Drug-refractory Ventricular Tachycardia Research Articles

Abstract 4113336: Characteristics and Outcomes of Ventricular Tachycardia Ablation in Patients with the HeartMate 3 Left Ventricular Assist Devices: Results From a Large Single-Center Registry

HeartMate 3 (HM3) is a fully magnetically levitated continuous flow left ventricular assist device (LVAD). In patients with HM3 and recurrent ventricular tachycardia (VT), data on the outcomes of catheter ablation (CA) are insufficient. We report our institutional experience with CA of VT in patients with the HM3.Consecutive patients with HM3 and recurrent drug-refractory VT undergoing CA were included. Ablation sites were identified using activation/entrainment mapping (stable VTs) and/or late/fractionated potential ablation and pace-mapping (unstable VTs). Between 2016-2023 a total of 431 patients (age 58±13, INTERMACS 3±0.98, 44% ischemic cardiomyopathy) received an HM3 LVAD at our institution. Of these, 15 (3.4%) underwent CA for recurrent VT despite therapy with 1.3±0.8 antiarrhythmic drugs a median of 700 days from the LVAD surgery (2 patients <1 month from the surgery). The LV access was transseptal in 12 (80%) cases, retrograde aortic in 2 (13%) and both in 1 (7%). A total of 23 distinct VTs were targeted. Of these, 21 (91%) were mapped with activation/entrainment mapping, always utilizing an intracardiac RV reference due to excessive surface ECG noise, and 2 (9%) were hemodynamically unstable with reduced LVAD flows and targeted with substrate-based ablation. A total of 3 (13%) VTs were targeted adjacent to the HM3 inflow cannula, and 20 (87%) from substrate remote from the HM3 cannula. At post-procedural programmed ventricular stimulation, non-inducibility of all targeted VTs was achieved in 13 (87%) patients, 1 patient had residual inducible clinical VT, and in 1 patient no post-procedural programmed stimulation was performed. Periprocedural complications occurred in 1 (7%) case (small pericardial effusion not requiring intervention). At 12 months follow-up following the index procedure, no death occurred and one patient received heart transplantation. Of the remaining 14 patients, 6 (42%) remained free from VT (2 with VT ablation <1 month post-LVAD and 12 with VT ablation >=1 month post-LVAD). In this large single-center HM3 registry, a minority of patients underwent CA for recurrent drug-refractory VT (3.4% over a 7-year period). CA of VT in HM3 recipients is feasible and appears safe also when performed soon after LVAD surgery. Myocardial scar from the underlying cardiomyopathic process rather than the apical cannula is the dominant substrate responsible for VT in these patients.

Substrate Characterization and Outcomes of Ventricular Tachycardia Ablation in Amyloid Cardiomyopathy: A Multicenter Study.

Sustained ventricular tachycardia (VT) in cardiac amyloidosis is uncommon, and the substrate and outcomes of catheter ablation are not defined. We included 22 consecutive patients (mean age, 68±10 years; male sex, 91%) with cardiac amyloidosis (ATTR [transthyretin], n=16; light chain, n=6) undergoing catheter ablation for VT/ventricular fibrillation (VF) between 2013 and 2023 in a retrospective, observational, international study. The primary efficacy outcome was recurrent VT/VF during follow-up, while the primary safety end point included major procedure-related adverse events. The indication for ablation was drug-refractory VT in 17 patients (77%), and premature ventricular complex-initiated polymorphic VT/VF in 5 patients (23%). Catheter ablation was performed using endocardial (n=17.77%) or endo-epicardial approaches (n=5.23%). Complete endocardial electroanatomical voltage maps of the left and right ventricles were obtained in 17 (77%) and 10 (45%) patients, respectively. Each patient had evidence of low-voltage areas, most commonly involving the interventricular septum (n=16); late potentials were recorded in 16 patients (73%). A median of 1 (1-2) VT was inducible per patient; 12 of the 26 mappable VTs (46%) originated from the interventricular septum. Complete procedural success was achieved in 16 patients (73%), with 4 (18%) major procedure-related adverse events. After a median follow-up of 32 (14-42) months, sustained VT/VF recurrence was observed in 9 patients (41%); survival free from VT/VF recurrence was 56% (95% CI, 36%-86%) at 36-month follow-up, and most patients remained on antiarrhythmic drugs. A significant reduction in per patient implantable cardioverter defibrillator therapies was noted in the 6-month period after ablation (before: 6 [4-9] versus after: 0 [0-0]; P<0.001). In multivariable analysis, complete procedural success was associated with reduced risk of recurrent VT/VF (hazard ratio, 0.002; P=0.034). Catheter ablation can achieve control of recurrent VT/VF in more than half of patients with cardiac amyloidosis, and the reduction in VT/VF burden post-ablation may be relevant for quality of life. Septal substrate and risk of procedure-related complications challenge successful management of patients with cardiac amyloidosis and VT/VF.

Substrate characterization and outcomes of ventricular tachycardia ablation in amyloid cardiomyopathy: a worldwide study

Abstract Background the electrophysiological substrate underpinning ventricular tachycardia (VT) in cardiac amyloidosis (CA) remains elusive, and outcomes of catheter ablation in this peculiar population are currently unknown. Purpose we sought to describe the electrophysiological substrate and clinical outcomes of VT ablation in a cohort of patients with CA. Methods we included 19 consecutive patients (mean age, 69±10 years; male sex, 89%) with CA (ATTR, n=13; AL, n=6) undergoing catheter ablation for VT/ventricular fibrillation (VF) between 2013 and 2023 in a retrospective, observational, international study, involving 7 referral European and North American electrophysiology units. The primary efficacy outcome was recurrent VT/VF during follow-up, while the primary safety outcome included major procedure-related adverse events. Results the indication for ablation was drug-refractory VT in 16 patients (84%), and PVC-initiated polymorphic VT/VF in 3 (16%). Catheter ablation was performed using endocardial (n=14, 74%) or endo-epicardial approaches (n=5, 26%). Complete endocardial electroanatomical voltage maps of the left and right ventricles were obtained in 14 (74%) and 6 (32%) patients, respectively. Each patient had evidence of low-voltage areas, most commonly involving the interventricular septum (n=12); late potentials were recorded in 13 patients (68%). A median of 1 (1-2) VTs were inducible per patient; in 10 subjects (43% of mappable VTs), activation mapping was consistent with septal VT origin. Complete procedural success was obtained in 13 patients (68%), at the expense of 4 (21%) major procedure-related adverse events. After a median follow-up of 36 (18-54) months, sustained VT/VF recurrence was observed in 9 patients (47%); survival free from VT/VF recurrence was 74% (95%CI, 56-96%) at 12 months, and 53% (95%CI, 34-94%) at 36-month follow-up; the majority of patients remained on antiarrhythmic drugs (Figure). Low-voltage QRS (HR,21.96; p=0.022) and complete procedural success (HR,0.08; p=0.029) were associated with recurrent VT/VF at multivariable analysis (Figure). Conclusions catheter ablation of VT/VF is associated with favorable acute and mid-term arrhythmia control, yet with substantial risk of procedure-related complications and long-term recurrences. Septal substrate and frailty challenge successful management of patients with CA and VT/VF.Multimodality evaluation of LV substrateMain Study Outcomes

Effects of Biventricular Pacing Locations on Anti-Tachycardia Pacing Success in a Patient-Specific Model.

Patients with drug-refractory ventricular tachycardia (VT) often undergo implantation of a cardiac defibrillator (ICD). While life-saving, shock from an ICD can be traumatic. To combat the need for defibrillation, ICDs come equipped with low-energy pacing protocols. These anti-tachycardia pacing (ATP) methods are conventionally delivered from a lead inserted at the apex of the right ventricle (RV) with limited success. Recent studies have shown the promise of biventricular leads placed in the left ventricle (LV) for ATP delivery. This study tested the hypothesis that stimulating ATP from multiple biventricular locations will improve termination rates in a patient-specific computational model. VT was first induced in the model, followed by ATP delivery from 1-4 biventricular stimulus sites. We found that combining stimulation sites does not alter termination success so long as a critical stimulus site is included. Combining the RV stimulus site with any combination of LV sites did not affect ATP success except for one case. Including the RV site may allow biventricular ATP to be a robust approach across different scar distributions without affecting the efficacy of other stimulation sites. Combining sites may increase the likelihood of including a critical stimulus site when such information cannot be ascertained.

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

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

PO-04-189 CLINICAL OUTCOMES OF VENTRICULAR TACHYCARDIA ABLATION IN CARDIAC SARCOIDOSIS

Cardiac sarcoidosis (CS) is a known cause of ventricular tachycardia (VT) and sudden death. CS-related ventricular tachycardia (VT) is a rare disorder, and the underlying substrate and response to ablation are poorly understood. We aimed to assess clinical outcomes after catheter ablation for VT in CS patients. The meta-analysis was performed using a meta-package for R version 4.0/RStudio version 1.2, and Freeman Tukey double arcsine transformation with Hartung-Knapp random effect model was used. Outcomes measured included – (1) acute procedure success (defined as non-inducible for any VT); (2) freedom from recurrent VT; (3) redo VT ablation; (4) procedure-related complication; and (5) all-cause mortality. Eight studies from 2006 to 2021 incorporating a total of 273 patients with CS with drug-refractory VT underwent VT ablation (67% were men, mean age 50.3 ± 11.4 years, mean left ventricular ejection fraction 43.3 ± 15.3%). 83% had inducible VT with a mean inducible VT per patient of 2.9 ± 2.6. 14.7% of patients underwent epicardial-endocardial ablation, while the rest underwent endocardial-only ablation. Overall, acute procedural success was 73.7% (95% CI 45-95.1), with a procedure-related complication rate of 4.7% (95% CI 2.6-7.2). During the follow-up period (3.3±3.4 years), the pooled incidence of freedom from recurrent VT was 46.4% (95% CI 26.9–66.5), while 27.1% (95% CI 16.9-38.5) underwent redo VT ablation. All-cause mortality was 8.1% (95% CI 3.3-14.2). Catheter ablation of VT in conjunction with antiarrhythmic drugs in CS patients is safe and effective in eliminating VT or reducing the VT burden; however, recurrences are common, probably due to the inflammatory disease phase.

Stereotactic radioablation in clinical practice for the treatment of a patient with ventricular tachycardia: case report

The aim of the study is the demonstration of the 1st clinical experience of stereotactic arrhythmia radioablation (STAR) of the patient with antiarrhythmic drug (AAD) refractory ventricular tachycardia (VT) in Russia. The results of STAR of 57 years old patient with AAD and multiple radiofrequency ablation refractory VT are described. This clinical study demonstrates efficacy and safety of STAR of VT.

Impact of Amiodarone Therapy on the Ablation Outcome of Ventricular Tachycardia in Arrhythmogenic Right Ventricular Cardiomyopathy.

(1) Background: Catheter ablation (CA) is an accepted treatment option for drug-refractory ventricular tachycardia (VT) in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). This study investigates the effect of amiodarone on ablation outcomes in ARVC. (2) Methods: The study enrolled patients with ARVC undergoing CA of sustained VT. In all patients, substrate modification was performed to achieve non-inducible VT. The patients were categorized into two groups according to whether they had used amiodarone before CA. Baseline and electrophysiological characteristics, substrate, and outcomes were compared. (3) Results: A total of 72 ARVC patients were studied, including 29 (40.3%) "off" amiodarone and 43 (56.7%) "on" amiodarone. The scar area was similar between the two groups. Patients "off" amiodarone had smaller endocardial and epicardial areas with abnormal electrograms. Twenty of 43 patients (47.5%) "on" amiodarone discontinued it within 3 months after CA. During a mean follow-up period of 43.2 ± 29.5 months, higher VT recurrence was observed in patients "on" amiodarone. Patients "on" amiodarone who discontinued amiodarone after CA had a lower recurrence than those without. (4) Conclusions: Patients with ARVC "on" amiodarone before CA had distinct substrate characteristics and worse ablation outcomes than patients "off" amiodarone, especially in those who had used amiodarone continuously.

Catheter Ablation for Ventricular Arrhythmias in Hypertrophic Cardiomyopathy.

Implantable cardioverter-defibrillators are the mainstay of therapy for prevention of sudden cardiac death in high-risk patients with hypertrophic cardiomyopathy (HCM). Catheter ablation is a useful option for patients with recurrent, drug refractory monomorphic ventricular tachycardia (VT), and device therapy. Compared with other nonischemic substrates, there are limited data on the role and outcomes of catheter ablation in HCM. The challenges of VT ablation in HCM patients include deep intramural and epicardial substrates, suboptimal power delivery, and higher recurrence due to progression of disease. Patient selection, using cardiac MRI scar localization, and optimizing ablation techniques can improve outcomes in these patients.

Abstract 11905: Dexmedetomidine for Sedation During Epicardial Ablation for Ventricular Tachycardia: A Single-Center Experience

Introduction: Epicardial ablation of ventricular tachycardia (VT) is mainly performed under general anesthesia (GA). However, GA lowers blood pressure, may interfere with arrhythmia induction, and the use of muscle relaxants precludes identification of the phrenic nerve. Moreover, an anesthesiologist's is required during GA for the whole procedure, which may not always be possible. Hypothesis: The aim of there study was to evaluate the feasibility and safety of epicardial VT ablations under conscious sedation using dexmedetomidine. Methods: Between 2018 and 2022, all patients who underwent epicardial VT ablation under dexmedetomidine infusion were prospectively enrolled. All patients received premedication with paracetamol 1 g (acetaminophen 10 mg/ml) and ketorolac 30 mg. Sedation protocol included an i.v. bolus of midazolam (0.03-0.05 mg/kg) followed by continuous infusion of dexmedetomidine (0.2-0.7 mcg/kg/h). In addition, an i.v. fentanyl bolus (0.7-1.4 mcg/kg) was given for short-term analgesia, followed by a second dose after 30-45 minutes. Sedation-related complications were: hypoxia (S02&lt;90%), severe hypotension (MAP&lt;60 mmHg), and bradycardia (HR &lt;45 b/m). Results: Seventy-one patients with drug-refractory recurrent VT underwent epicardial or endo-epi ablation under conscious sedation. Standard percutaneous sub-xiphoid access was attempted in all patients. in 2 patients the procedure was switched to GA because of intractable pain during epicardial catheter's manipulation. Data from 69 patients were analyzed. Mean age was 65.4±12.1 years and 66.6% of patients were males. Forty-seven patients (68.1%) had non-ischemic cardiomyopathy, 13 patients (18.9%) had ischemic-cardiomyopathy, and 9 patients (13%) had myocarditis. Procedural-related complications occurred in five patients (7.2%), one transient phrenic nerve palsy, two pericarditis, and two vascular complications. No severe adverse events related to the sedation occurred. Conclusions: Prompt availability of anesthesia support remains crucial for epicardial VT ablation. Continuous infusion of dexmedetomidine in addition to midazolam and fentanyl seems to be a safe and effective sedation protocol in patients undergoing epicardial VT ablation.

Promising Therapies for Atrial Fibrillation and Ventricular Tachycardia.

Sudden cardiac death due to arrhythmias, such as atrial fibrillation or ventricular tachycardia, account for 15–20% of all deaths. Myocardial infarction increases the burden of atrial fibrillation and ventricular tachycardia by structural and electrical remodeling of the heart. The current management of new-onset atrial fibrillation includes electric cardioversion with very high conversion rates and pharmacologic cardioversion, with less a than 50% conversion rate. If atrial fibrillation cannot be converted, the focus becomes the control of the symptoms ensuring a constant rhythm and rate control, without considering other contributory factors such as autonomic imbalance. Recently, a huge success was obtained by developing ablation techniques or addressing the vagal nerve stimulation. On the other hand, ventricular tachycardia is more sensitive to drug therapies. However, in cases of non-responsiveness to drugs, the usual therapeutic choice is represented by stereotactic ablative therapy or catheter ablation. This review focuses on these newly developed strategies for treatment of arrhythmias in clinical practice, specifically on vernakalant and low-level tragus stimulation for atrial fibrillation and stereotactic ablative therapy for drug-refractory ventricular tachycardia. These therapies are important for the significant improvement of the management of atrial fibrillation and ventricular tachycardia, providing: (1) a safer profile than current therapies, (2) higher success rate than current solutions, (3) low cost of delivery.

Dexmedetomidine for sedation during epicardial ablation for ventricular tachycardia: a single-center experience.

Epicardial approach to ventricular tachycardia (VT) ablation is mainly performed under general anesthesia (GA). Although catheter manipulation and ablation in the epicardial space could be painful, GA lowers blood pressure and may interfere with arrhythmia induction and mapping, and the use of muscle relaxants precludes identification of the phrenic nerve (PN). Moreover, an anesthesiologist's presence is required during GA for the whole procedure, which may not always be possible. Therefore, we evaluated the feasibility and safety of epicardial VT ablations performed under conscious sedation using dexmedetomidine in our center. Between January 2018 and January 2022, all patients who underwent epicardial VT ablation under continuous dexmedetomidine infusion were prospectively included in the study. All patients received premedication 30min before the epicardial puncture with paracetamol (acetaminophen 10mg/ml) 1000mg and ketorolac 30mg. Sedation protocol included an intravenous bolus of midazolam hydrochloride (0.03-0.05mg/kg) followed by continuous infusion of dexmedetomidine (0.2-0.7 mcg/kg/h). In addition, an intravenous fentanyl citrate bolus (0.7-1.4 mcg/kg) was given for short-term analgesia, followed by a second dose repeated after 30 to 45min. Sedation-related complications were defined in case of respiratory failure, severe hypotension, and bradycardia requiring treatment. Sixty-nine patients underwent epicardial or endo-epi VT ablation under conscious sedation and were included in the analysis. The mean age was 65.4 ± 12.1years; forty-six patients were males (66.6%). All patients had drug-refractory recurrent VT. Forty-seven patients (68.1%) had non-ischemic cardiomyopathy (NICM), 13 patients (18.9%) had ischemic-cardiomyopathy (ICM), and 9 patients (13%) had myocarditis. Standard percutaneous sub-xiphoid access was attempted in all patients. Non-inducibility of any VT was achieved in 82.6% (9/9 myocarditis, 10/13 ICM, 38/47 NICM, n = 57/69 patients), inducibility of non-clinical VT in 13% (3/13 ICM, 6/38 NICM, n = 9/69 patients), and failure in 4.3% (3/38 NICM, n = 3/69 patients). Although we observed procedural-related complications in five patients (7.2%), one transient PN palsy, two pericarditis, and two vascular complications, those were not related to the conscious sedation protocol. No respiratory failure, severe hypotension, or bradycardia requiring treatment has been observed among the patients. Prompt availability of anesthesiology support remains crucial for complex procedures such as epicardial VT ablation. Continuous infusion of dexmedetomidine and administration of midazolam and fentanyl seem to be a safe and effective sedation protocol in patients undergoing epicardial VT ablation.

Stereotactic body radiotherapy for refractory ventricular tachycardia: the overall czech experience

Abstract Funding Acknowledgements Type of funding sources: None. Background Catheter ablation (CA) is a well-established treatment strategy for the management of drug-refractory ventricular tachycardia (VT) in patients with structural heart disease. Stereotactic body radiotherapy (SBRT) was proposed recently as a treatment option for cases of failed CA. Purpose This study reports overall experience with the SBRT from two Czech centers. Methods Since 2014, we enrolled consecutive patients who underwent at least one prior CA for recurrent scar-related VT and had subsequent VT recurrences due to inaccessible substrate. Single-session SBRT for VT was performed without the use of general anesthesia or sedation. A dose of 25 Gy was delivered. Results The study investigated 33 patients (3 women) with a mean age of 66 ± 9 years. Underlying heart disease was ischemic (58%) and nonischemic (39%) cardiomyopathy; one patient had large cardiac fibroma. The mean left ventricular ejection fraction was 31 ± 8%. Seventy-six percent of patients were on amiodarone. Before SBRT, they underwent a median of 2 (IQR: 1-3; range: 1-5) CA that included epicardial access in 42% of patients. Following SBRT with a planned target volume of 42.6 ± 22.8 ml, the immediate effect was not observed in any patient, VT burden gradually decreased over weeks or months. Seventeen (52%) patients died (2 of them suddenly) during the mean follow up of 29 ± 23 months mainly due to the progression of heart failure (Figure 1). One patient died due to bleeding associated with esophagopericardial fistula that developed 9 months after SBRT. Overall, the number of DC shocks after a single procedure decreased significantly from 0.9 ± 1.9 per month in the period of 6 months before SBRT to 0.1 ± 0.3 per month in the period of 6-12 months after SBRT (P=0.008, Figure 2). However, 14 patients (42%) had to undergo additional CA due to VT recurrences at a mean interval of 13 ± 14 months after SBRT. Three patients underwent repeated SBRT (after 3, 29, and 38 months), which was successful in 2 of them. Conclusions SBRT in patients with refractory VT is feasible but the long-term mortality after the procedure is high and reflects mainly the severity of the underlying disease. The treatment effect of SBRT is delayed and additional CA is often necessary for VT suppression. At present, SBRT should be offered as only a bailout procedure for otherwise intractable VT.

Catheter ablation of ventricular tachycardia in dilated-phase hypertrophic cardiomyopathy: Substrate characterization and ablation outcome.

Catheter ablation is a therapeutic option to suppress ventricular tachycardia (VT) in the setting of dilated-phase hypertrophic cardiomyopathy (DHCM). However, the characteristics of the arrhythmogenic substrate and the ablation outcome are not fully illustrated. A total of 23 ablation procedures for drug-refractory sustained monomorphic VTs in 13 DHCM patients (60 ± 11 years, one female, the left ventricular [LV] ejection fraction 39% ± 9%, the LV mass index 156 ± 39 g/m2 ) were performed. The distribution of VT substrate as endocardial or epicardial/intramural was based on detailed mapping and ablation response during VT. Two patients underwent ablation of sustained monomorphic VT that was not scar-mediated tachycardia. Of the remaining 11 patients, eight (73%) patients had VT substrate in the basal regions, most frequently at the epicardial and/or intramural basal antero-septum. None of the patients had VT substrate located at the LV inferolateral region. Ablation at the right ventricular septum and the aortic cusps was done in four and five patients, respectively. Other approaches including bipolar and chemical ablations, were done in three and two patients, respectively. Six (55%) out of 11 patients (two patients lost follow-up) had VT recurrence. All the six patients had basal substrate. However, anti-tachycardia pacing was sufficient for VT termination except in one patient. Catheter ablation of VT in patients with DHCM is challenging because of the predominant basal anteroseptal epicardial/intramural location of arrhythmogenic substrate. An ablation approach from multiple sites and/or adjunctive interventional techniques are often required.

CA-533-03 STEREOTACTIC BODY RADIOTHERAPY FOR REFRACTORY VENTRICULAR TACHYCARDIA: THE OVERALL CZECH EXPERIENCE

Catheter ablation (CA) is a well-established treatment strategy for the management of drug-refractory ventricular tachycardia (VT) in patients with structural heart disease. Stereotactic body radiotherapy (SBRT) was proposed recently as a treatment option for cases of failed CA.

CA-531-04 CANADIAN EXPERIENCE WITH SALINE ENHANCED RADIOFREQUENCY NEEDLE TIP ABLATION FOR VENTRICULAR TACHYCARDIA (SERF VT CANADA TRIAL)

Endocardial catheter ablation for ventricular tachycardia (VT) may fail because of the inability to deliver transmural lesions. Saline-enhanced radiofrequency (SERF) ablation uses a needle tip catheter which is placed at varying depths into the myocardial tissue and heated saline is injected along with radiofrequency (RF) creating fully transmural lesions. We report the first in-human SERF ablation for VT in Canada. The purpose of this study is to describe the prospective outcomes on a seriesof patients undergoing first-in-human SERF ablation for VT in Canada under an Investigational Testing Authorization. Twenty-five patients with ischemic and non-ischemic cardiomyopathy, with recurrent monomorphic drug-refractory VT which had failed a prior catheter ablation underwent SERF ablation in 3 different centers in Canada. After a voltage map, the mapping catheter was replaced with the needle-tipped ablation catheter, which was located perpendicular to the myocardium and extended either 6 or 8 mm into the tissue. Sterile saline solution was infused with a flow rate of 10 ml/min and 60° C and 50 watts of RF was used. LVEF was 33.3% ± 8.6, mean age was 69.5 ± 6.4 years; 92% were male. From 43 clinical VT induced, 42 were attempted and 266 SERF lesions were delivered (10.6 ± 4.9 per patient). At the end of the case, 41 VT were non-inducible (98%) and 24 patients (96%) had their VT eliminated. At 6 months follow-up, VT burden was reduced by 87%. Complications included 2 strokes, 2 pericardial effusion and one patient had ischemic bowel and 1died. SERF ablation is feasible and permits control of symptomatic monomorphic VT in drug-refractory patients with a prior failed ablation.

Factors associated with recurrent postinfarction ventricular tachycardia following ablation.

INTRODUCTION Ablation of ventricular tachycardia is the main therapy for patients with drug-refractory ventricular tachycardia (VT). Although evidence suggests that VT ablation could lower the incidence of recurrent VT, many cases still develop VT in follow-up. In this study, we performed a systematic review and meta-analysis to examine risk factors for recurrent VT in patients with postinfarction VT who underwent VT ablation. EVIDENCE ACQUISITION We comprehensively searched the databases of MEDLINE and EMBASE from inception to March 2020. Included studies were cohort studies, experimental trials, or randomized controlled trials that evaluate the risk of recurrent VT in postinfarction VT patients who underwent VT ablation. Data from each study were combined using random-effects. EVIDENCE SYNTHESIS Thirteen studies involving 1803 postinfarction patients who underwent VT ablation were included. Inducibility after the procedure (pooled HR=1.71, P<0.001), lower baseline left ventricular ejection fraction (LVEF) (pooled HR=0.98, P<0.001) and higher baseline New York Heart Association (NYHA) classification (pooled HR=1.34, P=0.003) were significantly associated with VT recurrence during the follow-up. There was no significant association between age, gender or diabetes mellitus and VT recurrence. CONCLUSIONS Our meta-analysis demonstrated that inducibility after the procedure, lower baseline LVEF and higher baseline NYHA classification were associated with an increased risk of VT recurrence in postinfarction VT patients who underwent VT ablation.

Ventricular Tachycardia Storm Ablation With Pre-Emptive Circulatory Support by Extracorporeal Membrane Oxygenation: Australian Experience

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) can provide circulatory support in high-risk patients undergoing drug refractory ventricular tachycardia (VT) ablation procedures. We report experience using VA-ECMO in a pre-emptive approach for high-risk patients with VT storm and previously ineffective ablation procedures. Four (4) patients with drug refractory ventricular tachycardia (mean age 61±3 years; left ventricular ejection fraction 21±5%) presenting for VT ablation had pre-emptive VA-ECMO. All patients during current admission had VT storm. Pre-ablation, 22 total monomorphic VTs (cycle length 402±69 ms) were induced or spontaneously observed (median of 4, IQR25-75% 1-6). At the end of the procedure, 86% of all inducible VTs were rendered non-inducible. Median hospitalisation following VA-ECMO supported ablation was 5 days (IQR25-75% 3-12). During follow-up (median 138 days [IQR25-75% 57-277]), VT recurred in one patient as an isolated episode reverted by anti-tachycardia pacing. There was a 99% reduction in VT burden post ablation. One (1) patient died of cardiogenic shock within 24 hours whilst still on VA-ECMO, all other patients were successfully weaned off support and discharged. Two (2) patients underwent cardiac transplantation at 199 and 512 days post ablation following implantation of ventricular assist devices for worsening heart failure. The pre-emptive use of VA-ECMO for high-risk patients undergoing catheter ablation for VT storm was found to be effective in maintaining haemodynamic status, and allowing successful mapping and catheter ablation for VT.

Prophylactic Catheter Ablation of Ventricular Tachycardia in Ischemic Cardiomyopathy: a systematic review and meta-analysis of randomized controlled trials Electrophysiology Collaborative Consortium for Metaanalysis - ELECTRAM Investigators.

Catheter ablation is an effective strategy for drug-refractory ventricular tachycardia (VT) in ischemic cardiomyopathy. We aimed to perform a systematic review and meta-analysis of outcomes of prophylactic catheter ablation (PCA) of Ventricular Tachycardia (VT) in ischemic cardiomyopathy patients. We performed a comprehensive literature search through February 10, 2020, for all eligible randomized controlled trials that compared "PCA" versus "No PCA" for VT. Primary efficacy outcomes included - appropriate ICD therapy (composite of anti-tachycardia pacing and ICD shock), appropriate ICD shocks, electrical storm, cardiac mortality, and all-cause mortality. The primary safety outcome was any adverse events. Four randomized controlled trials (N = 505) met inclusion criteria. Prophylactic catheter ablation was associated significant reduction in appropriate ICD therapies (RR 0.70; 95% CI 0.55 - 0.89, p = 0.004), appropriate ICD shocks (RR 0.57 95% CI 0.40 - 0.80, p = 0.001) with a trend towards reduced risk of electrical storm (RR 0.64; CI 0.39 - 1.05; p = 0.075) compared to "No PCA". There was no significant difference in cardiac mortality (RR 0.66, 95% CI 0.31 - 1.43, p = 0.29) and all-cause mortality (RR 0.98, 95% CI 0.52 - 1.82, p = 0.94) with similar adverse events (RR 1.46, 95% CI 0.73 - 2.95, p = 0.29) between two groups. Prophylactic catheter ablation in ischemic cardiomyopathy patients was associated with a lower risk of ICD therapies, including ICD shocks and VT storm with no difference in cardiac and all-cause mortality.

Factors associated with recurrent postinfarction ventricular tachycardia following ablation.

Ablation of ventricular tachycardia is the main therapy for patients with drug-refractory ventricular tachycardia (VT). Although evidence suggests that VT ablation could lower the incidence of recurrent VT, many cases still develop VT in follow-up. In this study, we performed a systematic review and meta-analysis to examine risk factors for recurrent VT in patients with postinfarction VT who underwent VT ablation. We comprehensively searched the databases of MEDLINE and EMBASE from inception to March 2020. Included studies were cohort studies, experimental trials, or randomized controlled trials that evaluate the risk of recurrent VT in postinfarction VT patients who underwent VT ablation. Data from each study were combined using random-effects. Thirteen studies involving 1803 postinfarction patients who underwent VT ablation were included. Inducibility after the procedure (pooled HR=1.71, P<0.001), lower baseline left ventricular ejection fraction (LVEF) (pooled HR=0.98, P<0.001) and higher baseline New York Heart Association (NYHA) classification (pooled HR=1.34, P=0.003) were significantly associated with VT recurrence during the follow-up. There was no significant association between age, gender or diabetes mellitus and VT recurrence. Our meta-analysis demonstrated that inducibility after the procedure, lower baseline LVEF and higher baseline NYHA classification were associated with an increased risk of VT recurrence in postinfarction VT patients who underwent VT ablation.