Recurrent Ventricular Arrhythmias Research Articles

Emergency out-of-hours catheter ablation for ventricular arrhythmia storm: a UK and Australian experience.

There are limited data on emergency catheter ablation (CA) for ventricular arrhythmia (VA) storm. We describe the feasibility and safety of performing emergency CA in an out-of-hours setting for VA storm refractory to medical therapy at 2 tertiary hospitals. Twenty-five consecutive patients underwent out-of-hours (5pm-8am [weekday] or Friday 5pm-Monday 8am [weekend]) CA for VA storm refractory to anti-arrhythmic drugs and sedation. Baseline and procedural characteristics along with outcomes were compared to 91 consecutive patients undergoing weekday daytime-hours (8am-5pm) CA for VA storm. More patients undergoing out-of-hours CA had a left ventricular ejection fraction ≤35% (68% vs. 42%, P = 0.022), chronic kidney disease (60% vs. 20%, P < 0.001), and presented following a resuscitated out-of-hospital cardiac arrest (56% vs. 5%, P < 0.001), compared to the daytime-hours group. During median follow-up (377 [interquartile range 138-826] days), both groups experienced similar survival free from recurrent VA and VA storm. Survival free from cardiac transplant and/or mortality was lower in the out-of-hours group (44% vs. 81%, P = 0.007), but out-of-hours CA was not independently associated with increased cardiac transplant and/or mortality (hazard ratio 1.34, 95% confidence interval 0.61-2.96, P = 0.47). Of the 11 patients in the out-of-hours group who survived follow-up, VA-free survival was 91% and VA storm-free survival was 100% at 1-year after CA. Out-of-hours CA may occasionally be required to control VA storm and can be safe and efficacious in this scenario. During follow-up, cardiac transplant and/or mortality is common but undergoing out-of-hours CA was not predictive of this composite endpoint.

Left Ventricular Abnormal Substrate in Brugada Syndrome

BackgroundSlow-conductive structural abnormalities located in the epicardium of the right ventricle (RV) underlie Brugada syndrome (BrS). The extent of such substrate in the left ventricle (LV) has not been investigated. ObjectivesThis study sought to characterize the extent of epicardial substrate abnormalities in BrS. MethodsWe evaluated 22 consecutive patients (mean age 46 ± 11 years, 21 male) referred for recurrent ventricular arrhythmias (mean 10 ± 13 episodes) in the setting of BrS. The patients underwent clinical investigations and wide genetic screening to identify SCN5A mutations and common risk variants. High-density biventricular epicardial mapping was performed to detect prolonged (>70 ms) fragmented electrograms, indicating abnormal substrate area. ResultsAll patients presented with abnormal substrate in the epicardial anterior RV (27 ± 11 cm2). Abnormal substrate was also identified on the LV epicardium in 10 patients (45%), 9 at baseline and 1 after ajmaline infusion, covering 15 ± 11 cm2. Of these, 4 had severe LV fascicular blocks. Patients with LV substrate had a longer history of arrhythmia (11.4 ± 6.7 years vs 4.3 ± 4.3 years; P = 0.003), longer PR (217 ± 24 ms vs 171 ± 14 ms; P < 0.001) and HV (60 ± 12 ms vs 46 ± 5 ms; P = 0.005) intervals, and abnormal substrate also extending into the inferior RV (100% vs 33%; P = 0.001). SCN5A mutation was present in 70% of patients with LV substrate (vs 25%; P = 0.035). SCN5A BrS patients with recurrent ventricular arrhythmias present a higher polygenic risk score compared with a nonselected BrS population (median of differences: −0.86; 95% CI: −1.48 to −0.27; P = 0.02). ConclusionsA subset of patients with BrS present an abnormal substrate extending onto the LV epicardium and inferior RV that is associated with SCN5A mutations and multigenic variants.

Hybrid Epicardial Ventricular Ablation for Arrhythmogenic Right Ventricular Cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) causes progressive fibro-fatty infiltration of the right ventricle (RV) and is associated with ventricular arrhythmias (VA). The disease progresses from the subepicardium to subendocardium; thus. epicardial ablation improves outcome in patients with recurrent VA. When percutaneous epicardial ablation is unsuccessful, a surgical approach may be required. Limited data are available for minimally invasive hybrid surgical-catheter techniques. Case: A 28-year-old man with ARVC presented with recurrent VA refractory to medical therapy following COVID-19 infection and underwent endocardial ablation with attempted epicardial ablation. He had nine or more different inducible VA morphologies at this study. Epicardial access was unsuccessful due to adhesions. Minimally invasive surgical access for epicardial ablation was scheduled as a multidisciplinary procedure in the electrophysiology suite. A left thoracoscopic approach provided intrapericardial access. Surgical ports were used to facilitate catheter placement and mapping. Relevant clinical arrhythmias were targeted, and substrate modification was performed. The patient was discharged the following morning. No subjective symptoms or implanted-device defibrillation has been required post procedure. Combined surgical and catheter-based approaches for ARVC ablation are safe and feasible. Multidisciplinary team collaboration is key for case planning and success.

Safety and efficacy of bipolar radiofrequency catheter ablation in ventricular arrhythmias of mural vs non-mural origin

Abstract Funding Acknowledgements Type of funding sources: None. Background Bipolar radiofrequency catheter ablation (B-RFA) has shown promising results in refractory ventricular arrhythmia (VA) of septal origin and underlying non-ischemic cardiomyopathy (NICM). However, its efficacy and safety in other locations such as the free wall and papillary muscles (PM) has not yet been fully determined. Purpose To describe and analyse the procedural data, safety and efficacy results of B-RFA in a cohort of patients with VA of different locations and underlying substrate. Methods We enrolled 21 patients with recurrent VA after prior failed ablation into this study, of whom 16 patients required B-RFA for effective ablation. Seven of the patients had ventricular ectopy (VE) and 9 presented with ventricular tachycardia (VT). During B-RFA, a contact-force-sensing, saline-irrigated catheter was connected to the ablation catheter connection on the radiofrequency generator and a second ablation catheter (saline-irrigated in 6 of the cases) was connected to the ground patch terminal through a custom-made switch box. This allowed visualization of both catheters on the 3D mapping system and acquisition of electrograms from both simultaneously. Procedure data, related complications and acute and long-term outcomes during follow-up were assessed. Results The VA distribution was septal (31.3%, n=5), PM (31.3%, n=5), right ventricle free wall (18.8%, n=3), left ventricle (LV) free wall (12.5%, n=2) and LV summit (6.3%, n=1). Compared to septal ablation, contact force obtained during B-RFA ablation was significantly lower in PM ablation (p=0.01), as was the impedance drop (p=0.03). There were no significant differences in the number of energy applications, their mean duration, the total ablation time, the power and the temperature among locations. Acute success was achieved in 15 patients (93.6%). Long-term success, defined as no recurrence of sustained VT or less than 1% VE burden on 24-hour Holter at 12-month follow up, was achieved in 11 patients (68.8%), and another 2 patients (12.5%) had partial success. Papillary muscle VA had lower acute and long-term success (80% and 60%, respectively) after B-RFA. On the other hand, patients with NICM appeared to have superior outcomes (figure 1). No steam pops or major peri-procedural complications were observed. However, the use of a non-irrigated indifferent electrode resulted in char formation. Conclusions B-RFA can be used successfully and safely in NICM involving the septum and free walls but has limited use for PM arrhythmias. This could be related to a lack of catheter stability and reduced energy transfer. In addition, when using B-RFA, any catheter in the circulatory system should be irrigated.

P120 NEW MALIGNANT MUTATION IN HYPERTROPHIC CARDIOMYOPATHY

Abstract A 62–year–old man diagnosed with non–obstructive hypertrophic cardiomyopathy and dual–chamber pacemaker wearer since the age of 40, for third–degree atrioventricular block, came to our attention for atrial fibrillation (AF) episodes (one complicated by cardiogenic shock and multiorgan failure) and flutter with high ventricular response. For a progressive worsening of the systolic function, and the onset of multiple episodes of sustained ventricular tachycardia, an upgrade to the defibrillator was performed, which, in the following months, intervened appropriately for recurrences of ventricular arrhythmias. The patient was admitted to our ward for exacerbation of heart failure. The echocardiography showed moderate concentric hypertrophy with mild ventricular dilatation and ejection fraction 33%, inferior and inferoseptal wall, and apex akinesia with thrombotic apposition. Due to a sudden deterioration of the clinical conditions, the patient died. After genetic counseling the patient‘s family agreed to genetic testing in the proband. This highlighted the presence of a missense mutation, i.e. the substitution of the cysteine ​​residue with a serine, in the codon 905 of the MYH7 gene, encoding the cardiac isoform of myosin heavy chain. The mutation is probably pathogenetic as it falls in the region where most of the missense variants are clustered and statistically associated with the HCM phenotype. Only in one previous case of HCM was detected a mutation of the same codon, Cys905Phe. Several studies have reported that AF tends to be more prevalent in patients carrying MYH7 mutations and is associated with a substantial risk of heart failure–related mortality, stroke, and severe functional disability. Knowledge of the entire spectrum of MYH7 mutations, especially those related to a high arrhythmic burden or SCD, combined with an accurate clinical and molecular characterization of the patient, can improve the genotype–phenotype correlation by clarifying the mechanism of HCM and allowing a better clinical and therapeutic decision–making of patients.

PO-04-029 TRIANGULATING THE LV SUMMIT: A NOVEL BIPOLAR RADIOFREQUENCY CATHETER ABLATION STRATEGY

Bipolar radiofrequency catheter ablation (RFCA) is an off-label strategy used to target ventricular arrhythmias (VA) from difficult substrates such as the LV summit. To achieve greater transmural RFCA lesions in challenging anatomy with a novel bipolar RFCA strategy. N/A A 51-year-old male with familial HCM and prior catheter ablation for persistent AF presented with pallor and palpitations in the setting of wide complex tachycardia of 210 BPM (Figure A). The patient was given a bolus of IV amiodarone and externally cardioverted. Amiodarone was discontinued given his history of amiodarone-induced hyperthyroidism. During the hospitalization, he had recurrences of sustained VAs that were suppressed with lidocaine. Cardiac MRI was obtained, which showed LVEF 42% and an extensive LGE in the LV (Figure B). The patient was brought to the EP lab for VT ablation. Extensive mapping in the RVOT, distal CS, and peri-aortic area was performed. The best pacemap was achieved with the 2F EPstar catheter (Baylis Medical) in the AIV. The ablation catheter was not able to be advanced into the distal branch in the coronary sinus. A total of 17 unipolar RFCA lesions were delivered from endocardial LV but the clinical VA remained easily inducible. A second ablation catheter was advanced to the posteroseptal RVOT on the opposite side of the septum for bipolar RFCA. The 2F EPstar catheter was positioned in the AIV near the region of best pacemap for tripolar effect (Figure C). A significant difference in the ablation impedance decline was noted between unipolar and bipolar ablations utilizing this novel strategy (Figure D top - unipolar, D bottom - bipolar). Following five bipolar RCFA lesions, the clinical VA was no longer inducible. The patient tolerated the procedure well with no further recurrence of VAs. Bipolar RFCA with a mapping catheter triangulating the target may help achieve deeper lesions.

PO-04-232 PERCUTANEOUS STELLATE GANGLION BLOCKADE FOR ELECTRICAL STORM: LARGE SINGLE CENTRE EXPERIENCE

Electrical storm (ES) is defined as three or more episodes of ventricular arrhythmia requiring defibrilltaion or anti tachycardia pacing within a day.Some times electrical storm may not respond to anti-arrhythmic drugs alone.Increased sympathetic activity plays significant role in electrical storm.Stellate ganglion blockade reduces sympathetic activity and helpful in reduction of ventricular arrhythmias. We aimed to study the effectiveness and outcomes of percutaneous stellate ganglion blockade (SGB) in the patients with drug-refractory electrical storm. The study included patients with a drug-refractory electrical storm. Before giving SGB, at least two anti-arrhythmic drugs(AAD) were given before SGB. Bupivacaine was injected in the vicinity of the stellate ganglion under Ultrasound quidance. A total of 83 procedures were performed on 56 patients (71% males, 60+6 years).Fourty three patients (76%) had ischemic heart disease. Nearly 66%(37/56) of patients were free from ventricular arrhythmias(VA) at 24 hours after left SGB and 51%(29/56) were arrhythmia free at 72 hours. Bilateral SGB was done in 16 patients who had failed left-sided SGB with a success rate of 36%. Heart failure and shock were documented in 65% and 55% respectively. Twenty Five (44%) patients were on both Intra-aortic balloon counterpulsation and inotrope support. All-cause mortality was 32% (18/56). Cardiovascular mortality was 28% (16/56). Septic shock in one patient and Ischemic brain stroke was the cause of death in the other patient. VA recurrence, poor left ventricular ejection fraction, and failed stellate ganglion blockade were associated with increased mortality. Procedure-related complications like transient bradycardia(16%), hematoma(14%), hoarseness of voice (10%), persistent ptosis(5%), and monoparesis(3.5%) were noted, all of which were resolved within two weeks of post-procedure. SGB helps to stabilize the hemodynamic status of the patients with electrical storm. It also provides time for

PO-04-233 MULTIDISCIPLINARY APPROACHES TO TREAT VENTRICULAR ARRHYTHMIAS WITH RADIOABLATION AND CARDIAC SYMPATHECTOMY (MAVERICS)

Ventricular arrhythmias (VAs) are the most lethal arrhythmias. Established therapies to prevent occurrence of VAs include anti-arrhythmic drugs (AADs) and catheter ablation (CA). For patients with recurrent VAs despite AADs and CA, there exist novel treatment modalities such as cardiac sympathetic denervation (CSD) via percutaneous and surgical approach and stereotactic body radiation therapy (SBRT). The current study reports the outcomes of CSD and SBRT from a tertiary care academic center. To report outcomes of CSD and SBRT for treatment of VAs refractory to conventional treatment with AADs and CA. Study comprises all patients undergoing CSD or SBRT at our center from 10/2018 to 10/2021. Patients with less than 2 months of available follow-up data were excluded. Retrospective chart review was performed to collate data for demographics, clinical characteristics, arrhythmia burden before and after novel therapies (maximum 12 months), and complications during study period. Burden of VAs in the form of episodes of anti-tachycardia pacing (ATP) and defibrillator shocks per month were assessed as primary efficacy outcome. Complications during CSD and SBRT were assessed as primary safety outcome. Overall, 25 patients underwent novel therapies for VAs. Thirteen were excluded due to insufficient follow up data. Of 12 included patients, a total of 4, 5, and 3 patients underwent SBRT, CSD, and both CSD/SBRT, respectively. Median age of the study population was 66 years (55-72). The majority of the patients (10/12) were male. Median left ventricular ejection fraction was 30% (25%-34%). Eight patients had non-ischemic cardiomyopathy. Median number of AADs and CA prior to novel therapies was 3 (2-5) and 1 (0-2), respectively. Follow up was available for a median of 12 (12-12) months before and 12 (9-12) months after intervention. Overall, 11 of 12 patients demonstrated a reduction in VA burden. Mean number of ATP and shock episodes was significantly lower after novel therapies (39±43 vs 3±6; p= 0.008). No procedure-related complications were observed during the study period. Incorporation of novel VA treatment modalities is associated with a reduced arrhythmia burden in this single center study. Further studies are warranted to validate these findings.

CE-452779-4 DOFETILIDE FOR TREATMENT OF PREMATURE VENTRICULAR COMPLEXES AND VENTRICULAR TACHYCARDIA

Dofetilide is a class III antiarrhythmic agent approved for the treatment of atrial fibrillation and atrial flutter. Given the efficacy of other class III agents, it is used off-label for the treatment of premature ventricular complexes (PVCs) and ventricular tachycardia (VT), however its ability to suppress recurrent ventricular arrhythmia has not been well examined. In this study, we examined the use of dofetilide for the treatment of PVCs and VT. This was a single-center retrospective cohort study of patients admitted to the University of Michigan between 2015 and 2020 for dofetilide initiation. In patients for whom dofetilide was initiated for PVCs, VT or both, additional descriptive information was collected until date of last clinical follow-up. Successful PVC suppression was defined as 80% reduction in PVC burden compared to pre-dofetilide initiation. A total of 50 patients were admitted for dofetilide initiation for treatment of PVCs (18), VT (27) or both (5). Average left-ventricular ejection fraction was 32.0 +/- 17.2% with 32.7% of patients having ischemic cardiomyopathy and 67.3% of patients having non ischemic cardiomyopathy. A majority (90%) of patients in the cohort had an internal cardioverter defibrillator (ICD). Prior to dofetilide initiation, 40% of patients had undergone ventricular ablations. Previous antiarrhythmic treatments included amiodarone (54.0%), sotalol (28%) and mexilitine (36.0%). Dofetilide was stopped in 8 patients (16%) during index hospitalization for QT prolongation with 3 patients experiencing Torsades de Pointes. In an additional 24 patients, dofetilide was discontinued at a median of 3.3 months for inefficacy (50%) or QT prolongation (50%). Median follow was 36.3 months (range of 3.9 months to 84.8 months). Dofetilide dosing was 500 (35.7%), 250 (45.2%), 125 (19.1%) micrograms. In patients treated for PVCs, PVC frequency decreased from an average of 21.7% to 9.0% (p<.001) with 35.7% of patients meeting criteria for successful suppression. In patients with VT, 80.0% had recurrent ICD shocks after dofetilide (average 1.6 shocks/year of follow-up). 7 patients died over the follow-up period. Treatment with dofetilide was associated with a decrease in PVCs, however clinically significant suppression occurred in a minority of patients. Dofetilide failed to suppress ICD shocks in a majority of patients and was associated with significant toxicities requiring discontinuation in 40% of patients during the follow-up period.

PO-04-190 LONG TERM OUTCOMES OF VENTRICULAR TACHYCARDIA ABLATION IN DESMOPLAKIN ARRHYTHMOGENIC CARDIOMYOPATHY – A MULTICENTER STUDY

Desmoplakin (DSP) pathogenic/likely pathogenic (P/LP) variants have been associated with the development of highly arrhyhtmogenic phenotypes of the spectrum of the arrhythmogenic cardiomyopathy (DSP-ACM). Data addressing arrhythmic outcomes after ventricular tachycardia (VT) ablation in patients (pts) with DSP-ACM are scarce. To report on long-term outcomes of pts with DSP-ACM undergoing VT-ablation All pts with P/LP DSP variant at 8 tertiary academic institutions in North America and Europe undergoing VT ablation were included in the study. Demographic, clinical, and instrumental data, as well as all arrhythmic events including per patient rates of VA episodes/year were collected. Sustained ventricular arrhythmia (VA) episodes (defined as a combination of sustained VT, proper implantable cardioverter defibrillator (ICD) intervention, and ventricular fibrillation episodes) after index procedure were the primary outcome of the study and reported with Kaplan Meyer curves. A per-pt pre- and post- VT ablation paired comparison of VA episodes/year rates was performed as well. Nineteen DSP-ACM pts (29 [25–36] y.o.; 68.4% male; 94.7% probands) referred for VT ablation were included. At the time of index procedures, all patients had a highly arrhythmic profile with a high PVC burden and over 30 different VT morphologies (56.6% right bundle branch block (BBBB); 26.6% left BBB; 16.8% unknown)(Table1). VT ablation targets were located in the LV in 7/19 pts, the RV in 7/19 pts, and both ventricles in 5/19 pts. An epicardial ablation was needed in 14/19 pts. Over a median follow-up of 27 [20–72] months, 10/19 (52.6%) pts experienced recurrent VA episodes (Figure1-PanelA). A significant reduction in per-patient event/year pre- and post- VT ablation was observed (0.50 0.25–0.94] vs 0.14 [0–0.40]; Matched Pair Wilcoxon p=0.009) (Figure1-Panel B). VT ablation in DSP-ACM is effective in significantly reducing the VA burden of the disease. However, it is not uncommon for pts to experience VA recurrences during follow up.

Combination of Intracardiac Echocardiography and Contact Force Sensing for Left Ventricular Papillary Muscle Arrhythmias.

The catheter ablation of ventricular arrhythmias (VAs) arising from the left ventricular (LV) papillary muscles (PMs) is challenging. This study sought to address whether the combination of intracardiac echocardiography (ICE) and contact force sensing (CFS) can improve the acute and long-term ablation outcomes of left ventricular papillary muscle arrhythmias. From May 2015 to August 2022, a total of thirty-three patients underwent catheter ablation for LV PM arrhythmias: VAs were located in anterolateral PMs in 11 and posteromedial PMs in 22. A combination of intracardiac echocardiography (ICE) and contact force sensing (CFS) was used in 21 of the 33 procedures. A mean of 6.93 ± 4.91 for lesions was used per patient, comparable between the CFS/ICE and no ICE/CFS (4.90 ± 2.23 vs. 10.17 ± 5.89; p = 0.011). The mean CF achieved in the ICE/CFS group was 7.52 ± 3.31 g. Less X-ray time was used in the combination group (CFS/ICE: 165.67 ± 47.80 S vs. no ICE/CFS: 365.00 ± 183.73 S; p < 0.001). An acute success rate of 100% was achieved for the ICE/CFS group (n = 22) and 66.67% for the no ICE/CFS group (n = 8). VA recurrence at the 11.21 ± 7.21-month follow-up was 14.2% for the ICE/CFS group and 50% for the no ICE/CFS group (p = 0.04). No severe complications occurred in all patients. The combination of intracardiac echocardiography (ICE) and contact force sensing (CFS) could provide precise geometries of cardiac endocavitary structures and accurate contact information for the catheter during ablation, which improved acute and long-term ablation outcomes. The routine adoption of this strategy should be considered to improve the outcomes of LV PM VA ablation.

The Brugada syndrome: pharmacological therapy.

Brugada syndrome is an inherited channelopathy with an increased risk of sudden cardiac death (SCD) due to ventricular arrhythmias (VA) and an increased incidence of supraventricular arrhythmias, as compared with the general population. For the prevention of SCD, the guidelines recommend the implantable cardioverter-defibrillator (ICD); however, ICD does not prevent VA. In this article, we provide a brief review of the literature on the Brugada syndrome pharmacological therapy, mainly focusing on quinidine treatment. The efficacy of quinidine therapy in the prevention of VA in Brugada syndrome has been demonstrated by several small studies in patients with ICD and recurrent shocks or in asymptomatic patients with inducible ventricular fibrillation (VF) at electrophysiological study. Quinidine has also been tested for the prophylaxis of supraventricular arrhythmias, especially atrial fibrillation/flutter, and in paediatric patients. In these studies, quinidine proved highly effective in preventing re-induction of VF and spontaneous recurrences of both ventricular and supraventricular arrhythmias. Unfortunately, this therapy is burdened by a high incidence of side effects, which may lead to drug discontinuation.

Catheter Ablation of Ventricular Arrhythmia in Patients With an Implantable Cardioverter-Defibrillator: A Systematic Review and Meta-analysis.

Implantable cardioverter-defibrillator (ICD) shocks are associated with higher rates of mortality and reduced quality of life. In this study we aimed to investigate the effectiveness of catheter ablation (CA) of ventricular tachycardia in patients with an ICD. An electronic literature search was conducted to identify randomized controlled trials that compared CA vs control. The primary outcomes were recurrence of ventricular arrhythmia (ventricular tachycardia or ventricular fibrillation) and mortality. Kaplan-Meier curves for these outcomes were digitized to obtain individual patient data, which were pooled in a 1-stage meta-analysis to determine hazard ratios (HRs) and 95% confidence intervals (CIs). Secondary outcomes included cardiac hospitalization, electrical storm, syncope, appropriate ICD therapies, appropriate ICD shocks, and inappropriate shocks. For these, study-level HRs or risk ratios were obtained and pooled in random effects meta-analyses. Subgroup analysis was performed for trials that investigated prophylactic CA (before or during ICD implantation). Data on 9 studies and 1103 patients were retrieved. CA significantly reduced ventricular tachycardia/ventricular fibrillation recurrence compared with control (shared frailty HR, 0.63; 95% CI, 0.49-0.81; P < 0.001) but not mortality (shared frailty HR, 0.84; 95% CI, 0.57-1.23; P= 0.361). CA was associated with significantly lower rates of cardiac hospitalization, electrical storm, appropriate ICD therapies and shocks, but not syncope or inappropriate shocks. Subgroup analysis showed similar results for prophylactic CA except that no significant difference was observed for cardiac hospitalizations. CA is associated with reduced ventricular arrhythmia recurrence, appropriate ICD therapies/shocks, electrical storm, and cardiac hospitalization, and might be effective in preventing future morbidity. Future trials are needed to support the continued benefit of these promising results, and to investigate the optimal timing of ablation.

Outcomes of Catheter Ablation of Left Ventricular Summit Arrhythmias.

The left ventricular summit (LVS) is the area in the highest portion of the left ventricular epicardium, bounded by the left coronary arteries and the coronary venous circulation, and can be surrounded by thick epicardial fat that may preclude epicardial ablation. Ablation of LVS ventricular arrhythmias (VA) can be achieved from adjacent structures with good success rates. The long-term freedom from LVS VA recurrence remains variable. This article reviews the spatial and anatomic relationship of the structures surrounding the LVS, which provide vantage points for ablation, and the acute and long-term outcomes of different ablation approaches in LVS VA ablation.

Stellate ganglion instrumentation for pharmacological blockade, nerve recording, and stimulation in patients with ventricular arrhythmias: Preliminary experience

Stellate ganglion blockade (SGB) can control ventricular arrhythmias (VAs), but outcomes are unclear. Percutaneous stellate ganglion (SG) recording and stimulation in humans has not been reported. The purpose of this study was to assess the outcomes of SGB and the feasibility of SG stimulation and recording in humans with VA. Two patient cohorts were included-group 1: patients undergoing SGB for drug-refractory VA. SGB was performed by injection of liposomal bupivacaine. Incidence of VA at 24 and 72 hours and clinical outcomes were collected; group 2: patients undergoing SG stimulation and recording during VA ablation; a 2-F octapolar catheter was placed at the SG at the C7 level. Recording (30 kHz sampling, 0.5-2 kHz filter) and stimulation (up to 80 mA output, 50 Hz, 2 ms pulse width for 20-30 seconds) was performed. Group 1 included 25 patients (mean age 59.2 ± 12.8 years; 76% men) who underwent SGB for VAs. Nineteen patients (76.0%) were free of VA up to 72 hours postprocedure. However, 15 (60.0%) had VA recurrence for a mean of 5.47 ± 4.52 days. Group 2 included 11 patients (mean age 63 ± 12.7 years; 82.7% men). SG stimulation caused consistent increases in systolic blood pressure. We recorded unequivocal signals with temporal association with arrhythmias in 4 of 11 patients. SGB provides short-term VA control, but has no benefit in the absence of definitive VA therapies. SG recording and stimulation is feasible and may have value to elicit VA and understand neural mechanisms of VA in the electrophysiology laboratory.

Efficacy and safety of catheter ablation as first-line therapy for the management of ventricular tachycardia

BackgroundVentricular tachycardia (VT) is associated with significantly increased morbidity and mortality. Catheter ablation (CA) in line with an implantable cardioverter-defibrillator (ICD) is highly effective in VT management; however, it is unknown if CA should be considered as first-line therapy. The aim of this study is to verify the efficacy and safety of CA as first-line therapy for the first VT presentation (as adjunctive to ICD insertion), compared to initial ICD insertion and anti-arrhythmic drug (AAD) therapy.MethodsData from patients with the first presentation for VT from January 2017 to January 2021 was reviewed. Patients were classified as “ablation first” vs “ICD first” groups and compared the clinical outcomes between groups.ResultsOne hundred and eighty-four consecutive patients presented with VT; 34 underwent CA as first-line therapy prior to ICD insertion, and 150 had ICD insertion/AAD therapy as first‐line. During the median follow-up of 625 days, patients who underwent CA as first-line therapy had significantly higher ventricular arrhythmia (VA)-free survival (91% vs 59%, log-rank P = 0.002) and composite of VA recurrence, cardiovascular hospitalization, transplant, and death (84% vs 54%, log-rank P = 0.01) compared to those who did not undergo CA. Multivariate analysis revealed that first-line CA was the only protective predictor of VA recurrence (hazard ratio (HR) 0.20, P = 0.003). There were 3 (9%) peri-procedural complications with no peri-procedural deaths.ConclusionReal-world data supports the efficacy and safety of CA as first-line therapy at the time of the first VT hospitalization, compared to the initial ICD implant and AAD therapy.

Right ventricular epicardial arrhythmogenic substrate in long-QT syndrome patients at risk of sudden death.

The long-QT syndrome (LQTS) represents a leading cause of sudden cardiac death (SCD). The aim of this study was to assess the presence of an underlying electroanatomical arrhythmogenic substrate in high-risk LQTS patients. The present study enrolled 11 consecutive LQTS patients who had experienced frequent implantable cardioverter-defibrillator (ICD discharges triggered by ventricular fibrillation (VF). We acquired electroanatomical biventricular maps of both endo and epicardial regions for all patients and analyzed electrograms sampled from several myocardial regions. Abnormal electrical activities were targeted and eliminated by the means of radiofrequency catheter ablation. VF episodes caused a median of four ICD discharges in eleven patients (6 male, 54.5%; mean age 44.0 ± 7.8 years, range 22-53) prior to our mapping and ablation procedures. The average QTc interval was 500.0 ± 30.2 ms. Endo-epicardial biventricular maps displayed abnormally fragmented, low-voltage (0.9 ± 0.2 mV) and prolonged electrograms (89.9 ± 24.1 ms) exclusively localized in the right ventricular epicardium. We found electrical abnormalities extending over a mean epicardial area of 15.7 ± 3.1 cm2. Catheter ablation of the abnormal epicardial area completely suppressed malignant arrhythmias over a mean 12 months of follow-up (median VF episodes before vs. after ablation, 4 vs. 0; P = 0.003). After the procedure, the QTc interval measured in a 12-lead ECG analysis shortened to a mean of 461.8 ± 23.6 ms (P = 0.004). This study reveals that, among high-risk LQTS patients, regions localized in the epicardium of the right ventricle harbour structural electrophysiological abnormalities. Elimination of these abnormal electrical activities successfully prevented malignant ventricular arrhythmia recurrences.

Flecainide in patients with arrhythmic mitral valve syndrome: A case series

Arrhythmic symptoms are prevalent and life-threatening ventricular arrhythmias (VA) are a feared complication in patients with arrhythmic mitral valve syndrome (AMVS) (1). There is no established medical therapy to suppress VA and relieve arrhythmic symptoms in these patients beyond conventional beta-blocker therapy, which is often unsuccessful and not evaluated in randomized controlled trials. Catheter ablation can suppress VA in some patients, but is limited due to the multifocal nature of premature ventricular complexes (PVC), papillary muscle origin, and VA recurrence despite initial successful procedures.

578 LONG-TERM OUTCOME OF VENTRICULAR TACHYCARDIA CATHETER ABLATION IN PATIENTS WITH CHRONIC CORONARY TOTAL OCCLUSION

Abstract Background Chronic coronary total occlusions (CTO) are considered an emerging predictor of ventricular arrhythmias (VAs) but currently there are only few data on arrhythmic outcomes in patients affected by CTO undergoing radiofrequency catheter ablation of VAs. Objective This study sought to evaluate the impact of unrevascularized CTO on the recurrence of VAs after catheter ablation. Methods This was a single-center retrospective study that enrolled 120 patients, between 2015 and 2020. All patients were admitted for ventricular tachycardia (VT) or high premature ventricular contractions (PVCs) burden (&amp;gt;25% detected by Holter ECG), without evidence of acute coronary syndrome; they underwent coronary angiography, electrophysiology (EP) study and three-dimensional electroanatomic mapping (3D-EAM) followed by VAs ablation. Results Twenty-eight patients (23%) of 120 patients showed CTO at coronary angiography. At baseline, CTO group presented with higher prevalence of hypertension, chronic renal disease, systolic ventricular dysfunction, secondary prevention ICD implantation, higher rate of low abnormal activities by 3D-EAM compared to the non-CTO group. At a median follow-up of 15 months (range 1-96 months) after catheter ablation, the only independent predictor of VAs recurrence was the presence of moderate to severe left ventricular (LV) dysfunction (p=0.02). Conclusion The presence of CTO does not predict VAs recurrence after catheter ablation which is instead predicted by LV dysfunction.

1013 RADIOFREQUENCY CATHETER ABLATION OF IDIOPATHIC VENTRICULAR FIBRILLATION: A CURRENT SINGLE-CENTRE EXPERIENCE

Abstract Short-coupled idiopathic ventricular fibrillation (SC-IVF) is a rare, life-threatening arrhythmia, accountable for 5–10% of out-of-hospital cardiac arrests (OHCA). Catheter ablation of the short-coupled premature ventricular contraction (PVC) that triggers VF has been shown to prevent VF recurrences in outdated case series. Aim To evaluate the clinical outcome and summarize the recent experience of 3D electrophysiological mapping and radiofrequency catheter ablation (RFCA) of SC-IVFs in a tertiary high-volume referral centre. Methods from January 2016, we enrolled all consecutive patients diagnosed with SC-IVF and treated by RFCA. Structural heart disease was excluded in all patients by means of echocardiography, cardiac magnetic resonance, coronary angiography, and exercise test. Brugada syndrome and long QT syndrome were excluded by Ajmaline and Epinephrine tests, respectively. The CARTO system was used to construct detailed 3D electroanatomic maps of the right and left ventricle. Mapping and ablation were performed with a standard 3.5- irrigated tip catheter. The PVCs were localized by mapping the earliest bipolar electrogram relative to the onset of the ectopic surface QRS (confirmed by QS complex in the unipolar configuration). Pace mapping was used in patients with infrequent PVCs. The origin of PVCs from fascicles/Purkinje network was indicated by initial sharp potentials preceding the ectopic QRS complex. The procedural end point was the abolition of all clinical PVCs. Outcome (freedom from SC-PVCs and VF episodes) was assessed by Holter monitoring and defibrillator memory interrogation. Results eleven consecutive patients [8 men, 3 women; median age 41 (± 5 years)] were enrolled. 10/11 patients (91%) were asymptomatic prior the index VF event, while 1 patient (9%) experienced recurrent syncope. An aborted OHCA was the index event in all patients. Arrhythmic storm was observed at the index presentation in 2 patients (18%). No patient had family history of sudden cardiac death. All patients were implanted with an ICD after the index event. The delay in SC-IVF diagnosis was 3 (± 2 years) from the index event. 2 patients (18%) had ≥ 2 SC-PVC morphologies. The mean coupling interval (CI) of the SC-PVCs ranged from 230 to 330 msec (mean 303 ± 26 msec). The CI/QT ratio ranged from 0.6 to 1 (mean 0.81 ± 0.15). 10 patients underwent RFCA for recurrent VF/ICD shocks and 1 patient for refractory electrical storm. RFCA was based on activation mapping, pace-mapping, and both in 1 (9%), 1 (9%), and 9 (82%) patients, respectively. The sites of ablation were LV Purkinje, RV Purkinje, RV non-Purkinje (RV outflow tract and tricuspid annulus), and LV non-Purkinje (LV Summit) in 3 (27%), 4 (36%), 3 (27%), and 1 (9%) patient, respectively. The first ablation was acutely successful in all patients. 1 patient experienced recurrence of SC-PVCs and VF episodes after 5 days from the first ablation and underwent a second RFCA. There were no peri-procedural complications. After a median follow-up of 22 months (ranging from 6 to 39 months) all patients were free from sustained ventricular arrhythmia recurrences: 10 patients (91%) were free from VF and PVCs; 1 patient (9%) had recurrent SC-PVCs without VF episodes. Conclusions this retrospective study explored the effectiveness of RFCA combined with the advanced electroanatomic mapping in a current cohort of patients with history of OHCA diagnosed with SC-IVF. RFCA of SC-PVCs was safe and highly effective in abolishing VF episodes in all patients.