and after SBRT and except for one patient, it was performed from 24 hours before SBRT to 48 hours after SBRT to measure the early response after SBRT. <h3>Results</h3> The number of total ventricular beats decreased by 58% and 60% within 24 hours and 48 hours after SBRT, respectively. It further decreased to 29% of pre-SBRT number of total ventricular beats at one month after SBRT. The decrease of total ventricular beats could be attributed to the decrease of VT burden rather than that of premature ventricular contractions (PVCs) because the burden of VT decreased earlier and more dramatically than that of PVC. After cardiac radioablation, the duration of the longest VT run was shortened. This indicated that cardiac radioablation decreases the VT burden by shortening the durations of VTs. Notably, the cardiac radioablation was more effective for ischemic VTs than non-ischemic VTs in that the VT burden decreased more markedly after SBRT. The electrophysiologic characteristics of VT/PVC were changed after treatment. During one month after SBRT, there was no severe acute toxicity. <h3>Conclusion</h3> In six patients with intractable VT, the noninvasive cardiac radioablation with a dose of 25 Gy was effective even in 1-month follow-up. The decrease of VT burden through shortening of VTs already began within 24 hours after the procedure and continued to decrease until one month after the radioablation. The treatment effect was more remarkable in ischemic than non-ischemic VT patients.

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

Long-term outcomes of catheter ablation for ventricular arrhythmias in post- myocarditis patients; Insights from a meta-analysis of current datv

Abstract Background In the past decade, catheter ablation (CA) has become a rapidly expanding treatment option for ventricular tachycardia (VT), however it is not commonly utilized for patients with post-myocarditis VT. We aimed to systematically review up-to-date evidence regarding feasibility, effectiveness, and safety of CA, with a specific focus on long-term relapse rate and procedural complications. Methods A structured electronic database search (PubMed, Embase, Cochrane) of the scientific literature was performed for studies describing outcomes at up to 7.3 years after CA. The primary outcome measured was VT recurrence post-ablation. Procedural success was defined as freedom of ventricular arrhythmias (at the end of follow-up after an ablation procedure). The secondary outcome was significant procedural complications which included procedural death, stroke, cardiac tamponade, acute myocardial infarction, major vascular complications, and major bleeding, assessed on a study-by-study basis. Results A total of 186 patients were included in analysis with most patients (88%) being male. Over the follow up period there was a 18% relapse rate (n=34) (Confidence Interval (CI); 0.12–0.24, I2≈0, p=0.77) with the majority of patients remaining VT free for the duration of follow up. Only one study recorded the percentage of re-do procedures. The overall procedural complication rate was 3.0% (n=7, (CI; 0.01–0.07, I2≈0, p=0.44) and of note, there were no peri-procedural deaths or heart transplant surgeries reported. However, a single study reported a mortality of 10% (n=2) during the follow up period. Conclusions CA is an effective and durable long-term therapeutic strategy for post myocarditis VT patients with limited relapse rate and very low complication rates based on these non-randomised data. Larger randomised-controlled trials with standardised treatment and long follow-up are required to compare CA versus conventional treatment in the post-acute myocardial phase. Funding Acknowledgement Type of funding sources: None. Relapse rate during follow-upProcedural complication rate

Ablation of ventricular tachycardia in 2021.

Nowadays, ablation of ventricular tachycardia (VT) in structural heart disease is an increasingly used procedure. In fact, it is the most effective strategy in controlling arrhythmic burden in VT patients. The ablative approaches are the result of the last 10 years of technological advances (Catheters, 3D mapping systems) and the constant study of the pathophysiological mechanisms underlying arrhythmic circuits. This presentation seeks to revisit the state of the art in the ablative treatment of VT.

Efficacy and tolerability of quinidine as salvage therapy for monomorphic ventricular tachycardia in patients with structural heart disease.

Quinidine is an effective therapy for a subset of polymorphic ventricular tachycardia and ventricular fibrillation (VF) syndromes; however, the efficacy of quinidine in scar-related monomorphic ventricular tachycardia (MMVT) is unclear. Between 2009 and 2020 a single VT referral center, a total of 23 patients with MMVT and structural heart disease (age 66.7 ± 10.9, 20 males, 15 with ischemic cardiomyopathy, mean LVEF 22.2 ± 12.3%, 9 with left ventricular assist device [LVAD]) were treated with quinidine (14 quinidine gluconate; 996 ± 321 mg, 8 quinidine sulfate; 1062 ± 588 mg). Quinidine was used in combination with other antiarrhythmics (AAD) in 19 (13 also on amiodarone). All patients previously failed >1 AAD (amiodarone 100%, mexiletine 73%, sotalol 32%, other 32%) and eight had prior ablations (median of 1.5). Quinidine was initiated in the setting of VT storm despite AADs (6), inability to tolerate other AADs (4), or recurrent VT(12). Ventricular arrhythmias recurred despite quinidine in 13 (59%) patients at a median of 26 (4-240) days after quinidine initiation. In patients with recurrent MMVT, VT cycle length increased from 359 to 434 ms (p = .02). Six (27.3%) patients remained on quinidine at 1 year with recurrence of ventricular arrhythmias in all. The following adverse effects were seen: gastrointestinal side effects (6), QT prolongation (2), rash (1), thrombocytopenia (1), neurologic side effects (1). One patient discontinued due to cost. Quinidine therapy has limited tolerability and long-term efficacy when used in the management of amiodarone-refractory scar-related MMVT.

VENTRICULAR TACHYCARDIA ELECTRICAL STORM AS A MANIFESTATION OF REVERSE VARIANT TAKOTSUBO CARDIOMYOPATHY

TOPIC: Cardiovascular Disease TYPE: Medical Student/Resident Case Reports INTRODUCTION: Takotsubo cardiomyopathy (TTC) is a syndrome with transient systolic dysfunction in the absence of obstructive coronary arteries with the reverse variant being a rare entity (1,2). Here, we report a case of reverse TTC presenting with monomorphic ventricular tachycardia (VT) electrical storm. CASE PRESENTATION: A 76 year-old female with a history of recently diagnosed Stage IIIB lung adenocarcinoma presented to the emergency room with shortness of breath. On presentation, her vitals were: BP 134/82, pulse 120 beats/min, SPO2 93% in room air. Initial EKG showed no significant ST-T wave changes and normal QTc. Labs were significant for uptrending troponin from 0.8 to 4 ng/mL. Aspirin and heparin infusion were started for possible NSTEMI with a plan for catheterization. That night, she developed unstable, monomorphic VT (Figure 1). Consecutive synchronized cardioversions and amiodarone boluses were unsuccessful. Patient's VT terminated with repeated boluses of lidocaine followed by lidocaine infusion. Stat echocardiogram showed an ejection fraction of 25-30% with anterior and anteroseptal hypokinesis. Emergency cardiac catheterization revealed non-obstructive coronary arteries with akinesis of the basal wall and sparing of the apex suggesting reverse TTC (Figure 2). She was transferred to the critical care unit where she was transitioned to amiodarone infusion with no further VT episodes and was initiated on guideline-directed medical therapy. DISCUSSION: TTC usually occurs due to a surge of catecholamines leading to myocardial damage. The typical variant demonstrates apical ballooning with basal hypokinesis. Rarely, there may be basal hypokinesis with apical sparing, the reverse variant (2). Arrhythmias are uncommon in typical TTC and prior studies have indicated a low incidence of VT (3.2%) (3). There is sparse literature describing the incidence of VT or VT storm in the reverse variant. One of the postulated mechanisms for VT in TTC is transient QTc prolongation, however this remains controversial. (3). The incidence of arrhythmias is thought to be more prevalent during the acute phase leading to increased in-hospital mortality (3). Additionally, it remains uncertain whether prophylactic antiarrhythmics are beneficial in this population subset. Further studies are warranted to understand which variants of TTC develop critical arrhythmias. CONCLUSIONS: Reverse variant is a rare subset of TTC which can present with critical arrhythmias including VT storm. Awareness of this manifestation can help clinicians with early recognition and management of these critical arrhythmias. REFERENCE #1: Bybee KA., Prasad A. Stress-related cardiomyopathy syndromes. Circulation 2008;118(4):397–409. Doi: 10.1161/CIRCULATIONAHA.106.677625. REFERENCE #2: Templin C., Ghadri JR., Diekmann J., et al. Clinical Features and Outcomes of Takotsubo (Stress) Cardiomyopathy. New England Journal of Medicine 2015;373(10):929–38. Doi: 10.1056/NEJMoa1406761. REFERENCE #3: Pant S, Deshmukh A, Mehta K, et al. Burden of arrhythmias in patients with Takotsubo Cardiomyopathy (Apical Ballooning Syndrome). International Journal of Cardiology [Internet] 2013;170(1):64–68. Available from: https://doi.org/10.1016/j.ijcard.2013.10.041 DISCLOSURES: No relevant relationships by Anneka Hutton, source=Web Response No relevant relationships by Gagan Neupane, source=Web Response No relevant relationships by Enoemem Okpokpo, source=Web Response No relevant relationships by Bharadwaj Satyavolu, source=Web Response No relevant relationships by Raksha Sharma, source=Web Response No relevant relationships by Tracey Topacio, source=Web Response

Cardiac radiotherapy induces electrical conduction reprogramming in the absence of transmural fibrosis

Cardiac radiotherapy (RT) may be effective in treating heart failure (HF) patients with refractory ventricular tachycardia (VT). The previously proposed mechanism of radiation-induced fibrosis does not explain the rapidity and magnitude with which VT reduction occurs clinically. Here, we demonstrate in hearts from RT patients that radiation does not achieve transmural fibrosis within the timeframe of VT reduction. Electrophysiologic assessment of irradiated murine hearts reveals a persistent supraphysiologic electrical phenotype, mediated by increases in NaV1.5 and Cx43. By sequencing and transgenic approaches, we identify Notch signaling as a mechanistic contributor to NaV1.5 upregulation after RT. Clinically, RT was associated with increased NaV1.5 expression in 1 of 1 explanted heart. On electrocardiogram (ECG), post-RT QRS durations were shortened in 13 of 19 patients and lengthened in 5 patients. Collectively, this study provides evidence for radiation-induced reprogramming of cardiac conduction as a potential treatment strategy for arrhythmia management in VT patients.

Relation of Mitral Leaflet Elongation to Nonsustained Ventricular Tachycardia in Patients with Obstructive Hypertrophic Cardiomyopathy

The impact of mitral valve abnormality on the occurrence of non-sustained ventricular tachycardia (NSVT) in patients with hypertrophic cardiomyopathy (HC) has not been well determined. We sought to demonstrate the relation of mitral valve abnormalities with NSVT in patients with obstructive HC. Three hundred and sixteen adult patients with obstructive HC with at least 1 Holter electrocardiographic monitoring and cardiac magnetic resonance (CMR) from 2014 to 2018 were enrolled. CMR images and Holter electrocardiography were analyzed in all patients. NSVT occurred in 50 patients (16%). Compared with those without NSVT, anterior mitral leaflet and posterior mitral leaflet lengths was significantly increased in patients with NSVT (AML 32.0 ± 5.0mm vs. 26.1±4.8mm, p<0.001; PML 17.7±3.7mm vs. 15.2±2.7mm, p<0.001, respectively). Multivariate logistic regression analysis indicated that elongated AML and PML were significantly independent predictors of NSVT (AML: OR 1.261, 95%CI 1.156-1.375, p<0.001; PML: OR 1.126, 95%CI 1.001-1.265, p=0.047). Furthermore, the area under the receiver operating characteristic curve for AML was 0.812. At a cutoff valve of 27.5mm, AML length had a sensitivity of 86% and specificity of 65%. Elongated mitral leaflets independently correlated with NSVT in patients with obstructive HC. Furthermore, the morphological abnormalities of mitral valve could serve as a useful marker for improving risk stratification of SCD and may play a role in optimizing surgical strategy for patients with obstructive HC.

Epicardial ablation of ventricular tachycardia in patients with structural heart disease: a single-centre experience over 12 years.

Epicardial ablation has risen to an essential part of the treatment of ventricular tachycardias (VTs). In this study, we report the efficacy, risks, and current trends of epicardial ablation in structural heart disease as reported in a tertiary single centre over a 12-year period. Two hundred and thirty-six patients referred for VT ablation underwent a successful epicardial access and were included in the analysis (89% non-ischaemic cardiomyopathy, 90% males, mean age 60 years, mean left ventricular ejection fraction 38.4%). After performing epicardial ablation the clinical VTs were eliminated in 87% of the patients and 71% of the cohort achieved freedom from VT during 22-month follow-up. Twelve patients (5%) suffered major procedure-related complications. Until the end of follow-up 47 (20%) patients died, 9 (4%) underwent a left ventricular assist device implantation and 10 (4%) patients received a heart transplantation. Antiarrhythmic drugs at baseline and during follow-up were independent predictors of VT recurrence. Atrial fibrillation, renal dysfunction, worse New York Heart Association class, and antiarrhythmic drugs at follow-up were associated with worse survival in our cohort. In this large tertiary single-centre experience, percutaneous epicardial access was feasible in the large majority of the cohort with acceptably low complications rates. A combined endo-/epicardial approach resulted in 87% acute and 71% long-term success. Further studies are needed to clarify the role of routine combined endo-/epicardial ablation in these complex cardiomyopathies.

B-PO04-174 USE OF PET-CT IMAGING TO GUIDE TREATMENT OF VENTRICULAR TACHYCARDIA

Cardiac inflammation plays a significant role in the development of ventricular tachycardia (VT); however, the optimal treatment strategies remain unknown. PET-CT imaging can reveal underlying inflammation and select patients who may benefit from immunosuppression. Determine the utility of PET-CT in guiding management decisions for ventricular tachycardia. We retrospectively reviewed all patients who underwent PET-CT for VT at UCLA between 2012-2019. Clinical characteristics including PET-CT results, treatment, and outcomes were collected. Patients with pre-existing autoimmune disease or taking immunosuppressive medication prior to evaluation were excluded. PET-CT was performed in 137 patients (median age 58 years, 79.6% male, mean LVEF 45%) for VT. A cardiac inflammatory process was found in 33 scans, while 104 were negative or inconclusive. Patients were followed for a median of 27.6 months (IQR: 3.3, 54.9). Of the patients with positive PET scans, 21 were initially treated with immunosuppression (3 developed recurrent VT requiring a subsequent ablation), 6 were treated with concurrent ablation and immunosuppression, 1 was treated with ablation alone (patient ended up receiving a heart transplant), and 5 were managed with antiarrhythmic medications. There was no significant difference in recurrence between PET-positive and PET-negative groups (39.3% vs 32.4%; p = 0.50) or time to recurrence (p = 0.89). Of the PET-positive patients receiving immunosuppression, 8/21 (38.1%) had recurrence. Of the PET-negative patients who underwent ablation, 22/54 (40.7%) had recurrence. There was no significant difference in outcomes comparing PET-positive immunosuppression only versus PET-negative ablation patients (p=0.83). PET-CT can identify patients with a cardiac inflammatory process who may benefit from immunosuppression. In patients with PET-positive imaging, treatment with immunosuppression yielded similar results as in patients without inflammation who underwent ablation in this series. The incorporation of PET-CT imaging into the evaluation for ventricular arrhythmias can potentially obviate the need for invasive procedures.

Delayed papillary muscle rupture after radiofrequency catheter ablation: A case report

BACKGROUNDWith an increased number of surgical procedures involving the mitral annular region, the risk of mitral valve prolapse (MVP) has also increased. Previous studies have reported that worsening of MVP occurred early after radiofrequency catheter ablation (RFCA) at papillary muscles in ventricular tachycardia (VT) patients with preoperative MVP. CASE SUMMARYWe report a case where MVP and papillary muscle rupture occurred 2 wk after RFCA in a papillary muscle originated VT patient without mitral valve regurgitation or prolapse before. The patient then underwent mitral valve replacement with no premature ventricular contraction or VT. During the surgery, a papillary muscle rupture was identified. Pathological examination showed necrosis of the papillary muscle. The patient recovered after mitral valve replacement. CONCLUSIONToo many ablation procedures and energy should be avoided.

Delayed repolarization and ventricular tachycardia in patients with heart failure and preserved ejection fraction.

Sudden death is the most common mode of mortality in patients with heart failure and preserved ejection fraction (HFpEF). Ventricular arrhythmias (VA) have been suspected as the etiology but the supporting evidence in patients with HFpEF is scarce. We sought to investigate VA prevalence, and to determine if VA are associated with prolonged repolarization, in patients with HFpEF. In a retrospective case-control study design, Cedars-Sinai patients who underwent prolonged ambulatory electrocardiographic monitoring (Zio Patch) between 2016 and 2018 were screened for a clinical diagnosis of HFpEF. Patients with normal diastolic and systolic function who underwent Zio Patch monitoring were also reviewed as controls. Multivariable logistic regression was used to compare the prevalence of rhythm disturbances in patients with and without HFpEF. Ventricular tachycardia (VT) was more prevalent in patients with HFpEF (37% vs. 16% in controls, p = 0.001). Most episodes were non-sustained except for one case of sustained VT in a patient with HFpEF. Covariate-adjusted logistic regression including HFpEF diagnosis, age, sex, body mass index, and the presence of comorbidities revealed that only HFpEF was associated with increased risk of VT (relative risk 2.86, p = 0.023). Subgroup-analyses revealed an association between increased QTc interval and risk of VT (460 ± 38 ms in HFpEF patients with VT vs. 445 ± 28 ms in HFpEF patients without VT, p = 0.03). Non-sustained VT was more prevalent in patients with HFpEF compared to patients without HFpEF, and QTc interval prolongation was associated with VT in HFpEF.

Metabolic heterogeneous zone assessed by 18FDG‐PET is predictive of postablation mortality in patients with ventricular tachycardia

We sought to study the predictive value of the metabolic heterogeneous zone (HZ) as determined by 18 Fluorodeoxyglucose (18 FDG) positron emission tomography (PET) viability studies in ventricular tachycardia (VT) patients. PET studies utilizing 82 Rubidium (82 Rb) tracer for perfusion and 18 FDG tracer for viability were analyzed using PMOD (PMOD Technologies) and further analyzed using 684-segment plots. 18 FDG uptake was normalized to the area with maximal perfusion on the rest 82 Rb study. Metabolic scar, HZ, and healthy segments were defined with perfusion-normalized 18 FDG uptake between 0%-50%, 50%-70%, and >70%, respectively. Thirty-four VT patients (age, 63 ± 12 years) were evaluated with 18 FDG-PET viability study. Most (n = 31) patients underwent VT ablation. Patients were categorized to HZ < median versus HZ ≥ median based on a median HZ area size of 21.0 cm2 . HZ size was significantly larger in the deceased group than the alive group (35.2 cm2 vs. 18.1 cm2 , p = .01). Deaths were significantly higher in HZ ≥ 21 cm2 group than HZ < 21 cm2 group (58.8% vs. 11.8%, p = .005). Survival analysis showed significantly higher mortality in the HZ ≥ 21 cm2 group than the HZ < 21 cm2 group (HR = 4.1, 95% CI: 1.3-12.6, p = .016). In a multivariable analysis, HZ was found to be an independent predictor for all-cause mortality (HR = 1.07, 95% CI: 1.02-1.12, p = .01) CONCLUSIONS: Increased HZ size of myocardium was associated with increased mortality. Metabolic HZ quantification may be of value in risk stratification and management of ischemic and nonischemic patients with VT.

Comparative effectiveness of ventricular tachycardia ablation versus escalated antiarrhythmic drug therapy by location of myocardial infarction: A sub-study of the VANISH trial

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): Fonds de recherché du Québec-Santé (FRQS) [post doctoral award for Dr. Samuel) BACKGROUND Complexity of ventricular tachycardia (VT) substrate, efficiency of lesion formation, and the size and thickness of infarction area border zones differ based on location of myocardial infarctions (MI). These differences may translate into heterogeneity in risk of events and effectiveness of treatments for VT. Small observational studies suggest that VT from inferior infarctions have higher risk of early recurrence despite smaller infarct areas. However, differential effectiveness of VT treatments based on location of MI not been definitively established. PURPOSE The objective of this sub-study of the Ventricular tachycardia AblatioN versus escalated antiarrhythmic drug therapy in ISchemic Heart disease (VANISH) randomized trial was to compare the effectiveness of VT ablation by location of MI in reducing the composite endpoint of all-cause mortality, VT storm, or appropriate ICD therapy when compared to escalated pharmacological therapy in VT patients with a prior MI. METHODS VANISH participants were categorized into 3 subgroups based on MI location: 1. Inferior (may also have MI in other locations); 2. Non-inferior (no inferior MI, all patients not in group 1); and 3. Anterior (may also have MI in other locations). Inverse probability of treatment weighting was used to balance baseline characteristics (ie. age, sex, comorbidities, medications, and the location of additional infarctions) between patients randomized to ablation or escalated therapy within each subgroup. Weighted Cox proportional hazards models were calculated separately for each subgroup. RESULTS Of 259 patients enrolled in the VANISH trial [median age 69.8 (IQR 63.0-74.2) years, 7.0% women], 135 had an inferior MI, 124 a non-inferior MI, and 83 an anterior MI. Among patients with an inferior MI, no statistically significant difference in the primary outcome was detected between patients randomized to ablation or escalated therapy [aHR 0.78 (95% CI 0.51-1.20)]. In contrast, patients with non-inferior MIs had a statistically significant reduction in the incidence of the primary outcome with ablation [aHR 0.48 (95% CI 0.27-0.86)]; which was of greater magnitude than the reduction observed in the overall results of the VANISH trial [HR 0.72 (95% CI 0.53-0.98)]. In addition, a trend towards a reduction in the primary outcome with ablation was detected in patients with anterior MIs [aHR 0.50 (95% CI 0.23-1.09)]. CONCLUSION The effectiveness of VT ablation versus escalated pharmacological therapy varies based on the location of the MI. Patients with MI scars located only in non-inferior regions of the ventricles derive greater benefit from VT ablation in reducing VT-related events. Further studies are required to explore reasons for this finding and to assess the impact of VT treatment strategies based on MI location in optimizing outcomes.

Impact of high density mapping using a grid shaped catheter with orthogonal signal analysis on ventricular tachycardia ablation strategy

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Abbott Background Ventricular tachycardia (VT) in patients with structural heart disease (SHD) is related to scar and slow conduction areas. Substrate-based ablation has become the gold standard treatment in patients with SHD-related refractory VT. A new high-density grid shaped catheter that allows simultaneous analysis of adjacent orthogonal bipolar signals can allow better understanding of these slow conduction areas with the potential to improve ablation results. Purpose This was a prospective, multicenter observational study to characterize the utility of electroanatomical mapping with a high density grid-style mapping catheter (HD Grid) in subjects undergoing catheter ablation for ventricular tachycardia (VT) in real-world clinical settings. Methods During the study period, patients who underwent VT ablation using the HD Grid catheter as the primary mapping catheter were included. Comparisons both during the procedure and retrospectively were performed between conventional electrode configuration maps and simultaneous orthogonal bipole electrode configuration maps. The influence of these different configurations on ablation strategy was analyzed. Results During study period (January 2019 – April 2020) 57 maps were performed in 34 VT subjects (average age: 64.3yr, male: 85.3%, ischemic cardiomyopathy: 70.6%). The left ventricle was mapped in 94.1% of subjects, including left ventricular outflow tract and papillary muscles in 20.6% and 8.8% respectively, reporting minimal or no ectopic beats in 97.1% of the subjects. The total number of mapping points collected was 14172.0 ± 15174.8 in 24.3 ± 17.9 min per map. Simultaneous orthogonal bipole mapping identified differences in 67.6% of maps compared to linear along-the-spline electrode configurations. The differences consisted mainly in the surface area (92%) and location of low voltage (40%). When compared during the procedure, simultaneous orthogonal bipole mapping was used to identify ablation strategy in 100% of cases. When compared to a standard along-the-spline configuration retrospectively, the ablation strategy identified with simultaneous orthogonal bipoles was different in 30.1% of cases. The ablation strategy used in these subjects was mainly substrate ablation (late potentials and low voltage areas in scar regions) with an acute success rate of 97.1%. Conclusions The use of the HD Grid catheter with the ability to analyze orthogonal signals is feasible and has the potential to change the ablation strategy in one third of VT patients with a high acute success rate.

Detection of Ventricular Arrhythmia by using Heart rate variability signal and ECG beat image

Ventricular Arrhythmia (VA) such as Ventricular Tachycardia (VT) and Ventricular Fibrillation (VF) are the common type of arrhythmia in infants and children. Electrocardiogram (ECG) signal is used for the diagnosis of such type of cardiac abnormality. Manual ECG assessment is an error prone task because of vast difference in ECG morphology. Hence, a computer aided diagnosis (CAD) system for classification of cardiac abnormality can be useful in cardiac care units. Main goal of our study is to design a CAD system to classify ECG signals of VT and VF patients. This study proposed a technique for the process of cardiac scoring which is a significant diagnosis step in VA detection. ECG signals are used for the extraction of Heart Rate Variability (HRV) signals and ECG beat images. The features are computed from the HRV signals and ECG beat images using thirty different feature extraction methods. Skewness, Kurtosis, shape factor, fractal dimension, entropy, contrast and dissimilarity are the selected features used for classification process. The best classification accuracy has been achieved by the use of ensemble classifier. According to performance analysis, the system can be operated with 99.99% accuracy rate for the separation between healthy and VA persons.

Case series on stereotactic body radiation therapy in non-ischemic cardiomyopathy patients with recurrent ventricular tachycardia.

The efficacy of stereotactic body radiation therapy (SBRT) as an alternative treatment for recurrent ventricular tachycardia (VT) is still unclear. This study aimed to report the outcome of SBRT in VT patients with nonischemic cardiomyopathy (NICM). The determination of the target substrate for radiation was based on the combination of CMR results and electroanatomical mapping merged with the real-time CT scan image. Radiation therapy was performed by Flattening-filter-free (Truebeam) system, and afterward, patients were followed up for 13.5 ± 2.8 months. We analyzed the outcome of death, incidence of recurrent VT, ICD shocks, anti-tachycardia pacing (ATP) sequences, and possible irradiation side-effects. A total of three cases of NICM patients with anteroseptal scar detected by CMR. SBRT was successfully performed in all patients. During the follow-up, we found that VT recurrences occurred in all patients. In one patient, it happened during a 6-week blanking period, while the others happened afterward. Re-hospitalization due to VT only appeared in one patient. Through ICD interrogation, we found that all patients have reduced VT burden and ATP therapies. All of the patients died during the follow-up period. Radiotherapy-related adverse events did not occur in all patients. SBRT therapy reduces the number of VT burden and ATP sequence therapy in NICM patients with VT, which had a failed previous catheter ablation. However, the efficacy and safety aspects, especially in NICM cases, remained unclear.

Clinical outcomes of catheter ablation of ventricular tachycardia in patients with arrhythmogenic right ventricular cardiomyopathy: Insights from the Johns Hopkins ARVC Program

Previous studies of radiofrequency catheter ablation (RFA) of ventricular tachycardia (VT) in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC), relying on limited numbers of procedures, have not reported VT-free survival in parallel for single and multiple procedures (ie, after the last procedure). Data regarding the impact of RFA on VT burden are scarce. The purpose of this study was to provide new insights on clinical outcomes based on a large series of VT ablation procedures from the current era in ARVC patients. We evaluated consecutive patients with definite ARVC who underwent RFA procedures between 2009 and 2019 at our center. We assessed VT-free survival, for single and multiple procedures, and changes in VT burden and antiarrhythmic drugs (AADs) after RFA. Among 116 patients, there were 166 RFA procedures, 106 (63.9%) of which involved epicardial ablation. Cumulative freedom from VT after a single procedure was 68.6% and 49.8% at 1 and 5 years, respectively. Cumulative VT-free survival after multiple procedures was 81.8% and 69.6% at 1 and 5 years, respectively. VT burden per RFA was reduced after vs before ablation (mean 0.7 vs 10.0 events/year; P <.001). Furthermore, VT burden per patient was reduced after last ablation vs before first ablation (mean 0.5 vs 10.9 events/year; P <.001). Use of AADs decreased after ablation (22.2% vs 51.9%; P <.001). In ARVC patients, RFA provided good VT-free survival after a single procedure, with multiple procedures required for more sustained freedom from VT recurrence. Marked reduction in VT burden permitted discontinuation of AADs.

Metabolic Scar Assessment with18F-FDG PET: Correlation to Ischemic Ventricular Tachycardia Substrate and Successful Ablation Sites.

The functional and molecular imaging characteristics of ischemic ventricular tachycardia (VT) substrate are incompletely understood. Our objective was to compare regional 18F-FDG PET tracer uptake with detailed electroanatomic maps (EAMs) in a more extensive series of postinfarction VT patients to define the metabolic properties of VT substrate and successful ablation sites. Methods: Three-dimensional (3D) metabolic left ventricular reconstructions were created from perfusion-normalized 18F-FDG PET images in consecutive patients undergoing VT ablation. PET defects were classified as severe (defined as <50% uptake) or moderate (defined as 50%-70% uptake), as referenced to the maximal 17-segment uptake. Color-coded PET scar reconstructions were coregistered with corresponding high-resolution 3D EAMs, which were classified as indicating dense scarring (defined as voltage < 0.5 mV), normal myocardium (defined as voltage > 1.5 mV), or border zones (defined as voltage of 0.5-1.5 mV). Results: All 56 patients had ischemic cardiomyopathy (ejection fraction, 29% ± 12%). Severe PET defects were larger than dense scarring, at 63.0 ± 48.4 cm2 versus 13.8 ± 33.1 cm2 (P < 0.001). Similarly, moderate/severe PET defects (≤70%) were larger than areas with abnormal voltage (≤1.5 mV) measuring 105.1 ± 67.2 cm2 versus 56.2 ± 62.6 cm2 (P < 0.001). Analysis of bipolar voltage (23,389 mapping points) showed decreased voltage among severe PET defects (n = 10,364; 0.5 ± 0.3 mV) and moderate PET defects (n = 5,243; 1.5 ± 0.9 mV, P < 0.01), with normal voltage among normal PET areas (>70% uptake) (n = 7,782, 3.2 ± 1.3 mV, P < 0.001). Eighty-eight percent of VT channel or exit sites (n = 44) were metabolically abnormal (severe PET defect, 78%; moderate PET defect, 10%), whereas 12% (n = 6) were in PET-normal areas. Metabolic channels (n = 26) existed in 45% (n = 25) of patients, with an average length and width of 17.6 ± 12.5 mm and 10.3 ± 4.2 mm, respectively. Metabolic channels were oriented predominantly in the apex or base (86%), harboring VT channel or exit sites in 31%. Metabolic rapid-transition areas (>50% change in 18F-FDG tracer uptake/15 mm) were detected in 59% of cases (n = 33), colocalizing to VT channels or exit sites (15%) or near these sites (85%, 12.8 ± 8.5 mm). Metabolism-voltage mismatches in which there was a severe PET defect but voltage indicating normal myocardium were seen in 21% of patients (n = 12), 41% of whom were harboring VT channel or exit sites. Conclusion: Abnormal 18F-FDG uptake categories could be detected using incremental 3D step-up reconstructions. They predicted decreasing bipolar voltages and VT channel or exit sites in about 90% of cases. Additionally, functional imaging allowed detection of novel molecular tissue characteristics within the ischemic VT substrate such as metabolic channels, rapid-transition areas, and metabolism-voltage mismatches demonstrating intrasubstrate heterogeneity and providing possible targets for imaging-guided ablation.